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Raming K, Pfau M, Herrmann P, Holz FG, Pfau K. Anti-VEGF treatment for secondary neovascularization in pseudoxanthoma elasticum - age of onset, treatment frequency and visual outcome. Am J Ophthalmol 2024:S0002-9394(24)00137-5. [PMID: 38614195 DOI: 10.1016/j.ajo.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/25/2024] [Accepted: 03/25/2024] [Indexed: 04/15/2024]
Abstract
PURPOSE To assess the onset, treatment frequency, and visual outcome of anti-vascular endothelial growth factor (anti-VEGF) treatment due to secondary choroidal neovascularization (CNV) in patients with pseudoxanthoma elasticum (PXE). DESIGN Retrospective cohort study METHODS: One-hundred six eyes of 53 patients with PXE were analyzed. The assessment of CNV activity relied on hemorrhage visible on funduscopy and intra- / subretinal fluid on optical coherence tomography (OCT), individually defining a shortening or extension of treatment interval. Best-corrected visual acuity (BCVA) at baseline, age at anti-VEGF therapy initiation, and BCVA-drop events at exudation onset (worsening of BCVA of 2 or more lines) were documented. Further, we assessed the number of injections during the first year and the total number of injections, the time to treatment initiation of the fellow eye, and BCVA over time. RESULTS During a median observation period of 77 months (IQR 49; 126) patients received a median number of 28.0 anti VEGF-injections (IQR 9.8; 43.5). Eight patients received no injection (median age at baseline 38.1 years), 11 patients underwent anti-VEGF treatment in one eye (median age 47.2 years) and 34 patients in both eyes (median age 51.8 years). The median age at the first anti-VEGF treatment was 52.80 years (IQR 47.2 - 57.6). Applying Cox regression models, the median 'survival' time of fellow eye until treatment initiation was 16.8 months. In the group of bilateral treated patients, the median time difference was 9.6 months (IQR 2.1 - 32.4, range 0 - 122) The median number of injections was 5.5 per eye in the first year of treatment (IQR 3 - 7) and was associated with the total number of injections in the observation period (2.33, CI 1.22 - 3.44, p<0.001). A better BCVA at the last follow-up visit was associated with a better baseline BCVA (p<0.001, R2=0.318) and with the absence of a BCVA drop at the onset of exudation (p=0.035, R2=0.339). CONCLUSIONS The results of this study indicate that anti-VEGF treatment is required for most PXE patients at a relatively young age. Once treatment in one eye is initiated, the time to fellow eye treatment is relatively short. A BCVA drop before treatment initiation is a risk factor for worse visual outcomes, suggesting that treatment is prudent before exudation affects the central retina. Given the young age of onset and intensive treatment needs, patients with PXE might particularly benefit from longer-acting anti-VEGF therapeutics.
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Affiliation(s)
- Kristin Raming
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Maximilian Pfau
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | | | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Kristina Pfau
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Department of Ophthalmology, University of Basel, Basel, Switzerland.
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MacRae VE. The Adaptive Immune System: A New Pseudoxanthoma Elasticum Protagonist? J Invest Dermatol 2024:S0022-202X(24)00203-3. [PMID: 38597853 DOI: 10.1016/j.jid.2024.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 03/06/2024] [Indexed: 04/11/2024]
Affiliation(s)
- Vicky E MacRae
- The Roslin Institute, The University of Edinburgh, Midlothian, United Kingdom; The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, United Kingdom.
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Brampton C, Pomozi V, Le Corre Y, Zoll J, Kauffenstein G, Ma C, Hoffmann PR, Martin L, Le Saux O. Bone Marrow-Derived ABCC6 Is an Essential Regulator of Ectopic Calcification In Pseudoxanthoma Elasticum. J Invest Dermatol 2024:S0022-202X(24)00110-6. [PMID: 38367909 DOI: 10.1016/j.jid.2024.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/31/2023] [Accepted: 01/26/2024] [Indexed: 02/19/2024]
Abstract
Physiological calcification of soft tissues is a common occurrence in aging and various acquired and inherited disorders. ABCC6 sequence variations cause the calcification phenotype of pseudoxanthoma elasticum (PXE) as well as some cases of generalized arterial calcification of infancy, which is otherwise caused by defective ENPP1. ABCC6 is primarily expressed in the liver, which has given the impression that the liver is central to the pathophysiology of PXE/generalized arterial calcification of infancy. The emergence of inflammation as a contributor to the calcification in PXE suggested that peripheral tissues play a larger role than expected. In this study, we investigated whether bone marrow-derived ABCC6 contributes to the calcification in PXE. In Abcc6‒/‒ mice, we observed prevalent mineralization in several lymph nodes and surrounding connective tissues and an extensive network of lymphatic vessels within vibrissae, a calcified tissue in Abcc6‒/‒ mice. Furthermore, we found evidence of lymphangiogenesis in patients with PXE and mouse skin, suggesting an inflammatory process. Finally, restoring wild-type bone marrow in Abcc6‒/‒ mice produced a significant reduction of calcification, suggesting that the liver alone is not sufficient to fully inhibit mineralization. With evidence that ABCC6 is expressed in lymphocytes, we suggest that the adaptative immune system and inflammation largely contribute to the calcification in PXE/generalized arterial calcification of infancy.
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Affiliation(s)
- Christopher Brampton
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; Bio-Rad Laboratories, Hercules, California, USA
| | - Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Yannick Le Corre
- PXE National Reference Center (MAGEC Nord), University Hospital of Angers, Angers, France
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Gilles Kauffenstein
- UMR INSERM 1260, Nano Regenerative Medicine, University of Strasbourg, Strasbourg, France
| | - Chi Ma
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Ludovic Martin
- PXE National Reference Center (MAGEC Nord), University Hospital of Angers, Angers, France; CNRS 6015, UMR INSERM U1083, MITOVASC Laboratory, University of Angers, Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.
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Kauffenstein G, Martin L, Le Saux O. The Purinergic Nature of Pseudoxanthoma Elasticum. Biology (Basel) 2024; 13:74. [PMID: 38392293 PMCID: PMC10886499 DOI: 10.3390/biology13020074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/13/2024] [Accepted: 01/19/2024] [Indexed: 02/24/2024]
Abstract
Pseudoxanthoma Elasticum (PXE) is an inherited disease characterized by elastic fiber calcification in the eyes, the skin and the cardiovascular system. PXE results from mutations in ABCC6 that encodes an ABC transporter primarily expressed in the liver and kidneys. It took nearly 15 years after identifying the gene to better understand the etiology of PXE. ABCC6 function facilitates the efflux of ATP, which is sequentially hydrolyzed by the ectonucleotidases ENPP1 and CD73 into pyrophosphate (PPi) and adenosine, both inhibitors of calcification. PXE, together with General Arterial Calcification of Infancy (GACI caused by ENPP1 mutations) as well as Calcification of Joints and Arteries (CALJA caused by NT5E/CD73 mutations), forms a disease continuum with overlapping phenotypes and shares steps of the same molecular pathway. The explanation of these phenotypes place ABCC6 as an upstream regulator of a purinergic pathway (ABCC6 → ENPP1 → CD73 → TNAP) that notably inhibits mineralization by maintaining a physiological Pi/PPi ratio in connective tissues. Based on a review of the literature and our recent experimental data, we suggest that PXE (and GACI/CALJA) be considered as an authentic "purinergic disease". In this article, we recapitulate the pathobiology of PXE and review molecular and physiological data showing that, beyond PPi deficiency and ectopic calcification, PXE is associated with wide and complex alterations of purinergic systems. Finally, we speculate on the future prospects regarding purinergic signaling and other aspects of this disease.
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Affiliation(s)
- Gilles Kauffenstein
- UMR INSERM 1260, Regenerative Nanomedicine, University of Strasbourg, 67084 Strasbourg, France
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Nord Reference Center for Rare Skin Diseases, Angers University Hospital, 49000 Angers, France
- MITOVASC-UMR CNRS 6015 INSERM 1083, University of Angers, 49000 Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Ferreira CR, Carpenter TO, Braddock DT. ENPP1 in Blood and Bone: Skeletal and Soft Tissue Diseases Induced by ENPP1 Deficiency. Annu Rev Pathol 2024; 19:507-540. [PMID: 37871131 PMCID: PMC11062289 DOI: 10.1146/annurev-pathmechdis-051222-121126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The enzyme ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) codes for a type 2 transmembrane glycoprotein that hydrolyzes extracellular ATP to generate pyrophosphate (PPi) and adenosine monophosphate, thereby contributing to downstream purinergic signaling pathways. The clinical phenotypes induced by ENPP1 deficiency are seemingly contradictory and include early-onset osteoporosis in middle-aged adults and life-threatening vascular calcifications in the large arteries of infants with generalized arterial calcification of infancy. The progressive overmineralization of soft tissue and concurrent undermineralization of skeleton also occur in the general medical population, where it is referred to as paradoxical mineralization to highlight the confusing pathophysiology. This review summarizes the clinical presentation and pathophysiology of paradoxical mineralization unveiled by ENPP1 deficiency and the bench-to-bedside development of a novel ENPP1 biologics designed to treat mineralization disorders in the rare disease and general medical population.
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Affiliation(s)
- Carlos R Ferreira
- Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas O Carpenter
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Demetrios T Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA;
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Harmsen IM, Kok M, Bartstra JW, de Jong PA, Spiering W, Foppen W. Do pseudoxanthoma elasticum patients have higher prevalence of kidney stones on computed tomography compared to hospital controls? Clin Exp Nephrol 2024; 28:75-79. [PMID: 37837579 PMCID: PMC10766656 DOI: 10.1007/s10157-023-02405-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/07/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is an autosomal recessive disease characterized by diminished inorganic plasma pyrophosphate (PPi), a strong calcification inhibitor. In addition to more typical calcification of skin, retina and arterial wall a diminished plasma PPi could lead to other ectopic calcification, such as formation of kidney stones. OBJECTIVE To compare the prevalence of kidney stones between PXE patients and hospital controls on computed tomography (CT). METHOD Low-dose CT images of PXE patients and controls were assessed by one radiologist, who was blinded for the diagnosis PXE. The number of kidney stones, and the size of the largest stone was recorded. Odds ratios (ORs) for having kidney stone were calculated using multivariable adjusted logistic regression. RESULTS Our study comprised 273 PXE patients and 125 controls. The mean age of PXE patients was 51.5 ± 15.9 years compared to 54.9 ± 14.2 in the control group (p = 0.04) and PXE patients more often were women (63 vs. 50%, p = 0.013). The prevalence of kidney stones on CT was similar: 6.9% in PXE patients, compared to 5.6% in controls (p = 0.6). In the multivariate analysis adjusting for age and sex, there was no significantly higher odds for PXE patients on having stones, compared to controls: OR 1.48 (95% CI 0.62-3.96). CONCLUSION There is no significant difference in the prevalence of incidental kidney stones on CT in PXE patients versus controls.
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Affiliation(s)
- Iris M Harmsen
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Madeleine Kok
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Jonas W Bartstra
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Pim A de Jong
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
| | - Wouter Foppen
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
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Kozák E, Bartstra JW, de Jong PA, Mali WPTM, Fülöp K, Tőkési N, Pomozi V, Risseeuw S, Norel JOV, van Leeuwen R, Váradi A, Spiering W. Plasma Level of Pyrophosphate Is Low in Pseudoxanthoma Elasticum Owing to Mutations in the ABCC6 Gene, but It Does Not Correlate with ABCC6 Genotype. J Clin Med 2023; 12:jcm12031047. [PMID: 36769695 PMCID: PMC9917606 DOI: 10.3390/jcm12031047] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/04/2023] [Accepted: 01/22/2023] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE), a monogenic disorder resulting in calcification affecting the skin, eyes and peripheral arteries, is caused by mutations in the ABCC6 gene, and is associated with low plasma inorganic pyrophosphate (PPi). It is unknown how ABCC6 genotype affects plasma PPi. METHODS We studied the association of ABCC6 genotype (192 patients with biallelic pathogenic ABCC6 mutations) and PPi levels, and its association with the severity of arterial and ophthalmological phenotypes. ABCC6 variants were classified as truncating or non-truncating, and three groups of the 192 patients were formed: those with truncating mutations on both chromosomes (n = 121), those with two non-truncating mutations (n = 10), and a group who had one truncating and one non-truncating ABCC6 mutation (n = 61). The hypothesis formulated before this study was that there was a negative association between PPi level and disease severity. RESULTS Our findings confirm low PPi in PXE compared with healthy controls (0.53 ± 0.15 vs. 1.13 ± 0.29 µM, p < 0.01). The PPi of patients correlated with increasing age (β: 0.05 µM, 95% CI: 0.03-0.06 per 10 years) and was higher in females (0.55 ± 0.17 vs. 0.51 ± 0.13 µM in males, p = 0.03). However, no association between PPi and PXE phenotypes was found. When adjusted for age and sex, no association between PPi and ABCC6 genotype was found. CONCLUSIONS Our data suggest that the relationship between ABCC6 mutations and reduced plasma PPi may not be as direct as previously thought. PPi levels varied widely, even in patients with the same ABCC6 mutations, further suggesting a lack of direct correlation between them, even though the ABCC6 protein-mediated pathway is responsible for ~60% of this metabolite in the circulation. We discuss potential factors that may perturb the expected associations between ABCC6 genotype and PPi and between PPi and disease severity. Our findings support the argument that predictions of pathogenicity made on the basis of mutations (or on the structure of the mutated protein) could be misleading.
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Affiliation(s)
- Eszter Kozák
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Jonas W. Bartstra
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Pim A. de Jong
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Willem P. T. M. Mali
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Krisztina Fülöp
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Natália Tőkési
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Viola Pomozi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Sara Risseeuw
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | | | - Redmer van Leeuwen
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - András Váradi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-88-7571188
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Kauffenstein G, Chappard D, Leftheriotis G, Martin L. ABCC6 deficiency and bone loss: A double benefit of etidronate for patient presenting with pseudoxanthoma elasticum? Exp Dermatol 2022; 31:1635-1637. [PMID: 35771123 PMCID: PMC9796561 DOI: 10.1111/exd.14636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/12/2022] [Accepted: 06/26/2022] [Indexed: 01/01/2023]
Affiliation(s)
| | | | | | - Ludovic Martin
- PXE National Reference Center (MAGEC Nord)Angers University HospitalAngersFrance,MITOVASC – UMR CNRS 6015 INSERM 1083Angers UniversityAngersFrance
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Nollet L, Van Gils M, Fischer S, Campens L, Karthik S, Pasch A, De Zaeytijd J, Leroy BP, Devos D, De Backer T, Coucke PJ, Vanakker OM. Serum Calcification Propensity T50 Associates with Disease Severity in Patients with Pseudoxanthoma Elasticum. J Clin Med 2022; 11. [PMID: 35807012 DOI: 10.3390/jcm11133727] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/21/2022] [Accepted: 06/26/2022] [Indexed: 11/17/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a currently intractable genetic disorder characterized by progressive ectopic calcification in the skin, eyes and arteries. Therapeutic trials in PXE are severely hampered by the lack of reliable biomarkers. Serum calcification propensity T50 is a blood test measuring the functional anticalcifying buffer capacity of serum. Here, we evaluated T50 in PXE patients aiming to investigate its determinants and suitability as a potential biomarker for disease severity. Fifty-seven PXE patients were included in this cross-sectional study, and demographic, clinical, imaging and biochemical data were collected from medical health records. PXE severity was assessed using Phenodex scores. T50 was measured using a validated, nephelometry-based assay. Multivariate models were then created to investigate T50 determinants and associations with disease severity. In short, the mean age of patients was 45.2 years, 68.4% was female and mean serum T50 was 347 min. Multivariate regression analysis identified serum fetuin-A (p < 0.001), phosphorus (p = 0.007) and magnesium levels (p = 0.034) as significant determinants of T50, while no correlations were identified with serum calcium, eGFR, plasma PPi levels or the ABCC6 genotype. After correction for covariates, T50 was found to be an independent determinant of ocular (p = 0.013), vascular (p = 0.013) and overall disease severity (p = 0.016) in PXE. To conclude, shorter serum T50—indicative of a higher calcification propensity—was associated with a more severe phenotype in PXE patients. This study indicates, for the first time, that serum T50 might be a clinically relevant biomarker in PXE and may thus be of importance to future therapeutic trials.
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Pelttari S, Väärämäki S, Vanakker O, Verschuere S, Uusitalo H, Huhtala H, Hinkka T, Pörsti I, Nevalainen PI. Various vascular malformations are prevalent in Finnish pseudoxanthoma elasticum ( PXE) patients: a national registry study. Orphanet J Rare Dis 2022; 17:185. [PMID: 35525997 PMCID: PMC9077871 DOI: 10.1186/s13023-022-02341-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/26/2022] [Indexed: 11/26/2022] Open
Abstract
Background Pseudoxanthoma elasticum (PXE, OMIM# 264800) is an inborn error of metabolism causing ectopic soft tissue calcification due to low plasma pyrophosphate concentration. We aimed to assess the prevalence of PXE in Finland and to characterize the Finnish PXE population. A nationwide registry search was performed to identify patients with ICD-10 code Q82.84. Information was gathered from available medical records which were requisitioned from hospitals and health centers. Misdiagnosed patients and patients with insufficient records were excluded. Results The prevalence of PXE in Finland was 1:260,000 with equal sex distribution. Patients with high conventional cardiovascular risk had more visual and vascular complications than patients with low risk. Four patients (19%) had at least one vascular malformation. A high proportion (33%) of ABCC6 genotypes were of the common homozygous c.3421C > T, p.Arg1141Ter variant. Nine other homozygous or compound heterozygous allelic variants were found. Conclusions The prevalence of diagnosed PXE appears to be lower in Finland than in estimates from other countries. Decreased visual acuity is the most prevalent complication. We suggest that various vascular malformations may be an unrecognized feature of PXE.
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Affiliation(s)
- Saku Pelttari
- Faculty of Medicine and Life Sciences, Tampere University, Tampere, Finland
| | - Suvi Väärämäki
- Centre for Vascular Surgery and Interventional Radiology, Tampere University Hospital and Tampere University, Tampere, Finland
| | - Olivier Vanakker
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Shana Verschuere
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Hannu Uusitalo
- SILK, Department of Ophthalmology, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Tays Eye Centre, Tampere University Hospital, Tampere, Finland
| | - Heini Huhtala
- Faculty of Social Sciences, Tampere University, Tampere, Finland
| | - Tero Hinkka
- Centre for Vascular Surgery and Interventional Radiology, Tampere University Hospital, Tampere, Finland
| | - Ilkka Pörsti
- Faculty of Medicine and Life Sciences, Tampere University, Tampere, Finland.,Department of Internal Medicine, Tampere University Hospital, Teiskontie 35, 33521, Tampere, Finland
| | - Pasi I Nevalainen
- Department of Internal Medicine, Tampere University Hospital, Teiskontie 35, 33521, Tampere, Finland.
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Lofaro FD, Mucciolo DP, Murro V, Pavese L, Quaglino D, Boraldi F. From Clinical Diagnosis to the Discovery of Multigene Rare Sequence Variants in Pseudoxanthoma elasticum: A Case Report. Front Med (Lausanne) 2021; 8:726856. [PMID: 34513887 PMCID: PMC8427021 DOI: 10.3389/fmed.2021.726856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/30/2021] [Indexed: 12/03/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a rare autosomal recessive disease clinically characterised by early cutaneous alterations, and by late clinically relevant ocular, and cardiovascular manifestations. ABCC6 genetic tests are used to confirm clinical PXE diagnosis, but this strategy may be rather challenging when only one ABCC6 pathogenic variant is found. A next-generation sequencing approach focusing on 362 genes related to the calcification process and/or to inherited retinal diseases was performed on a patient with clinical PXE diagnosis (skin papules and laxity, angioid streaks, and atrophy) who was carrier of only one ABCC6 rare sequence variant. Beside ABCC6, several rare sequence variants were detected which can contribute either to the occurrence of calcification (GGCX and SERPINF1 genes) and/or to ophthalmological manifestations (ABCA4, AGBL5, CLUAP1, and KCNV2 genes). This wide-spectrum analysis approach facilitates the identification of rare variants possibly involved in PXE, thus avoiding invasive skin biopsy as well as expensive and time-consuming diagnostic odyssey and allows to broaden and to deepen the knowledge on this complex rare disease and to improve patients' counselling, also with a future perspective of personalised medicine.
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Affiliation(s)
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Florence, Italy
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Florence, Italy
| | - Laura Pavese
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Florence, Italy
| | - Daniela Quaglino
- Department of Life Science, University of Modena and Reggio Emilia, Modena, Italy
| | - Federica Boraldi
- Department of Life Science, University of Modena and Reggio Emilia, Modena, Italy
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Boraldi F, Murro V, Lofaro FD, Mucciolo DP, Costa S, Pavese L, Quaglino D. Phenotypic Features and Genetic Findings in a Cohort of Italian Pseudoxanthoma Elasticum Patients and Update of the Ophthalmologic Evaluation Score. J Clin Med 2021; 10:2710. [PMID: 34205333 PMCID: PMC8235548 DOI: 10.3390/jcm10122710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is a rare ectopic calcification genetic disease mainly caused by ABCC6 rare sequence variants. The clinical phenotype is characterized by typical dermatological, ophthalmological and cardiovascular manifestations, whose frequency and severity are differently reported in the literature. METHODS A retrospective study was performed on 377 PXE patients of Italian origin, clinically evaluated according to the Phenodex Index, who underwent ABCC6 biomolecular analyses. Moreover, 53 PXE patients were further characterized by in-depth ophthalmological examinations. RESULTS A total of 117 different ABCC6 rare sequence variants were detected as being spread through the whole gene. The severity of the clinical phenotype was dependent on age, but it was not influenced by gender or by the type of sequence variants. In-depth ophthalmological examinations focused on the incidences of coquille d'oeuf, comet lesions, pattern dystrophy-like lesions, optic disk drusen and posterior-pole atrophy. Conclusion: Given the large number of patients analyzed, we were able to better evaluate the occurrence of less frequent alterations (e.g., stroke, myocardial infarction, nephrolithiasis). A more detailed description of ophthalmological abnormalities allowed us to stratify patients and better evaluate disease progression, thus suggesting a further update of the PXE score system.
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Affiliation(s)
- Federica Boraldi
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Viale Pieraccini 6, 50139 Florence, Italy; (V.M.); (D.P.M.); (L.P.)
| | - Francesco Demetrio Lofaro
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Viale Pieraccini 6, 50139 Florence, Italy; (V.M.); (D.P.M.); (L.P.)
| | - Sonia Costa
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
| | - Laura Pavese
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Viale Pieraccini 6, 50139 Florence, Italy; (V.M.); (D.P.M.); (L.P.)
| | - Daniela Quaglino
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
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Sun J, She P, Liu X, Gao B, Jin D, Zhong TP. Disruption of Abcc6 Transporter in Zebrafish Causes Ocular Calcification and Cardiac Fibrosis. Int J Mol Sci 2020; 22:ijms22010278. [PMID: 33383974 PMCID: PMC7795442 DOI: 10.3390/ijms22010278] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/18/2020] [Accepted: 12/25/2020] [Indexed: 12/14/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE), caused by ABCC6/MRP6 mutation, is a heritable multisystem disorder in humans. The progressive clinical manifestations of PXE are accompanied by ectopic mineralization in various connective tissues. However, the pathomechanisms underlying the PXE multisystem disorder remains obscure, and effective treatment is currently available. In this study, we generated zebrafish abcc6a mutants using the transcription activator-like effector nuclease (TALEN) technique. In young adult zebrafish, abcc6a is expressed in the eyes, heart, intestine, and other tissues. abcc6a mutants exhibit extensive calcification in the ocular sclera and Bruch's membrane, recapitulating part of the PXE manifestations. Mutations in abcc6a upregulate extracellular matrix (ECM) genes, leading to fibrotic heart with reduced cardiomyocyte number. We found that abcc6a mutation reduced levels of both vitamin K and pyrophosphate (PPi) in the serum and diverse tissues. Vitamin K administration increased the gamma-glutamyl carboxylated form of matrix gla protein (cMGP), alleviating ectopic calcification and fibrosis in vertebrae, eyes, and hearts. Our findings contribute to a comprehensive understanding of PXE pathophysiology from zebrafish models.
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Affiliation(s)
- Jianjian Sun
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China;
- Shanghai Key Laboratory of Regulatory Biology, Institute of Molecular Medicine, School of Life Sciences, East China Normal University, Shanghai 200241, China; (P.S.); (X.L.); (B.G.); (D.J.)
| | - Peilu She
- Shanghai Key Laboratory of Regulatory Biology, Institute of Molecular Medicine, School of Life Sciences, East China Normal University, Shanghai 200241, China; (P.S.); (X.L.); (B.G.); (D.J.)
| | - Xu Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Molecular Medicine, School of Life Sciences, East China Normal University, Shanghai 200241, China; (P.S.); (X.L.); (B.G.); (D.J.)
| | - Bangjun Gao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Molecular Medicine, School of Life Sciences, East China Normal University, Shanghai 200241, China; (P.S.); (X.L.); (B.G.); (D.J.)
| | - Daqin Jin
- Shanghai Key Laboratory of Regulatory Biology, Institute of Molecular Medicine, School of Life Sciences, East China Normal University, Shanghai 200241, China; (P.S.); (X.L.); (B.G.); (D.J.)
| | - Tao P. Zhong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Molecular Medicine, School of Life Sciences, East China Normal University, Shanghai 200241, China; (P.S.); (X.L.); (B.G.); (D.J.)
- Correspondence: ; Tel.: +86-021-54345021
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14
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Lofaro FD, Boraldi F, Garcia-Fernandez M, Estrella L, Valdivielso P, Quaglino D. Relationship Between Mitochondrial Structure and Bioenergetics in Pseudoxanthoma elasticum Dermal Fibroblasts. Front Cell Dev Biol 2020; 8:610266. [PMID: 33392199 PMCID: PMC7773789 DOI: 10.3389/fcell.2020.610266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a genetic disease considered as a paradigm of ectopic mineralization disorders, being characterized by multisystem clinical manifestations due to progressive calcification of skin, eyes, and the cardiovascular system, resembling an age-related phenotype. Although fibroblasts do not express the pathogenic ABCC6 gene, nevertheless these cells are still under investigation because they regulate connective tissue homeostasis, generating the “arena” where cells and extracellular matrix components can promote pathologic calcification and where activation of pro-osteogenic factors can be associated to pathways involving mitochondrial metabolism. The aim of the present study was to integrate structural and bioenergenetic features to deeply investigate mitochondria from control and from PXE fibroblasts cultured in standard conditions and to explore the role of mitochondria in the development of the PXE fibroblasts’ pathologic phenotype. Proteomic, biochemical, and morphological data provide new evidence that in basal culture conditions (1) the protein profile of PXE mitochondria reveals a number of differentially expressed proteins, suggesting changes in redox balance, oxidative phosphorylation, and calcium homeostasis in addition to modified structure and organization, (2) measure of oxygen consumption indicates that the PXE mitochondria have a low ability to cope with a sudden increased need for ATP via oxidative phosphorylation, (3) mitochondrial membranes are highly polarized in PXE fibroblasts, and this condition contributes to increased reactive oxygen species levels, (4) ultrastructural alterations in PXE mitochondria are associated with functional changes, and (5) PXE fibroblasts exhibit a more abundant, branched, and interconnected mitochondrial network compared to control cells, indicating that fusion prevail over fission events. In summary, the present study demonstrates that mitochondria are modified in PXE fibroblasts. Since mitochondria are key players in the development of the aging process, fibroblasts cultured from aged individuals or aged in vitro are more prone to calcify, and in PXE, calcified tissues remind features of premature aging syndromes; it can be hypothesized that mitochondria represent a common link contributing to the development of ectopic calcification in aging and in diseases. Therefore, ameliorating mitochondrial functions and cell metabolism could open new strategies to positively regulate a number of signaling pathways associated to pathologic calcification.
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Affiliation(s)
| | - Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Maria Garcia-Fernandez
- Department of Human Physiology, Biomedical Research Institute of Málaga, University of Malaga, Málaga, Spain
| | - Lara Estrella
- Department of Human Physiology, Biomedical Research Institute of Málaga, University of Malaga, Málaga, Spain
| | - Pedro Valdivielso
- Department of Medicine and Dermatology, Instituto de Investigación Biomédica de Málaga, University of Malaga, Málaga, Spain.,Internal Medicine Unit, Hospital Virgen de la Victoria, Málaga, Spain
| | - Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
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Murro V, Mucciolo DP, Giorgio D, Sodi A, Boraldi F, Quaglino D, Virgili G, Giansanti F. Pattern dystrophy-like changes and coquille d'oeuf atrophy in elderly patients affected by pseudoxanthoma elasticum. Graefes Arch Clin Exp Ophthalmol 2020; 258:1881-1892. [PMID: 32445016 DOI: 10.1007/s00417-020-04748-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/29/2020] [Accepted: 05/08/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To evaluate the retinal features of elderly patients affected by pseudoxanthoma elasticum (PXE). MATERIALS AND METHODS This is a retrospective case series of 62 eyes of 31 elderly PXE patients (age > 50 years). Clinical data, ultra-widefield fundus imaging (color, red-free (RF), infra-red imaging (IR), fundus autofluorescence (FAF)), and OCT examinations were collected. Diagnosis was confirmed by genetic testing or skin biopsy. RESULTS Thirty-one patients (10 males and 21 females (mean age 61.3 years, range 50-74 years)) were included in our study. Visual acuity ranged from 20/20 Snellen equivalent to 20/200. The mean follow-up was 66.4 ± 20.7 months (range 10-88). Pattern dystrophy-like changes (PD) (52 eyes of 26 patients, 83.8%) and atrophy resembling the "diffuse trickling" pattern described in geographic atrophy were present in the majority of patients. Twenty-three eyes of 12 patients (67.6%) had peripapillary atrophy, 9 eyes of 5 patients (26.4%) macular atrophy, 6 eyes of 3 patients (17.6%) displayed posterior pole atrophy and in 6 eyes of 3 patients (17.6%), atrophy could be detected beyond the vascular arcades (mid-peripheral atrophy). End-stage atrophy covered the entire area indicated as "coquille d'oeuf" (eggshell). Choroidal neovascularization occurred in 49 eyes of 26 patients (94.2%) with PD and in 6 eyes of 3 patients (60%) without PD. Genetic examinations were available for 29 patients (29/31, 93.5%). CONCLUSIONS The elderly PXE patients were characterized by pattern dystrophy-like changes with more or less extensive atrophy, progressive over time, which in some cases affected the whole area of the coquille d'oeuf during the course of the disease.
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Affiliation(s)
- Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy. .,Careggi Teaching Hospital, Florence, Italy.
| | - Dario Giorgio
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Andrea Sodi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Gianni Virgili
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Fabrizio Giansanti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
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Boraldi F, Lofaro FD, Costa S, Moscarelli P, Quaglino D. Rare Co-occurrence of Beta-Thalassemia and Pseudoxanthoma elasticum: Novel Biomolecular Findings. Front Med (Lausanne) 2020; 6:322. [PMID: 32039214 PMCID: PMC6989569 DOI: 10.3389/fmed.2019.00322] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/16/2019] [Indexed: 12/18/2022] Open
Abstract
A number of beta-thalassemia patients, independently from the type of beta-thalassemia (β0 or β+) and blood transfusion requirements, may develop, after puberty, dermal, cardiovascular, and ocular complications associated with an ectopic mineralization phenotype similar to that observed in another rare genetic disorder, namely, Pseudoxanthoma elasticum (PXE). To date, the causes of these alterations in beta-thalassemia patients are not known, but it has been suggested that they could be the consequence of oxidative stress-driven epigenetic regulatory mechanisms producing an ABCC6 down-regulation. Since, in the last years, several genes have been associated to the ectopic mineralization phenotype, this study, for the first time, applied, on beta-thalassemia patients with ectopic mineralization phenotype, a multigene testing strategy. Selection of genes to be analyzed was done on the basis of (i) their genetic involvement in calcification diseases or (ii) their role in calcium-phosphate equilibrium. Although, due to the rarity of these conditions, a limited number of patients was analyzed, the detection of pathogenic variants represents the proof of concept that PXE and beta-thalassemia traits co-occur on a genetic basis and that, in addition to causative mutations, functional polymorphisms may further influence connective tissue manifestations. The use of a multigene-based next-generation sequencing represents a useful time- and cost-effective approach, allowing to identify sequence variants that might improve prognostic assessment and better management of these patients, especially in the current era of precision medicine aiming to identify individual optimal care based on a unique personal profile.
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Affiliation(s)
- Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Sonia Costa
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Pasquale Moscarelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
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17
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Murro V, Mucciolo DP, Giorgio D, Sodi A, Boraldi F, Quaglino D, Virgili G, Rizzo S. Intraretinal hyperreflective foci in PXE-related retinopathy with acquired vitelliform lesions: a long-term follow-up. Ophthalmic Genet 2019; 40:385-387. [PMID: 31542970 DOI: 10.1080/13816810.2019.1666882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Purposes: To describe the long-term follow-up of a patient affected by Pseudoxanthoma Elasticum (PXE) and acquired macular vitelliform lesions in both eyes. Material and methods: Case report Results: We reported the 9-year follow-up of a patient affected by PXE. We described the onset and the resolution of the vitelliform macular lesions which lasted 5 years. The vitelliform lesion appeared almost simultaneously in both eyes with an initial increase in size, even though asymmetrical. We detected the intraretinal migration of hyper-reflective foci in both eyes during the follow-up. Choroidal neovascularization (CNV) occurred in her right eye during the follow-up. Visual acuity decreased from 20/20 to 20/32 in left eye; from 20/20 to 20/100 in her right eye. Conclusions: we reported the natural history of acquired vitelliform lesion in PXE-related retinopathy describing the Intraretinal hyperreflective foci migration.
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Affiliation(s)
- Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence , Florence , Italy
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence , Florence , Italy
| | - Dario Giorgio
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence , Florence , Italy
| | - Andrea Sodi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence , Florence , Italy
| | - Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia , Modena , Italy
| | - Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia , Modena , Italy
| | - Gianni Virgili
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence , Florence , Italy
| | - Stanislao Rizzo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence , Florence , Italy
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Kranenburg G, de Jong PA, Bartstra JW, Lagerweij SJ, Lam MG, Ossewaarde-van Norel J, Risseeuw S, van Leeuwen R, Imhof SM, Verhaar HJ, de Vries JJ, Slart RHJA, Luurtsema G, den Harder AM, Visseren FLJ, Mali WP, Spiering W. Etidronate for Prevention of Ectopic Mineralization in Patients With Pseudoxanthoma Elasticum. J Am Coll Cardiol 2019. [PMID: 29519353 DOI: 10.1016/j.jacc.2017.12.062] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND In pseudoxanthoma elasticum (PXE), low pyrophosphate levels may cause ectopic mineralization, leading to skin changes, visual impairment, and peripheral arterial disease. OBJECTIVES The authors hypothesized that etidronate, a pyrophosphate analog, might reduce ectopic mineralization in PXE. METHODS In the Treatment of Ectopic Mineralization in Pseudoxanthoma Elasticum trial, adults with PXE and leg arterial calcifications (n = 74) were randomly assigned to etidronate or placebo (cyclical 20 mg/kg for 2 weeks every 12 weeks). The primary outcome was ectopic mineralization, quantified with 18fluoride positron emission tomography scans as femoral arterial wall target-to-background ratios (TBRfemoral). Secondary outcomes were computed tomography arterial calcification and ophthalmological changes. Safety outcomes were bone density, serum calcium, and phosphate. RESULTS During 12 months of follow-up, the TBRfemoral increased 6% (interquartile range [IQR]: -12% to 25%) in the etidronate group and 7% (IQR: -9% to 32%) in the placebo group (p = 0.465). Arterial calcification decreased 4% (IQR: -11% to 7%) in the etidronate group and increased 8% (IQR: -1% to 20%) in the placebo group (p = 0.001). Etidronate treatment was associated with significantly fewer subretinal neovascularization events (1 vs. 9, p = 0.007). Bone density decreased 4% ± 12% in the etidronate group and 6% ± 9% in the placebo group (p = 0.374). Hypocalcemia (<2.20 mmol/l) occurred in 3 versus 1 patient (8.1% vs. 2.7%, p = 0.304). Eighteen patients (48.6%) treated with etidronate, compared with 0 patients treated with placebo (p < 0.001), experienced hyperphosphatemia (>1.5 mmol/l) and recovered spontaneously. CONCLUSIONS In patients with PXE, etidronate reduced arterial calcification and subretinal neovascularization events but did not lower femoral 18fluoride sodium positron emission tomography activity compared with placebo, without important safety issues. (Treatment of Ectopic Mineralization in Pseudoxanthoma elasticum; NTR5180).
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Affiliation(s)
- Guido Kranenburg
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Pim A de Jong
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Jonas W Bartstra
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Suzanne J Lagerweij
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Marnix G Lam
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | | | - Sara Risseeuw
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Redmer van Leeuwen
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Saskia M Imhof
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Harald J Verhaar
- Department of Geriatric Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Job J de Vries
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Riemer H J A Slart
- Medical Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Gert Luurtsema
- Medical Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Annemarie M den Harder
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Frank L J Visseren
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Willem P Mali
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands.
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Murro V, Mucciolo DP, Giorgio D, Sodi A, Boraldi F, Quaglino D, Virgili G, Rizzo S. Coquille d'oeuf in young patients affected with Pseudoxantoma elasticum. Ophthalmic Genet 2019; 40:242-246. [PMID: 31269855 DOI: 10.1080/13816810.2019.1627466] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Purpose: To evaluate the fundus phenotype of young patients affected with Pseudoxantoma Elasticum (PXE). Materials and Methods: Retrospective case series of five young PXE patients. Clinical data, ultra-widefield imaging (color, red-free (RF), choroidal (Ch) and fundus autofluorescence (FAF)) and OCT examination were collected. Diagnosis was confirmed by the characteristic histopathological abnormalities in skin biopsies and genetic testing results. Results: Five patients, 2 males and 3 females (mean age 16 years, range 12-20 years) were included in our study. The visual acuity was 20/20 in all subjects. Fundus evaluation revealed peau d'orange in all patients: multiple, yellowish/white round lesions, scattered from the posterior pole to the mid-peripheral retina of each eye. Ultra-wide field imaging allows us to capture and describe the entire area of coquille d'oeuf/peau d'orange in a single picture, facilitating their identification and discrimination. Angiod streaks were visible in both eyes of four patients. In one patient optic disc drusen were detected in both eyes. All patients presented comet lesions. Conclusions: PXE-related retinopathy findings: peau d'orange/coquille d'oeuf, angioid streaks, comet lesions and drusen of the optic disc were present early in PXE patients. The early detection of coquille d'oeuf/peau d'orange revealed a preferable area into midperiphery where Bruch's membrane will be more likely to be affected.
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Affiliation(s)
- Vittoria Murro
- a Department of Neuroscience, Psychology , Drug Research and Child Health, University of Florence , Florence , Italy
| | - Dario Pasquale Mucciolo
- a Department of Neuroscience, Psychology , Drug Research and Child Health, University of Florence , Florence , Italy
| | - Dario Giorgio
- a Department of Neuroscience, Psychology , Drug Research and Child Health, University of Florence , Florence , Italy
| | - Andrea Sodi
- a Department of Neuroscience, Psychology , Drug Research and Child Health, University of Florence , Florence , Italy
| | - Federica Boraldi
- b Department of Life Sciences , University of Modena and Reggio Emilia , Modena , Italy
| | - Daniela Quaglino
- b Department of Life Sciences , University of Modena and Reggio Emilia , Modena , Italy
| | - Gianni Virgili
- a Department of Neuroscience, Psychology , Drug Research and Child Health, University of Florence , Florence , Italy
| | - Stanislao Rizzo
- a Department of Neuroscience, Psychology , Drug Research and Child Health, University of Florence , Florence , Italy
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Tsang SH, Sharma T. Inborn Errors of Metabolism: Pseudoxanthoma Elasticum. Adv Exp Med Biol 2018; 1085:187-9. [PMID: 30578511 DOI: 10.1007/978-3-319-95046-4_38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Pseudoxanthoma elasticum (PXE) is an autosomal recessive multisystem disorder that involves the skin, GI tract, and heart, as well as the eye. It affects approximately 1 in 50,000 people worldwide and is seen twice as frequently in females as in males. Fundus findings include angioid streaks (Fig. 38.1), reticular macular dystrophy, speckled appearance temporal to the macula (peau d'orange, like the dimpled texture of an orange peel), drusen of the optic nerve, and vitelliform-like deposits. Peau d'orange may precede the development of an angioid streak. "Comets," with or without a tail, are seen as solitary subretinal, nodular white bodies of retinal pigment epithelium (RPE) atrophy, usually present in the mid periphery (Fig. 38.2). The tail points toward the optic disc. Patients sometimes develop choroidal neovascular membrane. Skin changes (plucked chicken-like appearance) occur on the flexure areas, including the neck and axilla, as well as increased skin laxity with excessive skin folding. Cardiovascular changes include accelerated atherosclerosis with occlusive vascular disease leading to angina, hypertension, restrictive cardiomyopathy, mitral valve prolapse, and others. Progressive calcification and fragmentation of elastic fibers in the skin, eye, and cardiovascular system is the underlying pathophysiology.
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Murro V, Mucciolo DP, Sodi A, Boraldi F, Quaglino D, Virgili G, Rizzo S. Peripapillary comet lesions and comet rain in PXE-related retinopathy. Graefes Arch Clin Exp Ophthalmol 2018; 256:1605-14. [PMID: 29948180 DOI: 10.1007/s00417-018-4037-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/25/2018] [Accepted: 06/02/2018] [Indexed: 10/14/2022] Open
Abstract
PURPOSE To study peripapillary comet lesions (PCL) in Italian patients affected with pseudoxanthoma elasticum (PXE). METHODS Retrospective review of fundoscopic and swept-source (SS) optical coherence tomography (OCT) images of patients with PXE examined at the Regional Reference Center for Hereditary Retinal Degenerations at the Careggi Teaching Hospital of Florence from 2012 to 2017. RESULTS From 148 eyes of 74 patients affected with PXE, we identified 24 eyes of 14 patients (11 were female) with a mean age of 39 years (range, 20-58 years) characterized by peripapillary comet lesions. Of these 24 eyes, 15 eyes (of 10 patients) were characterized by comet rain. The smallest comet lesion at the OCT examination appeared as a focal roundish hyper-reflective alteration at the level of the outer retinal segments and RPE-Bruch's membrane complex; the larger lesions appeared as circular and ovoid structures with hyper-reflective borders in the outer nuclear layer. CONCLUSION The comet lesion formation process involves the outer layers of the retina and RPE/Bruch's membrane complex. It consists of a degenerative/rearrangement process of the photoreceptors which occurs in an area of focal altered RPE/Bruch's membrane resembling the outer retinal tubulation.
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Kranenburg G, Visseren FLJ, de Borst GJ, de Jong PA, Spiering W. Arterial stiffening and thickening in patients with pseudoxanthoma elasticum. Atherosclerosis 2018; 270:160-165. [PMID: 29432933 DOI: 10.1016/j.atherosclerosis.2018.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 01/25/2018] [Accepted: 02/02/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND AIMS Patients with pseudoxanthoma elasticum (PXE), a monogenetic calcification disease, are at high vascular risk. Although the precise arterial phenotype remains unestablished, it is hypothesized that PXE predominantly affects the medial arterial layer leading to arterial stiffening. We aimed to test this hypothesis by measuring arterial wall characteristics in PXE and comparisons with the general population and diabetes mellitus type 2 (DM2), a condition typically associated with mixed intimal and medial arterial disease. METHODS Extensive arterial wall characterization was performed in 203 PXE patients involving intima-media thickness (IMT), pulse wave velocity (PWV) and pulse pressure (PP) measurements. IMT and PWV in PXE were compared with the general population using age, sex and mean arterial pressure corrected values for each PXE patient. IMT and PP were compared between PXE and DM2 independently of sex, age and systolic blood pressure, using data of DM2 patients (n = 1033) from the Second Manifestations of ARTerial disease (SMART) cohort. RESULTS PXE patients had significantly higher IMT (mean difference 0.09 mm; 95% CI 0.07-0.12 mm) and PWV (mean difference 2.5 m/s; 95% CI 1.9-3.0 m/s) compared to the general population. IMT in PXE was lower compared to DM2 (0.72 mm; 95% CI 0.68-0.75 mm vs. 0.85 mm; 95% CI 0.83-0.87 mm, p-value<0.01), whereas PP in PXE was higher compared to DM2 (60 mmHg; 95% CI 59-62 vs. 57 mmHg; 95% CI 57-58 mmHg, p-value<0.01). CONCLUSIONS PXE patients have thicker arterial walls than the general population, but thinner arterial walls than DM2 patients at similar age. Arterial stiffening is more pronounced in PXE patients compared to DM2 patients.
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Affiliation(s)
- Guido Kranenburg
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Frank L J Visseren
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Gert Jan de Borst
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Pim A de Jong
- Department of Radiology, University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, The Netherlands.
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Abstract
PURPOSE OF REVIEW We give an update on the etiology and potential treatment options of rare inherited monogenic disorders associated with arterial calcification and calcific cardiac valve disease. RECENT FINDINGS Genetic studies of rare inherited syndromes have identified key regulators of ectopic calcification. Based on the pathogenic principles causing the diseases, these can be classified into three groups: (1) disorders of an increased extracellular inorganic phosphate/inorganic pyrophosphate ratio (generalized arterial calcification of infancy, pseudoxanthoma elasticum, arterial calcification and distal joint calcification, progeria, idiopathic basal ganglia calcification, and hyperphosphatemic familial tumoral calcinosis; (2) interferonopathies (Singleton-Merten syndrome); and (3) others, including Keutel syndrome and Gaucher disease type IIIC. Although some of the identified causative mechanisms are not easy to target for treatment, it has become clear that a disturbed serum phosphate/pyrophosphate ratio is a major force triggering arterial and cardiac valve calcification. Further studies will focus on targeting the phosphate/pyrophosphate ratio to effectively prevent and treat these calcific disease phenotypes.
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MESH Headings
- Abnormalities, Multiple/drug therapy
- Abnormalities, Multiple/genetics
- Abnormalities, Multiple/metabolism
- Aortic Diseases/drug therapy
- Aortic Diseases/genetics
- Aortic Diseases/metabolism
- Basal Ganglia Diseases/drug therapy
- Basal Ganglia Diseases/genetics
- Basal Ganglia Diseases/metabolism
- Calcinosis/drug therapy
- Calcinosis/genetics
- Calcinosis/metabolism
- Cartilage Diseases/drug therapy
- Cartilage Diseases/genetics
- Cartilage Diseases/metabolism
- Dental Enamel Hypoplasia/drug therapy
- Dental Enamel Hypoplasia/genetics
- Dental Enamel Hypoplasia/metabolism
- Diphosphates/metabolism
- Enzyme Replacement Therapy
- Gaucher Disease/drug therapy
- Gaucher Disease/genetics
- Gaucher Disease/metabolism
- Hand Deformities, Congenital/drug therapy
- Hand Deformities, Congenital/genetics
- Hand Deformities, Congenital/metabolism
- Humans
- Hyperostosis, Cortical, Congenital/drug therapy
- Hyperostosis, Cortical, Congenital/genetics
- Hyperostosis, Cortical, Congenital/metabolism
- Hyperphosphatemia/drug therapy
- Hyperphosphatemia/genetics
- Hyperphosphatemia/metabolism
- Interferons/metabolism
- Metacarpus/abnormalities
- Metacarpus/metabolism
- Muscular Diseases/drug therapy
- Muscular Diseases/genetics
- Muscular Diseases/metabolism
- Odontodysplasia/drug therapy
- Odontodysplasia/genetics
- Odontodysplasia/metabolism
- Osteoporosis/drug therapy
- Osteoporosis/genetics
- Osteoporosis/metabolism
- Phosphates/metabolism
- Progeria/drug therapy
- Progeria/genetics
- Progeria/metabolism
- Pseudoxanthoma Elasticum/drug therapy
- Pseudoxanthoma Elasticum/genetics
- Pseudoxanthoma Elasticum/metabolism
- Pulmonary Valve Stenosis/drug therapy
- Pulmonary Valve Stenosis/genetics
- Pulmonary Valve Stenosis/metabolism
- Vascular Calcification/drug therapy
- Vascular Calcification/genetics
- Vascular Calcification/metabolism
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Affiliation(s)
- Yvonne Nitschke
- Department of General Pediatrics, Münster University Children's Hospital, Albert-Schweitzer-Campus 1, D-48149, Münster, Germany
| | - Frank Rutsch
- Department of General Pediatrics, Münster University Children's Hospital, Albert-Schweitzer-Campus 1, D-48149, Münster, Germany.
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Pingel S, Pausewang KS, Passon SG, Blatzheim AK, Gliem M, Charbel Issa P, Hendig D, Horlbeck F, Tuleta I, Nickenig G, Schahab N, Skowasch D, Schaefer CA. Increased vascular occlusion in patients with pseudoxanthoma elasticum. VASA 2016; 46:47-52. [PMID: 27927085 DOI: 10.1024/0301-1526/a000583] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is an autosomal recessive inherited multisystem disorder of the connective tissue caused by a loss-of-function mutation of the ABCC6 gene. It can affect the cardiovascular system, presumably leading to a high prevalence of atherosclerosis. PATIENTS AND METHODS 46 PXE patients and 18 controls underwent an angiological examination consisting of measurement of ankle-brachial index (ABI), strain-gauge arterial reserve (SGAR), arterial resting perfusion, pulse wave index (PWI), central pulse wave velocity, and ultrasound examination. RESULTS With an average age of 51.4 ± 12.4 years, 35/46 (76.1 %) of the PXE patients had atherosclerotic lesions, and 10 of them (28.6 %) had a chronic vascular occlusion of one or more peripheral vessels. 34/46 (73.9 %) had a pathologic ABI < 0.9, 15/42 (35.7 %) had a pathological SGAR < 10 mL/100 mL tissue/min, and 23/38 (60.5 %) had a pathological PWI > 180. The differences between the groups were statistically significant for ABI, arterial reserve, and PWI. CONCLUSIONS In PXE patients atherosclerosis was found with a much higher prevalence than expected. Moreover, they were at very high risk for total vessel occlusions.
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Affiliation(s)
- Simon Pingel
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany.,a These authors contributed equally
| | - Kristin Solveig Pausewang
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany.,a These authors contributed equally
| | - Sebastian Gorgonius Passon
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
| | - Anna Katharina Blatzheim
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
| | - Martin Gliem
- 2 University Hospital Bonn, Department of Ophthalmology, Germany
| | | | - Doris Hendig
- 3 Heart and Diabetes Center NRW, Institute of Laboratory and Transfusion Medicine, University Hospital of Ruhr-University Bochum, Bad Oeynhausen, Germany
| | - Fritz Horlbeck
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
| | - Izabela Tuleta
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
| | - Georg Nickenig
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
| | - Nadjib Schahab
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
| | - Dirk Skowasch
- 1 University Hospital Bonn, Internal Medicine II - Department of Cardiology, Angiology and Pneumology, Germany
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Dolz-Marco R, Andreu-Fenoll M, Hernández-Martínez P, Pinazo-Durán MD, Gallego-Pinazo R. Automated macular choroidal thickness measurement by swept-source optical coherence tomography in pseudoxanthoma elasticum. Int J Retina Vitreous 2016; 2:15. [PMID: 27847633 PMCID: PMC5088448 DOI: 10.1186/s40942-016-0040-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/07/2016] [Indexed: 11/28/2022] Open
Abstract
Introduction Pseudoxanthoma elasticum (PXE) typically involves elastic fibers in blood vessels and Bruch membrane. Our purpose was to analyze retinal and choroidal macular thickness in patients with angioid streaks due PXE compared with a control group. Methods Best-corrected visual acuity (BCVA), axial length (AL), and macular swept-source optical coherence tomography were obtained. Automated segmentations of the retina and the choroid were used to obtain the corresponding thickness values. An age, gender and AL matched control group was used to compare the thickness values. Results Twelve eyes of 6 patients were included. The mean BCVA was 0.68 ± 0.29 versus 1.0 in controls (p < 0.001). The mean macular retinal thickness was thinner in eyes with PXE (p = 0.038). Only patients with choroidal neovascularization (NV) showed statistically significant differences in the mean macular choroidal thickness (p = 0.008). Conclusions The present study shows that choroidal thickness may be thinner in eyes with NV due to angioid streaks in PXE compared with healthy eyes analyzed by an automated segmentation of the choroid. Further studies are warranted in order to assess the importance of this choroidal changes in the pathogenesis of retinal disturbances related to PXE and its influence in long-term follow-up.
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Affiliation(s)
- Rosa Dolz-Marco
- Unit of Macula, Department of Ophthalmology, University and Polytechnic Hospital La Fe, Bulevar Sur s/n, 46026 Valencia, Spain ; RETICS RD12/0034 Enfermedades oculares: «Prevención, detección precoz y tratamiento de la patología ocular prevalente degenerativa y crónica», Instituto de Salud Carlos III, Madrid, Spain
| | - María Andreu-Fenoll
- Unit of Macula, Department of Ophthalmology, University and Polytechnic Hospital La Fe, Bulevar Sur s/n, 46026 Valencia, Spain ; RETICS RD12/0034 Enfermedades oculares: «Prevención, detección precoz y tratamiento de la patología ocular prevalente degenerativa y crónica», Instituto de Salud Carlos III, Madrid, Spain
| | - Pablo Hernández-Martínez
- Unit of Macula, Department of Ophthalmology, University and Polytechnic Hospital La Fe, Bulevar Sur s/n, 46026 Valencia, Spain
| | - M Dolores Pinazo-Durán
- RETICS RD12/0034 Enfermedades oculares: «Prevención, detección precoz y tratamiento de la patología ocular prevalente degenerativa y crónica», Instituto de Salud Carlos III, Madrid, Spain ; Ophthalmology Research Unit "Santiago Grisolía", University Hospital Doctor Peset, Valencia, Spain ; Department of Surgery, Faculty of Medicine, University of Valencia, Valencia, Spain
| | - Roberto Gallego-Pinazo
- Unit of Macula, Department of Ophthalmology, University and Polytechnic Hospital La Fe, Bulevar Sur s/n, 46026 Valencia, Spain ; RETICS RD12/0034 Enfermedades oculares: «Prevención, detección precoz y tratamiento de la patología ocular prevalente degenerativa y crónica», Instituto de Salud Carlos III, Madrid, Spain
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Miglionico R, Gerbino A, Ostuni A, Armentano MF, Monné M, Carmosino M, Bisaccia F. New insights into the roles of the N-terminal region of the ABCC6 transporter. J Bioenerg Biomembr 2016; 48:259-67. [PMID: 26942607 DOI: 10.1007/s10863-016-9654-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/23/2016] [Indexed: 01/07/2023]
Abstract
ABCC6 is a human ATP binding cassette (ABC) transporter of the plasma membrane associated with Pseudoxanthoma elasticum (PXE), an autosomal recessive disease characterized by ectopic calcification of elastic fibers in dermal, ocular and vascular tissues. Similar to other ABC transporters, ABCC6 encloses the core structure of four domains: two transmembrane domains (TMDs) and two nucleotide binding domains (NBDs) but also an additional N-terminal extension, including a transmembrane domain (TMD0) and a cytosolic loop (L0), which is only found in some members of ABCC subfamily, and for which the function remains to be established. To investigate the functional roles of this N-terminal region, we generated several domain deletion constructs of ABCC6, expressed in HEK293 and polarized LLC-PK1 cells. ABCC6 lacking TMD0 displayed full transport activity as the wild type protein. Unlike the wild type protein, ABCC6 without L0 was not targeted to the basolateral membrane. Moreover, homology modeling of L0 suggests that it forms an ATPase regulatory domain. Furthermore, we show that the expression of ABCC6 is linked to a cellular influx of Ca(2+). The results suggest that TMD0 is not required for transport function and that L0 maintains ABCC6 in a targeting-competent state for the basolateral membrane and might be involved in regulating the NBDs. These findings shed new light on a possible physiological function of ABCC6 and may explain some of the hallmarks of the clinical features associated with PXE that could contribute to the identification of novel pharmacological targets.
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27
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Abstract
The mineralisation disorder pseudoxanthoma elasticum (PXE) is associated with mutations in the transporter protein ABCC6. Patients with PXE suffer from calcified lesions in the skin, eyes and vasculature, and PXE is related to a more severe vascular calcification syndrome called generalised arterial calcification of infancy (GACI). Mutations in ABCC6 are linked to reduced levels of circulating vitamin K. Here, we describe a mutation in the zebrafish (Danio rerio) orthologue abcc6a, which results in extensive hypermineralisation of the axial skeleton. Administration of vitamin K to embryos was sufficient to restore normal levels of mineralisation. Vitamin K also reduced ectopic mineralisation in a zebrafish model of GACI, and warfarin exacerbated the mineralisation phenotype in both mutant lines. These data suggest that vitamin K could be a beneficial treatment for human patients with PXE or GACI. Additionally, we found that abcc6a is strongly expressed at the site of mineralisation rather than the liver, as it is in mammals, which has significant implications for our understanding of the function of ABCC6.
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Affiliation(s)
- Eirinn W Mackay
- Hubrecht Institute - KNAW & University Medical Center Utrecht, Utrecht 3584 CT, The Netherlands
| | - Alexander Apschner
- Hubrecht Institute - KNAW & University Medical Center Utrecht, Utrecht 3584 CT, The Netherlands
| | - Stefan Schulte-Merker
- Hubrecht Institute - KNAW & University Medical Center Utrecht, Utrecht 3584 CT, The Netherlands EZO, WUR, Wageningen 6709 PG, The Netherlands Institute of Cardiovascular Organogenesis and Regeneration, University of Münster, Münster 48149, Germany Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Münster 48149, Germany
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28
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Affiliation(s)
- Stephanie N Moore
- Department of Orthopaedics; Vanderbilt University Medical Center; Nashville, TN USA
- Department of Pharmacology; Vanderbilt University Medical Center; Nashville, TN USA
| | - S Bobo Tanner
- Department of Rheumatology; Vanderbilt University Medical Center; Nashville, TN USA
| | - Jonathan G Schoenecker
- Department of Orthopaedics; Vanderbilt University Medical Center; Nashville, TN USA
- Department of Pharmacology; Vanderbilt University Medical Center; Nashville, TN USA
- Department of Center for Bone Biology; Vanderbilt University Medical Center; Nashville, TN USA
- Department of Pathology; Microbiology; and Immunology; Vanderbilt University Medical Center; Nashville, TN USA
- Department of Pediatrics; Vanderbilt University Medical Center; Nashville, TN USA
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29
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Apschner A, Huitema LFA, Ponsioen B, Peterson-Maduro J, Schulte-Merker S. Zebrafish enpp1 mutants exhibit pathological mineralization, mimicking features of generalized arterial calcification of infancy (GACI) and pseudoxanthoma elasticum ( PXE). Dis Model Mech 2014; 7:811-22. [PMID: 24906371 PMCID: PMC4073271 DOI: 10.1242/dmm.015693] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In recent years it has become clear that, mechanistically, biomineralization is a process that has to be actively inhibited as a default state. This inhibition must be released in a rigidly controlled manner in order for mineralization to occur in skeletal elements and teeth. A central aspect of this concept is the tightly controlled balance between phosphate, a constituent of the biomineral hydroxyapatite, and pyrophosphate, a physiochemical inhibitor of mineralization. Here, we provide a detailed analysis of a zebrafish mutant, dragonfish (dgf), which is mutant for ectonucleoside pyrophosphatase/phosphodiesterase 1 (Enpp1), a protein that is crucial for supplying extracellular pyrophosphate. Generalized arterial calcification of infancy (GACI) is a fatal human disease, and the majority of cases are thought to be caused by mutations in ENPP1. Furthermore, some cases of pseudoxanthoma elasticum (PXE) have recently been linked to ENPP1. Similar to humans, we show here that zebrafish enpp1 mutants can develop ectopic calcifications in a variety of soft tissues - most notably in the skin, cartilage elements, the heart, intracranial space and the notochord sheet. Using transgenic reporter lines, we demonstrate that ectopic mineralizations in these tissues occur independently of the expression of typical osteoblast or cartilage markers. Intriguingly, we detect cells expressing the osteoclast markers Trap and CathepsinK at sites of ectopic calcification at time points when osteoclasts are not yet present in wild-type siblings. Treatment with the bisphosphonate etidronate rescues aspects of the dgf phenotype, and we detected deregulated expression of genes that are involved in phosphate homeostasis and mineralization, such as fgf23, npt2a, entpd5 and spp1 (also known as osteopontin). Employing a UAS-GalFF approach, we show that forced expression of enpp1 in blood vessels or the floorplate of mutant embryos is sufficient to rescue the notochord mineralization phenotype. This indicates that enpp1 can exert its function in tissues that are remote from its site of expression.
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Affiliation(s)
- Alexander Apschner
- Hubrecht Institute - KNAW & UMC Utrecht, 3548CT Utrecht, The Netherlands
| | - Leonie F A Huitema
- Hubrecht Institute - KNAW & UMC Utrecht, 3548CT Utrecht, The Netherlands
| | - Bas Ponsioen
- Hubrecht Institute - KNAW & UMC Utrecht, 3548CT Utrecht, The Netherlands
| | | | - Stefan Schulte-Merker
- Hubrecht Institute - KNAW & UMC Utrecht, 3548CT Utrecht, The Netherlands. WUR, Experimental Zoology, 3700AH Wageningen, The Netherlands. Institute of Cardiovascular Organogenesis and Regeneration, Faculty of Medicine, University of Münster, 48149 Münster, Germany.
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30
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Hendig D, Knabbe C, Götting C. New insights into the pathogenesis of pseudoxanthoma elasticum and related soft tissue calcification disorders by identifying genetic interactions and modifiers. Front Genet 2013; 4:114. [PMID: 23802012 PMCID: PMC3685813 DOI: 10.3389/fgene.2013.00114] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/30/2013] [Indexed: 12/31/2022] Open
Abstract
Screening of the adenosine triphosphate binding cassette transporter protein subfamily C member 6 gene (ABCC6) in pseudoxanthoma elasticum (PXE) revealed a mutation detection rate of approximately 87%. Although 25% of the unidentified disease alleles underlie deletions/insertions, there remain several PXE patients with no clear genotype. The recent identification of PXE-related diseases and the high intra-familiar and inter-individual clinical variability of PXE led to the assumption that secondary genetic co-factors exist. Here, we summarize current knowledge of the genetics underlying PXE and PXE-related disorders based on human and animal studies. Furthermore, we discuss the role of genetic interactions and modifier genes in PXE and PXE-related diseases characterized by soft tissue calcification.
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Affiliation(s)
- Doris Hendig
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum Bad Oeynhausen, Germany
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31
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Abstract
Disease advocacy organizations have long played an important role in the continuum from basic science to therapy development in rare disease research. PXE International has led the field in innovative ways, venturing into specific activities that have traditionally been conducted by scientists. As lay founders, we have engaged in gene discovery, gene patenting, diagnostic test development, epidemiological studies, clinical trials, and therapy research and development. This article will describe the steps that we took, and the ways in which we have scaled these efforts for the larger community.
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Affiliation(s)
- Sharon F Terry
- Genetic Alliance Washington, DC, USA ; PXE International Washington, DC, USA
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32
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Ronchetti I, Boraldi F, Annovi G, Cianciulli P, Quaglino D. Fibroblast involvement in soft connective tissue calcification. Front Genet 2013; 4:22. [PMID: 23467434 PMCID: PMC3588566 DOI: 10.3389/fgene.2013.00022] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 02/11/2013] [Indexed: 12/19/2022] Open
Abstract
Soft connective tissue calcification is not a passive process, but the consequence of metabolic changes of local mesenchymal cells that, depending on both genetic and environmental factors, alter the balance between pro- and anti-calcifying pathways. While the role of smooth muscle cells and pericytes in ectopic calcifications has been widely investigated, the involvement of fibroblasts is still elusive. Fibroblasts isolated from the dermis of pseudoxanthoma elasticum (PXE) patients and of patients exhibiting PXE-like clinical and histopathological findings offer an attractive model to investigate the mechanisms leading to the precipitation of mineral deposits within elastic fibers and to explore the influence of the genetic background and of the extracellular environment on fibroblast-associated calcifications, thus improving the knowledge on the role of mesenchymal cells on pathologic mineralization.
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Affiliation(s)
| | - Federica Boraldi
- PXELab, University of Modena and Reggio EmiliaModena, Italy
- Department of Life Science, University of Modena and Reggio EmiliaModena, Italy
| | - Giulia Annovi
- PXELab, University of Modena and Reggio EmiliaModena, Italy
- Department of Life Science, University of Modena and Reggio EmiliaModena, Italy
| | | | - Daniela Quaglino
- PXELab, University of Modena and Reggio EmiliaModena, Italy
- Department of Life Science, University of Modena and Reggio EmiliaModena, Italy
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33
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Nitschke Y, Rutsch F. Generalized arterial calcification of infancy and pseudoxanthoma elasticum: two sides of the same coin. Front Genet 2012; 3:302. [PMID: 23269929 PMCID: PMC3529400 DOI: 10.3389/fgene.2012.00302] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/05/2012] [Indexed: 12/25/2022] Open
Abstract
Generalized arterial calcification of infancy (GACI) is associated with biallelic mutations in ENPP1 in the majority of cases, whereas mutations in ABCC6 (ATP-binding cassette subfamily C number 6) are known to cause pseudoxanthoma elasticum (PXE). However, ABCC6 mutations account for a significant subset of GACI cases, and ENPP1 mutations can also be associated with PXE lesions. Based on the considerable overlap of GACI and PXE, both entities appear to reflect two ends of a clinical spectrum of ectopic calcification rather than two distinct disorders. ABCC6 and ENPP1 mutations might lead to alterations of the same physiological pathways.
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Affiliation(s)
- Yvonne Nitschke
- Department of General Pediatrics, Münster University Children's Hospital Münster, Germany
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