Pro-Fibrotic Phenotype in a Patient with Segmental Stiff Skin Syndrome via TGF-β Signaling Overactivation

New clinical classification of stiff skin syndrome

BACKGROUND

Stiff skin syndrome (SSS) is a rare disease characterized by thickened, indurated skin and limited joint movement. Multiple diverse phenotypes have been reported, and the correlation of severity with the clinical heterogeneity and histopathological findings of SSS needs to be refined.

OBJECTIVE

To define subtypes based on clinical features and predict the prognosis of a new SSS classification.

METHODS

Eighty-three patients with SSS were retrospectively reviewed for clinicopathological manifestations and routine laboratory workup, including 59 cases obtained from a PubMed search between 1971 and 2022 and 24 cases diagnosed in our department between 2003 and 2022.

RESULTS

Among the 83 patients, 27.7, 41, and 31.3% had classic widespread, generalized segmental, and localized SSS, respectively. Joint immobility was present in 100, 71, and 20% of classic, generalized, and localized cases, respectively. Histopathologic findings were common among the 3 groups, and based on that, we further found a difference in the distribution of proliferative collagen. 54.5% of classic and 50% of generalized cases occurred throughout the dermis or the subcutis, whereas 76% of localized cases were mainly involved in the reticular dermis or subcutis. In patients with incipient localized SSS, 42% (21/50) developed generalized SSS, and only 6% (3/50) progressed to classic SSS, whereas more than half of the incipient generalized SSS cases (60.6%, 20/33) developed classic SSS.

LIMITATIONS

This retrospective study was limited to previously published cases with limited data.

CONCLUSIONS

We propose a distinct clinical classification characterized by lesion distribution, including classic widespread, generalized segmental, and localized SSS, associated with disease severity and prognosis.

Characteristics and onset of presentation of pediatric stiff skin syndrome: A retrospective cohort study of 11 patients in a tertiary care center

BACKGROUND/OBJECTIVE

Stiff skin syndrome (SSS) is a rare disorder characterized by "rock hard" indurated skin affecting different body parts. The localized variant poses a diagnostic challenge, as it is frequently mistaken for other inflammatory connective tissue disorders. The aim of this study is to provide insightful clinical, radiologic and diagnostic data that might prove useful for the evaluation, management and treatment of pediatric patients with segmental SS.

METHODS

This single-center cohort study included patients ≤18 years diagnosed with localized SSS from 1988 to 2021 in a quaternary pediatric healthcare center in Toronto, Canada. Data included demographics, clinical, histopathologic and radiologic features, treatments, and clinical course. Data were summarized with descriptive statistics (mean, standard deviation, medians, interquartile ranges [IQRs]) and frequencies.

RESULTS

A total of 11 patients were included. The sclerotic changes were measured clinically and radiologically, by a total of 16 imaging studies: 13 magnetic resonance imaging (MRI) and 3 ultrasound. MRI readings showed abnormal high signal intensity of the affected tissue correlating with the anatomical site of involvement in all cases, specifically, in the shoulder/pelvic girdle with limb extension. Shear wave ultrasound elastography (SWE) demonstrated higher values within the dermis compared to the control site.

CONCLUSION

The presence of segmental sclerotic changes that affects the pelvic/shoulder girdle with extension to the extremities, in the absence of inflammation on biopsy and abnormal signaling intensity on imaging is suggestive of SSS. Skin SWE is a feasible, noninvasive, and objective instrument to evaluate and monitor sclerotic changes overtime, it could be potentially extrapolated to other pediatric skin sclerotic conditions.

MFAP2 promotes HSCs activation through FBN1/TGF-β/Smad3 pathway

Liver fibrosis is a chronic inflammatory process characterized by the accumulation of extracellular matrix (ECM), which contributes to cirrhosis and hepatocellular carcinoma. Increasing evidence suggests that the activation of hepatic stellate cells (HSCs) under an inflammatory state leads to the secretion of collagens, which can cause cirrhosis. In this study, we analysed data from the Gene Expression Omnibus (GEO) databases to identify differentially expressed genes (DEGs) between quiescent and fibrotic HSCs. We found that Microfibril Associated Protein 2 (MFAP2) was elevated in carbon tetrachloride (CCl4)-induced liver fibrosis and Transforming Growth Factor-Beta 1 (TGF-β1)-activated HSCs. Knockdown of MFAP2 inhibited HSC proliferation and partially attenuated TGF-β-stimulated fibrogenesis markers. Bioinformatics analysis revealed that Fibrillin-1 (FBN1) was correlated with MFAP2, and the expression of FBN1 was significantly upregulated after MFAP2 overexpression. Silencing MFAP2 partially attenuated the activation of HSCs by inhibiting HSC proliferation and decreasing collagen deposits. In vitro results showed that the inhibition of MFAP2 alleviated hepatic fibrosis by inhibiting the activation and inducing the apoptosis of active HSCs in a CCl4-induced mouse model. In conclusion, our results suggest that MFAP2 is a potential target for the clinical treatment of liver fibrosis.

Chronic Exertional Compartment Syndrome Requiring Bilateral Fasciotomy: An Atypical Complication of Familial Stiff Skin Syndrome in a Father and Son

ABSTRACT

Stiff skin syndrome (SSS) is a rare cutaneous disorder characterized by cutaneous fibrosis resulting in the early onset of thickened and indurated skin, joint mobility restrictions, and contractures. We describe a father and son with familial SSS who presented with bilateral exertional pain and a confirmed diagnosis of chronic exertional compartment syndrome on 4-compartment pressure testing. Patients experienced restored functionality with bilateral 4-compartment fasciotomy. Chronic exertional compartment syndrome should be considered in the differential diagnosis of patients with SSS and chronic pain of the lower limbs.

Role of elastic fiber degradation in disease pathogenesis

Elastin is a crucial extracellular matrix protein that provides structural integrity to tissues. Crosslinked elastin and associated microfibrils, named elastic fiber, contribute to biomechanics by providing the elasticity required for proper function. During aging and disease, elastic fiber can be progressively degraded and since there is little elastin synthesis in adults, degraded elastic fiber is not regenerated. There is substantial evidence linking loss or damage of elastic fibers to the clinical manifestation and pathogenesis of a variety of diseases. Disruption of elastic fiber networks by hereditary mutations, aging, or pathogenic stimuli results in systemic ailments associated with the production of elastin degradation products, inflammatory responses, and abnormal physiology. Due to its longevity, unique mechanical properties, and widespread distribution in the body, elastic fiber plays a central role in homeostasis of various physiological systems. While pathogenesis related to elastic fiber degradation has been more thoroughly studied in elastic fiber rich tissues such as the vasculature and the lungs, even tissues containing relatively small quantities of elastic fibers such as the eyes or joints may be severely impacted by elastin degradation. Elastic fiber degradation is a common observation in certain hereditary, age, and specific risk factor exposure induced diseases representing a converging point of pathological clinical phenotypes which may also help explain the appearance of co-morbidities. In this review, we will first cover the role of elastic fiber degradation in the manifestation of hereditary diseases then individually explore the structural role and degradation effects of elastic fibers in various tissues and organ systems. Overall, stabilizing elastic fiber structures and repairing lost elastin may be effective strategies to reverse the effects of these diseases.

Classification and rising medication therapy in stiff skin syndrome: A case report and literature review

Stiff skin syndrome (SSS) is a rare disorder characterized by skin induration and limited joint mobility in the absence of visceral, musculoskeletal, vascular, or immunologic abnormalities. Distinctive subsets of SSS could be distinguished by various manifestation and mechanism, which accounts for the high heterogeneity in SSS cases. Although rehabilitation training remains the mainstay of management, rising medications has drawn awareness in recent years, owing to the potential efficacy. Nevertheless, experience was limited, especially in widespread SSS. We report on a 5-year-old girl with widespread SSS, whose lesion stopped progressing after combination therapy by mycophenolic acid (MPA) and losartan (LST) in addition to rehabilitation exercise. Despite limited experience, a combined therapy of MPA and LST seems to be effective in retarding progression of widespread SSS.

Transcriptome Analysis Reveals Altered Expression of Genes Involved in Hypoxia, Inflammation and Immune Regulation in Pdcd10-Depleted Mouse Endothelial Cells

Cerebral cavernous malformations (CCM) are capillary malformations affecting the central nervous system and commonly present with headaches, epilepsy and stroke. Treatment of CCM is symptomatic, and its prevention is limited. CCM are often sporadic but sometimes may be multifocal and/or affect multiple family members. Heterozygous pathogenic variants in PDCD10 cause the rarest and apparently most severe genetic variant of familial CCM. We carried out an RNA-Seq and a Q-PCR validation analysis in Pdcd10-silenced and wild-type mouse endothelial cells in order to better elucidate CCM molecular pathogenesis. Ninety-four differentially expressed genes presented an FDR-corrected p-value < 0.05. A functionally clustered dendrogram showed that differentially expressed genes cluster in cell proliferation, oxidative stress, vascular processes and immune response gene-ontology functions. Among differentially expressed genes, the major cluster fell in signaling related to inflammation and pathogen recognition, including HIF1α and Nos2 signaling and immune regulation. Validation analysis performed on wild-type, Pdcd10-null and Pdcd10-null reconstituted cell lines was consistent with RNA-Seq data. This work confirmed previous mouse transcriptomic data in endothelial cells, which are recognized as a critical tissue for CCM formation and expands the potential molecular signatures of PDCD10-related familial CCM to alterations in inflammation and pathogen recognition pathways.

Recombinant TSG-6 protein inhibits the growth of capsule fibroblasts in frozen shoulder via suppressing the TGF-β/Smad2 signal pathway

Background

The tumor necrosis factor-stimulated gene-6 (TSG-6) has been confirmed to inhibit inflammation. It is now generally accepted that local inflammatory stimulation around shoulder capsule causes proliferative fibrosis. This study aims to investigate the mechanism of recombinant TSG-6 protein inhibiting the growth of capsule fibroblasts in frozen shoulder via the TGF-β/Smad2 signal pathway.

Methods

Human frozen shoulder capsule tissue was taken for primary and passage culture, and the 3rd generation fibroblasts from pathological frozen shoulder capsule were treated with different concentrations of recombinant TSG-6 protein, or with TGF-β1 agonist SRI-011381. Immunoconfocal analysis was used to identify the isolated fibroblasts, and MTT assay, colony formation assay, and flow cytometry were used to detect the viability, proliferation, and apoptosis rate of fibroblast. The contents of fibrosis and inflammation indexes COL1A1, TNF-α, IL-6, and IL-1β in the cell supernatant were detected using ELISA and then further examined by qRT-PCR. The expression of Bax, Bcl-2, and proteins related to TGF-β/Smad2 pathway were detected by Western Blot.

Results

Compared with the blank control group, fibroblasts intervened with TSG-6 (2 μg and 5 μg) showed significantly decreased viability and proliferation ability and enhanced cell apoptosis, concurrent with the reductions in Bcl-2 expression; COL1A1, TNF-α, IL-6, and IL-1β levels; and the expression of TGF-β1 and phosphorylated Smad22, and an increase in Bax expression, while SRI-011381 treatment would reverse the effect of recombinant TSG-6 protein.

Conclusion

Recombinant TSG-6 protein inhibited the growth of primary fibroblasts from human frozen shoulder capsule by suppressing the TGF-β/Smad2 signaling pathway.

Segmental stiff skin syndrome (SSS): Clinical case and a brief review

Stiff skin syndrome (SSS) is a rare, scleroderma-like condition that is commonly characterised by stony hard skin and limited joint mobility, in the absence of visceral involvement or immunologic abnormalities. Depending on the distribution of the disease, this disorder can be further categorised into classic (widespread) SSS or its newly described segmental variant. Additional features of this syndrome may include hypertrichosis, lipodystrophy, dysmetria and scoliosis. In this report, we present the case of a patient with segmental SSS and we briefly review the current literature about the topic.