Relationships between circulating metabolites and facial skin aging: a Mendelian randomization study

BACKGROUND

Blood metabolites are important to various aspects of our health. However, currently, there is little evidence about the role of circulating metabolites in the process of skin aging.

OBJECTIVES

To examine the potential effects of circulating metabolites on the process of skin aging.

METHOD

In the primary analyses, we applied several MR methods to study the associations between 249 metabolites and facial skin aging risk. In the secondary analyses, we replicated the analyses with another array of datasets including 123 metabolites. MR Bayesian model averaging (MR-BMA) method was further used to prioritize the metabolites for the identification of predominant metabolites that are associated with skin aging.

RESULTS

In the primary analyses, only the unsaturation degree of fatty acids was found significantly associated with skin aging with the IVW method after multiple testing (odds ratio = 1.084, 95% confidence interval = 1.049-1.120, p = 1.737 × 10^-06). Additionally, 11 out of 17 unsaturation-related biomarkers showed a significant or suggestively significant causal effect [p < 0.05 and > 2 × 10^-4 (0.05/249 metabolites)]. In the secondary analyses, seven metabolic biomarkers were found significantly associated with skin aging [p < 4 × 10^-4 (0.05/123)], while six of them were related to the unsaturation degree. MR-BMA method validated that the unsaturation degree of fatty acids plays a dominant role in facial skin aging.

CONCLUSIONS

Our study used systemic MR analyses and provided a comprehensive atlas for the associations between circulating metabolites and the risk of facial skin aging. Genetically proxied unsaturation degree of fatty acids was highlighted as a dominant factor correlated with the risk of facial skin aging.

Precise Intradermal Injection of Nanofat-Derived Stromal Cells Combined with Platelet-Rich Fibrin Improves the Efficacy of Facial Skin Rejuvenation

BACKGROUND/AIMS

The rejuvenation properties of nanofat grafting have been described in recent years. However, it is not clear whether the clinical efficacy of the procedure is attributable to stem cells or linked to other components of adipose tissue. In this study we isolated nanofat-derived stem cells (NFSCs) to observe their biological characteristics and evaluate the efficacy of precise intradermal injection of nanofat combined with platelet-rich fibrin (PRF) in patients undergoing facial rejuvenation treatment.

METHODS

Third-passage NFSCs were isolated and cultured using a mechanical emulsification method and their surface CD markers were analyzed by flow cytometry. The adipogenic and osteogenic nature and chondrogenic differentiation capacity of NFSCs were determined using Oil Red O staining, alizarin red staining, and Alcian blue staining, respectively. Paracrine function of NFSCs was evaluated by enzyme-linked immunosorbent assay (ELISA) at 1, 3, 7, 14, and 28 days after establishing the culture. Then, the effects of PRF on NFSC proliferation were assessed in vitro. Finally, we compared the outcome in 103 patients with facial skin aging who underwent both nanofat and intradermal PRF injection (treatment group) and 128 patients who underwent hyaluronic acid (HA) injection treatment (control group). Outcomes in the two groups were compared by assessing pictures taken at the same angle before and after treatment, postoperative recovery, incidence of local absorption and cysts, and skin quality before treatment, and at 1, 12, 24 months after treatment using the VISIA Skin Image Analyzer and a SOFT5.5 skin test instrument.

RESULTS

NFSCs expressed CD29, CD44, CD49d, CD73, CD90, and CD105, but did not express CD34, CD45, and CD106. NFSCs also differentiated into adipocytes, osteoblasts, and chondrocytes under appropriate induction conditions. NFSCs released large amounts of growth factors such as VEGF, bFGF, EGF, and others, and growth factor levels increased in a time-dependent manner. At the same time, PRF enhanced proliferation of NFSCs in vitro in a dose-dependent manner, and the growth curves under different concentrations of PRF all showed plateaus 6d after seeding. Facial skin texture was improved to a greater extent after combined injection of nanofat and PRF than after control injection of HA. The nanofat-PRF group had a higher satisfaction rate. Neither treatment caused any complications such as infection, anaphylaxis, or paresthesia during long-term follow-up.

CONCLUSION

NFSCs demonstrate excellent multipotential differentiation and paracrine function, and PRF promotes proliferation of NFSCs during the early stage after seeding. Both nanofat-PRF and HA injection improve facial skin status without serious complications, but the former was associated with greater patient satisfaction, implying that nanofat-PRF injection is a safe, highly effective, and long-lasting method for skin rejuvenation.