Could autologous adipose-derived stromal vascular fraction turn out an unwanted source of profibrotic myofibroblasts in systemic sclerosis?

Comparison of the Behavior of Perivascular Cells (Pericytes and CD34+ Stromal Cell/Telocytes) in Sprouting and Intussusceptive Angiogenesis

Perivascular cells in the pericytic microvasculature, pericytes and CD34+ stromal cells/telocytes (CD34+SCs/TCs), have an important role in angiogenesis. We compare the behavior of these cells depending on whether the growth of endothelial cells (ECs) from the pre-existing microvasculature is toward the interstitium with vascular bud and neovessel formation (sprouting angiogenesis) or toward the vascular lumen with intravascular pillar development and vessel division (intussusceptive angiogenesis). Detachment from the vascular wall, mobilization, proliferation, recruitment, and differentiation of pericytes and CD34+SCs/TCs, as well as associated changes in vessel permeability and functionality, and modifications of the extracellular matrix are more intense, longer lasting over time, and with a greater energy cost in sprouting angiogenesis than in intussusceptive angiogenesis, in which some of the aforementioned events do not occur or are compensated for by others (e.g., sparse EC and pericyte proliferation by cell elongation and thinning). The governing mechanisms involve cell-cell contacts (e.g., peg-and-socket junctions between pericytes and ECs), multiple autocrine and paracrine signaling molecules and pathways (e.g., vascular endothelial growth factor, platelet-derived growth factor, angiopoietins, transforming growth factor B, ephrins, semaphorins, and metalloproteinases), and other factors (e.g., hypoxia, vascular patency, and blood flow). Pericytes participate in vessel development, stabilization, maturation and regression in sprouting angiogenesis, and in interstitial tissue structure formation of the pillar core in intussusceptive angiogenesis. In sprouting angiogenesis, proliferating perivascular CD34+SCs/TCs are an important source of stromal cells during repair through granulation tissue formation and of cancer-associated fibroblasts (CAFs) in tumors. Conversely, CD34+SCs/TCs have less participation as precursor cells in intussusceptive angiogenesis. The dysfunction of these mechanisms is involved in several diseases, including neoplasms, with therapeutic implications.

Cd34+ Stromal Cells/Telocytes in Normal and Pathological Skin

We studied CD34+ stromal cells/telocytes (CD34+SCs/TCs) in pathologic skin, after briefly examining them in normal conditions. We confirm previous studies by other authors in the normal dermis regarding CD34+SC/TC characteristics and distribution around vessels, nerves and cutaneous annexes, highlighting their practical absence in the papillary dermis and presence in the bulge region of perifollicular groups of very small CD34+ stromal cells. In non-tumoral skin pathology, we studied examples of the principal histologic patterns in which CD34+SCs/TCs have (1) a fundamental pathophysiological role, including (a) fibrosing/sclerosing diseases, such as systemic sclerosis, with loss of CD34+SCs/TCs and presence of stromal cells co-expressing CD34 and αSMA, and (b) metabolic degenerative processes, including basophilic degeneration of collagen, with stromal cells/telocytes in close association with degenerative fibrils, and cutaneous myxoid cysts with spindle-shaped, stellate and bulky vacuolated CD34+ stromal cells, and (2) a secondary reactive role, encompassing dermatitis—e.g., interface (erythema multiforme), acantholytic (pemphigus, Hailey–Hailey disease), lichenoid (lichen planus), subepidermal vesicular (bullous pemphigoid), psoriasiform (psoriasis), granulomatous (granuloma annulare)—vasculitis (leukocytoclastic and lymphocytic vasculitis), folliculitis, perifolliculitis and inflammation of the sweat and sebaceous glands (perifolliculitis and rosacea) and infectious dermatitis (verruca vulgaris). In skin tumor and tumor-like conditions, we studied examples of those in which CD34+ stromal cells are (1) the neoplastic component (dermatofibrosarcoma protuberans, sclerotic fibroma and solitary fibrous tumor), (2) a neoplastic component with varying presentation (fibroepithelial polyp and superficial myxofibrosarcoma) and (3) a reactive component in other tumor/tumor-like cell lines, such as those deriving from vessel periendothelial cells (myopericytoma), epithelial cells (trichoepithelioma, nevus sebaceous of Jadassohn and seborrheic keratosis), Merkel cells (Merkel cell carcinoma), melanocytes (dermal melanocytic nevi) and Schwann cells (neurofibroma and granular cell tumor).

Autologous fat grafting in the treatment of a scleroderma stump-skin ulcer: a case report

Here we describe the case of a 60‐year‐old-woman with systemic sclerosis sent to our Scleroderma Unit to treat digital stumps. The stumps were successfully treated with autologous fat grafting (crown-shape infiltration). Our technique of autologous lipotransfer improved wound healing in a scleroderma patient with stump-digital ulcers where all other options failed.

Autologous Fat Grafting for the Oral and Digital Complications of Systemic Sclerosis: Results of a Prospective Study

BACKGROUND

Systemic sclerosis is a connective tissue disease. Skin involvement of the mouth and hand may compromise function and quality of life. Autologous fat grafting has been described as a specific treatment of these clinical features. We report the results of our prospective study designed to treat and prevent skin complications in systemic sclerosis.

MATERIALS AND METHODS

We treated 25 patients with mouth and/or hand involvement (microstomia, xerostomia, skin sclerosis, Raynaud's phenomenon and long-lasting digital ulcers) with autologous fat grafting, according to the Coleman's technique, around the mouth and/or at the base of each finger. The surgical procedures were repeated in each patient every 6 months for a total of two or three times. Clinical data were collected before the first surgery and again 6 months after each surgical procedure. Pain, skin thickness, saliva production and disability were assessed with validated tests.

RESULTS

Overall we performed 63 autologous fat grafting sessions (either on the mouth, on the hands or on both anatomical areas). Results at 6 moths after the last session included improvement of xerostomia evaluated with a sialogram, reduction of the skin tension around the mouth and, in the hands, reduction of the Raynaud phenomenon as well as skin thickness. Pain was reduced while the perception of disability improved. Digital ulcers healed completely in 8/9 patients.

CONCLUSIONS

Our results confirm the efficacy and safety of autologous fat grafting for the treatment of skin complications and digital ulcers due to systemic sclerosis. In addition, the patients' subjective well-being improved. Level of evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The contribution of mesenchymal transitions to the pathogenesis of systemic sclerosis

Systemic sclerosis (SSc) is a multifaceted connective tissue disease characterized by widespread vasculopathy and autoimmune reactions that evolve into progressive interstitial, perivascular, and vessel wall fibrosis that affects the skin and multiple internal organs. Such an uncontrolled fibrotic process gradually disrupts the physiologic architecture of the affected tissues and frequently leads to significant organ dysfunction, thus representing a major cause of death in SSc patients. The main fibrosis orchestrators in SSc are represented by chronically activated myofibroblasts, a peculiar population of mesenchymal cells combining the extracellular matrix-synthesizing features of fibroblasts with cytoskeletal characteristics of contractile smooth muscle cells. Multiple lines of evidence support the notion that profibrotic myofibroblasts may derive not only from the activation of tissue resident fibroblasts but also from a variety of additional cell types, including pericytes, epithelial cells, vascular endothelial cells and preadipocytes/adipocytes. Here we overview an emerging picture that espouses that several cell transitional processes may be novel essential contributors to the pool of profibrotic myofibroblasts in SSc, potentially representing new suitable targets for therapeutic purposes. An in-depth dissection of the multiple origins of myofibroblasts and the underlying molecular mechanisms may be crucial in the process of deciphering the cellular bases of fibrosis persistence and refractoriness to the treatment and, therefore, may help in developing more effective and personalized therapeutic opportunities for SSc patients.

Anti-fibrotic mechanisms of exogenously-expanded mesenchymal stromal cells for fibrotic diseases

Most chronic diseases involving inflammation have a fibrotic component that involves remodeling and excess accumulation of extracellular matrix components. Left unchecked, fibrosis leads to organ failure and death. Mesenchymal stromal cells (MSCs) are emerging as a potent cell-based therapy for a wide spectrum of fibrotic conditions due to their immunomodulatory, anti-inflammatory and anti-fibrotic properties. This review provides an overview of known mechanisms by which MSCs mediate their anti-fibrotic actions and in relation to animal models of pulmonary, liver, renal and cardiac fibrosis. Recent MSC clinical trials results in liver, lung, skin, kidney and hearts are discussed and next steps for future MSC-based therapies including pre-activated or genetically-modified cells, or extracellular vesicles are also considered.

Adipose-Derived Stem Cells from Systemic Sclerosis Patients Maintain Pro-Angiogenic and Antifibrotic Paracrine Effects In Vitro

Innovative therapies based on autologous adipose-derived stem/stromal cells (ASC) are currently being evaluated for treatment of systemic sclerosis (SSc). Although paracrine angiogenic and antifibrotic effects are considered the predominant mechanisms of ASC therapeutic potential, the impact of SSc on ASC paracrine functions remains controversial. In this study, phenotype, senescence, differentiation potential, and molecular profile were determined in ASC from SSc patients (SSc-ASC) (n = 7) and healthy donors (HD-ASC) (n = 7). ASC were co-cultured in indirect models with dermal fibroblasts (DF) from SSc patients or endothelial cells to assess their pro-angiogenic and antifibrotic paracrine effects. The angiogenic activity of endothelial cells was measured in vitro using tube formation and spheroid assays. DF collagen and alpha smooth muscle actin (αSMA) content were quantified after five days of co-culture with ASC. Differentiation capacity, senescence, and mRNA profiles did not differ significantly between SSc-ASC and HD-ASC. SSc-ASC retained the ability to stimulate angiogenesis through paracrine mechanisms; however, functional assays revealed reduced potential compared to HD-ASC. DF fibrosis markers were significantly decreased after co-culture with SSc-ASC. Together, these results indicate that SSc effects do not significantly compromise the angiogenic and the antifibrotic paracrine properties of ASC, thereby supporting further development of ASC-based autologous therapies for SSc treatment.