Dietary supplementation with N-3 polyunsaturated fatty acid-enriched fish oil promotes wound healing after ultraviolet B-induced sunburn in mice

Fish skin dressing for wound regeneration: A bioactive component review of omega-3 PUFAs, collagen and ECM

Wound healing is a complex biological process that involves several stages, including hemostasis, inflammation, proliferation, and remodeling. Traditional wound dressings, to a certain extent, can provide wound protection but are limited in promoting wound healing, reducing scar formation, and preventing bacterial infections. In recent years, with the advancement of research in biomedical materials, fish skin dressings have become a research hotspot in the field of tissue regeneration due to their remarkable biocompatibility and precious bioactive components. However, current research on fish skin dressings remains focused on clinical treatment. To further deepen and promote the development of fish skin dressings, we put emphasis on discussing main bioactive components in fish skin. This article has reviewed the advantages of fish skin dressings in wound regeneration, especially the promotive effects of its main bioactive components-Omega-3 polyunsaturated fatty acids, collagen derived from fish skin, and the extracellular matrix of fish skin-on the wound healing process. Besides, by critically summarizing the research issues of each bioactive component, this review assists researchers in better defining the next direction of research, thereby designing the optimal dressing for different types of wounds.

Combination therapy of negative pressure wound therapy and antibiotic-loaded bone cement for accelerating diabetic foot ulcer healing: A prospective randomised controlled trial

Negative pressure wound therapy (NPWT) and antibiotic-loaded bone cement (ALBC) are commonly used treatments for diabetic foot ulcers (DFUs). However, the combined efficacy of these two modalities remains unclear. This clinical study aimed to assess the effectiveness and underlying mechanisms of NPWT&ALBC in the management of DFUs. A total of 28 patients were recruited, 16 of whom served as controls and received only NPWT, whilst 12 received NPWT&ALBC. Both groups underwent wound repair surgery following the treatments. Blood samples were obtained to detect infections and inflammation. Wound tissue samples were also collected before and after the intervention to observe changes in inflammation, vascular structure and collagen through tissue staining. Compared with the NPWT group, the NPWT&ALBC group exhibited a superior wound bed, which was characterised by reduced inflammation infiltration and enhanced collagen expression. Immunostaining revealed a decrease in IL-6 levels and an increase in α-SMA, CD68, CD206 and collagen I expression. Western blot analysis demonstrated that NPWT&ALBC led to a decrease in inflammation levels and an increase in vascularization and collagen content. NPWT&ALBC therapy tends to form a wound bed with increased vascularization and M2 macrophage polarisation, which may contribute to DFUs wound healing.

Diabetes Mellitus Inhibits Hair Follicle Regeneration by Inducing Macrophage Reprogramming-Mediated Pyroptosis

Background

Diabetes mellitus (DM) is known to inhibit skin self-renewal and hair follicle stem cell (HFSC) activation, which may be key in the formation of chronic diabetic wounds. This study aimed to investigate the reasons behind the suppression of HFSC activation in DM mice.

Methods

Type 1 DM (T1DM) was induced in 6-week-old mice via streptozotocin, and hair follicle growth was subsequently monitored. RNA sequencing, bioinformatics analyses, qRT‒PCR, immunostaining, and cellular experiments were carried out to investigate the underlying mechanisms involved.

Results

T1DM inhibited HFSC activation, which correlated with an increase in caspase-dependent programmed cell death. Additionally, T1DM triggered apoptosis and pyroptosis, predominantly in HFSCs and epidermal regions, with pyroptosis being more pronounced in the inner root sheath of hair follicles. Notably, significant cutaneous immune imbalances were observed, particularly in macrophages. Cellular experiments demonstrated that M1 macrophages inhibited HaCaT cell proliferation and induced cell death, whereas high-glucose environments alone did not have the same effect.

Conclusion

T1DM inhibits HFSC activation via macrophage reprogramming-mediated caspase-dependent pyroptosis, and there is a significant regional characterization of cell death. Moreover, T1DM-induced programmed cell death in the skin may be more closely related to immune homeostasis imbalance than to hyperglycemia itself. These findings shed light on the pathogenesis of diabetic ulcers and provide a theoretical basis for the use of hair follicle grafts in wound repair.

A New Generation of Postbiotics for Skin and Scalp: In Situ Production of Lipid Metabolites by Malassezia

Effects of pre- and probiotics on intestinal health are well researched and microbiome-targeting solutions are commercially available. Even though a trend to appreciate the presence of certain microbes on the skin is seeing an increase in momentum, our understanding is limited as to whether the utilization of skin-resident microbes for beneficial effects holds the same potential as the targeted manipulation of the gut microflora. Here, we present a selection of molecular mechanisms of cross-communication between human skin and the skin microbial community and the impact of these interactions on the host's cutaneous health with implications for the development of skin cosmetic and therapeutic solutions. Malassezia yeasts, as the main fungal representatives of the skin microfloral community, interact with the human host skin via lipid mediators, of which several are characterized by exhibiting potent anti-inflammatory activities. This review therefore puts a spotlight on Malassezia and provides a comprehensive overview of the current state of knowledge about these fungal-derived lipid mediators and their capability to reduce aesthetical and sensory burdens, such as redness and itching, commonly associated with inflammatory skin conditions. Finally, several examples of current skin microbiome-based interventions for cosmetic solutions are discussed, and models are presented for the use of skin-resident microbes as endogenous bio-manufacturing platforms for the in situ supplementation of the skin with beneficial metabolites.

In Situ Sodium Chloride Cross-Linked Fish Skin Collagen Scaffolds for Functional Hemostasis Materials

Current fish collagen hemostasis for wound healing products is commonly obtained by electrospinning or artificial cross-linking fish collagen fibers which lacks mechanical properties, and biofunctions. Here, a new bio-active fish skin scaffold (FSS) is shown using in situ cross-linked scaleless freshwater fish skin adding adipose-derived stem cells (ASCs)-produced exosomes for hemostasis and wound healing. The structure, pore size, and the thickness of FSS is studied by swelling test, Fourier-transform infrared (FT-IR) spectra, scanning electron microscope (SEM) images, and histological analysis. The biofunctions of the FSS are also tested in vitro and in vivo. FSS keeps two functional layers: The dermis layer collagen forms a sponge like structure after swelling and in situ cross-linking treatments. The pore size of the FSS is ≈152 ± 23.54 µm, which is suitable for cells growing, angiogenesis and ASCs exosomes accelerate wound healing. The fat-rich epidermis layer can keep the wound moisty and clean before completely healed. In vitro and in vivo experimental results indicate that FSS+Exosomes enhances rat skin cavity wound healing. In situ sodium chloride cross-linked FSS+Exosomes provides a new strategy as functional hemostatic dressing scaffold for wound healing.

Advancements in engineered exosomes for wound repair: current research and future perspectives

Wound healing is a complex and prolonged process that remains a significant challenge in clinical practice. Exosomes, a type of nanoscale extracellular vesicles naturally secreted by cells, are endowed with numerous advantageous attributes, including superior biocompatibility, minimal toxicity, and non-specific immunogenicity. These properties render them an exceptionally promising candidate for bioengineering applications. Recent advances have illustrated the potential of exosome therapy in promoting tissue repair. To further augment their therapeutic efficacy, the concept of engineered exosomes has been proposed. These are designed and functionally modifiable exosomes that have been tailored on the attributes of natural exosomes. This comprehensive review delineates various strategies for exosome engineering, placing specific emphasis on studies exploring the application of engineered exosomes for precision therapy in wound healing. Furthermore, this review sheds light on strategies for integrating exosomes with biomaterials to enhance delivery effectiveness. The insights presented herein provide novel perspectives and lay a robust foundation for forthcoming research in the realm of cutaneous wound repair therapies.

The effects of unsaturated fatty acids on psoriasis: A two-sample Mendelian randomization study

Unsaturated fatty acids have been reported to be associated with the risk of psoriasis. However, the causal relationship between them remains unclear This study aimed to explore the causal relationship between unsaturated FAs and psoriasis. Firstly, we obtained genome-wide association study (GWAS) data for psoriasis from the FINNGEN database (number of cases = 4510, number of controls = 212,242) and different FA levels (number of samples = 114,999) from the IEU OpenGWAS Project. Secondly, the genetic correlation coefficient was calculated using linkage disequilibrium fractional regression. Thirdly, a two-sample Mendelian randomization (MR) analysis was performed using independent instrumental variables (p < 5 × 10-8) to determine the direction of randomization. Finally, expression quantitative trait loci (eQTL)-related analyses of common single nucleotide polymorphisms (SNPs) were carried out to explore the potential molecular mechanisms of unsaturated FAs affecting psoriasis. We found that an increase in the ratio of monounsaturated fatty acids (MUFAs) to total fatty acids could increase the risk of psoriasis (inverse-variance weighted [IVW], adjusted odds ratio [OR] = 1.175; adjusted 95% confidence interval [CI] = 1.045-1.321; adjusted p = .007). However, an increase in the ratio of polyunsaturated fatty acids (PUFAa) to total fatty acids could decrease the risk of psoriasis (IVW, adjusted OR = 0.754; adjusted 95% CI = 0.631-0.901; adjusted p = .002). Moreover, an increase in the ratio of PUFAs to MUFAs could decrease the risk of psoriasis (IVW, adjusted OR = 0.823; adjusted 95% CI = 0.715-0.948; adjusted p = .007). The heterogeneity of data was eliminated, and pleiotropy was not detected. There was no statistical difference in the MR analysis of other fatty acids indices with psoriasis. Further, no statistically significant evidence was found to verify a causal relationship between psoriasis and fatty acid levels in reverse MR. Functional enrichment analysis showed that these eQTL related to common SNPs were mainly involved in organic ion transport, choline metabolism, and the expression of key metabolic factors mediated by PKA, ChREBP, and PP2A. Our study indicated that the ratio of MUFAs to total fatty acids had a positive causal effect on psoriasis, while the ratio of PUFAs to total fatty acids and the ratio of PUFAs to MUFAs had a negative causal effect on psoriasis. Moreover, PKA-, PP2A-, and ChREBP-mediated activation of metabolic factors may play an important role in this process.

Arachidonate 15-lipoxygenase type B: Regulation, function, and its role in pathophysiology

As a lipoxygenase (LOX), arachidonate 15-lipoxygenase type B (ALOX15B) peroxidizes polyenoic fatty acids (PUFAs) including arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA) to their corresponding fatty acid hydroperoxides. Distinctive to ALOX15B, fatty acid oxygenation occurs with positional specificity, catalyzed by the non-heme iron containing active site, and in addition to free PUFAs, membrane-esterified fatty acids serve as substrates for ALOX15B. Like other LOX enzymes, ALOX15B is linked to the formation of specialized pro-resolving lipid mediators (SPMs), and altered expression is apparent in various inflammatory diseases such as asthma, psoriasis, and atherosclerosis. In primary human macrophages, ALOX15B expression is associated with cellular cholesterol homeostasis and is induced by hypoxia. Like in inflammation, the role of ALOX15B in cancer is inconclusive. In prostate and breast carcinomas, ALOX15B is attributed a tumor-suppressive role, whereas in colorectal cancer, ALOX15B expression is associated with a poorer prognosis. As the biological function of ALOX15B remains an open question, this review aims to provide a comprehensive overview of the current state of research related to ALOX15B.

Fatty Acid Supplementation Affects Skin Wound Healing in a Rat Model

Polyunsaturated fatty acids (PUFA) play an important role in reparative processes. The ratio of PUFAs n-3 to n-6 may affect wound healing. The study aimed to evaluate the effect of dietary supplementation with n-3 and n-6 PUFA in two proportions on skin wounds in laboratory rats. Adult male Wistar rats received 20% fat emulsion with a ratio of 1.4:1 (group A) or 4.3:1 (group B) for n-3:n-6 PUFAs at a daily dose of 1 mL/kg. The control group received water under the same conditions. The animals were supplemented a week before and a week after the skin excision performed on the back. The level of wound closure, various parameters of oxidative stress, and plasma fatty acids composition were evaluated. Wound tissue samples were examined by electron microscopy. The administration of fat emulsions led to significant changes in plasma polyunsaturated fatty acid composition. The increased production of reactive nitrogen species, as well as more numerous newly formed blood vessels and a greater amount of highly organized collagen fibrils in both groups A and B may indicate more intensive healing of the skin wound in rats supplemented with polyunsaturated fatty acids in high n-3:n-6 ratio.

Type 2 Diabetic Mellitus Inhibits Skin Renewal through Inhibiting WNT-Dependent Lgr5+ Hair Follicle Stem Cell Activation in C57BL/6 Mice

BACKGROUND

Hair follicles are important accessory organs of the skin, and it is important for skin renewal and performs variety of important functions. Diabetes can cause several dermatoses; however, its effect on hair follicles is unclear. The purpose of this study was to investigate the effect of type II diabetes (T2DM) on the hair follicles of mice.

METHODS

Seven-week-old male C57BL/6 littermate mice were divided into two groups. The treatment group was injected with streptozotocin (STZ) to induce T2DM, and the control group was parallelly injected with the same dose of buffer. Seven days after injection, the back is depilated to observe the hair follicle regeneration. Hair follicle regeneration was observed by naked eyes and HE staining. The proliferation of the skin cells was observed by PCNA and K14 staining. The altered genes were screened by RNA sequencing and verified by qRT-PCR. In addition, Lgr5 + GFP/mTmG transgenic mice were used to observe the effect of T2DM on Lgr5 hair follicle stem cells (HFSC). And the expression of WNT4 and WNT8A were measured by Western Blot.

RESULTS

T2DM inhibited hair follicle regeneration. Compared to control mice, T2DM mice had smaller hair follicles, reduced skin thickness, and less expression of PCNA and K14. RNA sequencing showed that the two groups had significant differences in cell cycle and proliferation-related pathways. Compared with the control mice, the mRNA expression of Lgr4, Lgr5, Wnt4, and Wnt8a was decreased in the T2DM group. Moreover, T2DM inhibited the activation of Lgr5 HFSC and the expression of WNT4 and WNT8A.

CONCLUSIONS

T2DM inhibited hair follicle regeneration and skin cells proliferation by inhibiting WNT-dependent Lgr5 HFSC activation. This may be an important reason for the reduction of skin renewal ability and the formation of chronic wounds caused by diabetes. It is important for the treatment of chronic diabetic wounds and the development of tissue engineering.

Umbilical Cord Mesenchymal Stem Cell Exosomes Alleviate the Progression of Kidney Failure by Modulating Inflammatory Responses and Oxidative Stress in an Ischemia-Reperfusion Mice Model

The efficacy of stem cells for the treatment of renal failure is widely recognized; however, an excessive volume of stem cells can block the capillaries; thus, the potential risks should not be ignored. Stem cell exosomes are secretory extracellular vesicles with a size of 30-150 nm, which have similar functions to stem cells but are much smaller in size. This study aims to investigate the role of human umbilical cord mesenchymal stem cells (UCMSCs)-derived exosomes in the treatment of renal failure caused by ischemia-reperfusion. Fifty 8-week-old female C57 mice underwent bilateral renal ischemia-reperfusion surgery for 30 minutes. After 4 weeks, the treated group received UCMSCs-derived exosomes treatment, and the control group was solely injected with the same amount of PBS. At the age of 16 weeks, the kidney function, kidney damage, inflammatory responses and oxidative stress were measured. Moreover, the effect of UCMSCs-derived exosomes on the phenotype of M1 macrophages was also tested. The results showed that UCMSCsderived exosomes significantly reduced the levels of blood urea nitrogen (BUN), serum creatinine (SCR), and urinary albumin and creatinine (ACR) and 8-isoprostane. UCMSCs-derived exosomes also improved the atrophy of the kidney and glomerulus, decreased kidney pro-inflammatory factors expression (mRNA of II-1β, II-6, Tnf-α, and Mcp-1) and oxidative stress (malondialdehyde), and increased glutathione level. However, F4/80 immunohistochemistry did not show significant differences between the two groups. In systemic inflammation measurement, UCMSCs-derived exosomes decreased proinflammatory factors TNF-α, IL-6, and IL-1β levels, and increased anti-inflammatory factor IL-10 level. In vitro experiments showed that UCMSCs-derived exosomes decreased the protein expression level of TNF-α and increased the protein expression level of IL-10 in M1 macrophages. UCMSCs-derived exosomes reduce kidney inflammation and oxidative stress by improving systemic inflammation, and thus reduce kidney damage and improve kidney function. This study shows the potential application value of exosomes in the treatment of renal failure.