Scleroderma: An insight into causes, pathogenesis and treatment strategies

M2 macrophage polarization in systemic sclerosis fibrosis: pathogenic mechanisms and therapeutic effects

Systemic sclerosis (SSc, scleroderma), is an autoimmune rheumatic disease characterized by fibrosis of the skin and internal organs, and vasculopathy. Preventing fibrosis by targeting aberrant immune cells that drive extracellular matrix (ECM) over-deposition is a promising therapeutic strategy for SSc. Previous research suggests that M2 macrophages play an essential part in the fibrotic process of SSc. Targeted modulation of molecules that influence M2 macrophage polarization, or M2 macrophages, may hinder the progression of fibrosis. Here, in an effort to offer fresh perspectives on the management of scleroderma and fibrotic diseases, we review the molecular mechanisms underlying the regulation of M2 macrophage polarization in SSc-related organ fibrosis, potential inhibitors targeting M2 macrophages, and the mechanisms by which M2 macrophages participate in fibrosis.

Survival in Swedish patients with systemic sclerosis: a nationwide population-based matched cohort study

OBJECTIVES

To conduct the first-ever nationwide, population-based cohort study investigating survival patterns of all patients with incident SSc in Sweden compared with matched individuals from the Swedish general population.

METHODS

We used the National Patient Register to identify patients with incident SSc diagnosed between 2004 and 2015 and the Total Population Register to identify comparators (1:5), matched on sex, birth year and residential area. We followed them until death, emigration or the end of 2016. Follow-up of the general population comparators started the same date as their matched patients were included. We estimated all-cause survival using the Kaplan-Meier method, crude mortality rates and hazard ratios (HRs) using flexible parametric models.

RESULTS

We identified 1139 incident patients with SSc and 5613 matched comparators. The median follow-up was 5.0 years in patients with SSc and 6.0 years for their comparators. During follow-up, 268 deaths occurred in patients with SSc and 554 in their comparators. The 5-year survival was 79.8% and the 10-year survival was 67.7% among patients with SSc vs 92.9% and 84.8%, respectively, for the comparators (P < 0.0001). The mortality rate in patients with SSc was 42.1 per 1000 person-years and 15.8 per 1000 person-years in their comparators, corresponding to an HR of 3.7 (95% CI 2.9, 4.7) at the end of the first year of follow-up and 2.0 (95% CI 1.4, 2.8) at the end of the follow-up period.

CONCLUSION

Despite advances in understanding the disease and in diagnostic methods over the past decades, survival is still severely impacted in Swedish patients diagnosed with SSc between 2004 and 2015.

Downregulation of Vascular Hemeoxygenase-1 Leads to Vasculopathy in Systemic Sclerosis

Systemic sclerosis (SSc) is a terminal disease characterized by vasculopathy, tissue fibrosis, and autoimmunity. Although the exact etiology of SSc remains unknown, endothelial dysfunction, oxidative stress, and calcium handling dysregulation have been associated with a large number of SSc-related complications such as neointima formation, vasculogenesis, pulmonary arterial hypertension, impaired angiogenesis, and cardiac arrhythmias. Hemeoxygenase-1 (HO-1) is an antioxidant enzyme involved in multiple biological actions in the cardiovascular system including vascular tone, angiogenesis, cellular proliferation, apoptosis, and oxidative stress. The aim of this work was to investigate the physiological role of HO-1 and its relevance in the cardiovascular complications occurring in SSc. We found that, in early phases of SSc, the expression of HO-1 in dermal fibroblast is lower compared to those isolated from healthy control individuals. This is particularly relevant as reduction of the HO-1/CO signaling pathway is associated with endothelial dysfunction and vasculopathy. We show evidence of the role of HO-1/carbon monoxide (CO) signaling pathway in calcium handling. Using an in vitro model of pulmonary arterial hypertension (PAH) we investigated the role of HO-1 in Ca2+ mobilization from intracellular stores. Our results indicate that HO-1 regulates calcium release from intracellular stores of human pulmonary arterial endothelial cells. We interrogated the activity of HO-1 in angiogenesis using an organotypic co-culture of fibroblast-endothelial cell. Inhibition of HO-1 significantly reduced the ability of endothelial cells to form tubules. We further investigated if this could be associated with cell motility or migration of endothelial cells into the extracellular matrix synthesized by fibroblasts. By mean of holographic imaging, we studied the morphological and functional features of endothelial cells in the presence of an HO-1 activator and selective inhibitors. Our results demonstrate that inhibition of HO-1 significantly reduces cell proliferation and cell motility (migration) of cultured endothelial cells, whilst activation of HO-1 does not modify either morphology, proliferation or motility. In addition, we investigated the actions of CO on the Kv7.1 (KCQN1) channel current, an important component of the cardiac action potential repolarization. Using electrophysiology (whole-cell patch-clamp in a recombinant system overexpressing the KCQN1 channel), we assessed the regulation of KCQN1 by CO. CORM-2, a CO donor, significantly reduced the Kv7.1 current, suggesting that HO-1/CO signaling may play a role in the modulation of the cardiac action potential via regulation of this ion channel. In summary, our results indicate a clear link between: 1) downregulation of HO-1/CO signaling; and 2) pathophysiological processes occurring in early phases of SSc, such as calcium homeostasis dysregulation, impaired angiogenesis and cardiac arrhythmias. A better understanding of the canonical actions (mainly due to the biological actions of CO), and non-canonical actions of HO-1, as well as the interaction of HO-1/CO signaling with other gasotransmitters in SSc will contribute to the development of novel therapeutic approaches.

Incidence and prevalence of systemic sclerosis in Sweden, 2004-2015, a register-based study

OBJECTIVES

we aim to present an in-depth report of the incidence and prevalence of systemic sclerosis (SSc) in Sweden in a nation-wide register-based study covering the entire Swedish population METHODS: each individual residing in Sweden is given a unique personal identity number. We linked the National Patient Register and the Total Population Register to identify 1) patients with prevalent SSc on 2015-12-31 and 2) patients with incident SSc during the time period 2004-2015 based on ICD-10 codes. We estimated prevalence and incidence overall and stratified on age, sex, and county.

RESULTS

we identified 1774 prevalent cases, median age was 65 years (IQR 19.2) and 84% were women. The point prevalence estimate was 22.7 per 100,000 (95%CI 13.3-32.0). 1139 individuals were newly diagnosed with SSc during 2004-2015 with a median age of 60 years (IQR 20.6) and 80% were women. The mean standardized incidence was 11.9 per 1,000,000 person-years (95%CI 5.1-18.7). The annual incidence remained stable over the study period. Women had five times higher incidence and prevalence than men. The highest prevalence stratified by age strata was observed in the group aged 70-79.

CONCLUSION

SSc incidence and prevalence in Sweden are comparable to estimates from southern Europe, as opposed to the previous assumption of lower occurrence in northern Europe. We further observe that SSc incidence has been rather constant throughout recent years in Sweden with no obvious increase.

Case Report: Chemotherapy-Associated Systemic Sclerosis: Is DNA Damage to Blame?

Systemic sclerosis, also known as scleroderma, is an autoimmune disease characterized by cutaneous and visceral fibrosis, immune dysregulation, and vasculopathy. Generally, the degree of skin fibrosis is associated with an increased likelihood of visceral organ involvement. Its pathogenesis is poorly understood; however, it is clear that changes in both the innate and adaptive immune responses are associated with fibroblast dysfunction and vascular damage. Further, DNA damage has been postulated as one of the triggering factors in systemic sclerosis, although the association of DNA damage with the progression of this disease is more poorly established. Recently, abnormal DNA damage response repair pathways have also been identified in patients with systemic sclerosis, suggesting that cells from patients with this disease may be more susceptible to DNA damaging agents. Chemotherapeutic drugs and other DNA damaging agents have been associated with the development of systemic sclerosis, as these agents may provide additional "hits" that promote abnormal DNA damage responses and subsequent inflammatory changes. Herein, we present the case of a 39-year-old female who developed scleroderma after the treatment of her breast cancer with chemotherapeutic agents. Her scleroderma was subsequently successfully treated with autologous hematopoietic stem cell transplantation. We also completed a literature review for previously published cases of chemotherapy associated with systemic sclerosis and highlighted a role of DNA damage in promoting the disease. Our case is the first case of chemotherapy associated with systemic sclerosis treated with hematopoietic stem cell transplantation.

Bioengineered Efficacy Models of Skin Disease: Advances in the Last 10 Years

Models of skin diseases, such as psoriasis and scleroderma, must accurately recapitulate the complex microenvironment of human skin to provide an efficacious platform for investigation of skin diseases. Skin disease research has been shifting from less complex and less relevant 2D (two-dimensional) models to significantly more relevant 3D (three-dimensional) models. Three-dimensional modeling systems are better able to recapitulate the complex cell–cell and cell–matrix interactions that occur in vivo within skin. Three-dimensional human skin equivalents (HSEs) have emerged as an advantageous tool for the study of skin disease in vitro. These 3D HSEs can be highly complex, containing both epidermal and dermal compartments with integrated adnexal structures. The addition of adnexal structures to 3D HSEs has allowed researchers to gain more insight into the complex pathology of various hereditary and acquired skin diseases. One method of constructing 3D HSEs, 3D bioprinting, has emerged as a versatile and useful tool for generating highly complex HSEs. The development of commercially available 3D bioprinters has allowed researchers to create highly reproducible 3D HSEs with precise integration of multiple adnexal structures. While the field of bioengineered models for study of skin disease has made tremendous progress in the last decade, there are still significant efforts necessary to create truly biomimetic skin disease models. In future studies utilizing 3D HSEs, emphasis must be placed on integrating all adnexal structures relevant to the skin disease under investigation. Thorough investigation of the intricate pathology of skin diseases and the development of effective treatments requires use of highly efficacious models of skin diseases.

CD21low B cells are predictive markers of new digital ulcers in systemic sclerosis

The objective of this study was to evaluate the predictive role of CD21^low B cells as markers of new digital ulcers in systemic sclerosis patients. Peripheral blood B cell subpopulations and clinical assessments have been evaluated in 74 systemic sclerosis patients at baseline and after a 12‐month follow‐up. After a 12‐month follow‐up, 23 (31.1%) systemic sclerosis patients developed new digital ulcers. The median percentage of CD21^low B cells was significantly higher in patients with than without new digital ulcers [10.1 (4.3–13.6) versus 4.8 (3.5–7.4); p < 0.01]. The 10% cut‐off shows good diagnostic accuracy [area under the curve (AUC) = 0.732, confidence interval (CI) = 0.587–0.878; P = 0.01]. Kaplan–Meier curves show a significantly reduced free survival from new digital ulcers in systemic sclerosis patients with CD21^low B cells ≥ 10% (p < 0.0001). In multivariate analysis, CD21^low B cells ≥ 10%, modified Rodnan skin score (mRSS) and systolic pulmonary arterial pressure (sPAP) are associated with the development of new digital ulcers. We hypothesize that CD21^low B cells are a predictive marker of new digital ulcers in systemic sclerosis patients.

Targeting the α7 nicotinic acetylcholine receptor-A novel road towards the future treatment of skin diseases

Nicotinic acetylcholine receptors (nAChRs) are members of the superfamily of neurotransmitter-gated ion channels. The natural ligand for nAChRs is the endogenous neurotransmitter acetylcholine. Among the nAChRs is the α7nAChR. It is not only expressed by neural tissues but also in the skin. A number of different resident cutaneous cell types including epidermal keratinocytes, sebocytes and dermal fibroblasts express functional α7nAChR. Moreover, cells of the immune system such as lymphocytes, macrophages and monocytes, playing an important role in skin homeostasis, also express α7nAChR. Translational research focusing on the exploitation of the α7nAChR in dermatology has revealed that this neuroendocrine receptor could be promising target for the treatment of inflammatory skin diseases. For example, α7nAChR agonists can counteract transforming growth factor-β1-mediated responses in dermal fibroblasts, key effector cells in scleroderma. In accordance with this α7nAChR, agonists are effective in both inflammation and non-inflammation-driven models of experimentally induced skin fibrosis. Moreover, α7nAChR agonists can modulate expression of proinflammatory cytokines in epidermal keratinocytes that are crucially involved in the pathogenesis of psoriasis and other inflammatory skin diseases. Finally, the capability of α7nAChR agonists to suppress ultraviolet light A/B-induced responses, for example production of proinflammatory cytokines and oxidative stress, the latter crucially involved in dermal photoageing, points to a potential of such agents in the prevention of extrinsic skin ageing. Therefore, emphasis on translational research targeting the α7nAChR in skin may lead to the development of new treatment and prevention modalities against fibrosclerotic skin diseases, psoriasis vulgaris, atopic dermatitis, acne, photodermatoses and extrinsic skin ageing.

Avascular necrosis in systemic sclerosis patients: a case-based review of demographics, presentation, and management

Avascular necrosis (AVN) is a pathologic process involving death of bony tissue resulting from loss of blood supply from various causes. Various traumatic and nontraumatic causes of AVN are known, including systemic autoimmune diseases. AVN has been well described in patients with autoimmune diseases such as systemic lupus erythematosus, but in systemic sclerosis (SSc) patients, there have been limited case reports and case series. There have only been three case reports of AVN in multiple anatomic sites (multifocal AVN) reported in SSc patients in the literature. We present a case of multifocal AVN in an SSc patient and a review of literature on the previously reported cases of SSc-related AVN in terms of demographics, clinical presentation, and management. To our knowledge, this is the only literature review of reported AVN cases in SSc patients.

CD21low B cells in systemic sclerosis: A possible marker of vascular complications

OBJECTIVES

To evaluate expansion of CD21^low B cells and their role in B cell homeostasis, apoptosis, clinical manifestations and serum vascular endothelial growth factor (VEGF) in systemic sclerosis (SSc).

MATERIALS AND METHODS

B-cells subpopulations and apoptosis have been assessed in 74 SSc patients and 20 healthy donors. Renal Doppler ultrasound, echocardiography, pulmonary function test and VEGF were performed.

RESULTS

SSc patients with expanded CD21^low B cells (SSc-CD21^low) show a distinct B cell profile with increased memory B cells compared to patients without CD21^low B cells (SSc-CD21⁺). Renal resistive index, systolic pulmonary arterial pressure and FVC/DLCO ratio were significantly higher in SSc-CD21^low group than SSc-CD21⁺, DLCO was lower in SSc-CD21^low group than SSc-CD21⁺. We found a positive linear correlation between CD21^low and sPAP, RI and FVC/DLCO ratio whereas a negative correlation was observed between CD21^low and DLCO and VEGF levels.

CONCLUSIONS

CD21^low B cells are increased in SSc patients with visceral vascular manifestations.

Microbiome, Autoimmune Diseases and HIV Infection: Friends or Foes?

Several studies highlighted the importance of the interaction between microbiota and the immune system in the development and maintenance of the homeostasis of the human organism. Dysbiosis is associated with proinflammatory and pathological state-like metabolic diseases, autoimmune diseases and HIV infection. In this review, we discuss the current understanding of the possible role of dysbiosis in triggering and/or exacerbating symptoms of autoimmune diseases and HIV infection. There are no data about the influence of the microbiome on the development of autoimmune diseases during HIV infection. We can hypothesize that untreated patients may be more susceptible to the development of autoimmune diseases, due to the presence of dysbiosis. Eubiosis, re-established by probiotic administration, can be used to reduce triggers for autoimmune diseases in untreated HIV patients, although clinical studies are needed to evaluate the role of the microbiome in autoimmune diseases in HIV patients.

Systemic Sclerosis Associated Interstitial Lung Disease: New Directions in Disease Management

A subgroup of patients with systemic sclerosis (SSc) develop interstitial lung disease (ILD), characterized by inflammation and progressive scarring of the lungs that can lead to respiratory failure. Although ILD remains the major cause of death in these individuals, there is no consensus statement regarding the classification and characterization of SSc-related ILD (SSc-ILD). Recent clinical trials address the treatment of SSc-ILD and the results may lead to new disease-altering therapies. In this review, we provide an update to the diagnosis, management and treatment of SSc-ILD.