The prognostic values of plasma desmosines, crosslinking molecules of elastic fibers, in the disease progression of Moyamoya disease.

Moyamoya disease (MMD) is a cerebrovascular disease which is characterized by the chronic progression of steno-occlusive changes at the terminal portion of internal carotid arteries and the development of "moyamoya vessels." Dysregulation of the extracellular matrix is regarded as a key pathophysiology underlying unique vascular remodeling. Here, we measured the concentration of elastin crosslinkers desmosine and isodesmosine in the plasma of MMD patients. We aimed to reveal its diagnostic values of desmosines in the progression of steno-occlusive lesions. The concentrations of plasma desmosines were determined by liquid chromatography-tandem mass spectrometry. The temporal profiles of steno-occlusive lesions on magnetic resonance angiography were retrospectively evaluated, and the correlation between the progression of steno-occlusive changes in intracranial arteries and plasma desmosines concentrations was further analyzed. Plasma desmosines were significantly higher in MMD patients with disease progression compared to MMD patients without disease progression. Also, the incidence of disease progression was higher in MMD patients with plasma desmosines levels over limit of quantitation (LOQ) than those with plasma desmosines levels below LOQ. In conclusion, plasma desmosines could be potential biomarkers to predict the progression of steno-occlusive changes in MMD patients.

Stereological comparison of smooth muscle, collagen, and elastic fibers of the clitoris and glans penis in young adults.

OBJECTIVE: To compare the collagen, elastic fibers, and smooth muscle content of the clitoris and the glans penis in young adults. MATERIALS AND METHODS: The clitoris and the glans penis of six women and six men (mean age 25±3) who died as a result of accidents were excised. The samples were placed under a formaldehyde solution and histologically processed. Masson's trichrome and Weigert's resorcin-fuchsin stain was used to highlight the elastic fibers, smooth muscle, and collagen. Stereological analysis was conducted in 5 random fields of 5 slides for each sample. For statistical analysis, the unpaired t-test was used to compare values between groups, and a value of P<0.05 was considered as significant for all analyses. RESULTS: Stereology revealed a mean smooth muscle content of 35.84±6.46% and 31.64±4.74% for the clitoris and glans penis, respectively, while it also revealed collagen content of 26.11±7.41% and 28.44±3.55% and elastic fibers content of 24.12±4.34% and 30.97±6.13% for the clitoris and glans penis, respectively. The statistical analysis showed no significant differences between them. CONCLUSION: Regardless of anatomical differences, the volumetric density of collagen, elastic fibers, and smooth muscle were similar for the clitoris and glans penis in young adults, a feature possibly explained by their embryology.

Qualitative Assessment of Collagen and Elastic Fibers in Oral Submucous Fibrosis (OSMF), OSMF with Dysplasia and Oral Squamous Cell Carcinoma Arising from OSMF: A Histochemical Study.

BACKGROUND: Oral submucous fibrosis (OSMF) is a habit related potentially malignant disorder seen mainly in South Asian people. The malignancy arising from OSMF has been regarded as low grade with better outcome. The present study was orchestrated to histochemically analyze collagen and elastic fibres in OSMF without dysplasia, OSMF with dysplasia and OSMF turning malignant. MATERIALS AND METHODS: 100 cases (80 cases and 20 healthy controls) were included after obtaining clearance from ethical committee. All cases were subjected to Van Gieson staining for collagen and a novel simple method for elastic fibres (Orcein staining). Data were analyzed using SPSS software. RESULTS: Controls showed haphazard arrangement of collagen and elastic fibres. The collagen bundles were parallelly arranged in OSMF without dysplasia and OSMF with dysplasia; the collagen was however haphazard in cases of OSMF turning malignant. As with collagen, elastic fibres were also haphazardly arranged in the control group; in contrast, the elastic fibres were predominantly arranged in a criss-cross pattern in the other study groups. The difference in orientation and density among the groups was statistically significant. CONCLUSION: With advancement of stage there is increased collagenization of OSMF, as the condition acquires dysplastic changes and turns malignant, microenvironment alters resulting in increased activity of collagenases. However, the arrangement of more resistant elastic fibres depicts the better outcome, once OSMF shows malignant transformation, limiting locoregional and distant spread.

Insights into elastic fiber fragmentation: Mechanisms and treatment of aortic aneurysm in Marfan syndrome.

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in fibrillin 1 (FBN1) gene. These mutations result in defects in the skeletal, ocular, and cardiovascular systems. Aortic aneurysm is the leading cause of premature mortality in untreated MFS patients. Elastic fiber fragmentation in the aortic vessel wall is a hallmark of MFS-associated aortic aneurysms. FBN1 mutations result in FBN1 fragments that also contribute to elastic fiber fragmentation. Although recent research has advanced our understanding of MFS, the contribution of elastic fiber fragmentation to the pathogenesis of aneurysm formation remains poorly understood. This review provides a comprehensive overview of the molecular mechanisms of elastic fiber fragmentation and its role in the pathogenesis of aortic aneurysm progression. Increased comprehension of elastic fragmentation has significant clinical implications for developing targeted interventions to block aneurysm progression, which would benefit not only individuals with Marfan syndrome but also other patients with aneurysms. Moreover, this review highlights an overlooked connection between inhibiting aneurysm and the restoration of elastic fibers in the vessel wall with various aneurysm inhibitors, including drugs and chemicals. Investigating the underlying molecular mechanisms could uncover innovative therapeutic strategies to inhibit elastin fragmentation and prevent the progression of aneurysms.

Pseudoxanthoma-elasticum-like changes on the soft palate.

Pseudoxanthoma elasticum (PXE) is an autosomal recessive genetic disorder characterized by aberrant fragmentation and calcification of elastic fibers, leading to characteristic cutaneous, ophthalmic, and cardiovascular manifestations. PXE demonstrates significant phenotypic variability; involvement of the oral mucosa may be the only clue to the diagnosis. Reports on mucous membrane involvement in PXE are scarce. Here, we present a case of PXE-like changes in the oral cavity. A 70-year-old male patient presented with a painless leukoplakic lesion on the soft palate. Biopsy revealed numerous degenerated fibers in the lamina propria. Verhoeff-van Gieson and von Kossa staining confirmed their identity as calcified elastic fibers. A histopathological diagnosis of PXE-like changes was made; the patient was referred to ophthalmology where angioid streaks were visualized fundoscopically. PXE-like changes in the absence of the characteristic genetic mutation have also been reported with or without systemic manifestations. Furthermore, PXE-like changes have been reported in up to 10% of oral biopsy specimens undertaken without clinical suspicion for PXE. Therefore, the significance of such changes in isolation is unclear. Clinicians and pathologists should be aware of the potential oral manifestations of PXE to facilitate prompt diagnosis and subspecialist referral.

Differentiating morphea from lichen Sclerosus by using multiphoton microscopy combined with U-Net model for elastic fiber segmentation.

This paper describes a methodology to differentiate morphea from lichen sclerosus based on examination with multiphoton microscopy (MPM) composed of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Subcellular-resolution images were acquired by MPM from unstained lesion tissues then process spectral analysis to quantify the TPEF and SHG signals. Moreover, U-Net was employed to segment elastic fiber in TPEF images to combine with collagen fiber in SHG images for precise fiber quantification. Predictions of segmentation showed excellent performance on several evaluation indicators. The mIoU, mPA, and F1 score reach 0.8516, 0.9281, and 0.941. The quantitative analysis demonstrated the increase of collagen fibers in morphea compared to that in lichen sclerosus cases. Meanwhile, the great diminution of elastic fiber in the dermis of lichen sclerosus was depicted based on MPM imaging. Thus, MPM was comparable to the histopathological examination and our experimental results accurately distinguish between morphea and lichen sclerosus.

Papillary dermal elastolysis histopathology mimicking folliculotropic mycosis fungoides.

Papillary dermal elastolysis is a rare acquired disease of the elastic tissue that mainly affects elderly women with a clinical presentation of small firm papules in the neck, the supraclavicular areas and the upper back. Histopathologically, it is characteristic to find a complete or almost complete absence of elastic fibers in the papillary dermis with stains such as orcein or Verhoeff-Van Gieson. We present the case of an adult female patient presenting a clinical picture of years of evolution of elastic skin-colored papules on her neck, occasionally pruritic. Two biopsies were performed. In one of them an inflammatory infiltrate affecting the hair follicles was observed, and she was diagnosed with mycosis fungoides. The other biopsy showed a total absence of elastic fibers in the papillary dermis and was diagnosed as elastolysis of the papillary dermis. In early stages of papillary dermal elastolysis, a perivascular and periadnexal lymphocytic inflammatory infiltrate has been described, as is the case described above. It is important for dermatopathologist to know this atypical but possible presentation, as it may require a differential diagnosis with other entities such as follicular mycosis fungoides.

Linear focal elastosis.

Linear focal elastosis (LFE) is an uncommon, benign, acquired elastotic condition with uncertain pathogenesis. It is characterized clinically by asymptomatic, multiple, yellowish, elevated, irregularly indurated, striae-like lines or bands distributed horizontally across the lower and middle part of the posterior trunk. The histopathological hallmark of LFE is a focal increase of elastic fibres in the dermis. The differential diagnosis is varied, and striae distensae is the closest mimic of LFE. Response of LFE to treatment is often poor. The focus of this article is to provide insights into this condition for dermatologists.

Specific Overexpression of YAP in Vascular Smooth Muscle Attenuated Abdominal Aortic Aneurysm Formation by Activating Elastic Fiber Assembly via LTBP4.

Abdominal aortic aneurysm (AAA) is a fatal vascular disease. Vascular smooth muscle cells (VSMCs) play a crucial role in the pathogenesis of AAA. Increasing evidence has shown that Yes-associated protein (YAP) is involved in diverse vascular diseases. However, the role of YAP in AAA remains unclear. The current study aimed to determine the role of YAP in AAA formation and the underlying mechanism. We found that YAP expression in VSMCs was markedly decreased in human and experimental AAA samples. Furthermore, VSMC-specific YAP overexpression prevented several pathogenic factor-induced AAA. Mechanistically, YAP overexpression in VSMCs promoted latent transforming growth factor-ß binding protein 4 (LTBP4) expression, an important factor in elastic fiber assembly. Finally, silencing of LTBP4 in VSMCs abolished the protective role of YAP in AAA formation in vivo. Our results suggest that YAP promotes LTBP4-mediated elastic fibril assembly in VSMCs, which mitigates elastin degradation and AAA formation.

Perieccrine Coil Elastosis: An Unusual and Previously Unrecognized Aging-Related Phenomenon.

ABSTRACT: Elastic fibers are present as a thin line around the normal secretory coil of eccrine and apocrine glands, although they are virtually imperceptible with hematoxylin-eosin staining. Skin aging is a consequence of intrinsic and extrinsic factors, and glycation and ultraviolet irradiation are involved in this process favoring elastosis. We report an unusual and prominent perieccrine elastosis on the left temple in the vicinity of a basal cell carcinoma in a 78-year old man with type 2 diabetes, dyslipidemia, and hypertension. Very thick multilamellar and tortuous elastic fibers surrounded the eccrine coils. This increased amount of elastic fibers was confirmed by orcein staining as well as amyloid-P and lysozyme immunostaining. Perieccrine coil elastosis is a very unusual phenomenon that to the best of our knowledge has not been reported. Similar to dermal actinic elastosis, the presence of perieccrine coil elastosis in a skin cancer microenvironment might hypothetically promote tumor growth because of the release of elastin-derived peptides.

[Idiopathic pleuroparenehymal fibroelastosis: five case reports and review of literature].

Objective: To raise the awareness of idiopathic pleuroparenehymal fibroelastosis (iPPFE) through investigating the clinical, radiographic and pathological features. Methods: Five cases of iPPFE proved by pathology. The clinical data were studied respectively, and the relevant literature was reviewed. Results: All the cases of iPPFE were manifested by cough and dyspnea. The patients including 3 males and 2 females, aged from 30 to 70 years Chest CT scan showed pleural thickening, subpleural consolidation in both upper lungs complicated with tractive bronchiectasis.Computed tomography-guided percutaneous lung biopsy or surgical lung were performed and the same pathological showed pleura and subpleural dense elastic and collagen fibers. The elastic fibers stain was also positive,which was consistent with PPFE. One patient received low-dose corticosteroid, two received pirfenidone therapy, the others received no treatment. Three patients were stable during the follow-up. Conclusions: iPPFE has characteristic pathological features. However, the number of clinically reported cases is low due to missed diagnosis or misdiagnosed. Improving the understanding of features of iPPFE is helpful for the dianosis, therapy, and prognosis of this disease.

A Retrospective Study of 105 Patients with Elastolytic Giant Cell Granuloma and a Proposal for a New Clinical Classification.

Elastolytic giant cell granuloma, an idiopathic granulomatous dermatosis, is characterized by annular plaques on sun-exposed areas, and has been termed actinic granuloma or annular elastolytic giant cell granuloma. Many atypical clinical manifestations and lesions involving sun-protected areas have been reported. The aims of this retrospective study of 105 patients were to summarize the clinical and histological features of patients with this condition; to provide evidence for the viewpoint that elastolytic giant cell granuloma is a better term to include all clinical morphological types presenting with elastolysis, elastophagocytosis, and an infiltrate of multinucleated giant cells histologically; and to establish a new clinical classification. The varying clinical manifestations were further categorized into annular, papular, giant, mixed and generalized forms. The pathological manifestations were classified into giant cell, necrobiotic, histiocytic, sarcoidal and mixed patterns. Diabetes mellitus or impaired glucose tolerance were the most commonly identified comorbidities. Oral low-dose corticosteroid may be an effective treatment.

Zebrafish as a Model to Study Vascular Elastic Fibers and Associated Pathologies.

Many extensible tissues such as skin, lungs, and blood vessels require elasticity to function properly. The recoil of elastic energy stored during a stretching phase is provided by elastic fibers, which are mostly composed of elastin and fibrillin-rich microfibrils. In arteries, the lack of elastic fibers leads to a weakening of the vessel wall with an increased risk to develop cardiovascular defects such as stenosis, aneurysms, and dissections. The development of new therapeutic molecules involves preliminary tests in animal models that recapitulate the disease and whose response to drugs should be as close as possible to that of humans. Due to its superior in vivo imaging possibilities and the broad tool kit for forward and reverse genetics, the zebrafish has become an important model organism to study human pathologies. Moreover, it is particularly adapted to large scale studies, making it an attractive model in particular for the first steps of investigations. In this review, we discuss the relevance of the zebrafish model for the study of elastic fiber-related vascular pathologies. We evidence zebrafish as a compelling alternative to conventional mouse models.

Degeneration and Regeneration of Smooth Muscle Cells in Two Different Abdominal Aortic Aneurysm Models in Rabbits.

BACKGROUND: We aimed to investigate the formation and self-healing process of rabbit abdominal aortic aneurysm (AAA) by focus on the degeneration and regeneration of smooth muscle cells (SMCs) in elastase-induced AAA model and enlarging AAA model in rabbits. METHODS: Sixty rabbits were equally divided into 2 aneurysm groups (Group A and Group B). Rabbits received a 10-min incubation of elastase in Group A (10 units/µL) and Group B (1 unit/µL). Rabbits underwent aortic stenosis above the incubated segment in Group B. Aortic diameter was measured and rabbits were sacrificed for histopathological and immunohistochemical studies. RESULTS: The incubated aorta dilated immediately and ran up to maxima by day 21 in Group A. All aneurysms formed by day 21 and enlarged progressively in Group B. SMCs content, elastin content and intima-media thickness decreased significantly by day 0 in Group A. SMCs and elastic fibers were destroyed gradually in Group B, however, SMCs content was significantly lower than Group A by day 70. Intimal thickness increased significantly by day 70 in the Aneurysm groups. MMP2 maintained moderate expression in Group A, which decreased significantly by day 3 in Group B. MMP9 and RAM11 expressions were higher by day 1, but decreased significantly by day 3 in Group B. CONCLUSIONS: Irreversible degeneration of SMCs is critical to a rapid formation of elastase-induced rabbit AAA model, and SMCs excessive regeneration accounts for the selfhealing process. SMCs degradation and regeneration remain relatively stable in an enlarging AAA model. SMCs should be the key target for studying the mechanism of AAA and intervention therapy.

A Second Case of Localized Cutaneous Amyloid Elastosis: Expanding the Discussion of Associations With a Unique Histopathologic Entity.

ABSTRACT: Amyloid elastosis is an exceedingly rare form of amyloidosis characterized by amyloid material deposited on dermal elastic fibers. Most reported cases have been associated with systemic amyloid light-chain amyloidosis. A single previously reported case of amyloid elastosis showed evidence that the amyloid material was derived from light-chain proteins and was associated with a monoclonal plasma cell infiltrate but failed to demonstrate systemic involvement. As a result, the case was felt to represent localized cutaneous amyloid elastosis. We present a case of localized cutaneous amyloid elastosis that is not associated with a definitive monotypic plasma cell population or with systemic amyloidosis. We also review the clinical and histopathologic features of reported cases of amyloid elastosis and discuss possible etiologic considerations. Because amyloid elastosis can be either localized to the skin or associated with systemic involvement, additional workup to exclude an underlying plasma cell dyscrasia or hematologic malignancy is warranted.

Microstructural Characterization of Resistance Artery Remodelling in Diabetes Mellitus.

INTRODUCTION: Microvascular remodelling is a symptom of cardiovascular disease. Despite the mechanical environment being recognized as a major contributor to the remodelling process, it is currently only understood in a rudimentary way. OBJECTIVE: A morphological and mechanical evaluation of the resistance vasculature in health and diabetes mellitus. METHODS: The cells and extracellular matrix of human subcutaneous resistance arteries from abdominal fat biopsies were imaged using two-photon fluorescence and second harmonic generation at varying transmural pressure. The results informed a two-layer mechanical model. RESULTS: Diabetic resistance arteries reduced in wall area as pressure was increased. This was attributed to the presence of thick, straight collagen fibre bundles that braced the outer wall. The abnormal mechanical environment caused the internal elastic lamina and endothelial and vascular smooth muscle cell arrangements to twist. CONCLUSIONS: Our results suggest diabetic microvascular remodelling is likely to be stress-driven, comprising at least 2 stages: (1) Laying down of adventitial bracing fibres that limit outward distension, and (2) Deposition of additional collagen in the media, likely due to the significantly altered mechanical environment. This work represents a step towards elucidating the local stress environment of cells, which is crucial to build accurate models of mechanotransduction in disease.

Penile Lichen Sclerosus and "Nevus Elasticus".

The association between penile lichen sclerosus and striking accumulation of elastic fibers in deep dermis has been described in rare reports, mostly in vulvar lesions. We describe one case of severe balanopreputial adhesions related to lichen sclerosus and this form of elastosis, with no concomitant neoplasia. Aggregates of elastic fibers were seen in deep dermis and in blood vessels. The lesion mirrors nevus elasticus and nevus elasticus vascularis - a well described cutaneous lesion with no known association with lichen sclerosus.

PKCδ deficiency inhibits fetal development and is associated with heart elastic fiber hyperplasia and lung inflammation in adult PKCδ knockout mice.

Protein kinase C-delta (PKCδ) has a caspase-3 recognition sequence in its structure, suggesting its involvement in apoptosis. In addition, PKCδ was recently reported to function as an anti-cancer factor. The generation of a PKCδ knockout mouse model indicated that PKCδ plays a role in B cell homeostasis. However, the Pkcrd gene, which is regulated through complex transcription, produces multiple proteins via alternative splicing. Since gene mutations can result in the loss of function of molecular species required for each tissue, in the present study, conditional PKCδ knockout mice lacking PKCδI, II, IV, V, VI, and VII were generated to enable tissue-specific deletion of PKCδ using a suitable Cre mouse. We generated PKCδ-null mice that lacked whole-body expression of PKCδ. PKCδ+/- parental mice gave birth to only 3.4% PKCδ-/- offsprings that deviated significantly from the expected Mendelian ratio (χ2(2) = 101.7, P < 0.001). Examination of mice on embryonic day 11.5 (E11.5) showed the proportion of PKCδ-/- mice implanted in the uterus in accordance with Mendelian rules; however, approximately 70% of the fetuses did not survive at E11.5. PKCδ-/- mice that survived until adulthood showed enlarged spleens, with some having cardiac and pulmonary abnormalities. Our findings suggest that the lack of PKCδ may have harmful effects on fetal development, and heart and lung functions after birth. Furthermore, our study provides a reference for future studies on PKCδ deficient mice that would elucidate the effects of the multiple protein variants in mice and decipher the roles of PKCδ in various diseases.