Cutis laxa: A review

Elastogenesis in Focus: Navigating Elastic Fibers Synthesis for Advanced Dermal Biomaterial Formulation

Elastin, a fibrous extracellular matrix (ECM) protein, is the main component of elastic fibers that are involved in tissues' elasticity and resilience, enabling them to undergo reversible extensibility and to endure repetitive mechanical stress. After wounding, it is challenging to regenerate elastic fibers and biomaterials developed thus far have struggled to induce its biosynthesis. This review provides a comprehensive summary of elastic fibers synthesis at the cellular level and its implications for biomaterial formulation, with a particular focus on dermal substitutes. The review delves into the intricate process of elastogenesis by cells and investigates potential triggers for elastogenesis encompassing elastin-related compounds, ECM components, and other molecules for their potential role in inducing elastin formation. Understanding of the elastogenic processes is essential for developing biomaterials that trigger not only the synthesis of the elastin protein, but also the formation of a functional and branched elastic fiber network.

Acquired cutis laxa: a clinical review

Acquired cutis laxa (ACL) is a rare, nonhereditary cutaneous disorder characterized by saggy inelastic skin. It has been associated with various inflammatory, autoimmune, and neoplastic diseases, in addition to certain infections and medication. This article reviews ACL the demographical, clinical, and histological features of ACL, focusing on all associated disorders. Additionally, this review article provides an in-depth discussion of all the mechanisms implicated in the pathogenesis of ACL and all therapeutic options available; we also present an algorithm for the workup of patients with ACL. A systematic literature review was performed on PubMed/Medline and EMBASE databases, searching for all available articles on ACL with no limits on participant age, race, sex, nationality, or publication date. Ninety-eight articles were included. The total number of included patients was 110, with a mean age of 36.4 years at presentation (range 0.25-78) and a M:F sex ratio of 1.24. ACL was most commonly associated with inflammatory disorders (43%) followed by neoplastic disorders (27%). In 73% of the neoplastic-associated cases, ACL occurred on average 2.4 years before malignancy onset. ACL occurs months to years after an underlying inflammatory disorder. In 10% of the cases, ACL was associated with a particular drug, and in 2%, it was associated with specific infections. Data were derived from case reports, case series, letters to editors, observational studies, and abstracts. Limitations include the accuracy of published data, potential patient selection, and reporting bias. Dermatologists should be alert to these associations to provide adequate screening and management of patients with ACL.

NOVEL RETINAL FINDINGS IN A PATIENT WITH AUTOSOMAL RECESSIVE CUTIS LAXA TYPE 2A

PURPOSE

To report a case of autosomal recessive cutis laxa type 2A with novel retinal findings.

METHODS

Case report.

RESULTS

A 22-year-old female patient presented with a long-standing history of reduced visual acuity in her right eye. She has generalized redundant skin, downslanting of palpebral fissures, and long philtrum. Ophthalmic examination showed ptosis in her right eye and visual acuity of 20/2000 in the right eye and 20/30p in the left eye. Funduscopic examination showed a round macular scar lesion in the right eye macula and a chorioretinal scar superonasally in the left eye. Multimodal imaging showed macular atrophy in the right eye with speckled hypoautofluorescence of the described lesions. Genetic testing showed a homozygous splice acceptor variant of the ATP6V0A2 gene.

CONCLUSION

The natural history of the presented pigmentary lesions is not known, and further follow-up is needed to assess any progressive nature. Our case adds to the variability of ophthalmic manifestations reported in autosomal recessive cutis laxa type 2A and, therefore, to the importance of regular ophthalmic surveillance in patients with cutis laxa.

Type I acquired cutis laxa: Report of a unique progressive case and short review

Cutis laxa is a rare connective tissue disorder, characterized by a reduced number and abnormal properties of elastic fibers throughout the dermis, creating a clinical appearance of premature aging. It can be subdivided into inherited and acquired, the latter rarer than the former, and skin involvement may be localized or generalized. The etiology of acquired cutis laxa (ACL) remains unknown and there is no definitive treatment. We present the case of a 30-year-old man diagnosed with type I ACL with progressive systemic involvement at the renal, pulmonary, and digestive levels. Histological analysis of the skin revealed reduction and fragmentation of elastic fibers. Immunosuppressive treatment was started with prednisone, cyclophosphamide, and rituximab, with which a complete response to proteinuria was achieved and the progression of lung damage was limited. Autoimmune, infectious, and neoplastic diseases were ruled out.

A rare case of secondary cutaneous lymphoplasmacytic lymphoma clinically presenting as acquired cutis laxa

Lymphoplasmacytic lymphoma (LPL) is a rare variant of non-Hodgkin lymphoma, accounting for <1% of cases. Skin involvement in LPL is quite rare-accounting for approximately 5% of extramedullary disease-and includes a variety of clinical morphologies, such as erythematous-to-violaceous plaques, violaceous nodules or tumors, and ulceration at various anatomical sites. Herein, we report the case of a 45-year-old Korean woman who presented with generalized erythematous indurated plaques and pendulous skin growths, which were asymptomatic, with marked diffuse infiltration of lymphocytes and plasma cells in the dermis. Immunohistochemical studies revealed that the lymphoid cells expressed CD3, CD79a, and cytoplasmic IgG, but lacked CD10 and IgM. Moreover, kappa light chain restriction and monoclonal immunoglobulin heavy chain gene rearrangement were observed. Upon further workup, lymphoma involvement was reported in multiple lymph nodes, including those in the cervical and axillary regions. This case shows a unique form of cutaneous LPL clinically presenting as acquired cutis laxa, emphasizing the dermatologists' need to be vigilant for variant forms of this disease.

A novel deletion mutation in the ATP6V0A2 gene in an Iranian patient affected by autosomal recessive cutis laxa

Cutis laxa (CL) can be caused by mutations in a number of genes. Cutis laxa with autosomal recessive inheritance due to mutations in several genes, including mutations in the ATP6V0A2 gene, causes autosomal recessive cutis laxa type 2A (ARCL2A). The ATP6V0A2 gene encodes the a2 subunit in the V-ATPases pump. The V-ATPases are located in the membrane of some organelles, including the Golgi or some vesicles, and act as ATP-dependent proton pumps to pH adjustment intracellular segments. Mutations in the ATP6V0A2 gene consist present in ARCL2A patients. We present the case of a 12-year-old girl who was referred to Rasad Laboratory (Tehran, Iran) at the age of 5 with a set of symptoms of congenital disorders. Her clinical phenotype contains distal symmetrical sensory and motor polyneuropathy, loose joints, large nasal roots, growth delay, and wrinkled skin. Also, there was a history of the parental marriage of consanguinity. A potentially pathogenic homozygous deletion mutation was detected in the ATP6V0A2 gene related to ARCL2A. This mutation has not been reported in the other patients with ARCL2A. A novel homozygous deletion mutation in ATP6V0A2 is supposed to be the reason for disease in our proband.

Progeroid syndrome of De Barsy - a case report and review of ophthalmic literature

BACKGROUND

This report describes a very rare case of progeroid syndrome of De Barsy (Cutis laxa-corneal clouding syndrome).

MATERIALS AND METHODS

A 2 year-old child presented to the pediatric ophthalmology outpatients with bilateral congenital corneal opacification along with dysmorphic facial features, including loose wrinkled skin, progeroid appearance, delayed milestones, short stature, multiple hyper-extensible joints, muscular hypotonia, pectus excavatum and congenital dislocation of the hip joint. The child underwent a detailed ophthalmic work up and systemic evaluation by a clinical geneticist.

RESULTS

Ophthalmic management in the form of bilateral sequential penetrating keratoplasties and a left eye trabeculectomy for medically uncontrolled angle-closure glaucoma was performed. Visual rehabilitation with glasses and amblyopia therapy is ongoing. Histopathology of the corneal button revealed loss of the bowman's layer which was replaced by a fibrous pannus while the stroma showed loss of stromal lamellar architecture with anterior and mid stroma showing vascularization. Genetic testing confirmed a mutation in the PYCR1 gene for a homozygous autosomal recessive cutis laxa type IIB.

CONCLUSIONS

Although rare, De Barsy syndrome is an important cause of corneal opacification at birth with multiple systemic abnormalities that requires intervention.

[Progeroid syndromes : Aging, skin aging, and mechanisms of progeroid syndromes]

Progeroid syndromes (PSs) are characterized by the premature onset of age-related pathologies. PSs display a wide range of heterogeneous pathological symptoms that also manifest during natural aging, including vision and hearing loss, atrophy, hair loss, progressive neurodegeneration, and cardiovascular defects. Recent advances in molecular pathology have led to a better understanding of the underlying mechanisms of these diseases. The genetic mutations underlying PSs are functionally linked to genome maintenance and repair, supporting the causative role of DNA damage accumulation in aging. While some of those genes encode proteins with a direct involvement in a DNA repair machinery, such as nucleotide excision repair (NER), others destabilize the genome by compromising the stability of the nuclear envelope, when lamin A is dysfunctional in Hutchinson-Gilford progeria syndrome (HGPS) or regulate the DNA damage response (DDR) such as the ataxia telangiectasia-mutated (ATM) gene. Understanding the molecular pathology of progeroid diseases is crucial in developing potential treatments to manage and prevent the onset of symptoms. This knowledge provides insight into the underlying mechanisms of premature aging and could lead to improved quality of life for individuals affected by progeroid diseases.

Analysis of matrisome expression patterns in murine and human dorsal root ganglia

The extracellular matrix (ECM) is a dynamic structure of molecules that can be divided into six different categories and are collectively called the matrisome. The ECM plays pivotal roles in physiological processes in many tissues, including the nervous system. Intriguingly, alterations in ECM molecules/pathways are associated with painful human conditions and murine pain models. Nevertheless, mechanistic insight into the interplay of normal or defective ECM and pain is largely lacking. The goal of this study was to integrate bulk, single-cell, and spatial RNA sequencing (RNAseq) datasets to investigate the expression and cellular origin of matrisome genes in male and female murine and human dorsal root ganglia (DRG). Bulk RNAseq showed that about 65% of all matrisome genes were expressed in both murine and human DRG, with proportionally more core matrisome genes (glycoproteins, collagens, and proteoglycans) expressed compared to matrisome-associated genes (ECM-affiliated genes, ECM regulators, and secreted factors). Single cell RNAseq on male murine DRG revealed the cellular origin of matrisome expression. Core matrisome genes, especially collagens, were expressed by fibroblasts whereas matrisome-associated genes were primarily expressed by neurons. Cell-cell communication network analysis with CellChat software predicted an important role for collagen signaling pathways in connecting vascular cell types and nociceptors in murine tissue, which we confirmed by analysis of spatial transcriptomic data from human DRG. RNAscope in situ hybridization and immunohistochemistry demonstrated expression of collagens in fibroblasts surrounding nociceptors in male and female human DRG. Finally, comparing human neuropathic pain samples with non-pain samples also showed differential expression of matrisome genes produced by both fibroblasts and by nociceptors. This study supports the idea that the DRG matrisome may contribute to neuronal signaling in both mouse and human, and that dysregulation of matrisome genes is associated with neuropathic pain.

Cutis Laxa and the Value of Rhytidectomy: 4 Patients and Years of Follow-Up

The modalities of the esthetic treatment of cutis laxa (CL) patients have rarely been discussed. Here, the authors present 4 CL rhytidectomy cases. The surgery method was designed based on the traditional full-incision face-lift technique combined with lamellar superficial musculoaponeurotic system flap elevation and plication. Temporal, buccal, mandibular, and cervical regions were targeted. The shortest follow-up was 30 months, and the longest was 72. The results were assessed by subjective satisfaction and third-party photo evaluation. The subjective satisfaction was graded into worse than preoperation, no improvement, slight improvement, moderate improvement, and obvious improvement. The satisfaction rate was the sum of moderate and obvious improvement. Eighteen uncorrelated professionals participated in the third-party photo evaluation, in which the preoperative and follow-up photos were presented, and frontal, temporal, mid-face (including jowl), and cervical (including mandibular line) regions were evaluated as improved or nonimproved. The outcome of the subjective satisfaction was graded as no improvement (2/12, 16.7%), slight improvement (3/12, 25%), moderate improvement (4/12, 33.3%), and obvious improvement (3/12, 25%). The satisfaction rate was 58.3%, most investigators denied the frontal and temporal region improvement, 60% observed mid-face improvement, and 80% noticed cervical improvement. Most patients and their parents had positive attitudes towards the treatment results; however, the full expectation was not achieved. The cervical region maintained the best improvement after our treatment and the mid-face ranked second. This surgery method conduces to the esthetic requirement of CL patients; however, skin laxity remains a challenge.

Clinical features in adults with acquired cutis laxa: a retrospective review

Acquired cutis laxa (ACL) is a very rare dermatological condition with numerous proposed aetiologies. Herein, we report on 10 adult patients with ACL, three of which were found to have genetic mutations suggesting a genetic predisposition for the development of ACL following exposure to an environmental insult. Four patients were presumed to develop ACL in association with medication exposure. Overall, if a case of potential ACL arises, providers should carefully review patient history and comorbidities, perform thorough systemic investigations based on symptomatology, and consider genetic analysis.

Autosomal dominant cutis laxa and critical stenosis of the left main coronary artery in a 21-year-old female with an intronic mutation in the elastin gene

Cutis laxa (CL) is a rare, inherited or acquired connective tissue disorder characterized by abnormal elastic fibers causing loose and redundant skin and a prematurely aged appearance. The syndrome has been associated with hypertension, but cases with early-onset ischemic heart disease have never been described. Here, we report a 21-year-old Danish female with activity-related shortness of breath and oedema of the lower extremities. The patient had a clinical diagnosis of autosomal dominant CL, but no genotyping had been performed prior to the index admission. The patient was diagnosed with ischemic heart disease, based on results of non-invasive cardiovascular imaging (including MRI and PET-CT) followed by invasive treatment of a critical left main coronary artery stenosis. Subsequent referral to genetic testing revealed a likely pathogenic intronic variant in ELN. This case report includes the clinical findings and relates these to known molecular mechanisms of CL.

Arterial dissections: Common features and new perspectives

Arterial dissections, which involve an abrupt tear in the wall of a major artery resulting in the intramural accumulation of blood, are a family of catastrophic disorders causing major, potentially fatal sequelae. Involving diverse vascular beds, including the aorta or coronary, cervical, pulmonary, and visceral arteries, each type of dissection is devastating in its own way. Traditionally they have been studied in isolation, rather than collectively, owing largely to the distinct clinical consequences of dissections in different anatomical locations - such as stroke, myocardial infarction, and renal failure. Here, we review the shared and unique features of these arteriopathies to provide a better understanding of this family of disorders. Arterial dissections occur commonly in the young to middle-aged, and often in conjunction with hypertension and/or migraine; the latter suggesting they are part of a generalized vasculopathy. Genetic studies as well as cellular and molecular investigations of arterial dissections reveal striking similarities between dissection types, particularly their pathophysiology, which includes the presence or absence of an intimal tear and vasa vasorum dysfunction as a cause of intramural hemorrhage. Pathway perturbations common to all types of dissections include disruption of TGF-β signaling, the extracellular matrix, the cytoskeleton or metabolism, as evidenced by the finding of mutations in critical genes regulating these processes, including LRP1, collagen genes, fibrillin and TGF-β receptors, or their coupled pathways. Perturbances in these connected signaling pathways contribute to phenotype switching in endothelial and vascular smooth muscle cells of the affected artery, in which their physiological quiescent state is lost and replaced by a proliferative activated phenotype. Of interest, dissections in various anatomical locations are associated with distinct sex and age predilections, suggesting involvement of gene and environment interactions in disease pathogenesis. Importantly, these cellular mechanisms are potentially therapeutically targetable. Consideration of arterial dissections as a collective pathology allows insight from the better characterized dissection types, such as that involving the thoracic aorta, to be leveraged to inform the less common forms of dissections, including the potential to apply known therapeutic interventions already clinically available for the former.

Monoclonal gammopathies of clinical significance (MGCS): In pursuit of optimal treatment

Monoclonal gammopathy of clinical significance (MGCS) represents a new clinical entity referring to a myriad of pathological conditions associated with the monoclonal gammopathy of undetermined significance (MGUS). The establishment of MGCS expands our current understanding of the pathophysiology of a range of diseases, in which the M protein is often found. Aside from the kidney, the three main organ systems most affected by monoclonal gammopathy include the peripheral nervous system, skin, and eye. The optimal management of these MGUS-related conditions is not known yet due to the paucity of clinical data, the rarity of some syndromes, and limited awareness among healthcare professionals. Currently, two main treatment approaches exist. The first one resembles the now-established therapeutic strategy for monoclonal gammopathy of renal significance (MGRS), in which chemotherapy with anti-myeloma agents is used to target clonal lesion that is thought to be the culprit of the complex clinical presentation. The second approach includes various systemic immunomodulatory or immunosuppressive options, including intravenous immunoglobulins, corticosteroids, or biological agents. Although some conditions of the MGCS spectrum can be effectively managed with therapies aiming at the etiology or pathogenesis of the disease, evidence regarding other pathologies is severely limited to individual patient data from case reports or series. Future research should pursue filling the gap in knowledge and finding the optimal treatment for this novel clinical category.

The response to growth hormone treatment in a child with short stature, growth hormone deficiency and autosomal dominant cutis laxa type 3 - case report

OBJECTIVES

The aetiology of short stature in cutis laxa (CL) syndromes is largely unknown. Herein, we report a case with autosomal dominant CL type 3 (ADCL3) with severe short stature and growth hormone (GH) deficiency.

CASE PRESENTATION

A male patient with a genetically confirmed diagnosis of ADCL3 was referred for endocrinological evaluation of short stature at the age of 3.4 years. The examination revealed severe proportional short stature (-4.14 standard deviations (SD) score for height) in a patient born small for gestational age (birth weight 2080 g, -2.46 SD, birth length 41 cm, -4.22 SD). Assessment of GH reserve with two clonidine stimulation tests (0.15 mg/m²) with peak GH values of 8.07 ng/mL and 2.98 ng/mL, respectively, were indicative of GH deficiency. Also, the MRI examination revealed a small size pituitary. Thus, the treatment with somatropin was started. The height deficit significantly improved (from -4.14 SD to -1.48 SD) without side effects during the follow-up of 4.5 years.

CONCLUSIONS

With this report, the GH deficiency as a possible cause of short stature in ADCL3 and the response to somatropin administration were reported for the first time in the literature.

Autosomal recessive cutis laxa type 1C with a homozygous LTBP4 splicing variant: a case report and update of literature

BACKGROUND

Autosomal recessive cutis laxa (ARCL) is a heterogeneous disorder with three primary forms (ARCL 1, ARCL 2 and ARCL 3). Latent transforming growth factor beta binding protein 4 (LTBP4) anomalies cause ARCL1C and are connected to different problems in the skin and other organs. Herein, we present a seven month old Iranian boy with a clinical manifestation of ARCL1 with literature review of previous cases with attributes of ARCL1C.

METHODS

Considering the craniofacial characteristics and respiratory distress of the proband, cutis laxa (CL) was expected and whole-exome sequencing (WES) was performed.

RESULTS

In the proband, signs of CL were mainly located in the face, thorax, and abdomen. The prenatal investigation revealed a diaphragmatic hernia and certain uncommon signs, such as an atrial septal defect and pyloric stenosis. The WES showed a novel homozygous mutation (c.533-1G > A) in exon six of the LTBP4 gene.

CONCLUSION

This report showed a new variant with uncommon clinical features, such as a stenosis atrial septal defect and pyloric stenosis, which causes ARCL1C. Unfortunately, the proband developed several heart problems and died at the age of seven months and seven days. Thus, a more in-depth evaluation is needed to clarify the different aspects of CL related to LTBP4 disorder.

Congenital Cutis Laxa: A Case Report and Literature Review

Cutis Laxa is a rare connective tissue disease featuring inelastic and saggy skin. It is thought that plastic surgery might be the most effective treatment, while the previous pieces of literature on the surgical treatment for Cutis Laxa complained of the recurrence. We report a patient of Congenital Cutis Laxa who has received systematic and sequential treatment based on plastic surgery. The patient is content with the effect of treatment, and there are no signs of recurrence after 5 months. By referring to relevant pieces of literature, we evaluate the clinical manifestations and diagnosis of the disease. A multi-step, systematic, and sequential treatment is recommended for the treatment of Congenital Cutis Laxa.

Clinical and Molecular Delineation of Cutis Laxa Syndromes: Paradigms for Homeostasis

Cutis laxa (CL) syndromes are a large and heterogeneous group of rare connective tissue disorders that share loose redundant skin as a hallmark clinical feature, which reflects dermal elastic fiber fragmentation. Both acquired and congenital-Mendelian- forms exist. Acquired forms are progressive and often preceded by inflammatory triggers in the skin, but may show systemic elastolysis. Mendelian forms are often pleiotropic in nature and classified upon systemic manifestations and mode of inheritance. Though impaired elastogenesis is a common denominator in all Mendelian forms of CL, the underlying gene defects are diverse and affect structural components of the elastic fiber or impair metabolic pathways interfering with cellular trafficking, proline synthesis, or mitochondrial functioning. In this chapter we provide a detailed overview of the clinical and molecular characteristics of the different cutis laxa types and review the latest insights on elastic fiber assembly and homeostasis from both human and animal studies.

Basic Components of Connective Tissues and Extracellular Matrix: Fibronectin, Fibrinogen, Laminin, Elastin, Fibrillins, Fibulins, Matrilins, Tenascins and Thrombospondins

Collagens are the most abundant components of the extracellular matrix (ECM) and many types of soft tissues. Elastin is another major component of certain soft tissues, such as arterial walls and ligaments. It is an insoluble polymer of the monomeric soluble precursor tropoelastin, and the main component of elastic fibers in matrix tissue where it provides elastic recoil and resilience to a variety of connective tissues, e.g., aorta and ligaments. Elastic fibers regulate activity of transforming growth factors β (TGFβ) through their association with fibrillin microfibrils. Elastin also plays a role in cell adhesion, cell migration, and has the ability to participate in cell signaling. Mutations in the elastin gene lead to cutis laxa. Many other molecules, though lower in quantity, function as essential, structural and/or functional components of the extracellular matrix in soft tissues. Some of these are reviewed in this chapter. Besides their basic structure, biochemistry and physiology, their roles in disorders of soft tissues are discussed only briefly as most chapters in this volume deal with relevant individual compounds. Fibronectin with its multidomain structure plays a role of "master organizer" in matrix assembly as it forms a bridge between cell surface receptors, e.g., integrins, and compounds such collagen, proteoglycans and other focal adhesion molecules. It also plays an essential role in the assembly of fibrillin-1 into a structured network. Though the primary role of fibrinogen is in clot formation, after conversion to fibrin by thrombin it also binds to a variety of compounds, particularly to various growth factors, and as such, fibrinogen is a player in cardiovascular and extracellular matrix physiology. Laminins contribute to the structure of the ECM and modulate cellular functions such as adhesion, differentiation, migration, stability of phenotype, and resistance towards apoptosis. Fibrillins represent the predominant core of microfibrils in elastic as well as non-elastic extracellular matrixes, and interact closely with tropoelastin and integrins. Not only do microfibrils provide structural integrity of specific organ systems, but they also provide basis for elastogenesis in elastic tissues. Fibrillin is important for the assembly of elastin into elastic fibers. Mutations in the fibrillin-1 gene are closely associated with Marfan syndrome. Latent TGFβ binding proteins (LTBPs) are included here as their structure is similar to fibrillins. Several categories of ECM components described after fibrillins are sub-classified as matricellular proteins, i.e., they are secreted into ECM, but do not provide structure. Rather they interact with cell membrane receptors, collagens, proteases, hormones and growth factors, communicating and directing cell-ECM traffic. Fibulins are tightly connected with basement membranes, elastic fibers and other components of extracellular matrix and participate in formation of elastic fibers. Matrilins have been emerging as a new group of supporting actors, and their role in connective tissue physiology and pathophysiology has not been fully characterized. Tenascins are ECM polymorphic glycoproteins found in many connective tissues in the body. Their expression is regulated by mechanical stress both during development and in adulthood. Tenascins mediate both inflammatory and fibrotic processes to enable effective tissue repair and play roles in pathogenesis of Ehlers-Danlos, heart disease, and regeneration and recovery of musculo-tendinous tissue. One of the roles of thrombospondin 1 is activation of TGFβ. Increased expression of thrombospondin and TGFβ activity was observed in fibrotic skin disorders such as keloids and scleroderma. Cartilage oligomeric matrix protein (COMP) or thrombospondin-5 is primarily present in the cartilage. High levels of COMP are present in fibrotic scars and systemic sclerosis of the skin, and in tendon, especially with physical activity, loading and post-injury. It plays a role in vascular wall remodeling and has been found in atherosclerotic plaques as well.

Dermatologic manifestations of pediatric cardiovascular diseases: Skin as a reflection of the heart

Cutaneous disease can often be an initial clue of an underlying cardiovascular disease. Many congenital conditions (ie, Noonan syndrome with multiple lentigines, Carney complex, and Fabry disease) and acquired conditions may present initially with specific cutaneous features that should prompt clinicians to conduct a full cardiac workup. Given the extensive number of conditions with both cardiovascular and cutaneous findings, this review will focus on diseases with cardiocutaneous pathology with hopes of raising clinician awareness of these associations to decrease morbidity and mortality, as several of these diseases often result in fatal outcomes.

Dynamic Crosstalk between Vascular Smooth Muscle Cells and the Aged Extracellular Matrix

Vascular aging is accompanied by the fragmentation of elastic fibers and collagen deposition, leading to reduced distensibility and increased vascular stiffness. A rigid artery facilitates elastin to degradation by MMPs, exposing vascular cells to greater mechanical stress and triggering signaling mechanisms that only exacerbate aging, creating a self-sustaining inflammatory environment that also promotes vascular calcification. In this review, we highlight the role of crosstalk between smooth muscle cells and the vascular extracellular matrix (ECM) and how aging promotes smooth muscle cell phenotypes that ultimately lead to mechanical impairment of aging arteries. Understanding the underlying mechanisms and the role of associated changes in ECM during aging may contribute to new approaches to prevent or delay arterial aging and the onset of cardiovascular diseases.

PAD2-mediated citrullination of Fibulin-5 promotes elastogenesis

The formation of elastic fibers is active only in the perinatal period. How elastogenesis is developmentally regulated is not fully understood. Citrullination is a unique form of post-translational modification catalyzed by peptidylarginine deiminases (PADs), including PAD1-4. Its physiological role is largely unknown. By using an unbiased proteomic approach of lung tissues, we discovered that FBLN5 and LTBP4, two key elastogenic proteins, were temporally modified in mouse and human lungs. We further demonstrated that PAD2 citrullinated FBLN5 preferentially in young lungs compared to adult lungs. Genetic ablation of PAD2 resulted in attenuated elastogenesis in vitro and age-dependent emphysema in vivo. Mechanistically, citrullination protected FBLN5 from proteolysis and subsequent inactivation of its elastogenic activity. Furthermore, citrullinated but not native FBLN5 partially rescued in vitro elastogenesis in the absence of PAD activity. Our data uncover a novel function of citrullination, namely promoting elastogenesis, and provide additional insights to how elastogenesis is regulated.

Aortic enlargement in chronic obstructive pulmonary disease (COPD) and emphysema: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD study

BACKGROUND

The prevalence of abdominal aortic aneurysm is high in chronic obstructive pulmonary disease (COPD) population. Emphysema involves proteolytic destruction of elastic fibers. Therefore, emphysema may also contribute to thoracic aorta dilatation. This study assessed aorta dilation in smokers stratified by presence of COPD, emphysema and airway thickening.

METHODS

Aorta diameters were measured on 3D magnetic resonance angiography in smokers recruited from the Multi-Ethnic Study of Atherosclerosis (MESA), the Emphysema and Cancer Action Project (EMCAP), and the local community. COPD was defined by standard spirometric criteria; emphysema was measured quantitatively on computed tomography and bronchitis was determined from medical history.

RESULTS

Participants (n = 315, age 58-79) included 150 with COPD and 165 without COPD, of whom 56% and 19%, respectively, had emphysema. Subjects in the most severe quartile of emphysematous change showed the largest diameter at all four aorta locations compared to those in the least severe quartiles (all p < 0.001). Comparing subjects with and without COPD, aorta diameters were larger in participants with severe COPD in ascending and arch (both p < 0.001), and abdominal aorta (p = 0.001). Chronic bronchitis and bronchial wall thickness did not correlate with aorta diameter. In subjects with emphysema, subjects with coexistence of COPD showed larger aorta than those without COPD in ascending (p = 0.003), arch (p = 0.002), and abdominal aorta (p = 0.04).

CONCLUSIONS

This study showed larger aorta diameter in subjects with COPD and severe emphysema compared to COPD related to chronic bronchitis or bronchial wall thickening.

New insight into clinical heterogeneity and inheritance diversity of FBLN5-related cutis laxa

Background

FBLN5-related cutis laxa (CL) is a rare disorder that involves elastic fiber-enriched tissues and is characterized by lax skin and variable systemic involvement such as pulmonary emphysema, arterial involvement, inguinal hernias, hollow viscus diverticula and pyloric stenosis. This type of CL follows mostly autosomal recessive (AR) and less commonly autosomal dominant patterns of inheritance.

Results

In this study, we detected a novel homozygous missense variant in exon 6 of FBLN5 gene (c.G544C, p.A182P) by using whole exome sequencing in a consanguineous Iranian family with two affected members. Our twin patients showed some of the clinical manifestation of FBLN5-related CL but they did not present pulmonary complications, gastrointestinal and genitourinary abnormalities. The notable thing about this monozygotic twin sisters is that only one of them showed ventricular septal defect, suggesting that this type of CL has intrafamilial variability. Co-segregation analysis showed the patients’ parents and relatives were heterozygous for detected variation suggesting AR form of the CL. In silico prediction tools showed that this mutation is pathogenic and 3D modeling of the normal and mutant protein revealed relative structural alteration of fibulin-5 suggesting that the A182P can contribute to the CL phenotype via the combined effect of lack of protein function and partly misfolding-associated toxicity.

Conclusion

We underlined the probable roles and functions of the involved domain of fibulin-5 and proposed some possible mechanisms involved in AR form of FBLN5-related CL. However, further functional studies and subsequent clinical and molecular investigations are needed to confirm our findings.

Emerging insights on the role of V-ATPase in human diseases: Therapeutic challenges and opportunities

The control of the intracellular pH is vital for the survival of all organisms. Membrane transporters, both at the plasma and intracellular membranes, are key players in maintaining a finely tuned pH balance between intra- and extracellular spaces, and therefore in cellular homeostasis. V-ATPase is a housekeeping ATP-driven proton pump highly conserved among prokaryotes and eukaryotes. This proton pump, which exhibits a complex multisubunit structure based on cell type-specific isoforms, is essential for pH regulation and for a multitude of ubiquitous and specialized functions. Thus, it is not surprising that V-ATPase aberrant overexpression, mislocalization, and mutations in V-ATPase subunit-encoding genes have been associated with several human diseases. However, the ubiquitous expression of this transporter and the high toxicity driven by its off-target inhibition, renders V-ATPase-directed therapies very challenging and increases the need for selective strategies. Here we review emerging evidence linking V-ATPase and both inherited and acquired human diseases, explore the therapeutic challenges and opportunities envisaged from recent data, and advance future research avenues. We highlight the importance of V-ATPases with unique subunit isoform molecular signatures and disease-associated isoforms to design selective V-ATPase-directed therapies. We also discuss the rational design of drug development pipelines and cutting-edge methodological approaches toward V-ATPase-centered drug discovery. Diseases like cancer, osteoporosis, and even fungal infections can benefit from V-ATPase-directed therapies.

Inhibition of lysyl oxidase stimulates TGF-β signaling and metalloproteinases-2 and -9 expression and contributes to the disruption of ascending aorta in rats: protection by propylthiouracil

Mutations in lysyl oxidase (LOX) genes cause severe vascular anomalies in mice and humans. LOX activity can be irreversibly inhibited by the administration of β-aminoproprionitrile (BAPN). We investigated the mechanisms underlying the damage to the ascending thoracic aorta induced by LOX deficiency and evaluated whether 6-propylthiouracil (PTU) can afford protection in rats. BAPN administration caused disruption of the ascending aortic wall, increased the number of apoptotic cells, stimulated TGF-β signaling (increase of nuclear p-SMAD2 staining), and up-regulated the expression of metalloproteinases-2 and -9. In BAPN-treated animals, PTU reduced apoptosis, p-SMAD2 staining, MMP-2, and -9 expression, and markedly decreased the damage to the aortic wall. Our results suggest that, as in some heritable vascular diseases, enhanced TGF-β signaling and upregulation of MMP-2 and -9 can contribute to the pathogenesis of ascending aorta damage caused by LOX deficiency. We have also shown that PTU, a drug already in clinical use, protects against the effects of LOX inhibition. MMP-2 and -9 might be potential targets of new therapeutic strategies for the treatment of vascular diseases caused by LOX deficiency.

Ehlers-Danlos Syndrome: Immunologic contrasts and connective tissue comparisons

Ehlers-Danlos Syndrome (EDS) is a family of multisystemic hereditary connective tissue disorders now comprised of 13 recognized subtypes, classical, classical-like, cardiac-valvular, vascular, hypermobile, arthrochlasia, dermosparaxis, kyphoscoliotic, brittle cornea syndrome, spondylodysplastic, musculocontractural, myopathic, and periodontal, as designated by the most recent 2017 International classification system. Clinical presentation of this disease can range from mild manifestations including skin hyperextensibility and joint hypermobility, to more severe complications such as vascular and organ rupture. While there may be accompanying inflammation in some of the subtypes of EDS, the pathogenic mechanisms have not been clearly defined. Thorough evaluation incorporates clinical examination, family history, laboratory testing, and imaging. In recent years, studies have identified multiple gene variants involved in the pathogenesis of specific EDS subtypes as well as elaborate clinical diagnostic criteria and classification models used to differentiate overlapping conditions. The differential diagnosis of EDS includes hypermobility spectrum disorders, Marfan syndrome, Loey-Dietz syndrome, Cutis laxa syndromes, autosomal dominant polycystic kidney disease, osteogenesis Imperfecta Type 1, fibromyalgia, depression, and chronic fatigue syndrome. Surgical treatment is reserved for complications, or emergencies involving vascular or orthopedic injury because of the risk of poor wound healing. Management techniques each have their own consequences and benefits, which will also be discussed in this review article. Patients affected by this spectrum of disorders are impacted both phenotypically and psychosocially, diminishing their quality of life.

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There are 13 of EDS as defined by the International EDS Consortium, some with an identified genetic etiology.

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Skin hyperextensibility, joint hypermobility, easy bruising, and organ rupture are common features of EDS.

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Hypermobile EDS is a poorly defined entity that has been associated with MCAS and POTs.

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The association of hEDS, MCAS and POTS has not been confirmed.

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There is a paucity of evidence for an immunological mechanism for EDS.

Dysregulated assembly of elastic fibers in fibulin-5 knockout mice results in a tendon-specific increase in elastic modulus

Elastic fiber assembly is coordinated in part by fibulin-5, a matricellular protein. When fibulin-5 is not available to guide elastogenesis, elastin forms into disconnected globules instead of the dense elastic fiber core found in healthy tissues. Despite the growing evidence for a significant role of elastic fibers in tendon mechanics and the clinical relevance to cutis laxa, a human disease which can be caused by a mutation in the gene encoding fibulin-5, it is unknown how malformed elastic fibers affect tendon function. Therefore, this study investigated the effects of dysregulated elastic fiber assembly in tendons from fibulin-5 knockout mice in comparison to wild-type controls. Due to evidence for a more prominent role of elastic fibers in tendons with higher functional demands, both the energy-storing Achilles tendon and the more positional tibialis anterior tendon were evaluated. The linear modulus of knockout Achilles tendons was increased compared to controls, yet there was no discernible change in mechanical properties of the tibialis anterior tendon across genotypes. Transmission electron microscopy confirmed the presence of malformed elastic fibers in knockout tendons while no other changes to tendon composition or structure were found. The mechanism behind the increase in linear modulus in fibulin-5 knockout Achilles tendons may be greater collagen engagement due to decreased regulation of strain-induced structural reorganization. These findings support the theory of a significant, functionally distinct role of elastic fibers in tendon mechanics.

Overview of the Pulmonary Manifestations in Patients with Autosomal Recessive Cutis Laxa Type IC

Background: Autosomal recessive cutis laxa type IC (ARCL1C) is characterized by cutis laxa accompanied by pulmonary, gastrointestinal, urinary, musculoskeletal involvement caused by biallelic mutations in latent transforming growth factor-beta binding protein 4 (LTBP4) gene. The overall prognosis is poor, and most patients die in infancy because of severe pulmonary emphysema (PE). Aim: We aimed to evaluate 3 ARCL1C patients, 2 of whom are still alive and in their childhood period, from 2 unrelated families with novel LTBP4 mutations, to demonstrate the clinical variability of pulmonary involvement. Materials and Methods: Three children who were molecularly confirmed by LTBP4 sequencing analysis were comprehensively reviewed in terms of pulmonary manifestations through chest examination, lung function tests (LFTs), chest X-ray, and thorax computed tomography. Results: Family 1 (c.3740A>G LTBP4 mutation): A 5-year-old male patient with pulmonary artery stenosis (PAS) presented with persistent cough and exhibited mild restriction on LFT. Family 2 (c.2T>G LTBP4 mutation): Radiographic examinations revealed PE in a 7-year-old female patient who was operated for diaphragmatic hernia. She had recurrent bronchiolitis and pulmonary infections. LFT revealed both obstructive and restrictive pattern. Her cousin also had respiratory distress with the onset of the newborn period and died due to bilateral pneumothorax in early infancy. Conclusion: The variable severity of pulmonary findings was shown in these patients. It should also be kept in mind that there could be intrafamilial variability of systemic manifestations. Although obstructive lung disease is expected to be seen in ARLC1C patients, restrictive LFT patterns may also be detected as a result of comorbidities such as diaphragmatic hernia and PAS.

Elastic fibers in orthopedics: Form and function in tendons and ligaments, clinical implications, and future directions

Elastic fibers are an essential component of the extracellular matrix of connective tissues. The focus of both clinical management and scientific investigation of elastic fiber disorders has centered on the cardiovascular manifestations due to their significant impact on morbidity and mortality. As such, the current understanding of the orthopedic conditions experienced by these patients is limited. The musculoskeletal implications of more subtle elastic fiber abnormalities, whether due to allelic variants or age-related tissue degeneration, are also not well understood. Recent advances have begun to uncover the effects of elastic fiber deficiency on tendon and ligament biomechanics; future research must further elucidate mechanisms governing the role of elastic fibers in these tissues. The identification of population-based genetic variations in elastic fibers will also be essential. Minoxidil administration, modulation of protein expression with micro-RNA molecules, and direct injection of recombinant elastic fiber precursors have demonstrated promise for therapeutic intervention, but further work is required prior to consideration for orthopedic clinical application. This review provides an overview of the role of elastic fibers in musculoskeletal tissue, summarizes current knowledge of the orthopedic manifestations of elastic fiber abnormalities, and identifies opportunities for future investigation and clinical application.

The fibrillin microfibril/elastic fibre network: A critical extracellular supramolecular scaffold to balance skin homoeostasis

Supramolecular networks composed of fibrillins (fibrillin-1 and fibrillin-2) and associated ligands form intricate cellular microenvironments which balance skin homoeostasis and direct remodelling. Fibrillins assemble into microfibrils which are not only indispensable for conferring elasticity to the skin, but also control the bioavailability of growth factors targeted to the extracellular matrix architecture. Fibrillin microfibrils (FMF) represent the core scaffolds for elastic fibre formation, and they also decorate the surface of elastic fibres and form independent networks. In normal dermis, elastic fibres are suspended in a three-dimensional basket-like lattice of FMF intersecting basement membranes at the dermal-epidermal junction and thus conferring pliability to the skin. The importance of FMF for skin homoeostasis is illustrated by the clinical features caused by mutations in the human fibrillin genes (FBN1, FBN2), summarized as "fibrillinopathies." In skin, fibrillin mutations result in phenotypes ranging from thick, stiff and fibrotic skin to thin, lax and hyperextensible skin. The most plausible explanation for this spectrum of phenotypic outcomes is that FMF regulate growth factor signalling essential for proper growth and homoeostasis of the skin. Here, we will give an overview about the current understanding of the underlying pathomechanisms leading to fibrillin-dependent fibrosis as well as forms of cutis laxa caused by mutational inactivation of FMF-associated ligands.

Recognizing genetic disease: A key aspect of pediatric pulmonary care

Advancement in technology has improved recognition of genetic etiologies of disease, which has impacted diagnosis and management of rare disease patients in the pediatric pulmonary clinic. This review provides an overview of genetic conditions that are likely to present with pulmonary features and require extensive care by the pediatric pulmonologist. Increased familiarity with these conditions allows for improved care of these patients by reducing time to diagnosis, tailoring management, and prompting further investigation into these disorders.

The Importance of Genetic Factors in the Management of Spontaneous Pneumothorax

Purpose of Review

Spontaneous pneumothoraces can be the presenting phenotype in a variety of different syndromic genetic conditions. Respiratory physicians therefore have the opportunity to diagnose and manage these patients early to prevent serious complications associated with these syndromes.

Recent Findings

The genetic syndromes that present with pneumothoraces can be split broadly between those resulting from defective extracellular matrix formation and those caused by defective tumour-suppressor pathways. When connective tissues are weakened, lifelong surveillance for arterial dilatation can be life-saving as surgical intervention is effective. Long-term aggressive treatment of blood pressure can also commence, although some controversy surrounds which drugs are most effective and precisely how these drugs modify disease progression. Rational treatments of syndromes in which tumour suppressor function is lost are being developed and, in some instances, can already be offered.

Summary

Careful clinical assessment of spontaneous pneumothorax may identify an underlying causal condition and facilitate life-saving intervention. Respiratory physicians must therefore be aware of these diseases and their diagnostic criteria.

[Congenital cutis laxa: a case study]

Les « cutis laxa » (CL) sont des affections rares du tissu élastique, caractérisées par une hyperlaxité cutanée. Elles peuvent être congénitales ou acquises. Les formes héréditaires constituent un groupe hétérogène par la gravité de leurs atteintes viscérales et leur mode de transmission. Trois groupes ont été individualisés sur la base de la transmission génétique: autosomique dominante, autosomique récessive et récessive liée à l'X. La sévérité des atteintes viscérales conditionne le pronostic des CL héréditaires qui peut être fatal à brève échéance en cas d'atteinte cardiaque ou pulmonaire. L'objectif de notre travail est de rappeler aux praticiens cette affection rarissime, ceci à travers l'observation d'un nourrisson suivi depuis son seizième jour de vie pour une détresse respiratoire.

Generalized Acquired Cutis Laxa Associated with Monoclonal Gammopathy of Dermatological Significance

Background

Cutis laxa is a rare dermatosis that is inherited or acquired and clinically features loose, wrinkled, and redundant skin with decreased elasticity. This heterogeneous connective tissue disorder may be localized or generalized, with or without internal manifestations. Generalized cutis laxa often has a cephalocaudal progression and is attributed to inflammatory cutaneous eruptions, medications, and infections. Cutis laxa is also associated with several other conditions including rheumatoid arthritis, systemic lupus erythematosus, and plasma-cell dyscrasias. Case Presentation. We report an unusual case of a 35-year-old male with progression of generalized acquired cutis laxa and vasculitis that occurred over a period of one year. No cutaneous inflammatory eruption preceded or accompanied his decreased skin elasticity, and a biopsy of the skin showed elastolysis. His cutaneous manifestation led to systemic evaluation and an eventual diagnosis of smoldering multiple myeloma accompanied by aortitis and anemia. His myeloma and vasculitis were successfully treated with cyclophosphamide, bortezomib, and dexamethasone and high-dose prednisone, respectively, with no improvement to his cutis laxa.

Conclusions

The presence of monoclonal gammopathy is strongly associated with several dermatological entities such as acquired cutis laxa. We propose a new term for the dermatological manifestations caused by paraproteinemia: monoclonal gammopathy of dermatological significance, or MGODS, and stress the evaluation of an underlying gammopathy in the setting of certain dermatologic conditions, including scleromyxedema and amyloidosis. We present a case of a newly acquired cutis laxa secondary to plasma-cell dyscrasias that exemplifies MGODS, alongside a brief literature review, and underscore the clinical relevance of monoclonal gammopathies of dermatological significance.

Cutaneous disorders characterized by elastolysis or loss of elastic tissue

Along with collagen, elastic fibers are integral components of cutaneous connective tissue. A decrease in elastic fibers or loss thereof has been described in a number of clinically distinct skin diseases, both hereditary and acquired. In disorders associated with inflammation, elastophagocytosis is an important histological hallmark. Treatment is generally difficult.

The Skin in Celiac Disease Patients: The Other Side of the Coin

Celiac disease (CD) is an autoimmune enteropathy that primarily affects the small intestine and is characterized by atrophy of intestinal villi. The manifestations of the disease improve following a gluten-free diet (GFD). CD is associated with various extra-intestinal diseases. Several skin manifestations are described in CD patients. The present paper reviews all CD-associated skin diseases reported in the literature and tries to analyze the pathogenic mechanisms possibly involved in these associations. Different hypotheses have been proposed to explain the possible mechanisms involved in every association between CD and cutaneous manifestations. An abnormal small intestinal permeability seems to be implicated in various dermatological manifestations. However, most of the associations between CD and cutaneous diseases is based on case reports and case series and a few controlled studies. To better assess the real involvement of the cutaneous district in CD patients, large multicentric controlled clinical trials are required.

Keratoglobus with ARCL1B (EFEMP2 gene) cutis laxa

Purpose

To report a case of keratoglobus in a patient with autosomal recessive (AR) cutis laxa.

Observations

A 38 year old male presented with decreased vision in both eyes uncorrectable with spectacles and a history of corneal rupture in the left eye from incidental trauma a decade prior. His ocular exam was consistent with keratoglobus. His medical and family history indicated AR cutis laxa.

Conclusions and importance

We believe that this is the first reported case of keratoglobus associated with cutis laxa.

Giant aortic aneurysm due to fibulin- 4 deficiency: case series

Cutis laxa tip1b is a rare autosomal recessive disorder caused by FBLN 4 mutation and primarily characterized by vascular anomalies. Herein, we present five patients who are the members of the same family. The primary cardiac findings of these patients were giant aortic aneurysms. One 2.5-year-old patient with a massive aneurysm of the ascending aorta died as a result of compression to the heart chambers, trachea, and bronchi. The bentall procedure was performed in three of our patients who are under follow-up. One patient is still under clinical follow-up without surgery. After the diagnosis of the first patient, a genetic study was performed in which FBLN 4 mutations were investigated. Four new patients were detected during genetic screening of the family. Other 29 family members were screened bur were negative in physical examinations and echocardiography. Pedigree is important for early diagnosis of genetic diseases in asymptomatic individuals.

Autosomal recessive cutis laxa: a novel mutation in the FBLN5 gene in a family

FBLN5-related cutis laxa (CL) is a rare syndrome that can be inherited in an autosomal dominant or recessive manner. Autosomal recessive cutis laxa (ARCL), type IA, has been reported to be more severe. The disease is characterized by microcephaly, sagging cheeks, loose, wrinkled and redundant skin, emphysema, aorta or pulmonary artery abnormalities, inguinal hernia, and anomalies of internal organs. Homozygous mutations in the FBLN5 gene are responsible for the clinical manifestations. We report a family study of a child with ARCL. FBLN5 genes of the patient and parents were sequenced using next-generation sequencing technologies. Analyses showed that the patient was homozygous for the novel c.518A>G, p.R173H mutation in exon 6 of the FBLN5 gene, whereas the parents were heterozygous. The mutation was found to be 'possibly pathogenic' in bioinformatic analysis. We identified a novel FBLN5 mutation in a CL patient; pedigree and parental genetic analyses suggested ARCL. Our results also suggest that the mutation analysis provides useful evidence to support the clinical diagnosis and define the inheritance mode of CL in an apparently sporadic case.