Diabetic microenvironment deteriorates the regenerative capacities of adipose mesenchymal stromal cells.

BACKGROUND: Type 2 diabetes is an endocrine disorder characterized by compromised insulin sensitivity that eventually leads to overt disease. Adipose stem cells (ASCs) showed promising potency in improving type 2 diabetes and its complications through their immunomodulatory and differentiation capabilities. However, the hyperglycaemia of the diabetic microenvironment may exert a detrimental effect on the functionality of ASCs. Herein, we investigate ASC homeostasis and regenerative potential in the diabetic milieu. METHODS: We conducted data collection and functional enrichment analysis to investigate the differential gene expression profile of MSCs in the diabetic microenvironment. Next, ASCs were cultured in a medium containing diabetic serum (DS) or normal non-diabetic serum (NS) for six days and one-month periods. Proteomic analysis was carried out, and ASCs were then evaluated for apoptosis, changes in the expression of surface markers and DNA repair genes, intracellular oxidative stress, and differentiation capacity. The crosstalk between the ASCs and the diabetic microenvironment was determined by the expression of pro and anti-inflammatory cytokines and cytokine receptors. RESULTS: The enrichment of MSCs differentially expressed genes in diabetes points to an alteration in oxidative stress regulating pathways in MSCs. Next, proteomic analysis of ASCs in DS revealed differentially expressed proteins that are related to enhanced cellular apoptosis, DNA damage and oxidative stress, altered immunomodulatory and differentiation potential. Our experiments confirmed these data and showed that ASCs cultured in DS suffered apoptosis, intracellular oxidative stress, and defective DNA repair. Under diabetic conditions, ASCs also showed compromised osteogenic, adipogenic, and angiogenic differentiation capacities. Both pro- and anti-inflammatory cytokine expression were significantly altered by culture of ASCs in DS denoting defective immunomodulatory potential. Interestingly, ASCs showed induction of antioxidative stress genes and proteins such as SIRT1, TERF1, Clusterin and PKM2. CONCLUSION: We propose that this deterioration in the regenerative function of ASCs is partially mediated by the induced oxidative stress and the diabetic inflammatory milieu. The induction of antioxidative stress factors in ASCs may indicate an adaptation mechanism to the increased oxidative stress in the diabetic microenvironment.

Comparative evaluation of propolis nanostructured lipid carriers and its crude extract for antioxidants, antimicrobial activity, and skin regeneration potential.

BACKGROUND: Propolis extracted from beehives has been conferred with natural antimicrobial and antioxidant properties. Hence, it has been recommended as a wound healing therapy. This study investigated the additive value of nanotechnology to the herbal extract, (propolis rebuts), after which we examined its efficacy in wound healing. METHODS: Propolis nanostructured lipid carriers (NLCs) were first prepared using the emulsion-evaporation-solidification method at three concentrations. Then, we compared their flavonoid and phenolic contents and phenolic contents. Their antioxidant, antibacterial, and antifungal effects were also investigated after which, the skin regenerative capacity of propolis-NLCs was assessed using full-thickness skin wounds in rabbits. RESULTS: This study showed that propolis-NLCs had increased the phenolic and flavonoid contents compared to the raw propolis extract (EXTR) (9-fold and 2-fold, respectively). This increase was reflected in their antioxidant activities, which dramatically increased by 25-fold higher than the propolis-EXTR. Also, propolis-NLCs exhibited a 2-fold higher potent inhibitory effect than propolis-EXTR on Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacterium (Salmonella spp.), and fungus (Candida albicans) microbes (p < 0.0001). Investigations also revealed that treatment of full-thickness skin injuries with propolis-NLCs resulted in significantly higher wound closure compared to propolis-EXTR and the control after two weeks (p < 0.0001). CONCLUSION: With a prominent broad-spectrum antibacterial effect propolis-NLCs exhibited higher skin regenerative potency than propolis-EXTR. We also highlighted the additive impact of nanotechnology on herbal extract, which accounted for the increased flavonoid content and hence a better antioxidant and antimicrobial effect and propose it as a potential therapy for wound healing.

Bone Marrow Mesenchymal Stem Cell-Derived Tissues are Mechanically Superior to Meniscus Cells.

Bone marrow-derived mesenchymal stem cells (BMSCs) have the potential to form the mechanically responsive matrices of joint tissues, including the menisci of the knee joint. The purpose of this study is to assess BMSC's potential to engineer meniscus-like tissue relative to meniscus fibrochondrocytes (MFCs). MFCs were isolated from castoffs of partial meniscectomy from nonosteoarthritic knees. BMSCs were developed from bone marrow aspirates of the iliac crest. All cells were of human origin. Cells were cultured in type I collagen scaffolds under normoxia (21% O2) for 2 weeks followed by hypoxia (3% O2) for 3 weeks. The structural and functional assessment of the generated meniscus constructs were based on glycosaminoglycan (GAG) content, histological appearance, gene expression, and mechanical properties. The tissues formed by both cell types were histologically positive for Safranin O stain and appeared more intense in the BMSC constructs. This observation was confirmed by a 2.7-fold higher GAG content. However, there was no significant difference in collagen I (COL1A2) expression in BMSC- and MFC-based constructs (p = 0.17). The expression of collagen II (COL2A1) and aggrecan (ACAN) were significantly higher in BMSCs than MFC (p ≤ 0.05). Also, the gene expression of the hypertrophic marker collagen X (COL10A1) was 199-fold higher in BMSCs than MFC (p < 0.001). Moreover, relaxation moduli were significantly higher in BMSC-based constructs at 10-20% strain step than MFC-based constructs. BMSC-based constructs expressed higher COL2A1, ACAN, COL10A1, contained higher GAG content, and exhibited higher relaxation moduli at 10-20% strain than MFC-based construct. Impact statement Cell-based tissue engineering (TE) has the potential to produce functional tissue replacements for irreparably damaged knee meniscus. But the source of cells for the fabrication of the tissue replacements is currently unknown and of research interest in orthopedic TE. In this study, we fabricated tissue-engineered constructs using type I collagen scaffolds and two candidate cell sources in meniscus TE. We compared the mechanical properties of the tissues formed from human meniscus fibrochondrocytes and bone marrow-derived mesenchymal stem cells (BMSCs). Our data show that the tissues engineered from the BMSC are mechanically superior in relaxation modulus.