16S rRNA gene sequencing reveals the correlation between the gut microbiota and the susceptibility to pathological scars.

The gut microbiome profile in patients with pathological scars remains rarely known, especially those patients who are susceptible to pathological scars. Previous studies demonstrated that gut microbial dysbiosis can promote the development of a series of diseases via the interaction between gut microbiota and host. The current study aimed to explore the gut microbiota of patients who are prone to suffer from pathological scars. 35 patients with pathological scars (PS group) and 40 patients with normal scars (NS group) were recruited for collection of fecal samples to sequence the 16S ribosomal RNA (16S rRNA) V3-V4 region of gut microbiota. Alpha diversity of gut microbiota showed a significant difference between NS group and PS group, and beta diversity indicated that the composition of gut microbiota in NS and PS participants was different, which implied that dysbiosis exhibits in patients who are susceptible to pathological scars. Based on phylum, genus, species levels, we demonstrated that the changing in some gut microbiota (Firmicutes; Bacteroides; Escherichia coli, etc.) may contribute to the occurrence or development of pathological scars. Moreover, the interaction network of gut microbiota in NS and PS group clearly revealed the different interaction model of each group. Our study has preliminary confirmed that dysbiosis exhibits in patients who are susceptible to pathological scars, and provide a new insight regarding the role of the gut microbiome in PS development and progression.

A multifunctional hydrogel loaded with two nanoagents improves the pathological microenvironment associated with radiation combined with skin wounds.

Persistent oxidative stress and recurring waves of inflammation with excessive reactive oxygen species (ROS) and free radical accumulation could be generated by radiation. Exposure to radiation in combination with physical injuries such as wound trauma would produce a more harmful set of medical complications, which was known as radiation combined with skin wounds (RCSWs). However, little attention has been given to RCSW research despite the unsatisfactory therapeutic outcomes. In this study, a dual-nanoagent-loaded multifunctional hydrogel was fabricated to ameliorate the pathological microenvironment associated with RCSWs. The injectable, adhesive, and self-healing hydrogel was prepared by crosslinking carbohydrazide-modified gelatin (Gel-CDH) and oxidized hyaluronic acid (OHA) through the Schiff-base reaction under mild condition. Polydopamine nanoparticles (PDA-NPs) and mesenchymal stem cell-secreted small extracellular vesicles (MSC-sEV) were loaded to relieve radiation-produced tissue inflammation and oxidation impairment and enhance cell vitality and angiogenesis individually or jointly. The proposed PDA-NPs@MSC-sEV hydrogel enhanced cell vitality, as shown by cell proliferation, migration, colony formation, and cell cycle and apoptosis assays in vitro, and promoted reepithelization by attenuating microenvironment pathology in vivo. Notably, a gene set enrichment analysis of proteomic data revealed significant enrichment with adipogenic and hypoxic pathways, which play prominent roles in wound repair. Specifically, target genes were predicted based on differential transcription factor expression. The results suggested that MSC-sEV- and PDA-NP-loaded multifunctional hydrogels may be promising nanotherapies for RCSWs. STATEMENT OF SIGNIFICANCE: The small extracellular vesicle (sEV) has distinct advantages compared with MSCs, and polydopamine nanoparticles (PDA-NPs), known as the biological materials with good cell affinity and histocompatibility which have been reported to scavenge ROS free radicals. In this study, an adhesive, injectable, self-healing, antibacterial, ROS scavenging and amelioration of the radiation related microenvironment hydrogel encapsulating nanoscale particles of MSC-sEV and PDA-NPs (PDA-NPs@MSC-sEV hydrogel) was synthesized for promoting radiation combined with skin wounds (RCSWs). GSEA analysis profiled by proteomics data revealed significant enrichments in the regulations of adipogenic and hypoxic pathways with this multi-functional hydrogel. This is the first report of combining this two promising nanoscale agents for the special skin wounds associated with radiation.

Do obese patients with type A aortic dissection benefit from total arch repair through a partial upper sternotomy?

Background: Minimal research has been performed regarding total arch replacement through partial upper sternotomy in patients with acute type A aortic dissection who are obese, and the safety and feasibility of this procedure need to be further investigated. The present study investigated the potential clinical advantages of using a partial upper sternotomy versus a conventional full sternotomy for total arch replacement in patients who were obese. Methods: This was a retrospective study. From January 2017 to January 2020, a total of 65 acute type A aortic dissection patients who were obese underwent total arch replacement with triple-branched stent graft. Among them, 35 patients underwent traditional full sternotomy, and 30 patients underwent partial upper sternotomy. The perioperative clinical data and postoperative follow-up results of the two groups were collected, and the feasibility and clinical effect of partial upper sternotomy in total arch replacement were summarized. Results: The in-hospital mortality rates of the two groups were similar. The total operative time, cardiopulmonary bypass, aortic cross-clamp, cerebral perfusion, and deep hypothermic circulatory arrest times were also similar in both groups. The thoracic drainage and postoperative red blood cell transfusion volumes in the partial upper sternotomy group were significantly lower than those in the full sternotomy group. Mechanical ventilation time was shorter in the partial upper sternotomy group than that in the full sternotomy group. Additionally, the incidences of pulmonary infection, hypoxemia, and sternal diaphoresis were lower in the partial upper sternotomy group than those in the full sternotomy group. Conclusion: This study showed that total arch replacement surgery through a partial upper sternotomy in patients with acute type A aortic dissection who are obese is safe, effective, and superior to full sternotomy in terms of blood loss, postoperative blood transfusion, and respiratory complications.

Single-Cell and Spatial Transcriptomics Decodes Wharton's Jelly-Derived Mesenchymal Stem Cells Heterogeneity and a Subpopulation with Wound Repair Signatures.

The highly heterogeneous characteristics of Wharton's jelly mesenchymal stem cells (WJ-MSCs) may be responsible for the poor clinical outcomes and poor reproducibility of treatments based on WJ-MSCs. Exploration of WJ-MSC heterogeneity with multimodal single-cell technologies will aid in establishing accurate MSC subtyping and developing screening protocols for dominant functional subpopulations. Here, the characteristics of WJ-MSCs are systematically analyzed by single cell and spatial transcriptome sequencing. Single-cell transcriptomics analysis identifies four WJ-MSC subpopulations, namely proliferative_MSCs, niche-supporting_MSCs, metabolism-related_MSCs and biofunctional-type_MSCs. Furthermore, the transcriptome, cellular heterogeneity, and cell-state trajectories of these subpopulations are characterized. Intriguingly, the biofunctional-type MSCs (marked by S100A9, CD29, and CD142) selected in this study exhibit promising wound repair properties in vitro and in vivo. Finally, by integrating omics data, it has been found that the S100A9+ CD29+ CD142+ subpopulation is more enriched in the fetal segment of the umbilical cord, suggesting that this subpopulation deriving from the fetal segment may have potential for developing into an ideal therapeutic agent for wound healing. Overall, the presented study comprehensively maps the heterogeneity of WJ-MSCs and provides an essential resource for future development of WJ-MSC-based drugs.

Stem cell-derived exosomes in the treatment of melasma and its percutaneous penetration.

BACKGROUND AND OBJECTIVES: Melasma is a refractory skin disease due to its complex pathogenesis and difficult treatment. Studies have found that human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) could serve as a novel cell-free therapeutic strategy in regenerative and esthetic medicine. It could potentially treat melasma, but the skin barrier is a challenge. In this study, we aim to explore the safety and efficacy of hUCMSC-Exos in the treatment of melasma and the means to promote its percutaneous penetration. MATERIALS AND METHODS: In the animal study about the effect of penetration, percutaneous penetration of PKH67-labeled hUCMSC-Exos was studied under microneedles, 1565 nm nonablative fractional laser (NAFL), and a plasma named Peninsula Blue Aurora Shumin Master (PBASM) treatments, observed by confocal laser scanning microscopy. In the clinical application study, 60 patients with melasma treated in our department were divided into four groups. NAFL combined with normal saline treatment was used for Group A. Microneedles, NAFL, and PBASM combined with hUCMSC-Exos treatments were used for Groups B, C, and D, respectively. Each patient received four treatments at 1-month intervals. Assessments were done using the degree of pain posttreatment, melasma area and severity score, improvement rate, physician global assessment score, satisfaction, and complications. RESULTS: In the animal study about the effect of penetration, hUCMSC-Exos can penetrate the deep dermis under microneedles, NAFL, and PBASM treatments. In the clinical application study, compared with Group A, Groups B, C, and D showed significantly improved therapeutic effect and patient satisfaction (p < 0.05), and there was no significant difference among Groups B, C, and D.(p > 0.05). Patients in Group B reported higher pain levels than those in the other three groups (p < 0.05); the treatment experience of patients in Group D was better. CONCLUSION: hUCMSC-Exos can improve the symptoms of melasma safely and effectively. Compared with microneedles, NAFL and PBASM can also achieve a good effect toward promoting penetration. These findings are worthy of exploration and clinical application.

Wharton's jelly mesenchymal stem cell-derived small extracellular vesicles as natural nanoparticles to attenuate cartilage injury via microRNA regulation.

The main strategy of tissue repair and regeneration focuses on the application of mesenchymal stem cells and cell-based nanoparticles, but there are still multiple challenges that may have negative impacts on human safety and therapeutic efficacy. Cell-free nanotechnology can effectively overcome these obstacles and limitations. Mesenchymal stem cell (MSC)-derived natural small extracellular vesicles (sEVs) represent ideal nanotherapeutics due to their low immunogenicity and lack of tumorigenicity. Here, sEVs harvested from Wharton's jelly mesenchymal stem cells (WJMSCs) were identified. In vitro results showed that WJMSC-sEVs efficiently entered chondrocytes in the osteoarthritis (OA) model, further promoted chondrocyte migration and proliferation and modulated immune reactivity. In vivo, WJMSC-sEVs notably promoted chondrogenesis, which was consistent with the effect of WJMSCs. RNA sequencing results revealed that sEV-microRNA-regulated biocircuits can significantly contribute to the treatment of OA, such as by promoting the activation of the calcium signaling pathway, ECM-receptor interaction pathway and NOTCH signaling pathway. In particular, let-7e-5p, which is found in WJMSC-sEVs, was shown to be a potential core molecule for promoting cartilage regeneration by regulating the levels of STAT3 and IGF1R. Our findings suggest that WJMSC-sEV-induced chondrogenesis is a promising innovative and feasible cell-free nanotherapy for OA treatment.

Comparison of Curative Effect of Human Umbilical Cord-Derived Mesenchymal Stem Cells and Their Small Extracellular Vesicles in Treating Osteoarthritis.

INTRODUCTION: Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) and their small extracellular vesicles (hUC-MSC-sEVs) have shown attractive prospects applying in regenerative medicine. This study aimed to compare the therapeutic effects of two agents on osteoarthritis (OA) and investigate underlying mechanism using proteomics. METHODS: In vitro, the proliferation and migration abilities of chondrocytes treated with hUC-MSCs or hUC-MSC-sEVs were detected by Cell Counting Kit-8 assay and scratch wound assay. In vivo, hUC-MSCs (a single dose of 5 × 105) or hUC-MSC-sEVs (30 µg/time) were injected into the knee joints of anterior cruciate ligament transection-induced OA model. Hematoxylin and eosin, Safranin O/Fast Green staining were used to observe cartilage degeneration. The levels of cartilage matrix metabolic molecules (Collagen II, MMP13 and ADAMTS5) and macrophage polarization markers (CD14, IL-1ß, IL-10 and CD206) were assessed by immunohistochemistry. Finally, proteomics analysis was performed to characterize the proteinaceous contents of two agents. RESULTS: In vitro data showed that hUC-MSC-sEVs were taken up by chondrocytes. A total of 15 µg/mL of sEVs show the greatest proliferative and migratory capacities among all groups. In the animal study, hUC-MSCs and hUC-MSC-sEVs alleviated cartilage damage. This effect was mediated via maintaining cartilage homeostasis, as was confirmed by upregulation of the COL II and downregulation of the MMP13 and ADAMTS5. Moreover, the M1 macrophage markers (CD14) were significantly reduced, while the M2 macrophage markers (CD206 and IL-10) were increased in the hUC-MSCs and hUC-MSC-sEVs relative to the untreated group. Mechanistically, we found that many proteins connected to cartilage repair were more abundant in sEVs. Notably, compared to hUC-MSCs, the upregulated proteins in sEVs were mostly involved in the regulation of immune effector process, extracellular matrix organization, PI3K-AKT signaling pathways, and Rap1 signaling pathway. CONCLUSION: Our study indicated that hUC-MSC-sEVs protect cartilage from damage and many cartilage repair-related proteins are probably involved in the restoration process. These data suggest the promising potential of hUC-MSC-sEVs as a therapeutic agent for OA.

Combination of lyophilized adipose-derived stem cell concentrated conditioned medium and polysaccharide hydrogel in the inhibition of hypertrophic scarring.

BACKGROUND: Mesenchymal stem cell-based acellular therapies have been widely exploited in managing hypertrophic scars. However, low maintenance dose and transitory therapeutic effects during topical medication remain a thorny issue. Herein, this study aimed to optimize the curative effect of adipose-derived stem cell conditioned medium (ADSC-CM) in the prevention of hypertrophic scarring. METHODS: In the present study, ADSC-CM was concentrated via the freeze-drying procedure. The efficacy of different dose groups (CM, CM5, CM10) was conducted on the proliferation, apoptosis, and α-smooth muscle actin (α-SMA) expression of human keloid fibroblasts (HKFs) in vitro. Incorporation of adipose-derived stem cell concentrated conditioned medium (ADSCC-CM) into polysaccharide hydrogel was investigated in rabbit ear, in vivo. Haematoxylin-eosin (H&E) and Masson's trichrome staining were performed for the evaluation of scar hyperplasia. RESULTS: We noted that ADSCC-CM could downregulate the α-SMA expression of HKFs in a dose-dependent manner. In the rabbit ear model, the scar hyperplasia in the medium-dose group (CM5) and high-dose group (CM10) was inhibited with reduced scar elevation index (SEI) under 4 months of observation. It is noteworthy that the union of CM5 and polysaccharide hydrogel (CM5+H) yielded the best preventive effect on scar hyperplasia. Briefly, melanin, height, vascularity, and pliability in the CM5+H group were better than those of the control group. Collagen was evenly distributed, and skin appendages could be regenerated. CONCLUSIONS: Altogether, ADSCC-CM can downregulate the expression of α-SMA due to its anti-fibrosis effect and promote the rearrangement of collagen fibres, which is integral to scar precaution. The in situ cross bonding of ADSCC-CM and polysaccharide hydrogel could remarkably enhance the therapeutic outcomes in inhibiting scar proliferation. Hence, the alliance of ADSCC-CM and hydrogel may become a potential alternative in hypertrophic scar prophylaxis.