Osteoporosis is a major skeletal disease associated with estrogen deficiency in postmenopausal women. Kefir-fermented peptides (KPs) are bioactive peptides with health-promoting benefits that are produced from the degradation of dairy milk proteins by the probiotic microflora in kefir grains. This study aimed to evaluate the effects of KPs on osteoporosis prevention and the modulation of the composition of the gut microbiota in ovariectomized (OVX) mice. OVX mice receiving an 8-week oral gavage of 100 mg of KPs and 100 mg of KPs + 10 mg Ca exhibited lower trabecular separation (Tb. Sp), and higher bone mineral density (BMD), trabecular number (Tb. N) and bone volume (BV/TV), than OVX groups receiving Ca alone and untreated mice, and these effects were also reflected in bones with better mechanical properties of strength and fracture toughness. The gut microbiota of the cecal contents was examined by 16S rDNA amplicon sequencing. α-Diversity analysis indicated that the gut microbiota of OVX mice was enriched more than that of sham mice, but the diversity was not changed significantly. Treatment with KPs caused increased microbiota richness and diversity in OVX mice compared with those in sham mice. The microbiota composition changed markedly in OVX mice compared with that in sham mice. Following the oral administration of KPs for 8 weeks, the abundances of Alloprevotella, Anaerostipes, Parasutterella, Romboutsia, Ruminococcus_1 and Streptococcus genera were restored to levels close to those in the sham group. However, the correlation of these bacterial populations with bone metabolism needs further investigation. Taken together, KPs prevent menopausal osteoporosis and mildly modulate the structure of the gut microbiota in OVX mice.

Glial cell line-derived neurotrophic factor (GDNF), a potent neurotrophic factor, has been shown to affect cancer cell metastasis and invasion. However, the molecular mechanisms underlying GDNF-induced colon cancer cell migration remain unclear. GDNF is found to be positively correlated with malignancy in human colon cancer patients. The migratory activities of two human colon cancer cell lines, HCT116 and SW480, were found to be enhanced in the presence of human GDNF. The expression of vascular endothelial growth factor (VEGF) was also increased in response to GDNF stimulation, along with VEGF mRNA expression and transcriptional activity. The enhancement of GDNF-induced cancer cell migration was antagonized by a VEGF-neutralizing antibody. Our results also showed that the expression of VEGF receptor 1 (VEGFR1) was increased in response to GDNF stimulation, whereas GDNF-induced cancer cell migration was reduced by a VEGFR inhibitor. The GDNF-induced VEGF expression was regulated by the p38 and PI3K/Akt signaling pathways. Treatment with GDNF increased nuclear hypoxia-inducible factor 1 a (HIF1a) accumulation and its transcriptional activity in a time-dependent manner. Moreover, GDNF increased hypoxia responsive element (HRE)-containing VEGF promoter transcriptional activity but not that of the HRE-deletion VEGF promoter construct. Inhibition of HIF1a by a pharmacological inhibitor or dominant-negative mutant reduced the GDNF-induced migratory activity in human colon cancer cells. These results indicate that GDNF enhances the migration of colon cancer cells by increasing VEGF-VEGFR interaction, which is mainly regulated by the p38, PI3K/Akt, and HIF1a signaling pathways.

Background Autologous platelet concentrates are currently widely used across different areas of regenerative medicine in order to enhance the wound healing process. Although several protocols for platelet concentrates are available, their application remains difficult due to different protocols leading to distinct products with vary potential biological uses. In this study, we attempted to make a platelet patch (PP) using mixtures of platelet rich plasma (PRP) injection and platelet rich fibrin (PRF) to promote wound repair and regeneration. Results Experiments were performed using a full-thickness wound model in mini-pigs. Autologous PRP, PRF and PP were prepared immediately before creating four full-thickness skin wounds in pigs. We quantified concentrations of platelets, thrombin and various growth factors to ensure that the desired effect can be produced. After surgery, hydrocolloid dressing, PRP injection, PRF and PP was applied to experimentally induced wounds. Application efficacy was evaluated by measurement of wound sizes and histological examination. The results indicated that all wounds showed a significant size reduction. Wound repair efficacy in response to PP treatment exhibited enhanced re-epithelialization compared to PRP and PRF ( P < 0.05) and higher wound contraction than did PRF application ( P < 0.05). Another aspect, experiment using DsRed transgenic pigs as blood donors demonstrated that leucocytes in PP were incorporated into the wound bed at the end of the study, suggesting that leucocytes activity is stimulated in response to PP application. Safety of the experimental processes was also confirmed by examination of organ biopsies. Conclusions We used a mini-pig model to evaluate the efficacy of lab-made PP on induced full-thickness wound healing. Results demonstrated that application of one piece of PP was enough to obtain comparable efficacy versus general utilization of PRP or PRF for wound care. We also demonstrated that leucocytes in PP were incorporated into the wound bed and no safety concerns have been found in the whole experiment. This study provides a novel and feasible method for veterinary or clinical wound care.

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