Medical students' interest in research: changing trends during university training.

Introduction: Research is an important aspect of medical training and plays a vital role in the advancement of evidence-based medicine. However, little is known about medical students' attitudes towards research. So, the aim of this study was to assess the opinion of medical students on scientific research. Methods: A cross-sectional study was designed that included students from the Faculty of Medicine of the University of Granada (UGR), Granada, Spain. A survey was distributed to assess their interest about research during undergraduate studies (1) and following graduation (2), participation in research activities (3), barriers towards research (4), expectation values and self-perceived skills (5). The opinions of students who had not taken clinical subjects (2nd year students) and students who had taken clinical subjects (4th and 6th year students) were compared. Results: 91 students were included in the study (32 were 2nd year students and 59 were 4th and 6th year students). More 4th and 6th year students showed no interest in research (50.4% vs. 28.1%, p = 0.042) or in pursuing a doctoral thesis (75% vs. 50.9%, p = 0.079) than 2nd year students. In addition, more 4th and 6th year students felt that they did not have sufficient skills to engage in scientific research (52.4% vs. 18.9%, p = 0.002). Likewise a greater number of 4th and 6th year students considered that the professors did not encourage scientific research activities (74.6% vs. 40.6%, p = 0.002). Generally, students do not participate in scientific dissemination events. The main barriers to research identified were lack of funding and lack of awareness of opportunities. Conclusion: Interest in research among medical students seems to decrease as the academic years progress. More research promotion could be implemented during the years of university studies.

Cardioprotective function of sclerostin by reducing calcium deposition, proliferation, and apoptosis in human vascular smooth muscle cells.

BACKGROUND: Sclerostin is an inhibitor of the Wnt/b-catenin pathway, which regulates bone formation, and can be expressed in vascular smooth muscle cells (VSMCs). Type 2 diabetes (T2D) is associated with an increased risk of cardiovascular disease (CVD) and increased serum and tissue expression of sclerostin. However, whether the role of sclerostin is detrimental or protective in the development of CVD is unknown. Therefore, our aims are to determine the level of sclerostin in T2D patients with/without CVD and in controls, both at serum and vascular tissue, and to analyze the role of sclerostin in VSMCs under calcified environments. METHODS: Cross-sectional study including 121 controls and 139 T2D patients with/without CVD (48/91). Sclerostin levels in serum were determined by ELISA, and sclerostin expression was analyzed by RT-qPCR and immunohistochemistry in calcified and non-calcified artery of lower limb from T2D patients (n = 7) and controls (n = 3). In vitro experiments were performed in VSMCs (mock and sclerostin overexpression) under calcifying conditions analyzing the sclerostin function by determination of calcium and phosphate concentrations, and quantification of calcium deposits by Alizarin Red. Proliferation and apoptosis were analyzed by MTT assay and flow cytometry, respectively. The regulation of the expression of genes involved in bone metabolism was determined by RT-qPCR. RESULTS: A significant increase in serum sclerostin levels in T2D patients with CVD compared to T2D patients without CVD and controls (p < 0.001) was observed. Moreover, higher circulating sclerostin levels were independently associated with CVD in T2D patients. Increased sclerostin expression was observed in calcified arteries of T2D patients compared to non-calcified arteries of controls (p = 0.003). In vitro experiments using VSMCs under calcified conditions, revealed that sclerostin overexpression reduced intracellular calcium (p = 0.001), calcium deposits (p < 0.001), cell proliferation (p < 0.001) and promoted cell survival (p = 0.015). Furthermore, sclerostin overexpression exhibited up-regulation of ALPL (p = 0.009), RUNX2 (p = 0.001) and COX2 (p = 0.003) and down-regulation of inflammatory genes, such as, IL1ß (p = 0.005), IL6 (p = 0.001) and IL8 (p = 0.003). CONCLUSIONS: Sclerostin could play a protective role in the development of atherosclerosis in T2D patients by reducing calcium deposits, decreasing proliferation and inflammation, and promoting cell survival in VSMCs under calcifying conditions. Therefore, considering the bone-vascular axis, treatment with anti-sclerostin for bone disease should be used with caution.

Exploring the role of osteoglycin in type 2 diabetes: implications for insulin resistance and vascular pathophysiology.

Osteoglycin, a fundamental proteoglycan within the vascular extracellular matrix, is expressed in vascular smooth muscle cells (VSMCs). Type 2 diabetes (T2D) is associated with cardiovascular disease (CVD) but the role of osteoglycin in the development of CVD is controversial to date. Therefore, our aims are to determine and compare the level of osteoglycin in T2D patients with/without CVD versus control subjects both at serum and vascular tissue and to analyze in vitro role of osteoglycin in VSMCs under calcified conditions. For this, serum osteoglycin levels were determined by enzyme-linked immunosorbent assay (ELISA) in 117 controls and 129 patients with T2D (46 with CVD and 83 without CVD), revealing a significant increase in patients with T2D compared with controls. Osteoglycin level was not an estimator of CVD but correlated with markers of insulin resistance (triglycerides and triglycerides/high-density lipoprotein cholesterol index) in patients with T2D. At the vascular level, osteoglycin expression was assessed by RT-qPCR and immunohistochemistry, and no significant differences were observed between calcified arteries from patients with T2D and noncalcified arteries from controls. In vitro experiments using VSMCs (mock and overexpressing osteoglycin) under calcifying conditions were performed to analyze the osteoglycin function. The overexpression of osteoglycin in VMSCs under calcifying conditions revealed an increase of cell proliferation without effect on apoptosis and an upregulation of the expression of autotaxin (ATX) involved in inflammatory processes. In conclusion, osteoglycin could play a role in glycemic homeostasis, being a potential biomarker of insulin resistance in patients with T2D. Furthermore, osteoglycin could indirectly participate in the development of atherosclerosis through its regulatory effect on ATX and by proliferating VSMCs.NEW & NOTEWORTHY This study uncovers an increase of serum osteoglycin levels in patients with type 2 diabetes, which does not appear to be associated with the development of atherosclerosis, but rather with insulin resistance in this population. Overexpression of osteoglycin increased proliferation and upregulated the expression of autotaxin in vascular smooth muscle cells within calcified environments. Osteoglycin could be a biomarker of insulin resistance for type 2 diabetes and could be indirectly involved in the development of atherosclerosis.

Stratum Corneum Hydration As a Potential Marker of Response to Dupilumab in Atopic Dermatitis: A Prospective Observational Study.

Background: Dupilumab is an effective treatment for atopic dermatitis (AD) and it also restores skin barrier function. Nevertheless, early changes in epidermal barrier parameters related to sustained treatment response or treatment failure are not known. So, the objective of this study is to evaluate whether changes in skin barrier function after 16 weeks dupilumab treatment could predict sustained treatment response or treatment failure. Materials and Methods: A prospective observational study was conducted that included patients with AD starting dupilumab. Clinical scores, patient-reported outcome measures (PROMs), and skin barrier function parameters were assessed at baseline and after 16 weeks treatment. Patients were followed until they failed to dupilumab or until the end of the study period. Participants were divided into 2 groups: patients with treatment failure and those with sustained treatment response. Results: In total, 32 patients with AD were included in the study, with a mean age of 28.03 years (standard deviation 10.65), being 20 (60.6%) females. In total, 22 (66.7%) patients sustained dupilumab response during the study period and only 10 (33.3%) failed to treatment. After 16 weeks treatment, clinical scores were improved in both groups. Patients with sustained treatment response increased stratum corneum hydration (SCH) on noninvolved skin (34.25 arbitrary units [AU] vs 44.90AU, P = 0.001) and on eczematous lesions (20.71 AU vs 40.94 AU, P < 0.001) and also decreased transepidermal water loss (TEWL) on eczematous lesions (28.22 g/[m2·h] vs 14.83 g/[m2·h], P = 0.002). Patients with treatment failure did not change TEWL or SCH. SCH after 16 weeks treatment on noninvolved skin (odds ratio [OR] = 0.83, P = 0.018) and SCH after 16 weeks treatment on eczematous lesions (OR = 0.86, P = 0.028) were related to dupilumab failure. Conclusion: SCH could be used as a predictive biomarker of dupilumab response in patients with AD.

The impact of dupilumab on skin barrier function: A systematic review.

Skin barrier dysfunction plays an important role in atopic dermatitis (AD) aetiopathogenesis. Dupilumab, a drug that inhibits IL-4 and IL-13, is an effective treatment for AD but there is scarce evidence about its impact on epidermal barrier. The objective of this systematic review is to evaluate the influence of dupilumab on skin barrier in patients with AD using non-invasive tools. A systematic review was designed following PRISMA guidelines. The literature search identified 73 references and, finally, only 6 were selected, including a total of 233 participants. All the studies were prospective observational studies. Dupilumab improved clinical scores in all the research. Skin barrier function parameters were mainly measured on the volar forearm. Transepidermal water loss (TEWL) was the parameter most frequently measured, evaluated in all the studies. Dupilumab decreased TEWL on eczematous lesions and non-involved skin. About 33.6% (2/6) studies reported that dupilumab also increased stratum corneum hydration (SCH) on eczematous lesions while one study did not report any changes in this parameter. This drug also decreased temperature and improved ceramide composition. In conclusion, dupilumab improved skin barrier function in AD patients, mainly reflected in a decreased in TEWL values.

Analysis of the Genetic Relationship between Atherosclerosis and Non-Alcoholic Fatty Liver Disease through Biological Interaction Networks.

Non-alcoholic fatty liver disease (NAFLD) seems to have some molecular links with atherosclerosis (ATH); however, the molecular pathways which connect both pathologies remain unexplored to date. The identification of common factors is of great interest to explore some therapeutic strategies to improve the outcomes for those affected patients. Differentially expressed genes (DEGs) for NAFLD and ATH were extracted from the GSE89632 and GSE100927 datasets, and common up- and downregulated DEGs were identified. Subsequently, a protein-protein interaction (PPI) network based on the common DEGs was performed. Functional modules were identified, and the hub genes were extracted. Then, a Gene Ontology (GO) and pathway analysis of common DEGs was performed. DEGs analysis in NAFLD and ATH showed 21 genes that were regulated similarly in both pathologies. The common DEGs with high centrality scores were ADAMTS1 and CEBPA which appeared to be down- and up-regulated in both disorders, respectively. For the analysis of functional modules, two modules were identified. The first one was oriented to post-translational protein modification, where ADAMTS1 and ADAMTS4 were identified, and the second one mainly related to the immune response, where CSF3 was identified. These factors could be key proteins with an important role in the NAFLD/ATH axis.

Improvement of Sexual Function and Sleep Quality in Patients with Atopic Dermatitis Treated with Dupilumab: A Single-Centre Prospective Observational Study.

Atopic dermatitis (AD) is a chronic inflammatory skin disease presenting as xerosis, eczema and intense pruritus. These symptoms negatively impact patients' quality of life. However, the effect of AD on sexual function and sleep quality and how treatment with dupilumab could modify them have not been explored in depth. The aim of this study is to assess the effects of dupilumab on sexual and sleep quality in patients with AD. For that purpose, an observational prospective study was designed. Patients were evaluated at baseline and after 16 weeks of dupilumab treatment. Disease severity was assessed by Eczema Area and Severity (EASI) and SCORing Atopic Dermatitis index (SCORAD). Sexual function was evaluated using validated questionnaires, for men via the International Index of Erectile Dysfunction 5 (IIEF-5) and for women via the Female Sexual Function Index (FSFI). Sleep impairment was recorded through Pittsburgh Sleep Quality Index (PSQI). Thirty-two patients, with a mean age of 30.53 ± 14.48 years old, were included. Regarding sex, 59.8% (20) were female. Most patients had a severe disease reflected in a mean basal EASI of 23.24 ± 6.74 and a SCORAD of 54.07 ± 13.89. Clinical scores improved after dupilumab treatment. At baseline, 47.37% women presented sexual dysfunction and 66.67% men had erectile dysfunction. FSFI improved from 23.51 to 27.93 points (p = 0.008) after dupilumab. Desire, arousal, satisfaction and pain were the components with great improvement. Women with a great improvement in FSFI showed greater clinical results and increased quality of life. At first, 96.9% (31/32) of participants presented with poor sleep quality. After treatment with dupilumab, sleep quality was enhanced and PSQI scores decreased from 12.8 points at baseline to 7.73 points (p < 0.001). In conclusion, dupilumab is associated with reduced sexual dysfunction, mainly in women, and sleep quality.

Type D Personality as a Marker of Poorer Quality of Life and Mood Status Disturbances in Patients with Skin Diseases: A Systematic Review.

Type D personality is characterized by social inhibition and negative affectivity. Poorer outcomes and worse quality of life have been linked to type D personality in patients with a variety of non-dermatological diseases. Despite increasing evidence of the importance of type D personality in skin diseases, there are no reviews on this subject. The aim of this review is to summarize the current evidence regarding type D personality and skin diseases. A systematic search was performed using Medline and Web of Science databases from inception to 11 October 2022. Studies addressing the presence of type D personality, its associated factors, its impact on the outcomes of the disease or the quality of life of the patients were included in the systematic review. A total of 20 studies, including 3,124 participants, met the eligibility criteria and were included in the review. Acne, hidradenitis suppurativa, psoriasis, melanoma, atopic dermatitis, chronic spontaneous urticaria and pruritic disorders were the main diseases assessed. Type D personality was more frequent among patients with skin diseases than among controls. Type D personality was found to be associated with poorer quality of life and higher rates of psychological comorbidities in patients with skin diseases. In conclusion, type D personality appears to be a marker of patients with increased risk of poorer quality of life and higher rates of psychological comorbidities. Screening for type D personality in specialized dermatology units might be beneficial to identify patients who are more psychologically vulnerable to the consequences of chronic skin diseases.

Systemic effects of hypophosphatasia characterization of two novel variants in the ALPL gene.

Introduction: Hypophosphatasia (HPP) is an inborn metabolic error caused by mutations in the ALPL gene encoding tissue non-specific alkaline phosphatase (TNSALP) and leading to decreased alkaline phosphatase (ALP) activity. Although the main characteristic of this disease is bone involvement, it presents a great genetic and clinical variability, which makes it a systemic disease. Methods: Patients were recruited based on biochemical assessments. Diagnosis was made by measuring serum ALP and pyridoxal 5-phosphate levels and finally by Sanger sequencing of the ALPL gene from peripheral blood mononuclear cells. Characterization of the new variants was performed by transfection of the variants into HEK293T cells, where ALP activity and cellular localization were measured by flow cytometry. The dominant negative effect was analyzed by co-transfection of each variant with the wild-type gene, measuring ALP activity and analyzing cellular localization by flow cytometry. Results: Two previously undescribed variants were found in the ALPL gene: leucine 6 to serine missense mutation (c.17T>C, L6S) affecting the signal peptide and threonine 167 deletion (c.498_500delCAC, T167del) affecting the vicinity of the active site. These mutations lead mainly to non-pathognomonic symptoms of HPP. Structural prediction and modeling tools indicated the affected residues as critical residues with important roles in protein structure and function. In vitro results demonstrated low TNSALP activity and a dominant negative effect in both mutations. The results of the characterization of these variants suggest that the pleiotropic role of TNSALP could be involved in the systemic effects observed in these patients highlighting digestive and autoimmune disorders associated with TNSALP dysfunction. Conclusions: The two new mutations have been classified as pathogenic. At the clinical level, this study suggests that both mutations not only lead to pathognomonic symptoms of the disease, but may also play a role at the systemic level.

Exploring the Role of Sclerostin as a Biomarker of Cardiovascular Disease and Mortality: A Scoping Review.

Sclerostin is most recognized for its role in controlling bone formation; however, it is also expressed in the heart, aorta, coronary, and peripheral arteries. Human studies have associated high circulating sclerostin levels with the presence of different cardiovascular diseases (CVD), surrogate CVD markers, and a high risk of cardiovascular events in some populations. However, this is still a matter of scientific debate, as the results have been very heterogeneous among studies. In the present review, the association between serum sclerostin levels and CVD and/or cardiovascular mortality was analyzed. For this purpose, a scoping review was performed in which articles measuring serum sclerostin levels and cardiovascular risk in patients were selected. Eleven articles answered the research question; of these articles, 8/11 evaluated the association between sclerostin and CVD, of which 4/8 found a positive association, 2/8 found a negative association, and 2/8 found no association between variables. Five (5/11) of the articles included in the study evaluated cardiovascular mortality, of which 3/5 found a positive association, 1/5 found a negative association, and 1/5 found no association between variables. In conclusion, we did not find sufficient results to be able to demonstrate an association between elevated sclerostin levels and the development of CVD and/or cardiovascular mortality in the general population due to heterogeneity in the results. However, there seems to be a tendency to consider increased sclerostin levels as a risk factor for both the development of cardiovascular events and cardiovascular mortality in specific populations. Further studies in this field will help to solve some of the inconsistencies found during this scoping review and allow for the future use of sclerostin measurement as a strategy in the prevention and diagnosis of CVD and/or cardiovascular mortality.

The Assessment of Skin Homeostasis Changes after Using Different Types of Excipients in Healthy Individuals.

Excipients are used as vehicles for topical treatments; however, there are not many studies that evaluate the impact of different excipients themselves. The aim of this research is to assess skin homeostasis changes in healthy individuals after using water/oil (W/O), oil/water (O/W), Beeler base, foam and Vaseline excipients. A within-person randomized trial was conducted that included healthy individuals without previous skin diseases. Skin barrier function parameters, including stratum corneum hydration (SCH), transepidermal water loss (TEWL), pH, temperature, erythema, melanin and elasticity (R0, R2, R5 and R7), were measured on the volar forearm before and after using each excipient. Sixty participants were included in the study, with a mean age of 32 years. After applying w/o excipient erythema decreased by 25 AU, (p < 0.001) and elasticity increased by 6%. After using the o/w excipient, erythema decreased by 39.36 AU (p < 0.001) and SCH increased by 6.85 AU (p = 0.009). When applying the Beeler excipient, erythema decreased by 41.23 AU (p < 0.001) and SCH increased by 15.92 AU (p < 0.001). Foam and Vaseline decreased TEWL and erythema. Excipients have a different impact on skin barrier function. Knowing the effect of excipients on the skin could help to develop new topical treatments and help specialists to choose the best excipient according to the pathology.

The Contribution of Wnt Signaling to Vascular Complications in Type 2 Diabetes Mellitus.

Vascular complications are the leading cause of morbidity and mortality among patients with type 2 diabetes mellitus (T2DM). These vascular abnormalities result in a chronic hyperglycemic state, which influences many signaling molecular pathways that initially lead to increased oxidative stress, increased inflammation, and endothelial dysfunction, leading to both microvascular and macrovascular complications. Endothelial dysfunction represents the initial stage in both types of vascular complications; it represents "mandatory damage" in the development of microvascular complications and only "introductory damage" in the development of macrovascular complications. Increasing scientific evidence has revealed an important role of the Wnt pathway in the pathophysiology of the vascular wall. It is well known that the Wnt pathway is altered in patients with T2DM. This review aims to be an update of the current literature related to the Wnt pathway molecules that are altered in patients with T2DM, which may also be the cause of damage to the vasculature. Both microvascular complications (retinopathy, nephropathy, and neuropathy) and macrovascular complications (coronary artery disease, cerebrovascular disease, and peripheral arterial disease) are analyzed. This review aims to concisely concentrate all the evidence to facilitate the view on the vascular involvement of the Wnt pathway and its components by highlighting the importance of exploring possible therapeutic strategy for patients with T2DM who develop vascular pathologies.

Cytotoxicity, Epidermal Barrier Function and Cytokine Evaluation after Antiseptic Treatment in Bioengineered Autologous Skin Substitute.

Bioengineered autologous skin substitutes (BASS) technology is an emerging field for skin burn therapy. However, further studies on BASS characterization, viability against standard procedures for wound healing, and protocol optimization are necessary for the improvement of BASS technology for clinical use. The aim of this study is to evaluate the effect of common antiseptics for clinical use in BASS, focusing on cell viability, inflammatory cytokine pattern, and epithelium and skin barrier integrity, in order to establish the most adequate treatment for wound care after BASS grafting. Human keratinocytes (hKT) and dermal fibroblasts (hDF) were isolated from foreskin samples and integrated into hyaluronic acid-based BASS. The following antiseptics were applied every 48 h: ethanol (70%), chlorhexidine digluconate (1%), sodium hypochlorite (0.02%), povidone iodine (100 mg/mL), and polyhexanide (0.1%), during a follow-up of 16 days. Sodium hypochlorite was the only treatment that showed a high cell viability percentage throughout the evaluation time compared to other antiseptic treatments, as well as a similar cytokine secretion pattern as control BASS. No significant differences were found regarding epidermal barrier function. These findings point towards sodium hypochlorite being the least aggressive antiseptic treatment for BASS post-transplantation wound care.

Cytotoxicity and Wound Closure Evaluation in Skin Cell Lines after Treatment with Common Antiseptics for Clinical Use.

In recent years, new therapies, such as skin cell lines injections, have emerged to promote re-epithelialization of damaged areas such as chronic ulcers or to treat patients with severe burns. Antiseptics are commonly used during wound clinical management to avoid serious infections, but they may delay the healing process due to their apparent cytotoxicity to skin cells. The cytotoxicity of ethanol, chlorhexidine digluconate, sodium hypochlorite, povidone iodine and polyhexanide was evaluated in this in vitro study on human fibroblasts and keratinocytes. Treatments were applied to each cell type culture every 48 h for 14 days. To determine the cytotoxic of antiseptics, cell viability (Live/Dead®) and cell proliferation (AlamarBlue™) assays were performed on cell monolayers. Cell migration capacity was evaluated with a wound closure assay. Results showed how chlorhexidine digluconate and ethanol significantly reduced the viability of keratinocytes and inhibited cell migration. Povidone iodine followed by chlorhexidine digluconate significantly reduced fibroblast cell viability. Povidone iodine also inhibited cell migration. Sodium hypochlorite was the least detrimental to both cell types. If epithelial integrity is affected, the wound healing process may be altered, so the information gathered in this study may be useful in selecting the least aggressive antiseptic after treatment with new emerging therapies.

Characterization of Genetic Variants of Uncertain Significance for the ALPL Gene in Patients With Adult Hypophosphatasia.

Hypophosphatasia (HPP) a rare disease caused by mutations in the ALPL gene encoding for the tissue-nonspecific alkaline phosphatase protein (TNSALP), has been identified as a potentially under-diagnosed condition worldwide which may have higher prevalence than currently established. This is largely due to the overlapping of its symptomatology with that of other more frequent pathologies. Although HPP is usually associated with deficient bone mineralization, the high genetic variability of ALPL results in high clinical heterogeneity, which makes it difficult to establish a specific HPP symptomatology. In the present study, three variants of ALPL gene with uncertain significance and no previously described (p.Del Glu23_Lys24, p.Pro292Leu and p.His379Asn) were identified in heterozygosis in patients diagnosed with HPP. These variants were characterized at phenotypic, functional and structural levels. All genetic variants showed significantly lower in vitro ALP activity than the wild-type (WT) genotype (p-value <0.001). Structurally, p.His379Asn variant resulted in the loss of two Zn2+ binding sites in the protein dimer which may greatly affect ALP activity. In summary, we identified three novel ALPL gene mutations associated with adult HPP. The correct identification and characterization of new variants and the subsequent study of their phenotype will allow the establishment of genotype-phenotype relationships that facilitate the management of the disease as well as making it possible to individualize treatment for each specific patient. This would allow the therapeutic approach to HPP to be personalized according to the unique genetic characteristics and clinical manifestations of each patient.

Identification of Potential Targets Linked to the Cardiovascular/Alzheimer's Axis through Bioinformatics Approaches.

The identification of common targets in Alzheimer's disease (AD) and cardiovascular disease (CVD) in recent years makes the study of the CVD/AD axis a research topic of great interest. Besides aging, other links between CVD and AD have been described, suggesting the existence of common molecular mechanisms. Our study aimed to identify common targets in the CVD/AD axis. For this purpose, genomic data from calcified and healthy femoral artery samples were used to identify differentially expressed genes (DEGs), which were used to generate a protein-protein interaction network, where a module related to AD was identified. This module was enriched with the functionally closest proteins and analyzed using different centrality algorithms to determine the main targets in the CVD/AD axis. Validation was performed by proteomic and data mining analyses. The proteins identified with an important role in both pathologies were apolipoprotein E and haptoglobin as DEGs, with a fold change about +2 and -2, in calcified femoral artery vs healthy artery, respectively, and clusterin and alpha-2-macroglobulin as close interactors that matched in our proteomic analysis. However, further studies are needed to elucidate the specific role of these proteins, and to evaluate its function as biomarkers or therapeutic targets.

Mesenchymal Stromal Cell-Conditioned Medium for Skin Diseases: A Systematic Review.

The skin is the largest organ of the human body, and its dysfunction is related to many diseases. There is a need to find new potential effective therapies for some skin conditions such as inflammatory diseases, wound healing, or hair restoration. Mesenchymal stromal cell (MSC)-conditioned medium (CM) provides a potential opportunity in the treatment of skin disease. Thus, the objective of this review is to evaluate the uses of MSC-CM for treating skin diseases in both animal and human models. A systematic review was conducted regarding the use of MSC-CM for treating skin conditions. One hundred one studies were analyzed. MSC-CM was evaluated in wound healing (55), hypertrophic scars (9), flap reperfusion (4), hair restoration (15), skin rejuvenation (15), and inflammatory skin diseases (3). MSC-CM was obtained from different MSC sources, mainly adipose tissue, bone marrow, and umbilical cord blood. MSC-CM was tested intravenously, intraperitoneally, subcutaneously, intradermally or intralesionally injected or topically applied. MSC-CM was used in both animals and humans. MSC-CM improved wound healing, hair restoration, skin rejuvenation, atopic dermatitis, and psoriasis in both animals and humans. MSC-CM also decreased hypertrophic scars and flap ischemia in animal models. In conclusion, MSC-CM is a promising therapy for skin conditions. Further studies are needed to corroborate safety and effectiveness and to standardize CM manufacturing.

Alloreactive Immune Response Associated to Human Mesenchymal Stromal Cells Treatment: A Systematic Review.

The well-known immunomodulatory and regenerative properties of mesenchymal stromal cells (MSCs) are the reason why they are being used for the treatment of many diseases. Because they are considered hypoimmunogenic, MSCs treatments are performed without considering histocompatibility barriers and without anticipating possible immune rejections. However, recent preclinical studies describe the generation of alloantibodies and the immune rejection of MSCs. This has led to an increasing number of clinical trials evaluating the immunological profile of patients after treatment with MSCs. The objective of this systematic review was to evaluate the generation of donor specific antibodies (DSA) after allogeneic MSC (allo-MSC) therapy and the impact on safety or tolerability. Data from 555 patients were included in the systematic review, 356 were treated with allo-MSC and the rest were treated with placebo or control drugs. A mean of 11.51% of allo-MSC-treated patients developed DSA. Specifically, 14.95% of these patients developed DSA and 6.33% of them developed cPRA. Neither the production of DSA after treatment nor the presence of DSA at baseline (presensitization) were correlated with safety and/or tolerability of the treatment. The number of doses administrated and human leucocyte antigen (HLA) mismatches between donor and recipient did not affect the production of DSA. The safety of allo-MSC therapy has been proved in all the studies and the generation of alloantibodies might not have clinical relevance. However, there are very few studies in the area. More studies with adequate designs are needed to confirm these results.

Biodistribution of Mesenchymal Stromal Cells after Administration in Animal Models and Humans: A Systematic Review.

Mesenchymal Stromal Cells (MSCs) are of great interest in cellular therapy. Different routes of administration of MSCs have been described both in pre-clinical and clinical reports. Knowledge about the fate of the administered cells is critical for developing MSC-based therapies. The aim of this review is to describe how MSCs are distributed after injection, using different administration routes in animal models and humans. A literature search was performed in order to consider how MSCs distribute after intravenous, intraarterial, intramuscular, intraarticular and intralesional injection into both animal models and humans. Studies addressing the biodistribution of MSCs in "in vivo" animal models and humans were included. After the search, 109 articles were included in the review. Intravenous administration of MSCs is widely used; it leads to an initial accumulation of cells in the lungs with later redistribution to the liver, spleen and kidneys. Intraarterial infusion bypasses the lungs, so MSCs distribute widely throughout the rest of the body. Intramuscular, intraarticular and intradermal administration lack systemic biodistribution. Injection into various specific organs is also described. Biodistribution of MSCs in animal models and humans appears to be similar and depends on the route of administration. More studies with standardized protocols of MSC administration could be useful in order to make results homogeneous and more comparable.

The Role of Exosomes Derived From Mesenchymal Stromal Cells in Dermatology.

The skin is the largest organ of the human body and its main functions include providing protection from external harmful agents, regulating body temperature, and homeostatic maintenance. Skin injuries can damage this important barrier and its functions so research focuses on approaches to accelerate wound healing and treat inflammatory skin diseases. Due to their regenerative and immunomodulatory properties, mesenchymal stromal cells (MSCs) have been reported to play a significant role in skin repair and regeneration. However, it seems that the secretome of these cells and exosomes in particular may be responsible for their functions in skin regeneration and the immunomodulation field. The present review aims to gather the available information about the role of MSC-derived exosomes for both in vitro and in vivo models of different skin conditions and to highlight the need for further research in order to overcome any limitations for clinical translation.