A Novel Mucidosphaerium sp. Downregulates Inflammatory Gene Expression in Skin and Articular Cells.

CONTEXT: Hot-spring therapy is occasionally used for the treatment of inflammatory diseases. Microorganisms might contribute to the anti-inflammatory functions seen in thermal mud therapies. Natural microorganisms, derived from traditional spa resorts, could be useful as a preventive strategy for alternative medical applications. OBJECTIVE: The aim of the study was to find effective microalgae from prominent hot springs to use for the treatment of inflammatory diseases. DESIGN: The research team performed an in-vitro study. Microalgae, derived from Beppu hot springs, were isolated and homogeneously cultured. SETTING: The study took place at the Saravio Central Institute at Saravio Cosmetics in Oita, Japan and the Department of Bioscience and Biotechnology in the Graduate School of Agriculture at Shinshu University in Nagano, Japan. INTERVENTION: For identification, the 18S ribosomal RNA genes of microalgae were investigated by DNA sequencing and homology search, together with microscopic observation. OUTCOME MEASURES: To examine the pharmacological activities of the algal extracts, real-time polymerase chain reactions were performed, using either primary dermal fibroblasts (DFs), dermal papilla cells (DPCs), or fibroblast-like synoviocytes (FLSs). To test the antioxidant activity, both the oxygen radical absorbance capacity and the generation of intracellular reactive oxygen species (ROS) were evaluated. RESULTS: A novel strain of green algae, Mucidosphaerium sp., was isolated from a Beppu hot spring. The algal extract downregulated gene-expression levels of pro-inflammatory cytokines, such as interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor- alpha (TNF-α), in various primary cells pre-exposed to IL-1ß. The protein level of the risk factors was concomitantly reduced. In addition, the algal extract suppressed the IL-1ß-induced upregulation of cyclooxygenase-2, nerve growth factor, and matrix metalloproteinase-1 (MMP-1) and MMP-3 in DFs. It also inhibited that of MMP-1, -3, and -9 in FLSs. Moreover, the extract inhibited total MMP protease activities. The microalgae decreased the intracellular reactive oxygen species (ROS) level in FLSs with an antioxidant activity of 178.3 ± 0.9 µmol of trolox equivalent/g. CONCLUSIONS: The present study showed that the novel Mucidosphaerium sp., derived from a Beppu hot spring, suppressed inflammatory reactions in both cutaneous and articular cells, partly due to its antioxidative properties. The novel algal strain may be a useful tool as an alternative medicine for skin and joint inflammatory disorders.

Oral administration of spa-derived green alga improves insulin resistance in overweight subjects: Mechanistic insights from fructose-fed rats.

Advanced glycation end products (AGEs) and their receptor (RAGE) system evoke inflammatory reactions and insulin resistance in adipocytes. Spa-derived green alga Mucidosphaerium sp. (MS) had anti-inflammatory properties in vitro. We examined here whether and how MS could ameliorate insulin resistance in fructose-rich diet-fed rats, and conducted a randomized, double blind, placebo-controlled trial to investigate the effects of MS on insulin resistance in overweight subjects. Oral administration of MS for 8 weeks significantly decreased random blood glucose, and fasting insulin, oxidative stress levels, and improved homeostasis model assessment of insulin resistance (HOMA-IR) values in fructose-fed rats, which were associated with the reduction of AGEs, RAGE, 8-hydroxy-2'-deoxy-guanosine, NADPH oxidase activity, macrophage and lymphocyte infiltration, monocyte chemoattractant protein-1 (MCP-1) expression, and adipocyte size in the adipose tissues as well as restoration of adiponectin levels. MS decreased the AGE-induced NADPH oxidase activity, ROS generation, MCP-1 and RAGE gene expression, and lipid accumulation in differentiated adipocytes, while it restored the decrease in adiponectin mRNA levels. An anti-oxidant, N-acetylcysteine mimicked the effects of MS on ROS generation, RAGE gene expression, and lipid accumulation. Oral intake of MS for 12 weeks significantly decreased systolic and diastolic blood pressure, fasting plasma glucose, fasting insulin, HOMA-IR, HDL-cholesterol and creatinine in overweight subjects. Baseline-adjusted diastolic blood pressure, fasting plasma glucose, fasting insulin, and HOMA-IR values were significantly lower in MS treatment group than in placebo. Our present findings suggest that MS may improve insulin resistance by blocking the AGE-RAGE-oxidative stress axis in the adipose tissues.