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Toledano M, Osorio E, Osorio MT, Aguilera FS, Toledano R, Romero EF, Osorio R. Dexamethasone-doped nanoparticles improve mineralization, crystallinity and collagen structure of human dentin. J Dent 2023; 130:104447. [PMID: 36754111 DOI: 10.1016/j.jdent.2023.104447] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/01/2023] [Accepted: 02/04/2023] [Indexed: 02/09/2023] Open
Abstract
OBJECTIVES Bioactive materials have been used for functionalization of adhesives to promote dentin remineralization. This study aims to evaluate bonding ability and both mechanical and chemical behavior of demineralized dentin infiltrated with polymeric nanoparticles doped with dexamethasone (Dex-NPs). METHODS Dentin conditioned surfaces were infiltrated with NPs, Dex-NPs or Dex-Zn-NPs. Bonded interfaces were also created and stored for 24 h or 21d, and then submitted to microtensile bond strength testing. Dentin remineralization was analyzed by Nanohardness, Young's modulus and Raman analysis. RESULTS At 21d of storage, dentin treated with undoped-NPs attained the lowest nanohardness and Young's modulus. Dex-NPs and Zn-Dex-NPs increased dentin nanohardness and Young's modulus after 21d Raman analysis showed high remineralization, crystallinity, crosslinking and better structure of collagen when functionalized Dex-NPs were present at the dentin interface. CONCLUSIONS Infiltration of dentin with Dex-NPs promoted functional remineralization as proved by nanomechanical and morpho-chemical evaluation tests. Dexamethasone in dentin facilitated crystallographic maturity, crystallinity and improved maturity and secondary structure of dentin collagen. CLINICAL SIGNIFICANCE Using dexamethasone-functionalized NPs before resin infiltration is a clear option to obtain dentin remineralization, as these NPs produce the reinforcement of the dentin structure, which will lead to the improvement of the longevity of resin restorations.
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Affiliation(s)
- Manuel Toledano
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Estrella Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - María T Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Fátima S Aguilera
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain.
| | - Raquel Toledano
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Enrique Fernández- Romero
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Raquel Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
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Wölfel EM, von Kroge S, Matthies L, Koehne T, Petz K, Beikler T, Schmid-Herrmann CU, Kahl-Nieke B, Tsiakas K, Santer R, Muschol NM, Herrmann J, Busse B, Amling M, Rolvien T, Jandl NM, Barvencik F. Effects of Infantile Hypophosphatasia on Human Dental Tissue. Calcif Tissue Int 2023; 112:308-319. [PMID: 36414794 PMCID: PMC9968273 DOI: 10.1007/s00223-022-01041-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/02/2022] [Indexed: 11/23/2022]
Abstract
Hypophosphatasia (HPP) is an inherited, systemic disorder, caused by loss-of-function variants of the ALPL gene encoding the enzyme tissue non-specific alkaline phosphatase (TNSALP). HPP is characterized by low serum TNSALP concentrations associated with defective bone mineralization and increased fracture risk. Dental manifestations have been reported as the exclusive feature (odontohypophosphatasia) and in combination with skeletal complications. Enzyme replacement therapy (asfotase alfa) has been shown to improve respiratory insufficiency and skeletal complications in HPP patients, while its effects on dental status have been understudied to date. In this study, quantitative backscattered electron imaging (qBEI) and histological analysis were performed on teeth from two patients with infantile HPP before and during asfotase alfa treatment and compared to matched healthy control teeth. qBEI and histological methods revealed varying mineralization patterns in cementum and dentin with lower mineralization in HPP. Furthermore, a significantly higher repair cementum thickness was observed in HPP compared to control teeth. Comparison before and during treatment showed minor improvements in mineralization and histological parameters in the patient when normalized to matched control teeth. HPP induces heterogeneous effects on mineralization and morphology of the dental status. Short treatment with asfotase alfa slightly affects mineralization in cementum and dentin. Despite HPP being a rare disease, its mild form occurs at higher prevalence. This study is of high clinical relevance as it expands our knowledge of HPP and dental involvement. Furthermore, it contributes to the understanding of dental tissue treatment, which has hardly been studied so far.
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Affiliation(s)
- Eva Maria Wölfel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany
- Interdisciplinary Competence Center for Interface Research (ICCIR), Lottestr. 55A, Hamburg, Germany
| | - Simon von Kroge
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany
| | - Levi Matthies
- Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Till Koehne
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany
- Department of Orthodontics, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Karin Petz
- Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Thomas Beikler
- Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Carmen Ulrike Schmid-Herrmann
- Department of Orthodontics, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Bärbel Kahl-Nieke
- Department of Orthodontics, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Konstantinos Tsiakas
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Nicole Maria Muschol
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Jochen Herrmann
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Section of Pediatric Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany
- Interdisciplinary Competence Center for Interface Research (ICCIR), Lottestr. 55A, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany
| | - Tim Rolvien
- Division of Orthopaedics, Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Nico Maximilian Jandl
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany
- Division of Orthopaedics, Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Florian Barvencik
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529, Hamburg, Germany.
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Amadeu de Oliveira F, Mohamed FF, Kinoshita Y, Narisawa S, Farquharson C, Miyake K, Foster BL, Millan JL. Gene Therapy Using Recombinant AAV Type 8 Vector Encoding TNAP-D 10 Improves the Skeletal Phenotypes in Murine Models of Osteomalacia. JBMR Plus 2023; 7:e10709. [PMID: 36699639 PMCID: PMC9850441 DOI: 10.1002/jbm4.10709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/25/2022] [Accepted: 11/08/2022] [Indexed: 12/05/2022] Open
Abstract
Hypophosphatasia (HPP), caused by loss-of-function mutations in the ALPL gene encoding tissue-nonspecific alkaline phosphatase (TNAP), is characterized by skeletal and dental hypomineralization that can vary in severity from life-threatening to milder manifestations only in adulthood. PHOSPHO1 deficiency leads to early-onset scoliosis, osteomalacia, and fractures that mimic pseudo-HPP. Asfotase alfa, a life-saving enzyme replacement therapy approved for pediatric-onset HPP, requires subcutaneous injections 3 to 6 times per week. We recently showed that a single injection of an adeno-associated virus vector serotype 8 harboring TNAP-D10 (AAV8-TNAP-D10) effectively prevented skeletal disease and prolonged life in Alpl -/- mice phenocopying infantile HPP. Here, we aimed to determine the efficacy of AAV8-TNAP-D10 in improving the skeletal and dental phenotype in the Alpl Prx1/Prx1 and Phospho1 -/- mouse models of late-onset (adult) HPP and pseudo-HPP, respectively. A single dose of 3 × 1011 vector genomes per body (vg/b) was injected intramuscularly into 8-week-old Alpl Prx1/Prx1 and wild-type (WT) littermates, or into 3-day-old Phospho1 -/- and WT mice, and treatment efficacy was evaluated after 60 days for late-onset HPP mice and after 90 days for Phospho1 -/- mice. Biochemical analysis showed sustained serum alkaline phosphatase activity and reduced plasma PPi levels, and radiographic images, micro-computed tomography (micro-CT) analysis, and hematoxylin and eosin (H&E) staining showed improvements in the long bones in the late-onset HPP mice and corrected scoliosis in the Phospho1 -/- mice. Micro-CT analysis of the dentoalveolar complex did not reveal significant changes in the phenotype of late-onset HPP and pseudo-HPP models. Moreover, alizarin red staining analysis showed that AAV8-TNAP-D10 treatment did not promote ectopic calcification of soft organs in adult HPP mice after 60 days of treatment, even after inducing chronic kidney disease. Overall, the AAV8-TNAP-D10 treatment improved the skeletal phenotype in both the adult HPP and pseudo-HPP mouse models. This preclinical study will contribute to the advancement of gene therapy for the improvement of skeletal disease in patients with heritable forms of osteomalacia. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
| | - Fatma F. Mohamed
- Division of Biosciences, College of DentistryThe Ohio State UniversityColumbusOHUSA
| | - Yuka Kinoshita
- Human Genetics ProgramSanford Burnham Prebys Medical Discovery InstituteLa JollaCAUSA
| | - Sonoko Narisawa
- Human Genetics ProgramSanford Burnham Prebys Medical Discovery InstituteLa JollaCAUSA
| | - Colin Farquharson
- The Royal (Dick) School of Veterinary Studies (RDSVS), The Roslin InstituteUniversity of EdinburghEdinburghUK
| | - Koichi Miyake
- Department of Gene TherapyNippon Medical SchoolTokyoJapan
| | - Brian L Foster
- Division of Biosciences, College of DentistryThe Ohio State UniversityColumbusOHUSA
| | - Jose Luis Millan
- Human Genetics ProgramSanford Burnham Prebys Medical Discovery InstituteLa JollaCAUSA
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Okawa R, Nakano K. Dental manifestation and management of hypophosphatasia. JAPANESE DENTAL SCIENCE REVIEW 2022; 58:208-216. [PMID: 35814738 PMCID: PMC9260292 DOI: 10.1016/j.jdsr.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/22/2022] [Accepted: 06/26/2022] [Indexed: 11/24/2022] Open
Abstract
Hypophosphatasia is an inherited metabolic disorder characterized by defective mineralization of bones and teeth with a wide variety of manifestations, ranging from stillbirth to dental symptoms alone. Recently, the prognosis of severe hypophosphatasia patients has been greatly improved by the introduction of enzyme replacement therapy. The typical dental manifestation is early exfoliation of primary teeth due to disturbed cementum formation, so dentures are recommended to ensure that important oral functions are acquired. Some studies have shown that enzyme replacement therapy improves dental mineralization, resulting in the stabilization of periodontal tissues and better growth of tooth roots. A nationwide Japanese survey revealed the common genetic and dental manifestations of patients with mild hypophosphatasia, which markedly differ from those of the severe forms. There may be many undiagnosed mild patients, so dentists should contribute to the early diagnosis by screening possible cases based on the typical finding of early exfoliation of primary teeth. Early diagnosis is important for patients to receive early intervention in both medical and dental fields. The establishment of fundamental dental therapy to solve the dental problems is still underway and is eagerly anticipated.
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Roumpou A, Yavropoulou MP, Chronopoulos E, Kassi E. Novel Therapeutic Agents for Rare Diseases of Calcium and Phosphate Metabolism. Horm Metab Res 2022; 54:645-657. [PMID: 36049757 DOI: 10.1055/a-1917-0519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The last decade has been revolutionary regarding the management of rare bone diseases caused by impaired calcium and phosphate metabolism. Elucidation of the underlying genetic basis and pathophysiologic alterations has been the determinant factor for the development of new, disease-specific treatment agents. The phosphaturic hormone Fibroblast Growth Factor 23 (FGF23) possesses a critical role in the pathogenesis of various hypophosphatemic disorders. Among them, the genetic disorder of X-linked hypophosphatemia and the acquired syndrome of tumor-induced osteomalacia, although very rare, have attracted the scientific community's attention towards designing an FGF23-inhibitor as a potential specific therapy. The monoclonal antibody burosumab was approved for the treatment of children and adult patients with X-linked hypophosphatemia and recently for tumor-induced osteomalacia patients, demonstrating benefits regarding their symptoms, biochemical profile and bone mineralization status. Asfotase alfa is a hydroxyapatite-targeted recombinant alkaline phosphatase, an enzymatic replacement therapy, substituting the defective activity of tissue non-specific alkaline phosphatase, in patients suffering from hypophosphatasia. Promising data regarding its favorable effect on survival rate, bone quality, fracture healing, muscle strength, mobility, respiratory function, and general quality of life have led to the approval of the drug for the treatment of childhood-onset hypophosphatasia. Given the high costs of treatment for both agents and their limited clinical use until now, more data are needed to define patients' characteristics that make them ideal candidates for therapy. Long-term safety issues also need to be clarified.
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Affiliation(s)
- Afroditi Roumpou
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, "Aghia Sofia" Children's Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
- Laboratory for Research of the Musculoskeletal System, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Maria P Yavropoulou
- Centre of Expertise for Rare Endocrine Diseases, C.E.R.E.D. Disorders of Calcium & Phosphate Metabolism, First Department of Propaedeutic and Internal Medicine, Laiko Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Efstathios Chronopoulos
- Laboratory for Research of the Musculoskeletal System, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Eva Kassi
- Laboratory for Research of the Musculoskeletal System, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
- Centre of Expertise for Rare Endocrine Diseases, C.E.R.E.D. Disorders of Calcium & Phosphate Metabolism, First Department of Propaedeutic and Internal Medicine, Laiko Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
- Department of Biological Chemistry, National and Kapodistrian University of Athens, Athens, Greece
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Andras NL, Mohamed FF, Chu EY, Foster BL. Between a rock and a hard place: Regulation of mineralization in the periodontium. Genesis 2022; 60:e23474. [PMID: 35460154 PMCID: PMC9492628 DOI: 10.1002/dvg.23474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 12/30/2022]
Abstract
The periodontium supports and attaches teeth via mineralized and nonmineralized tissues. It consists of two, unique mineralized tissues, cementum and alveolar bone. In between these tissues, lies an unmineralized, fibrous periodontal ligament (PDL), which distributes occlusal forces, nourishes and invests teeth, and harbors progenitor cells for dentoalveolar repair. Many unanswered questions remain regarding periodontal biology. This review will focus on recent research providing insights into one enduring mystery: the precise regulation of the hard-soft tissue borders in the periodontium which define the interfaces of the cementum-PDL-alveolar bone structure. We will focus on advances in understanding the molecular mechanisms that maintain the unmineralized PDL "between a rock and a hard place" by regulating the mineralization of cementum and alveolar bone.
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Affiliation(s)
- Natalie L. Andras
- Biosciences Division, College of DentistryThe Ohio State UniversityColumbusOhioUSA
| | - Fatma F. Mohamed
- Biosciences Division, College of DentistryThe Ohio State UniversityColumbusOhioUSA
| | - Emily Y. Chu
- Division of Operative Dentistry, Department of General Dentistry, School of DentistryUniversity of MarylandBaltimoreMarylandUSA
| | - Brian L. Foster
- Biosciences Division, College of DentistryThe Ohio State UniversityColumbusOhioUSA
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Figueredo CA, Abdelhay N, Gibson MP. The Roles of SIBLING Proteins in Dental, Periodontal and Craniofacial Development. FRONTIERS IN DENTAL MEDICINE 2022. [DOI: 10.3389/fdmed.2022.898802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The majority of dental, periodontal, and craniofacial tissues are derived from the neural crest cells and ectoderm. Neural crest stem cells are pluripotent, capable of differentiating into a variety of cells. These cells can include osteoblasts, odontoblasts, cementoblasts, chondroblasts, and fibroblasts which are responsible for forming some of the tissues of the oral and craniofacial complex. The hard tissue forming cells deposit a matrix composed of collagen and non-collagenous proteins (NCPs) that later undergoes mineralization. The NCPs play a role in the mineralization of collagen. One such category of NCPs is the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family of proteins. This family is composed of dentin sialophosphosprotein (DSPP), osteopontin (OPN), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP), and matrix extracellular phosphoglycoprotein (MEPE). The SIBLING family is known to have regulatory effects in the mineralization process of collagen fibers and the maturation of hydroxyapatite crystals. It is well established that SIBLING proteins have critical roles in tooth development. Recent literature has described the expression and role of SIBLING proteins in other areas of the oral and craniofacial complex as well. The objective of the present literature review is to summarize and discuss the different roles the SIBLING proteins play in the development of dental, periodontal, and craniofacial tissues.
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Mohamed FF, Chavez MB, de Oliveira FA, Narisawa S, Farquharson C, Millán JL, Foster BL. Perspective on Dentoalveolar Manifestations Resulting From PHOSPHO1 Loss-of-Function: A Form of Pseudohypophosphatasia? FRONTIERS IN DENTAL MEDICINE 2022; 3:826387. [PMID: 36185572 PMCID: PMC9521815 DOI: 10.3389/fdmed.2022.826387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Mineralization of the skeleton occurs by several physicochemical and biochemical processes and mechanisms that facilitate the deposition of hydroxyapatite (HA) in specific areas of the extracellular matrix (ECM). Two key phosphatases, phosphatase, orphan 1 (PHOSPHO1) and tissue-non-specific alkaline phosphatase (TNAP), play complementary roles in the mineralization process. The actions of PHOSPHO1 on phosphocholine and phosphoethanolamine in matrix vesicles (MVs) produce inorganic phosphate (Pi) for the initiation of HA mineral formation within MVs. TNAP hydrolyzes adenosine triphosphate (ATP) and the mineralization inhibitor, inorganic pyrophosphate (PPi), to generate Pi that is incorporated into MVs. Genetic mutations in the ALPL gene-encoding TNAP lead to hypophosphatasia (HPP), characterized by low circulating TNAP levels (ALP), rickets in children and/or osteomalacia in adults, and a spectrum of dentoalveolar defects, the most prevalent being lack of acellular cementum leading to premature tooth loss. Given that the skeletal manifestations of genetic ablation of the Phospho1 gene in mice resemble many of the manifestations of HPP, we propose that Phospho1 gene mutations may underlie some cases of "pseudo-HPP" where ALP may be normal to subnormal, but ALPL mutation(s) have not been identified. The goal of this perspective article is to compare and contrast the loss-of-function effects of TNAP and PHOSPHO1 on the dentoalveolar complex to predict the likely dental phenotype in humans that may result from PHOSPHO1 mutations. Potential cases of pseudo-HPP associated with PHOSPHO1 mutations may resist diagnosis, and the dental manifestations could be a key criterion for consideration.
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Affiliation(s)
- Fatma F. Mohamed
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, United States
| | - Michael B. Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, United States
| | - Flavia Amadeu de Oliveira
- Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Sonoko Narisawa
- Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Colin Farquharson
- The Royal (Dick) School of Veterinary Studies (RDSVS), The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - José Luis Millán
- Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Brian L. Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, United States,,Correspondence: Brian L. Foster,
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Schroth RJ, Long C, Lee VHK, Alai-Towfigh H, Rockman-Greenberg C. Dental outcomes for children receiving asfotase alfa for hypophosphatasia. Bone 2021; 152:116089. [PMID: 34175501 DOI: 10.1016/j.bone.2021.116089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/01/2021] [Accepted: 06/22/2021] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Hypophosphatasia, a genetic disease impeding development of teeth and bones, is associated with premature exfoliation of primary teeth. Hypophosphatasia is caused by mutations in the ALPL gene, which encodes the tissue non-specific form of alkaline phosphatase. Asfotase alfa (Strensiq®) is a human recombinant bone-targeted alkaline phosphatase. OBJECTIVES To review development and exfoliation patterns of primary/permanent teeth in a cohort of patients with hypophosphatasia enrolled in an open-label clinical trial of enzyme replacement therapy (ERT) with asfotase alfa. METHODS Data were collected from existing study files of a cohort of patients ≤5 years of age with infantile hypophosphatasia. Children were recruited at the Winnipeg site of a global clinical trial and were treated with ERT. Dental information, including the exfoliation/eruption patterns, were recorded at each visit. RESULTS Eleven children (7 females, 4 males) participated. Participants enrolled as infants (5 infants; mean age 3.0 ± 2.3 months) prematurely lost significantly fewer teeth to hypophosphatasia than patients recruited as preschoolers (6 preschoolers; mean age 52.5 ± 11.3 months), who started on asfotase alfa at a later age. Conclusion The oral health of children with early onset infantile hypophosphatasia may be improved with early and continued administration of ERT, compared to institution of therapy later in childhood.
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Affiliation(s)
- Robert J Schroth
- Rady Faculty of Health Sciences, University of Manitoba, Canada; Children's Hospital Research Institute of Manitoba, Canada; Section of Pediatric Dentistry, Winnipeg Regional Health Authority, Canada; Shared Health Manitoba, Canada.
| | - Catherine Long
- Rady Faculty of Health Sciences, University of Manitoba, Canada
| | - Victor H K Lee
- Rady Faculty of Health Sciences, University of Manitoba, Canada; Children's Hospital Research Institute of Manitoba, Canada
| | | | - Cheryl Rockman-Greenberg
- Rady Faculty of Health Sciences, University of Manitoba, Canada; Children's Hospital Research Institute of Manitoba, Canada; Shared Health Manitoba, Canada
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Kinoshita Y, Mohamed FF, Amadeu de Oliveira F, Narisawa S, Miyake K, Foster BL, Millán JL. Gene Therapy Using Adeno-Associated Virus Serotype 8 Encoding TNAP-D 10 Improves the Skeletal and Dentoalveolar Phenotypes in Alpl -/- Mice. J Bone Miner Res 2021; 36:1835-1849. [PMID: 34076297 PMCID: PMC8446309 DOI: 10.1002/jbmr.4382] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 12/26/2022]
Abstract
Hypophosphatasia (HPP) is caused by loss-of-function mutations in the ALPL gene that encodes tissue-nonspecific alkaline phosphatase (TNAP), whose deficiency results in the accumulation of extracellular inorganic pyrophosphate (PPi ), a potent mineralization inhibitor. Skeletal and dental hypomineralization characterizes HPP, with disease severity varying from life-threatening perinatal or infantile forms to milder forms that manifest in adulthood or only affect the dentition. Enzyme replacement therapy (ERT) using mineral-targeted recombinant TNAP (Strensiq/asfotase alfa) markedly improves the life span, skeletal phenotype, motor function, and quality of life of patients with HPP, though limitations of ERT include frequent injections due to a short elimination half-life of 2.28 days and injection site reactions. We tested the efficacy of a single intramuscular administration of adeno-associated virus 8 (AAV8) encoding TNAP-D10 to increase the life span and improve the skeletal and dentoalveolar phenotypes in TNAP knockout (Alpl-/- ) mice, a murine model for severe infantile HPP. Alpl-/- mice received 3 × 1011 vector genomes/body of AAV8-TNAP-D10 within 5 days postnatal (dpn). AAV8-TNAP-D10 elevated serum ALP activity and suppressed plasma PPi . Treatment extended life span of Alpl-/- mice, and no ectopic calcifications were observed in the kidneys, aorta, coronary arteries, or brain in the 70 dpn observational window. Treated Alpl-/- mice did not show signs of rickets, including bowing of long bones, enlargement of epiphyses, or fractures. Bone microstructure of treated Alpl-/- mice was similar to wild type, with a few persistent small cortical and trabecular defects. Histology showed no measurable osteoid accumulation but reduced bone volume fraction in treated Alpl-/- mice versus controls. Treated Alpl-/- mice featured normal molar and incisor dentoalveolar tissues, with the exceptions of slightly reduced molar enamel and alveolar bone density. Histology showed the presence of cementum and normal periodontal ligament attachment. These results support gene therapy as a promising alternative to ERT for the treatment of HPP. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Yuka Kinoshita
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Fatma F Mohamed
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Flavia Amadeu de Oliveira
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Sonoko Narisawa
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Koichi Miyake
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan
| | - Brian L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - José Luis Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
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11
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Hasegawa A, Nakamura-Takahashi A, Kasahara M, Saso N, Narisawa S, Millán JL, Samura O, Sago H, Okamoto A, Umezawa A. Prenatal enzyme replacement therapy for Akp2 -/- mice with lethal hypophosphatasia. Regen Ther 2021; 18:168-175. [PMID: 34277899 PMCID: PMC8267436 DOI: 10.1016/j.reth.2021.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/28/2021] [Accepted: 06/06/2021] [Indexed: 11/21/2022] Open
Abstract
Hypophosphatasia (HPP) is a congenital skeletal disease. Impairment of bone mineralization and seizures are due to a deficiency of tissue-nonspecific alkaline phosphatase (TNAP). Enzyme replacement therapy (ERT) is available as a highly successful treatment for pediatric-onset HPP. However, the potential for prenatal ERT has not been fully investigated to date. In this study, we assessed outcomes and maternal safety using a combinational approach with prenatal and postnatal administration of recombinant TNAP in Akp2−/− mice as a model of infantile HPP. For the prenatal ERT, we administered subcutaneous injections of recombinant TNAP to pregnant mice from embryonic day 11.5–14.5 until delivery, and then sequentially to Akp2−/− pups from birth to day 18. For the postnatal ERT, we injected Akp2−/− pups from birth until day 18. Prenatal ERT did not cause any ectopic mineralization in heterozygous maternal mice. Both prenatal and postnatal ERT preserved growth, survival rate and improved bone calcification in Akp2−/− mice. However, the effects of additional prenatal treatment to newborn mice appeared to be minimal, and the difference between prenatal and postnatal ERT was subtle. Further improvement of the prenatal ERT schedule and long-term observation will be required. The present paper sets a standard for such future studies.
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Affiliation(s)
- Akihiro Hasegawa
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan.,Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | | | | | - Nana Saso
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan
| | - Sonoko Narisawa
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - José Luis Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Osamu Samura
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Haruhiko Sago
- Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Aikou Okamoto
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Akihiro Umezawa
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan
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12
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Yamunadevi A, Pratibha R, Rajmohan M, Mahendraperumal S, Ganapathy N, Srivandhana R. First Molars in Permanent Dentition and their Malformations in Various Pathologies: A Review. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2021; 13:S23-S30. [PMID: 34447037 PMCID: PMC8375929 DOI: 10.4103/jpbs.jpbs_744_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 11/20/2020] [Accepted: 11/21/2020] [Indexed: 11/19/2022] Open
Abstract
Permanent maxillary and mandibular first molars are the first permanent teeth to erupt into the oral cavity along with the mandibular incisors. It serves as an excellent record of maternal and fetal health, reflecting the prenatal, perinatal, and postnatal health and diseases. This review focuses on the molar morphogenesis, molar malformations, their etiopathogenesis, and pathologies causing specific pattern of molar malformations.
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Affiliation(s)
- Andamuthu Yamunadevi
- Department of Oral and Maxillofacial Pathology, Vivekanandha Dental College for Women, Namakkal, Tamil Nadu, India
| | - Ramani Pratibha
- Department of Oral and Maxillofacial Pathology, Saveetha Dental College, Chennai, Tamil Nadu, India
| | - Muthusamy Rajmohan
- Department of Oral and Maxillofacial Pathology, KSR Institute of Dental Science and Research, Namakkal, Tamil Nadu, India
| | - Sengottaiyan Mahendraperumal
- Department of Oral and Maxillofacial Surgery, KSR Institute of Dental Science and Research, Namakkal, Tamil Nadu, India
| | - Nalliappan Ganapathy
- Department of Oral and Maxillofacial Pathology, Vivekanandha Dental College for Women, Namakkal, Tamil Nadu, India
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13
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Spencer P, Ye Q, Kamathewatta NJB, Woolfolk SK, Bohaty BS, Misra A, Tamerler C. Chemometrics-Assisted Raman Spectroscopy Characterization of Tunable Polymer-Peptide Hybrids for Dental Tissue Repair. FRONTIERS IN MATERIALS 2021; 8:681415. [PMID: 34113623 PMCID: PMC8186416 DOI: 10.3389/fmats.2021.681415] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The interfaces that biological tissues form with biomaterials are invariably defective and frequently the location where failure initiates. Characterizing the phenomena that lead to failure is confounded by several factors including heterogeneous material/tissue interfaces. To seamlessly analyze across these diverse structures presents a wealth of analytical challenges. This study aims to develop a molecular-level understanding of a peptide-functionalized adhesive/collagen hybrid biomaterial using Raman spectroscopy combined with chemometrics approach. An engineered hydroxyapatite-binding peptide (HABP) was copolymerized in dentin adhesive and dentin was demineralized to provide collagen matrices that were partially infiltrated with the peptide-functionalized adhesive. Partial infiltration led to pockets of exposed collagen-a condition that simulates defects in adhesive/dentin interfaces. The spectroscopic results indicate that co-polymerizable HABP tethered to the adhesive promoted remineralization of the defects. The spatial distribution of collagen, adhesive, and mineral as well as crystallinity of the mineral across this heterogeneous material/tissue interface was determined using micro-Raman spectroscopy combined with chemometrics approach. The success of this combined approach in the characterization of material/tissue interfaces stems from its ability to extract quality parameters that are related to the essential and relevant portions of the spectral data, after filtering out noise and non-relevant information. This ability is critical when it is not possible to separate components for analysis such as investigations focused on, in situ chemical characterization of interfaces. Extracting essential information from complex bio/material interfaces using data driven approaches will improve our understanding of heterogeneous material/tissue interfaces. This understanding will allow us to identify key parameters within the interfacial micro-environment that should be harnessed to develop durable biomaterials.
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Affiliation(s)
- Paulette Spencer
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
- Correspondence: Paulette Spencer, , Qiang Ye,
| | - Qiang Ye
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Correspondence: Paulette Spencer, , Qiang Ye,
| | - Nilan J. B. Kamathewatta
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
| | - Sarah K. Woolfolk
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
| | - Brenda S. Bohaty
- Department of Pediatric Dentistry, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Anil Misra
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Department of Civil Engineering, University of Kansas, Lawrence, KS, United States
| | - Candan Tamerler
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
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14
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Nagasaki A, Nagasaki K, Kear BD, Tadesse WD, Thumbigere-Math V, Millán JL, Foster BL, Somerman MJ. Delivery of Alkaline Phosphatase Promotes Periodontal Regeneration in Mice. J Dent Res 2021; 100:993-1001. [PMID: 33840251 DOI: 10.1177/00220345211005677] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Factors regulating the ratio of pyrophosphate (PPi) to phosphate (Pi) modulate biomineralization. Tissue-nonspecific alkaline phosphatase (TNAP) is a key promineralization enzyme that hydrolyzes the potent mineralization inhibitor PPi. The goal of this study was to determine whether TNAP could promote periodontal regeneration in bone sialoprotein knockout mice (Ibsp-/- mice), which are known to have a periodontal disease phenotype. Delivery of TNAP was accomplished either systemically (through a lentiviral construct expressing a mineral-targeted TNAP-D10 protein) or locally (through addition of recombinant human TNAP to a fenestration defect model). Systemic TNAP-D10 delivered by intramuscular injection at 5 d postnatal (dpn) increased circulating alkaline phosphatase (ALP) levels in Ibsp-/- mice by 5-fold at 30 dpn, with levels returning to normal by 60 dpn when tissues were evaluated by micro-computed tomography and histology. Local delivery of recombinant human TNAP to fenestration defects in 5-wk-old wild type (WT) and Ibsp-/- mice did not alter long-term circulating ALP levels, and tissues were evaluated by micro-computed tomography and histology at postoperative day 45. Systemic and local delivery of TNAP significantly increased alveolar bone volume (20% and 37%, respectively) and cementum thickness (3- and 42-fold) in Ibsp-/- mice, with evidence for periodontal ligament attachment and bone/cementum marker localization. Local delivery significantly increased regenerated cementum and bone in WT mice. Addition of 100-μg/mL bovine intestinal ALP to culture media to increase ALP in vitro increased media Pi concentration, mineralization, and Spp1 and Dmp1 marker gene expression in WT and Ibsp-/- OCCM.30 cementoblasts. Use of phosphonoformic acid, a nonspecific inhibitor of sodium Pi cotransport, indicated that effects of bovine intestinal ALP on mineralization and marker gene expression were in part through Pi transport. These findings show for the first time through multiple in vivo and in vitro approaches that pharmacologic modulation of Pi/PPi metabolism can overcome periodontal breakdown and accomplish regeneration.
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Affiliation(s)
- A Nagasaki
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - K Nagasaki
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - B D Kear
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - W D Tadesse
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - V Thumbigere-Math
- Division of Periodontology, School of Dentistry, University of Maryland, Baltimore, MD, USA
| | - J L Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - B L Foster
- Biosciences Division, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M J Somerman
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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15
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Toledano M, Vallecillo-Rivas M, Aguilera FS, Osorio MT, Osorio E, Osorio R. Polymeric zinc-doped nanoparticles for high performance in restorative dentistry. J Dent 2021; 107:103616. [PMID: 33636241 DOI: 10.1016/j.jdent.2021.103616] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES The aim was to state the different applications and the effectiveness of polymeric zinc-doped nanoparticles to achieve dentin remineralization. DATA, SOURCES AND STUDY SELECTION Literature search was conducted using electronic databases, such as PubMed, MEDLINE, DIMDI, Embase, Scopus and Web of Science. A narrative exploratory review was undertaken. CONCLUSIONS Polymeric nanospheres (NPs) were efficiently loaded with zinc. NPs sequestered calcium and phosphate in the presence of silicon, and remained effectively embedded at the hybrid layer. NPs incorporation did not alter bond strength and inhibited MMP-mediated dentin collagen degradation. Zn-loaded NPs remineralized the hybrid layer inducing a generalized low-carbonate substitute apatite precipitation, chemically crystalline with some amorphous components, and an increase in mechanical properties was also promoted. Viscoelastic analysis determined that dentin infiltrated with Zn-NPs released the stress by breaking the resin-dentin interface and creating specific mineral formations in response to the energy dissipation. Bacteria were scarcely encountered at the resin-dentin interface. The combined antibacterial and remineralizing effects, when Zn-NPs were applied, reduced biofilm formation. Zn-NPs application at both cervical and radicular dentin attained the lowest microleakage and also promoted durable sealing ability. The new zinc-based salt minerals generated covered the dentin surface totally occluding cracks, porosities and dentinal tubules. CLINICAL SIGNIFICANCE Zinc-doped NPs are proposed for effective dentin remineralization and tubular occlusion. This offers new strategies for regeneration of eroded cervical dentin, effective treatment of dentin hypersensitivity and in endodontically treated teeth previous to the canal filling. Zn-NPs also do reduce biofilm formation due to antibacterial properties.
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Affiliation(s)
- Manuel Toledano
- University of Granada, Faculty of Dentistry, Dental Materials Section. Colegio Máximo de Cartuja s/n, Granada, 18071, Spain.
| | - Marta Vallecillo-Rivas
- University of Granada, Faculty of Dentistry, Dental Materials Section. Colegio Máximo de Cartuja s/n, Granada, 18071, Spain
| | - Fátima S Aguilera
- University of Granada, Faculty of Dentistry, Dental Materials Section. Colegio Máximo de Cartuja s/n, Granada, 18071, Spain
| | - María T Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section. Colegio Máximo de Cartuja s/n, Granada, 18071, Spain
| | - Estrella Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section. Colegio Máximo de Cartuja s/n, Granada, 18071, Spain
| | - Raquel Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section. Colegio Máximo de Cartuja s/n, Granada, 18071, Spain
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16
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Kramer K, Chavez MB, Tran AT, Farah F, Tan MH, Kolli TN, Dos Santos EJL, Wimer HF, Millán JL, Suva LJ, Gaddy D, Foster BL. Dental defects in the primary dentition associated with hypophosphatasia from biallelic ALPL mutations. Bone 2021; 143:115732. [PMID: 33160095 PMCID: PMC7769999 DOI: 10.1016/j.bone.2020.115732] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022]
Abstract
ALPL encodes tissue-nonspecific alkaline phosphatase (TNAP), an enzyme expressed in bone, teeth, liver, and kidney. ALPL loss-of-function mutations cause hypophosphatasia (HPP), an inborn error-of-metabolism that produces skeletal and dental mineralization defects. Case reports describe widely varying dental phenotypes, making it unclear how HPP comparatively affects the three unique dental mineralized tissues: enamel, dentin, and cementum. We hypothesized that HPP affected all dental mineralized tissues and aimed to establish quantitative measurements of dental tissues in a subject with HPP. The female proband was diagnosed with HPP during childhood based on reduced alkaline phosphatase activity (ALP), mild rachitic skeletal effects, and premature primary tooth loss. The diagnosis was subsequently confirmed genetically by the presence of compound heterozygous ALPL mutations (exon 5: c.346G>A, p.A116T; exon 10: c.1077C>G, p.I359M). Dental defects in 8 prematurely exfoliated primary teeth were analyzed by high resolution micro-computed tomography (micro-CT) and histology. Similarities to the Alpl-/- mouse model of HPP were identified by additional analyses of murine dentoalveolar tissues. Primary teeth from the proband exhibited substantial remaining root structure compared to healthy control teeth. Enamel and dentin densities were not adversely affected in HPP vs. control teeth. However, analysis of discrete dentin regions revealed an approximate 10% reduction in the density of outer mantle dentin of HPP vs. control teeth. All 4 incisors and the molar lacked acellular cementum by micro-CT and histology, but surprisingly, 2 of 3 prematurely exfoliated canines exhibited apparently normal acellular cementum. Based on dentin findings in the proband's teeth, we examined dentoalveolar tissues in a mouse model of HPP, revealing that the delayed initiation of mineralization in the incisor mantle dentin was associated with a broader lack of circumpulpal dentin mineralization. This study describes a quantitative approach to measure effects of HPP on dental tissues. This approach has uncovered a previously unrecognized novel mantle dentin defect in HPP, as well as a surprising and variable cementum phenotype within the teeth from the same HPP subject.
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Affiliation(s)
- K Kramer
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A T Tran
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - F Farah
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M H Tan
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - T N Kolli
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - E J Lira Dos Santos
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA; Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil
| | - H F Wimer
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA; National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - J L Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - L J Suva
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - D Gaddy
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA.
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17
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Reznikov N, Hoac B, Buss DJ, Addison WN, Barros NMT, McKee MD. Biological stenciling of mineralization in the skeleton: Local enzymatic removal of inhibitors in the extracellular matrix. Bone 2020; 138:115447. [PMID: 32454257 DOI: 10.1016/j.bone.2020.115447] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/14/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022]
Abstract
Biomineralization is remarkably diverse and provides myriad functions across many organismal systems. Biomineralization processes typically produce hardened, hierarchically organized structures usually having nanostructured mineral assemblies that are formed through inorganic-organic (usually protein) interactions. Calcium‑carbonate biomineral predominates in structures of small invertebrate organisms abundant in marine environments, particularly in shells (remarkably it is also found in the inner ear otoconia of vertebrates), whereas calcium-phosphate biomineral predominates in the skeletons and dentitions of both marine and terrestrial vertebrates, including humans. Reconciliation of the interplay between organic moieties and inorganic crystals in bones and teeth is a cornerstone of biomineralization research. Key molecular determinants of skeletal and dental mineralization have been identified in health and disease, and in pathologic ectopic calcification, ranging from small molecules such as pyrophosphate, to small membrane-bounded matrix vesicles shed from cells, and to noncollagenous extracellular matrix proteins such as osteopontin and their derived bioactive peptides. Beyond partly knowing the regulatory role of the direct actions of inhibitors on vertebrate mineralization, more recently the importance of their enzymatic removal from the extracellular matrix has become increasingly understood. Great progress has been made in deciphering the relationship between mineralization inhibitors and the enzymes that degrade them, and how adverse changes in this physiologic pathway (such as gene mutations causing disease) result in mineralization defects. Two examples of this are rare skeletal diseases having osteomalacia/odontomalacia (soft bones and teeth) - namely hypophosphatasia (HPP) and X-linked hypophosphatemia (XLH) - where inactivating mutations occur in the gene for the enzymes tissue-nonspecific alkaline phosphatase (TNAP, TNSALP, ALPL) and phosphate-regulating endopeptidase homolog X-linked (PHEX), respectively. Here, we review and provide a concept for how existing and new information now comes together to describe the dual nature of regulation of mineralization - through systemic mineral ion homeostasis involving circulating factors, coupled with molecular determinants operating at the local level in the extracellular matrix. For the local mineralization events in the extracellular matrix, we present a focused concept in skeletal mineralization biology called the Stenciling Principle - a principle (building upon seminal work by Neuman and Fleisch) describing how the action of enzymes to remove tissue-resident inhibitors defines with precision the location and progression of mineralization.
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Affiliation(s)
- N Reznikov
- Object Research Systems Inc., 760 St. Paul West, Montreal, Quebec H3C 1M4, Canada.
| | - B Hoac
- Faculty of Dentistry, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada
| | - D J Buss
- Department of Anatomy and Cell Biology, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada
| | - W N Addison
- Department of Molecular Signaling and Biochemistry, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka, Japan
| | - N M T Barros
- Departamento de Biofísica, São Paulo, Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, Brazil
| | - M D McKee
- Faculty of Dentistry, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada; Department of Anatomy and Cell Biology, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada.
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18
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Amadeu de Oliveira F, Narisawa S, Bottini M, Millán JL. Visualization of Mineral-Targeted Alkaline Phosphatase Binding to Sites of Calcification In Vivo. J Bone Miner Res 2020; 35:1765-1771. [PMID: 32343017 PMCID: PMC8383212 DOI: 10.1002/jbmr.4038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/01/2020] [Accepted: 04/20/2020] [Indexed: 02/02/2023]
Abstract
A mineral-targeted form of recombinant tissue-nonspecific alkaline phosphatase (TNAP), asfotase alfa, was approved multinationally as an enzyme replacement therapy for hypophosphatasia in 2015. Two reports to date have shown evidence of binding of this drug to mineralizing tissues using histochemistry and immunohistochemistry. Here, we sought to expand on those earlier studies by directly visualizing the in vivo binding of asfotase alfa conjugated with AnaTag HiLyte Fluor 750 or Alexa Fluor 647 fluorescent dye to sites of skeletal/dental mineralization and ectopic calcification. We utilized 40-day-old Tagln-Cre; HprtALPL/Y mice, a model of severe medial vascular calcification; Tie2-Cre; HprtALPL/Y mice, a model of severe intimal calcification; and sibling WT HprtALPL/Y mice, devoid of soft-tissue calcification. A single dose of 8 mg/kg labeled asfotase alfa was injected via the retro-orbital route. Skeletal tissues and soft organs were imaged ex vivo 2 days after the injection. Strong fluorescence signal was observed in all skeletal tissues (calvaria, vertebra, long bones, jaw, and mandibles) from mutant and WT mice. Fluorescence analysis of histological sections from bones revealed strong binding of asfotase alfa. Asfotase alfa binding to sites of ectopic calcification in the heart, aorta, and renal artery were found in both the Tagln-Cre; HprtALPL/Y and Tie2-Cre; HprtALPL/Y mice but not in WT mice. In addition, asfotase alfa binding was also found in the kidney stroma and brain of the Tie2-Cre; HprtALPL/Y mice. Our results show that fluorescence-labeled asfotase alfa administered in vivo binds not only to sites of skeletal and dental mineralization but also to sites of ectopic calcification in these animal models. © 2020 American Society for Bone and Mineral Research.
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Affiliation(s)
| | - Sonoko Narisawa
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Massimo Bottini
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - José Luis Millán
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
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19
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Chu EY, Vo TD, Chavez MB, Nagasaki A, Mertz EL, Nociti FH, Aitken SF, Kavanagh D, Zimmerman K, Li X, Stabach PR, Braddock DT, Millán JL, Foster BL, Somerman MJ. Genetic and pharmacologic modulation of cementogenesis via pyrophosphate regulators. Bone 2020; 136:115329. [PMID: 32224162 PMCID: PMC7482720 DOI: 10.1016/j.bone.2020.115329] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 11/27/2022]
Abstract
Pyrophosphate (PPi) serves as a potent and physiologically important regulator of mineralization, with systemic and local concentrations determined by several key regulators, including: tissue-nonspecific alkaline phosphatase (ALPL gene; TNAP protein), the progressive ankylosis protein (ANKH; ANK), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1; ENPP1). Results to date have indicated important roles for PPi in cementum formation, and we addressed several gaps in knowledge by employing genetically edited mouse models where PPi metabolism was disrupted and pharmacologically modulating PPi in a PPi-deficient mouse model. We demonstrate that acellular cementum growth is inversely proportional to PPi levels, with reduced cementum in Alpl KO (increased PPi levels) mice and excess cementum in Ank KO mice (decreased PPi levels). Moreover, simultaneous ablation of Alpl and Ank results in reestablishment of functional cementum in dKO mice. Additional reduction of PPi by dual deletion of Ank and Enpp1 does not further increase cementogenesis, and PDL space is maintained in part through bone modeling/remodeling by osteoclasts. Our results provide insights into cementum formation and expand our knowledge of how PPi regulates cementum. We also demonstrate for the first time that pharmacologic manipulation of PPi through an ENPP1-Fc fusion protein can regulate cementum growth, supporting therapeutic interventions targeting PPi metabolism.
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Affiliation(s)
- E Y Chu
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA.
| | - T D Vo
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - M B Chavez
- Biosciences Division, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A Nagasaki
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - E L Mertz
- National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - F H Nociti
- Department of Prosthodontics & Periodontics, State University of Campinas, Piracicaba Dental School, Piracicaba, São Paulo, Brazil
| | - S F Aitken
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - D Kavanagh
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - K Zimmerman
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - X Li
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - P R Stabach
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - D T Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - J L Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - B L Foster
- Biosciences Division, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M J Somerman
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
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Abstract
Hypophosphatasia (HPP) is a rare inherited systemic metabolic disease caused by mutations in the tissue-nonspecific alkaline phosphatase (TNSALP) gene. TNSALP is expressed in the liver, kidney and bone, and its substrates include TNSALP inorganic pyrophosphate, pyridoxal-5'-phosphate (PLP)/vitamin B6 and phosphoethanolamine (PEA). Autosomal recessive and dominant forms of the disease result in a range of clinical entities. Major hallmarks are low alkaline phosphatase (ALP) and elevated PLP and PEA levels. Very severe infantile forms of HPP cause premature death as a result of respiratory insufficiency and also present with hypo-mineralisation leading to deformed limbs with, in some cases, the near-absence of bones and skull altogether. Respiratory failure, rib fractures and seizures due to vitamin B6 deficiency are indicative of a poor prognosis. Craniosynostosis is frequent. HPP leads to an unusual presentation of rickets with high levels of calcium and phosphorus, resulting in hypercalciuria, nephrocalcinosis and low ALP levels. Hypercalcaemic crisis, failure to thrive and growth retardation are concerns in infants. Fractures are common in both infantile and adult forms of the disease, concomitantly occurring with unexplained chronic pain and fatigue. Dental clinical presentations, which include the premature loss of teeth, are also commonly found in HPP and specifically manifest as odontohypophosphatasia. A novel enzyme therapy for human HPP, asfotase alfa, which is specifically targeted to mineralised tissues, has been developed in the past decades. While this treatment seems very promising, especially for infantile HPP, many questions regarding its long-term effects, the management of treatment, and any potential secondary adverse effects remain unresolved.
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Bowden SA, Foster BL. Alkaline Phosphatase Replacement Therapy for Hypophosphatasia in Development and Practice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1148:279-322. [PMID: 31482504 DOI: 10.1007/978-981-13-7709-9_13] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hypophosphatasia (HPP) is an inherited disorder that affects bone and tooth mineralization characterized by low serum alkaline phosphatase. HPP is caused by loss-of-function mutations in the ALPL gene encoding the protein, tissue-nonspecific alkaline phosphatase (TNSALP). TNSALP is expressed by mineralizing cells of the skeleton and dentition and is associated with the mineralization process. Generalized reduction of activity of the TNSALP leads to accumulation of its substrates, including inorganic pyrophosphate (PPi) that inhibits physiological mineralization. This leads to defective skeletal mineralization, with manifestations including rickets, osteomalacia, fractures, and bone pain, all of which can result in multi-systemic complications with significant morbidity, as well as mortality in severe cases. Dental manifestations are nearly universal among affected individuals and feature most prominently premature loss of deciduous teeth. Management of HPP has been limited to supportive care until the introduction of a TNSALP enzyme replacement therapy (ERT), asfotase alfa (AA). AA ERT has proven to be transformative, improving survival in severely affected infants and increasing overall quality of life in children and adults with HPP. This chapter provides an overview of TNSALP expression and functions, summarizes HPP clinical types and pathologies, discusses early attempts at therapies for HPP, summarizes development of HPP mouse models, reviews design and validation of AA ERT, and provides up-to-date accounts of AA ERT efficacy in clinical trials and case reports, including therapeutic response, adverse effects, limitations, and potential future directions in therapy.
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Affiliation(s)
- S A Bowden
- Division of Endocrinology, Department of Pediatrics, Nationwide Children's Hospital/The Ohio State University College of Medicine, Columbus, OH, USA.
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
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Osorio R, Osorio E, Aguilera FS, Medina-Castillo AL, Toledano M, Toledano-Osorio M. Silver improves collagen structure and stability at demineralized dentin: A dynamic-mechanical and Raman analysis. J Dent 2018; 79:61-67. [DOI: 10.1016/j.jdent.2018.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/04/2018] [Indexed: 01/28/2023] Open
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Williams DK, Pinzón C, Huggins S, Pryor JH, Falck A, Herman F, Oldeschulte J, Chavez MB, Foster BL, White SH, Westhusin ME, Suva LJ, Long CR, Gaddy D. Genetic engineering a large animal model of human hypophosphatasia in sheep. Sci Rep 2018; 8:16945. [PMID: 30446691 PMCID: PMC6240114 DOI: 10.1038/s41598-018-35079-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 10/24/2018] [Indexed: 12/02/2022] Open
Abstract
The availability of tools to accurately replicate the clinical phenotype of rare human diseases is a key step toward improved understanding of disease progression and the development of more effective therapeutics. We successfully generated the first large animal model of a rare human bone disease, hypophosphatasia (HPP) using CRISPR/Cas9 to introduce a single point mutation in the tissue nonspecific alkaline phosphatase (TNSALP) gene (ALPL) (1077 C > G) in sheep. HPP is a rare inherited disorder of mineral metabolism that affects bone and tooth development, and is associated with muscle weakness. Compared to wild-type (WT) controls, HPP sheep have reduced serum alkaline phosphatase activity, decreased tail vertebral bone size, and metaphyseal flaring, consistent with the mineralization deficits observed in human HPP patients. Computed tomography revealed short roots and thin dentin in incisors, and reduced mandibular bone in HPP vs. WT sheep, accurately replicating odonto-HPP. Skeletal muscle biopsies revealed aberrant fiber size and disorganized mitochondrial cristae structure in HPP vs. WT sheep. These genetically engineered sheep accurately phenocopy human HPP and provide a novel large animal platform for the longitudinal study of HPP progression, as well as other rare human bone diseases.
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Affiliation(s)
- Diarra K Williams
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Carlos Pinzón
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Shannon Huggins
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Jane H Pryor
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Alyssa Falck
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Forrest Herman
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - James Oldeschulte
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Michael B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Brian L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Sarah H White
- Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Mark E Westhusin
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Larry J Suva
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Charles R Long
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Dana Gaddy
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, 43210, USA.
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Abstract
Dental anomalies exist in every subtype of hypophosphatasia (HPP), from the most severe to the most moderate, called odontohypophosphatasia. The forms are defined by the age at onset of the initial symptoms. These anomalies affect all dental mineralized tissues from enamel, dentin and cementum to alveolar bone in a gradient proportional to the severity of the disease. Early loss of the deciduous teeth, before 3 years of age, and then possibly of the permanent teeth, is due to an abnormality of the cementum, the tissue attaching the teeth to alveolar bone, and is the most frequent abnormality. Tooth loss is a very important diagnostic sign and needs to be recognized. Patients with HPP need specialized oral and dental care in coordination with the reference and expert centers. The oral and dental signs and their treatment remain poorly known. The recording of the abnormalities and their treatment in a registry is indispensable in order to enhance patient management and oral and dental health.
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Bowden SA, Foster BL. Profile of asfotase alfa in the treatment of hypophosphatasia: design, development, and place in therapy. Drug Des Devel Ther 2018; 12:3147-3161. [PMID: 30288020 PMCID: PMC6161731 DOI: 10.2147/dddt.s154922] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hypophosphatasia (HPP) is a multi-systemic metabolic disorder caused by loss-of-function mutations in the ALPL gene that encodes the mineralization-associated enzyme, tissue-nonspecific alkaline phosphatase (TNSALP). HPP is characterized by defective bone and dental mineralization, leading to skeletal abnormalities with complications resulting in significant morbidity and mortality. Management of HPP has been limited to supportive care until the introduction of a recently approved enzyme replacement therapy employing bone-targeted recombinant human TNSALP, asfotase alfa (AA). This new therapy has been transformative as it improves survival in severely affected infants, and overall quality of life in children and adults with HPP. This review provides an overview of HPP, focusing on important steps in the development of AA enzyme replacement therapy, including the drug design, preclinical studies in the HPP mouse model, and outcomes from clinical trials and case report publications to date, with special attention given to response to therapy of skeletal manifestations, biochemical features, and other clinical manifestations. The limitations, adverse effects, and outcomes of AA are outlined and the place in therapy for individuals with HPP is discussed.
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Affiliation(s)
- Sasigarn A Bowden
- Division of Endocrinology, Department of Pediatrics, Nationwide Children's Hospital/The Ohio State University College of Medicine, Columbus, OH 43205, USA,
| | - Brian L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH 43205, USA
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Ikeue R, Nakamura-Takahashi A, Nitahara-Kasahara Y, Watanabe A, Muramatsu T, Sato T, Okada T. Bone-Targeted Alkaline Phosphatase Treatment of Mandibular Bone and Teeth in Lethal Hypophosphatasia via an scAAV8 Vector. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2018; 10:361-370. [PMID: 30202773 PMCID: PMC6129726 DOI: 10.1016/j.omtm.2018.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/13/2018] [Indexed: 12/16/2022]
Abstract
Hypophosphatasia is an inherited disease caused by mutations in the gene encoding tissue-nonspecific alkaline phosphatase (TNALP), the major symptom of which is hypomineralization of the bones and teeth. We had recently demonstrated that TNALP-deficient (Akp2−/−) mice, which mimic the phenotype of the severe infantile form of hypophosphatasia, can be treated by intramuscular injection of a self-complementary (sc) type 8 recombinant adeno-associated virus (rAAV8) vector expressing bone-targeted TNALP with deca-aspartates at the C terminus (TNALP-D10) via the muscle creatine kinase (MCK) promoter. In this study, we focused on the efficacy of this scAAV8-MCK-TNALP-D10 treatment on the mandibular bone and teeth in neonatal Akp2−/− mice. Upon scAAV8-MCK-TNALP-D10 injection, an improvement of mandibular growth was observed by X-ray analysis. Micro-computed tomography analysis revealed progressive mineralization of the molar root in the treated Akp2−/− mice, and morphometric parameters of the alveolar bone were improved. These results suggest that the mandibular bones and teeth of hypophosphatasia were effectively treated by muscle directed rAAV-mediated TNALP-D10 transduction. Our strategy would be promising for future hypophosphatasia gene therapy because it induces dentoalveolar mineralization and reduces the risk of tooth exfoliation.
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Affiliation(s)
- Ryo Ikeue
- Department of Fixed Prosthodontics, Tokyo Dental College, Tokyo, Japan
| | - Aki Nakamura-Takahashi
- Department of Pharmacology, Tokyo Dental College, Tokyo, Japan.,Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan
| | | | - Atsushi Watanabe
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan.,Division of Clinical Genetics, Nippon Medical School Hospital, Tokyo, Japan
| | - Takashi Muramatsu
- Department of Operative Dentistry, Tokyo Dental College, Tokyo, Japan
| | - Toru Sato
- Department of Fixed Prosthodontics, Tokyo Dental College, Tokyo, Japan
| | - Takashi Okada
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan
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Zn-containing polymer nanogels promote cervical dentin remineralization. Clin Oral Investig 2018; 23:1197-1208. [PMID: 29971511 DOI: 10.1007/s00784-018-2548-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 06/27/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Nanogels designing for effective treatment of eroded cervical dentin lesions. MATERIALS AND METHODS Polymethylmetacrylate-based nanoparticles (NPs) were doxycycline (D), calcium, or zinc loaded. They were applied on eroded cervical dentin. Treated surfaces were characterized morphologically by atomic force and scanning electron microscopy, mechanically probed by a nanoindenter to test nanohardness and Young's modulus, and chemically analyzed by Raman spectroscopy at 24 h and 7 days of storage. Data were submitted to ANOVA and Student-Newman-Keuls multiple comparisons tests. RESULTS Dentin treated with Zn-NPs attained the highest nanomechanical properties, mineralization, and crystallinity among groups. Nanoroughness was lower in Zn-treated surfaces in comparison to dentin treated with undoped gels. Dentin treated with Ca-NPs created the minimal calcification at the surface and showed the lowest Young's modulus at peritubular dentin. Intertubular dentin appeared remineralized. Dentinal tubules were empty in samples treated with D-NPs, partially occluded in cervical dentin treated with undoped NPs and Ca-NPs, and mineral covered when specimens were treated with Zn-NPs. CONCLUSIONS Zn-loaded NPs permit functional remineralization of eroded cervical dentin. Based on the tested nanomechanical and chemical properties, Zn-based nanogels are suitable for dentin remineralization. CLINICAL RELEVANCE The ability of zinc-loaded nanogels to promote dentin mineralization may offer new strategies for regeneration of eroded cervical dentin and effective treatment of dentin hypersensitivity.
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Lubin JH, Pacella MS, Gray JJ. A Parametric Rosetta Energy Function Analysis with LK Peptides on SAM Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5279-5289. [PMID: 29630384 DOI: 10.1021/acs.langmuir.8b00212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Although structures have been determined for many soluble proteins and an increasing number of membrane proteins, experimental structure determination methods are limited for complexes of proteins and solid surfaces. An economical alternative or complement to experimental structure determination is molecular simulation. Rosetta is one software suite that models protein-surface interactions, but Rosetta is normally benchmarked on soluble proteins. For surface interactions, the validity of the energy function is uncertain because it is a combination of independent parameters from energy functions developed separately for solution proteins and mineral surfaces. Here, we assess the performance of the RosettaSurface algorithm and test the accuracy of its energy function by modeling the adsorption of leucine/lysine (LK)-repeat peptides on methyl- and carboxy-terminated self-assembled monolayers (SAMs). We investigated how RosettaSurface predictions for this system compare with the experimental results, which showed that on both surfaces, LK-α peptides folded into helices and LK-β peptides held extended structures. Utilizing this model system, we performed a parametric analysis of Rosetta's Talaris energy function and determined that adjusting solvation parameters offered improved predictive accuracy. Simultaneously increasing lysine carbon hydrophilicity and the hydrophobicity of the surface methyl head groups yielded computational predictions most closely matching the experimental results. De novo models still should be interpreted skeptically unless bolstered in an integrative approach with experimental data.
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Ao M, Chavez MB, Chu EY, Hemstreet KC, Yin Y, Yadav MC, Millán JL, Fisher LW, Goldberg HA, Somerman MJ, Foster BL. Overlapping functions of bone sialoprotein and pyrophosphate regulators in directing cementogenesis. Bone 2017; 105:134-147. [PMID: 28866368 PMCID: PMC5730356 DOI: 10.1016/j.bone.2017.08.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/24/2017] [Accepted: 08/28/2017] [Indexed: 12/19/2022]
Abstract
Although acellular cementum is essential for tooth attachment, factors directing its development and regeneration remain poorly understood. Inorganic pyrophosphate (PPi), a mineralization inhibitor, is a key regulator of cementum formation: tissue-nonspecific alkaline phosphatase (Alpl/TNAP) null mice (increased PPi) feature deficient cementum, while progressive ankylosis protein (Ank/ANK) null mice (decreased PPi) feature increased cementum. Bone sialoprotein (Bsp/BSP) and osteopontin (Spp1/OPN) are multifunctional extracellular matrix components of cementum proposed to have direct and indirect effects on cell activities and mineralization. Studies on dentoalveolar development of Bsp knockout (Bsp-/-) mice revealed severely reduced acellular cementum, however underlying mechanisms remain unclear. The similarity in defective cementum phenotypes between Bsp-/- mice and Alpl-/- mice (the latter featuring elevated PPi and OPN), prompted us to examine whether BSP is operating by modulating PPi-associated genes. Genetic ablation of Bsp caused a 2-fold increase in circulating PPi, altered mRNA expression of Alpl, Spp1, and Ank, and increased OPN protein in the periodontia. Generation of a Bsp knock-out (KO) cementoblast cell line revealed significantly decreased mineralization capacity, 50% increased PPi in culture media, and increased Spp1 and Ank mRNA expression. While addition of 2μg/ml recombinant BSP altered Spp1, Ank, and Enpp1 expression in cementoblasts, changes resulting from this dose were not dependent on the integrin-binding RGD motif or MAPK/ERK signaling pathway. Decreasing PPi by genetic ablation of Ank on the Bsp-/- mouse background reestablished cementum formation, allowing >3-fold increased acellular cementum volume compared to wild-type (WT). However, deleting Ank did not fully compensate for the absence of BSP. Bsp-/-; Ank-/- double-deficient mice exhibited mean 20-27% reduced cementum thickness and volume compared to Ank-/- mice. From these data, we conclude that the perturbations in PPi metabolism are not solely driving the cementum pathology in Bsp-/- mice, and that PPi is more potent than BSP as a cementum regulator, as shown by the ability to override loss of BSP by lowering PPi. We propose that BSP and PPi work in concert to direct mineralization in cementum and likely other mineralized tissues.
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Affiliation(s)
- M Ao
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - M B Chavez
- Biosciences Division, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - E Y Chu
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - K C Hemstreet
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Y Yin
- National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD, USA
| | - M C Yadav
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - J L Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - L W Fisher
- National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD, USA
| | - H A Goldberg
- Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - M J Somerman
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - B L Foster
- Biosciences Division, College of Dentistry, The Ohio State University, Columbus, OH, USA.
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30
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Oral findings in patient with lethal hypophosphatasia treated with enzyme replacement therapy. PEDIATRIC DENTAL JOURNAL 2017. [DOI: 10.1016/j.pdj.2017.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Conti F, Ciullini L, Pugliese G. Hypophosphatasia: clinical manifestation and burden of disease in adult patients. ACTA ACUST UNITED AC 2017; 14:230-234. [PMID: 29263739 DOI: 10.11138/ccmbm/2017.14.1.230] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hypophosphatasia (HPP) is a rare inherited disease with a heterogeneous clinical expression. The adult form of HPP is often difficult to be recognized with a delayed diagnosis and inappropriate treatments. Though severity of HPP decreases with age at onset, important complications could occur at any age and the burden of HPP among adult patients is found to be significant. Adult patients with HPP suffer of chronic pain, recurrent fractures and other orthopedics problems, with severe disability that have a serious negative impact on all aspects of their life. The aim of this paper is to summarize the main aspects of HPP in adult patients reviewing the literature and focusing on its burden for patients suffering from this condition.
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Affiliation(s)
- Francesco Conti
- Department of Clinical and Molecular Medicine, "Sapienza" University of Rome, "S. Andrea" Hospital, Diabetes Units, Rome, Italy
| | - Lorenzo Ciullini
- Department of Clinical and Molecular Medicine, "Sapienza" University of Rome, "S. Andrea" Hospital, Diabetes Units, Rome, Italy
| | - Giuseppe Pugliese
- Department of Clinical and Molecular Medicine, "Sapienza" University of Rome, "S. Andrea" Hospital, Diabetes Units, Rome, Italy
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Abstract
Hypophosphatasia (HPP) is the inborn-error-of-metabolism that features low serum alkaline phosphatase (ALP) activity (hypophosphatasemia) caused by loss-of-function mutation(s) of the gene that encodes the tissue-nonspecific isoenzyme of ALP (TNSALP). Autosomal recessive or autosomal dominant inheritance from among >300 TNSALP (ALPL) mutations largely explains HPP's remarkably broad-ranging severity. TNSALP is a cell-surface homodimeric phosphohydrolase richly expressed in the skeleton, liver, kidney, and developing teeth. In HPP, TNSALP substrates accumulate extracellularly. Among them is inorganic pyrophosphate (PPi), a potent inhibitor of mineralization. Superabundance of extracellular PPi explains the hard tissue complications of HPP that feature premature loss of deciduous teeth and often rickets or osteomalacia as well as calcific arthropathies in some affected adults. In infants with severe HPP, blocked entry of minerals into the skeleton can cause hypercalcemia, and insufficient hydrolysis of pyridoxal 5'-phosphate (PLP), the major circulating form of vitamin B6, can cause pyridoxine-dependent seizures. Elevated circulating PLP is a sensitive and specific biochemical marker for HPP. Also, the TNSALP substrate phosphoethanolamine (PEA) is usually elevated in serum and urine in HPP, though less reliably for diagnosis. Pathognomonic radiographic changes occur in pediatric HPP when the skeletal disease is severe. TNSALP mutation analysis is essential for recurrence risk assessment for HPP in future pregnancies and for prenatal diagnosis. HPP was the final rickets/osteomalacia to have a medical treatment. Now, significant successes using asfotase alfa, a mineral-targeted recombinant TNSALP, are published concerning severely affected newborns, infants, and children. Asfotase alfa was approved by regulatory agencies multinationally in 2015 typically for pediatric-onset HPP.
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Affiliation(s)
- Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, Missouri, USA.
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Lacruz RS, Habelitz S, Wright JT, Paine ML. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE. Physiol Rev 2017; 97:939-993. [PMID: 28468833 DOI: 10.1152/physrev.00030.2016] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/16/2022] Open
Abstract
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
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Affiliation(s)
- Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Stefan Habelitz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - J Timothy Wright
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Michael L Paine
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
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Lacruz RS. Enamel: Molecular identity of its transepithelial ion transport system. Cell Calcium 2017; 65:1-7. [PMID: 28389033 PMCID: PMC5944837 DOI: 10.1016/j.ceca.2017.03.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/14/2022]
Abstract
Enamel is the most calcified tissue in vertebrates. It differs from bone in a number of characteristics including its origin from ectodermal epithelium, lack of remodeling capacity by the enamel forming cells, and absence of collagen. The enamel-forming cells known as ameloblasts, choreograph first the synthesis of a unique protein-rich matrix, followed by the mineralization of this matrix into a tissue that is ∼95% mineral. To do this, ameloblasts arrange the coordinated movement of ions across a cell barrier while removing matrix proteins and monitoring extracellular pH using a variety of buffering systems to enable the growth of carbonated apatite crystals. Although our knowledge of these processes and the molecular identity of the proteins involved in transepithelial ion transport has increased in the last decade, it remains limited compared to other cells. Here we present an overview of the evolution and development of enamel, its differences with bone, and describe the ion transport systems associated with ameloblasts.
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Affiliation(s)
- Rodrigo S Lacruz
- Dept. Basic Science and Craniofacial Biology, New York University College of Dentistry, 345 East 24th Street, New York, NY 10010, United States.
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35
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Hughes SL, Parkes RC, Drage N, Collard M. Early Tooth Loss in Children: A Warning Sign of Childhood Hypophosphatasia. DENTAL UPDATE 2017; 44:317-321. [PMID: 29172356 DOI: 10.12968/denu.2017.44.4.317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Premature exfoliation of primary teeth may be the first manifestation of this serious condition and the general dental practitioner plays an important role in recognizing dental anomalies and referring patients at an appropriate time. This is imperative to ensuring early diagnosis and good quality patient care. This article describes the case of a 4-year-old boy affected by childhood hypophosphatasia, who presented with premature exfoliation of his primary teeth as the first manifestation of this condition. An overview of the condition is outlined including a discussion of the likelihood of permanent dentition involvement. Clinical relevance: Oral manifestations of hypophosphatasia may be the first and the only signs of this condition and may be the basis upon which a diagnosis is made.
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Nam HK, Sharma M, Liu J, Hatch NE. Tissue Nonspecific Alkaline Phosphatase (TNAP) Regulates Cranial Base Growth and Synchondrosis Maturation. Front Physiol 2017; 8:161. [PMID: 28377728 PMCID: PMC5359511 DOI: 10.3389/fphys.2017.00161] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 03/02/2017] [Indexed: 12/27/2022] Open
Abstract
Hypophosphatasia is a rare heritable disorder caused by inactivating mutations in the gene (Alpl) that encodes tissue nonspecific alkaline phosphatase (TNAP). Hypophosphatasia with onset in infants and children can manifest as rickets. How TNAP deficiency leads to bone hypomineralization is well explained by TNAP's primary function of pyrophosphate hydrolysis when expressed in differentiated bone forming cells. How TNAP deficiency leads to abnormalities within endochondral growth plates is not yet known. Previous studies in hypophosphatemic mice showed that phosphate promotes chondrocyte maturation and apoptosis via MAPK signaling. Alpl-/- mice are not hypophosphatemic but TNAP activity does increase local levels of inorganic phosphate. Therefore, we hypothesize that TNAP influences endochondral bone development via MAPK. In support of this premise, here we demonstrate cranial base bone growth deficiency in Alpl-/- mice, utilize primary rib chondrocytes to show that TNAP influences chondrocyte maturation, apoptosis, and MAPK signaling in a cell autonomous manner; and demonstrate that similar chondrocyte signaling and apoptosis abnormalities are present in the cranial base synchondroses of Alpl-/- mice. Micro CT studies revealed diminished anterior cranial base bone and total cranial base lengths in Alpl-/- mice, that were prevented upon injection with mineral-targeted recombinant TNAP (strensiq). Histomorphometry of the inter-sphenoidal synchondrosis (cranial base growth plate) demonstrated significant expansion of the hypertrophic chondrocyte zone in Alpl-/- mice that was minimized upon treatment with recombinant TNAP. Alpl-/- primary rib chondrocytes exhibited diminished chondrocyte proliferation, aberrant mRNA expression, diminished hypertrophic chondrocyte apoptosis and diminished MAPK signaling. Diminished apoptosis and VEGF expression were also seen in 15 day-old cranial base synchondroses of Alpl-/- mice. MAPK signaling was significantly diminished in 5 day-old cranial base synchondroses of Alpl-/- mice. Together, our data suggests that TNAP is essential for the later stages of endochondral bone development including hypertrophic chondrocyte apoptosis and VEGF mediated recruitment of blood vessels for replacement of cartilage with bone. These changes may be mediated by diminished MAPK signaling in TNAP deficient chondrocytes due to diminished local inorganic phosphate production.
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Affiliation(s)
- Hwa K Nam
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan Ann Arbor, MI, USA
| | - Monika Sharma
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan Ann Arbor, MI, USA
| | - Jin Liu
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan Ann Arbor, MI, USA
| | - Nan E Hatch
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan Ann Arbor, MI, USA
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Yamamoto-Nemoto S, Ogawa K, Yokoi E, Sawamoto K, Yamaguchi A, Tuna EB, Shimizu T. Improvement of Bone and Dental Phenotype of Murine Hypophosphatasia Mediated by a Single Injection of Lentiviral Gene Therapy. ACTA ACUST UNITED AC 2017. [DOI: 10.4236/ojst.2017.71005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Scott LJ. Asfotase Alfa in Perinatal/Infantile-Onset and Juvenile-Onset Hypophosphatasia: A Guide to Its Use in the USA. BioDrugs 2016; 30:41-8. [PMID: 26832358 DOI: 10.1007/s40259-016-0161-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Subcutaneous asfotase alfa (Strensiq™), a first-in-class bone-targeted human recombinant tissue-nonspecific alkaline phosphatase (TNSALP) replacement therapy, is approved in the USA for the treatment of patients with perinatal/infantile- or juvenile-onset hypophosphatasia (HPP). In clinical trials, asfotase alfa was an effective and generally well tolerated treatment for perinatal/infantile- and juvenile onset-HPP through at least 3 and 5 years' treatment, respectively. Relative to untreated age-matched, juvenile-onset-HPP historical control cohorts, survival and ventilation-free survival were significantly prolonged in asfotase alfa-treated patients, consequent to preceding improvements in bone mineralization.
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Affiliation(s)
- Lesley J Scott
- Springer, Private Bag 65901, Mairangi Bay, 0754, Auckland, New Zealand.
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39
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Abstract
Hypophosphatasia (HPP) is a rare inheritable disease that results from loss-of-function mutations in the ALPL gene encoding tissue-nonspecific alkaline phosphatase (TNSALP). Therapeutic options for treating the underlying pathophysiology of the disease have been lacking, with the mainstay of treatment being management of symptoms and supportive care. HPP is associated with significant morbidity and mortality in paediatric patients, with mortality rates as high as 100 % in perinatal-onset HPP and 50 % in infantile-onset HPP. Subcutaneous asfotase alfa (Strensiq(®)), a first-in-class bone-targeted human recombinant TNSALP replacement therapy, is approved in the EU for long-term therapy in patients with paediatric-onset HPP to treat bone manifestations of the disease. In noncomparative clinical trials in infants and children with paediatric-onset HPP, asfotase alfa rapidly improved radiographically-assessed rickets severity scores at 24 weeks (primary timepoint) as reflected in improvements in bone mineralization, with these benefits sustained after more than 3 years of treatment. Furthermore, patients typically experienced improvements in respiratory function, gross motor function, fine motor function, cognitive development, muscle strength (normalization) and ability to perform activities of daily living, and catch-up height-gain. In life-threatening perinatal and infantile HPP, asfotase alfa also improved overall survival. Asfotase alfa was generally well tolerated in clinical trials, with relatively few patients discontinuing treatment and most treatment-related adverse events being of mild to moderate intensity. Thus, subcutaneous asfotase alfa is a valuable emerging therapy for the treatment of bone manifestations in patients with paediatric-onset HPP.
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Affiliation(s)
- Lesley J Scott
- Springer, Private Bag 65901, Mairangi Bay, Auckland, 0754, New Zealand.
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40
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Foster BL, Kuss P, Yadav MC, Kolli TN, Narisawa S, Lukashova L, Cory E, Sah RL, Somerman MJ, Millán JL. Conditional Alpl Ablation Phenocopies Dental Defects of Hypophosphatasia. J Dent Res 2016; 96:81-91. [PMID: 27582029 DOI: 10.1177/0022034516663633] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Loss-of-function mutations in ALPL result in hypophosphatasia (HPP), an inborn error of metabolism that causes defective skeletal and dental mineralization. ALPL encodes tissue-nonspecific alkaline phosphatase, an enzyme expressed in bone, teeth, liver, and kidney that hydrolyzes the mineralization inhibitor inorganic pyrophosphate. As Alpl-null mice die before weaning, we aimed to generate mouse models of late-onset HPP with extended life spans by engineering a floxed Alpl allele, allowing for conditional gene ablation (conditional knockout [cKO]) when crossed with Cre recombinase transgenic mice. The authors hypothesized that targeted deletion of Alpl in osteoblasts and selected dental cells ( Col1a1-cKO) or deletion in chondrocytes, osteoblasts, and craniofacial mesenchyme ( Prx1-cKO) would phenocopy skeletal and dental manifestations of late-onset HPP. Col1a1-cKO and Prx1-cKO mice were viable and fertile, and they did not manifest the epileptic seizures characteristic of the Alpl-/- model of severe infantile HPP. Both cKO models featured normal postnatal body weight but significant reduction as compared with wild type mice by 8 to 12 wk. Plasma alkaline phosphatase for both cKO models at 24 wk was reduced by approximately 75% as compared with controls. Radiography revealed profound skeletal defects in cKO mice, including rachitic changes, hypomineralized long bones, deformations, and signs of fractures. Microcomputed tomography confirmed quantitative differences in cortical and trabecular bone, including decreased cortical thickness and mineral density. Col1a1-cKO mice exhibited classic signs of HPP dentoalveolar disease, including short molar roots with thin dentin, lack of acellular cementum, and osteoid accumulation in alveolar bone. Prx1-cKO mice exhibited the same array of periodontal defects but featured less affected molar dentin. Both cKO models exhibited reduced alveolar bone height and 4-fold increased numbers of osteoclast-like cells versus wild type at 24 wk, consistent with HPP-associated periodontal disease. These novel models of late-onset HPP can inform on long-term skeletal and dental manifestations and will provide essential tools to further studies of etiopathologies and therapeutic interventions.
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Affiliation(s)
- B L Foster
- 1 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - P Kuss
- 2 Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - M C Yadav
- 2 Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - T N Kolli
- 1 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - S Narisawa
- 2 Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - L Lukashova
- 3 Hospital for Special Surgery, New York, NY, USA
| | - E Cory
- 4 Department of Bioengineering, University of California-San Diego, La Jolla, CA, USA.,5 Center for Musculoskeletal Research, University of California-San Diego, La Jolla, CA, USA
| | - R L Sah
- 4 Department of Bioengineering, University of California-San Diego, La Jolla, CA, USA.,5 Center for Musculoskeletal Research, University of California-San Diego, La Jolla, CA, USA.,6 Department of Orthopaedic Surgery, University of California-San Diego, La Jolla, CA, USA
| | - M J Somerman
- 7 National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - J L Millán
- 2 Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
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Okawa R, Iijima O, Kishino M, Okawa H, Toyosawa S, Sugano-Tajima H, Shimada T, Okada T, Ozono K, Ooshima T, Nakano K. Gene therapy improves dental manifestations in hypophosphatasia model mice. J Periodontal Res 2016; 52:471-478. [PMID: 27561677 DOI: 10.1111/jre.12412] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND AND OBJECTIVE Hypophosphatasia is a rare inherited skeletal disorder characterized by defective bone mineralization and deficiency of tissue non-specific alkaline phosphatase (TNSALP) activity. The disease is caused by mutations in the liver/bone/kidney alkaline phosphatase gene (ALPL) encoding TNSALP. Early exfoliation of primary teeth owing to disturbed cementum formation, periodontal ligament weakness and alveolar bone resorption are major complications encountered in oral findings, and discovery of early loss of primary teeth in a dental examination often leads to early diagnosis of hypophosphatasia. Although there are no known fundamental treatments or effective dental approaches to prevent early exfoliation of primary teeth in affected patients, several possible treatments have recently been described, including gene therapy. Gene therapy has also been applied to TNSALP knockout mice (Alpl-/- ), which phenocopy the infantile form of hypophosphatasia, and improved their systemic condition. In the present study, we investigated whether gene therapy improved the dental condition of Alpl-/- mice. MATERIAL AND METHODS Following sublethal irradiation (4 Gy) at the age of 2 d, Alpl-/- mice underwent gene therapy using bone marrow cells transduced with a lentiviral vector expressing a bone-targeted form of TNSALP injected into the jugular vein (n = 3). Wild-type (Alpl+/+ ), heterozygous mice (Alpl+/- ) and Alpl-/- mice were analyzed at 9 d of age (n = 3 of each), while Alpl+/+ mice and treated or untreated Alpl-/- mice were analyzed at 1 mo of age (n = 3 of each), and Alpl+/- mice and Alpl-/- mice with gene therapy were analyzed at 3 mo of age (n = 3 of each). A single mandibular hemi-section obtained at 1 mo of age was analyzed using a small animal computed tomography machine to assess alveolar bone formation. Other mandibular hemi-sections obtained at 9 d, 1 mo and 3 mo of age were subjected to hematoxylin and eosin staining and immunohistochemical analysis of osteopontin, a marker of cementum. RESULTS Immunohistochemical analysis of osteopontin, a marker of acellular cementum, revealed that Alpl-/- mice displayed impaired formation of cementum and alveolar bone, similar to the human dental phenotype. Cementum formation was clearly present in Alpl-/- mice that underwent gene therapy, but did not recover to the same level as that in wild-type (Alpl+/+ ) mice. Micro-computed tomography examination showed that gene therapy improved alveolar bone mineral density in Alpl-/- mice to a similar level to that in Alpl+/+ mice. CONCLUSIONS Our results suggest that gene therapy can improve the general condition of Alpl-/- mice, and induce significant alveolar bone formation and moderate improvement of cementum formation, which may contribute to inhibition of early spontaneous tooth exfoliation.
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Affiliation(s)
- R Okawa
- Osaka University Graduate School of Dentistry, Osaka, Japan
| | - O Iijima
- Nippon Medical School, Tokyo, Japan
| | - M Kishino
- Osaka University Graduate School of Dentistry, Osaka, Japan
| | - H Okawa
- Osaka University Graduate School of Dentistry, Osaka, Japan
| | - S Toyosawa
- Osaka University Graduate School of Dentistry, Osaka, Japan
| | | | | | - T Okada
- Nippon Medical School, Tokyo, Japan
| | - K Ozono
- Osaka University Graduate School of Medicine, Osaka, Japan
| | - T Ooshima
- Osaka University Graduate School of Dentistry, Osaka, Japan
| | - K Nakano
- Osaka University Graduate School of Dentistry, Osaka, Japan
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42
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Wang ZY, Zhang K, Zheng GS, Qiao W, Su YX. Current concepts in odontohypophosphatasia form of hypophosphatasia and report of two cases. BMC Oral Health 2016; 16:70. [PMID: 27531358 PMCID: PMC4988024 DOI: 10.1186/s12903-016-0266-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 08/02/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Hypophosphatasia is a rare inherited disease derived from mutations in tissue non-specific alkaline phosphatase genes, with typical oral symptoms including short root anomaly and dysplasia of dentin or cementum. CASE PRESENTATION Two young female patients presented with short root anomaly with a history of premature loss of deciduous and/or permanent teeth. The laboratory and imaging investigations were performed. One case was diagnosed as odontohypophosphatasia concurrent with hyperthyroidism, the other was odontohypophosphatasia concurrent with multiple radicular cysts. CONCLUSION This report presents two cases of odontohypophosphatasia, a rare disease which is difficult to be diagnosed, and highlights that the history of premature loss of deciduous and/or permanent teeth, oral manifestation and laboratory tests are crucial for clinical diagnosis.
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Affiliation(s)
- Zhu-yu Wang
- Department of Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Kai Zhang
- Department of Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Guang-sen Zheng
- Department of Oral and Maxillofacial Surgery, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Wei Qiao
- Department of Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Yu-xiong Su
- Division of Oral and Maxillofacial Surgery, Faculty of Dentistry, the University of Hong Kong, 34 Hospital Road, Hong Kong, Hong Kong
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43
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Nakano Y, Le MH, Abduweli D, Ho SP, Ryazanova LV, Hu Z, Ryazanov AG, Den Besten PK, Zhang Y. A Critical Role of TRPM7 As an Ion Channel Protein in Mediating the Mineralization of the Craniofacial Hard Tissues. Front Physiol 2016; 7:258. [PMID: 27458382 PMCID: PMC4934143 DOI: 10.3389/fphys.2016.00258] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/13/2016] [Indexed: 01/24/2023] Open
Abstract
Magnesium ion (Mg(2+)) is the fourth most common cation in the human body, and has a crucial role in many physiological functions. Mg(2+) homeostasis is an important contributor to bone development, however, its roles in the development of dental mineralized tissues have not yet been well known. We identified that transient receptor potential cation channel, subfamily M, member 7 (TRPM7), was significantly upregulated in the mature ameloblasts as compared to other ameloblasts through our whole transcript microarray analyses of the ameloblasts. TRPM7, an ion channel for divalent metal cations with an intrinsic serine/threonine protein kinase activity, has been characterized as a key regulator of whole body Mg(2+) homeostasis. Semi-quantitative PCR and immunostaining for TRMP7 confirmed its upregulation during the maturation stage of enamel formation, at which ameloblasts direct rapid mineralization of the enamel matrix. The significantly hypomineralized craniofacial structures, including incisors, molars, and cranial bones were demonstrated by microCT analysis, von Kossa and trichrome staining in Trpm7 (Δkinase∕+) mice. A previously generated heterozygous mouse model with the deletion of the TRPM7 kinase domain. Interestingly, the skeletal phenotype of Trpm7 (Δkinase∕+) mice resembled those found in the tissue-nonspecific alkaline phosphatase (Alpl) KO mice, thus we further examined whether ALPL protein content and alkaline phosphatase (ALPase) activity in ameloblasts, odontoblasts and osteoblasts were affected in those mice. While ALPL protein in Trpm7 (Δkinase∕+) mice remained at the similar level as that in wt mice, ALPase activities in the Trpm7 (Δkinase∕+) mice were almost nonexistent. Supplemented magnesium successfully rescued the activities of ALPase in ameloblasts, odontoblasts and osteoblasts of Trpm7 (Δkinase∕+) mice. These results suggested that TRPM7 is essential for mineralization of enamel as well as dentin and bone by providing sufficient Mg(2+) for the ALPL activity, underlining the key importance of ALPL for biomineralization.
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Affiliation(s)
- Yukiko Nakano
- Department of Orofacial Sciences, University of California, San FranciscoSan Francisco, CA, USA; Center for Children's Oral Health Research, University of California, San FranciscoSan Francisco, CA, USA
| | - Michael H Le
- Department of Orofacial Sciences, University of California, San Francisco San Francisco, CA, USA
| | - Dawud Abduweli
- Department of Orofacial Sciences, University of California, San Francisco San Francisco, CA, USA
| | - Sunita P Ho
- Preventive and Restorative Dental Sciences, University of California, San Francisco San Francisco, CA, USA
| | - Lillia V Ryazanova
- Department of Pharmacology, Robert Wood Johnson Medical School Piscataway, NJ, USA
| | - Zhixian Hu
- Department of Pharmacology, Robert Wood Johnson Medical School Piscataway, NJ, USA
| | - Alexey G Ryazanov
- Department of Pharmacology, Robert Wood Johnson Medical School Piscataway, NJ, USA
| | - Pamela K Den Besten
- Department of Orofacial Sciences, University of California, San FranciscoSan Francisco, CA, USA; Center for Children's Oral Health Research, University of California, San FranciscoSan Francisco, CA, USA
| | - Yan Zhang
- Department of Orofacial Sciences, University of California, San FranciscoSan Francisco, CA, USA; Center for Children's Oral Health Research, University of California, San FranciscoSan Francisco, CA, USA
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Abstract
Hypophosphatasia (HPP) is an inherited systemic bone disease that is characterized by bone hypomineralization. HPP is classified into six forms according to the age of onset and severity as perinatal (lethal), perinatal benign, infantile, childhood, adult, and odontohypophosphatasia. The causative gene of the disease is the ALPL gene that encodes tissue-nonspecific alkaline phosphatase (TNAP). TNAP is expressed ubiquitously, and its physiological role is apparent in bone mineralization. A defect in bone mineralization can manifest in several ways, including rickets or osteomalacia in HPP patients. Patients with severe forms suffer from respiratory failure because of hypoplastic chest, which is the main cause of death. They sometimes present with seizures due to a defect in vitamin B6 metabolism resulting from the lack of alkaline phosphatase activity in neuronal cells, which is also lethal. Patients with a mild form of the disease exhibit rickets or osteomalacia and a functional defect of exercise. Odontohypophosphatasia shows only dental manifestations. To date, 302 mutations in the ALPL gene have been reported, mainly single-nucleotide substitutions, and the relationships between phenotype and genotype have been partially elucidated. An established treatment for HPP was not available until the recent development of enzyme replacement therapy. The first successful enzyme replacement therapy in model mice using a modified human TNAP protein (asfotase alfa) was reported in 2008, and subsequently success in patients with severe form of the disease was reported in 2012. In 2015, asfotase alfa was approved in Japan in July, followed by in the EU and Canada in August, and then by the US Food and Drug Administration in the USA in October. It is expected that therapy with asfotase alfa will drastically change treatments and prognosis of HPP.
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Affiliation(s)
- Hideo Orimo
- Division of Metabolism and Nutrition, Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan
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45
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Abstract
Hypophosphatasia is the inborn error of metabolism characterized by low serum alkaline phosphatase activity (hypophosphatasaemia). This biochemical hallmark reflects loss-of-function mutations within the gene that encodes the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP). TNSALP is a cell-surface homodimeric phosphohydrolase that is richly expressed in the skeleton, liver, kidney and developing teeth. In hypophosphatasia, extracellular accumulation of TNSALP natural substrates includes inorganic pyrophosphate, an inhibitor of mineralization, which explains the dento-osseous and arthritic complications featuring tooth loss, rickets or osteomalacia, and calcific arthopathies. Severely affected infants sometimes also have hypercalcaemia and hyperphosphataemia due to the blocked entry of minerals into the skeleton, and pyridoxine-dependent seizures from insufficient extracellular hydrolysis of pyridoxal 5'-phosphate, the major circulating form of vitamin B6, required for neurotransmitter synthesis. Autosomal recessive or dominant inheritance from ~300 predominantly missense ALPL (also known as TNSALP) mutations largely accounts for the remarkably broad-ranging expressivity of hypophosphatasia. High serum concentrations of pyridoxal 5'-phosphate represent a sensitive and specific biochemical marker for hypophosphatasia. Also, phosphoethanolamine levels are usually elevated in serum and urine, though less reliably for diagnosis. TNSALP mutation detection is important for recurrence risk assessment and prenatal diagnosis. Diagnosing paediatric hypophosphatasia is aided by pathognomic radiographic changes when the skeletal disease is severe. Hypophosphatasia was the last type of rickets or osteomalacia to await a medical treatment. Now, significant successes for severely affected paediatric patients are recognized using asfotase alfa, a bone-targeted recombinant TNSALP.
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Affiliation(s)
- Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, 4400 Clayton Avenue, Saint Louis, Missouri 63110, USA
- Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, 660 South Euclid Avenue, Saint Louis, Missouri 63110, USA
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46
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Abstract
Hypophosphatasia (HPP) results from ALPL mutations leading to deficient activity of the tissue-non-specific alkaline phosphatase isozyme (TNAP) and thereby extracellular accumulation of inorganic pyrophosphate (PPi), a natural substrate of TNAP and potent inhibitor of mineralization. Thus, HPP features rickets or osteomalacia and hypomineralization of teeth. Enzyme replacement using mineral-targeted TNAP from birth prevented severe HPP in TNAP-knockout mice and was then shown to rescue and substantially treat infants and young children with life-threatening HPP. Clinical trials are revealing aspects of HPP pathophysiology not yet fully understood, such as craniosynostosis and muscle weakness when HPP is severe. New treatment approaches are under development to improve patient care.
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Affiliation(s)
- José Luis Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, St. Louis, MO, 63110, USA
- Division of Bone and Mineral Diseases, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO, 63110, USA
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47
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Bianchi ML. Hypophosphatasia: an overview of the disease and its treatment. Osteoporos Int 2015; 26:2743-57. [PMID: 26245849 DOI: 10.1007/s00198-015-3272-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 07/28/2015] [Indexed: 11/30/2022]
Abstract
This review presents the current knowledge on hypophosphatasia, a rare genetic disease of very variable severity (from lethal to mild) and clinical presentation, caused by defective production of tissue-non-specific alkaline phosphatase (TNSALP). Hypophosphatasia can affect babies in utero as well as infants, children, and adults. The article first presents the genetics of TNSALP and its many known mutations underlying the disease. Then, it presents the epidemiology, classification, and clinical presentation of the six different forms of the disease (perinatal lethal, prenatal benign, infantile, childhood, adult, and odontohypophosphatasia) as well as the essential diagnostic clues. The last section on treatment presents a survey of the therapeutic approaches, up to the ongoing phase 2 studies of enzyme replacement therapy.
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Affiliation(s)
- M L Bianchi
- Experimental Laboratory for Children's Bone Metabolism Research, Bone Metabolism Unit, Istituto Auxologico Italiano IRCCS, via L. Ariosto 13, 20145, Milano, Italy.
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48
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Abstract
The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation.
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Affiliation(s)
- Hans U Luder
- Center of Dental Medicine, Institute of Oral Biology, University of Zurich Zurich, Switzerland
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49
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Foster BL, Ao M, Willoughby C, Soenjaya Y, Holm E, Lukashova L, Tran AB, Wimer HF, Zerfas PM, Nociti FH, Kantovitz KR, Quan BD, Sone ED, Goldberg HA, Somerman MJ. Mineralization defects in cementum and craniofacial bone from loss of bone sialoprotein. Bone 2015; 78:150-64. [PMID: 25963390 PMCID: PMC4466207 DOI: 10.1016/j.bone.2015.05.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/21/2015] [Accepted: 05/02/2015] [Indexed: 01/15/2023]
Abstract
Bone sialoprotein (BSP) is a multifunctional extracellular matrix protein found in mineralized tissues, including bone, cartilage, tooth root cementum (both acellular and cellular types), and dentin. In order to define the role BSP plays in the process of biomineralization of these tissues, we analyzed cementogenesis, dentinogenesis, and osteogenesis (intramembranous and endochondral) in craniofacial bone in Bsp null mice and wild-type (WT) controls over a developmental period (1-60 days post natal; dpn) by histology, immunohistochemistry, undecalcified histochemistry, microcomputed tomography (microCT), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and quantitative PCR (qPCR). Regions of intramembranous ossification in the alveolus, mandible, and calvaria presented delayed mineralization and osteoid accumulation, assessed by von Kossa and Goldner's trichrome stains at 1 and 14 dpn. Moreover, Bsp(-/-) mice featured increased cranial suture size at the early time point, 1 dpn. Immunostaining and PCR demonstrated that osteoblast markers, osterix, alkaline phosphatase, and osteopontin were unchanged in Bsp null mandibles compared to WT. Bsp(-/-) mouse molars featured a lack of functional acellular cementum formation by histology, SEM, and TEM, and subsequent loss of Sharpey's collagen fiber insertion into the tooth root structure. Bsp(-/-) mouse alveolar and mandibular bone featured equivalent or fewer osteoclasts at early ages (1 and 14 dpn), however, increased RANKL immunostaining and mRNA, and significantly increased number of osteoclast-like cells (2-5 fold) were found at later ages (26 and 60 dpn), corresponding to periodontal breakdown and severe alveolar bone resorption observed following molar teeth entering occlusion. Dentin formation was unperturbed in Bsp(-/-) mouse molars, with no delay in mineralization, no alteration in dentin dimensions, and no differences in odontoblast markers analyzed. No defects were identified in endochondral ossification in the cranial base, and craniofacial morphology was unaffected in Bsp(-/-) mice. These analyses confirm a critical role for BSP in processes of cementogenesis and intramembranous ossification of craniofacial bone, whereas endochondral ossification in the cranial base was minimally affected and dentinogenesis was normal in Bsp(-/-) molar teeth. Dissimilar effects of loss of BSP on mineralization of dental and craniofacial tissues suggest local differences in the role of BSP and/or yet to be defined interactions with site-specific factors.
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Affiliation(s)
- B L Foster
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA.
| | - M Ao
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA.
| | - C Willoughby
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA.
| | - Y Soenjaya
- Biomedical Engineering Program, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - E Holm
- Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - L Lukashova
- Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
| | - A B Tran
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA.
| | - H F Wimer
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
| | - P M Zerfas
- Office of Research Services, Division of Veterinary Resources, National Institutes of Health (NIH), 9000 Rockville Pike, 112 Building 28A, MSC 5230, Bethesda, MD 20892, USA.
| | - F H Nociti
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA; Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry, Campinas State University, Piracicaba, SP 13414-903, Brazil.
| | - K R Kantovitz
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA; Department of Pediatric Dentistry, School of Dentistry, Campinas State University, Piracicaba, SP 13414-903, Brazil.
| | - B D Quan
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 320A Mining Building, Toronto, ON M5S 3G9, Canada.
| | - E D Sone
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 320A Mining Building, Toronto, ON M5S 3G9, Canada; Department of Materials Science and Engineering, University of Toronto, Toronto, ON, Canada; Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.
| | - H A Goldberg
- Biomedical Engineering Program, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada; Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada; School of Dentistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - M J Somerman
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), 9000 Rockville Pike, 4120 Building 50, Bethesda, MD 20892, USA.
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50
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Liu J, Campbell C, Nam HK, Caron A, Yadav MC, Millán JL, Hatch NE. Enzyme replacement for craniofacial skeletal defects and craniosynostosis in murine hypophosphatasia. Bone 2015; 78:203-11. [PMID: 25959417 PMCID: PMC4466206 DOI: 10.1016/j.bone.2015.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/13/2015] [Accepted: 05/02/2015] [Indexed: 12/30/2022]
Abstract
Hypophosphatasia (HPP) is an inborn-error-of-metabolism disorder characterized by deficient bone and tooth mineralization due to loss-of function mutations in the gene (Alpl) encoding tissue-nonspecific alkaline phosphatase (TNAP). Alpl(-/-) mice exhibit many characteristics seen in infantile HPP including long bone and tooth defects, vitamin B6 responsive seizures and craniosynostosis. Previous reports demonstrated that a mineral-targeted form of TNAP rescues long bone, vertebral and tooth mineralization defects in Alpl(-/-) mice. Here we report that enzyme replacement with mineral-targeted TNAP (asfotase-alfa) also prevents craniosynostosis (the premature fusion of cranial bones) and additional craniofacial skeletal abnormalities in Alpl(-/-) mice. Craniosynostosis, cranial bone volume and density, and craniofacial shape abnormalities were assessed by microscopy, histology, digital caliper measurements and micro CT. We found that craniofacial shape defects, cranial bone mineralization and craniosynostosis were corrected in Alpl(-/-) mice injected daily subcutaneously starting at birth with recombinant enzyme. Analysis of Alpl(-/-) calvarial cells indicates that TNAP deficiency leads to aberrant osteoblastic gene expression and diminished proliferation. Some but not all of these cellular abnormalities were rescued by treatment with inorganic phosphate. These results confirm an essential role for TNAP in craniofacial skeletal development and demonstrate the efficacy of early postnatal mineral-targeted enzyme replacement for preventing craniofacial abnormalities including craniosynostosis in murine infantile HPP.
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Affiliation(s)
- Jin Liu
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Cassie Campbell
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Hwa Kyung Nam
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | | | - Manisha C Yadav
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | | | - Nan E Hatch
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA..
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