Hyaluronan (HA) is present in many tissues of the body and is essential to maintain moistness in the skin tissues, which contain approximately half the body’s HA mass. Due to its viscosity and moisturizing effect, HA is widely distributed as a medicine, cosmetic, food, and, recently marketed in Japan as a popular dietary supplement to promote skin moisture. In a randomized, double-blind, placebo-controlled clinical study it was found that ingested HA increased skin moisture and improved treatment outcomes for patients with dry skin. HA is also reported to be absorbed by the body distributed, in part, to the skin. Ingested HA contributes to the increased synthesis of HA and promotes cell proliferation in fibroblasts. These effects show that ingestion of HA moisturizes the skin and is expected to improve the quality of life for people who suffer from dry skin. This review examines the moisturizing effects of dry skin by ingested HA and summarizes the series of mechanisms from absorption to pharmacological action.

Low molecular weight hyaluronan enhances or induces inflammation through toll-like receptor 4 (TLR-4).However, the effects of high molecular weight hyaluronan (HA900) on TLR-4 are unknown. In this study, HA900 (900 kDa) was administered orally to MRL-lpr/lpr mice, a Th-1-type autoimmune disease model. Lymphoaccumulation of double-negative T cells, which is enhanced by proinflammatory cytokines, was suppressed by HA900 treatment. Cytokine array analysis showed that HA900 treatment enhanced production of interleukin-10, an anti-inflammatory cytokine, and down-regulated chemokine production. HA900 colocalized with TLR-4 on the luminal surface of epithelial cells in the large intestine. These cells are parts of the immune system and express cytokines. DNA array analysis of the tissue from the large intestine showed that HA900 treatment up-regulated suppressor of cytokine signaling 3 (SOCS3) expression and down-regulated pleiotrophin expression. Treatment of cultured double-negative T cells from MRL-lpr/lpr mice with pleiotrophin rescued these cells. SOCS3, which is known to suppress inflammation, was enhanced by HA900 treatment. In TLR-4 knockdown HT29 cells (a cell line derived from large intestinal cells), HA900 did not bind to HT29 cells and did not up-regulate SOCS3 expression. Our results suggest that oral administration of HA900 modulates Th-1-type autoimmune disease and inflammation by up-regulating SOCS3 expression and down-regulating pleiotrophin expression via TLR-4 in intestinal epithelial cells.Many reports have shown that low molecular weight hyaluronan (HA) 2 enhances or induces inflammation via toll-like receptor 4 (TLR-4) (1, 2). It is well known that the functions of HA are molecular weight-dependent (3, 4). Therefore, we hypothesized that the actions of HA via TLR-4 depend on its molecular weight. MRL-lpr/lpr mice (3) are characterized by lymphoaccumulation of double-negative T cells (DNT cells), i.e. lymph node enlargement in their lymph nodes and spleens, and proliferation of these cells is enhanced by proinflammatory cytokines (5, 6).TLR-4 is a type of HA receptor found on the surface of large intestinal epithelial cells, which form part of the immune system and express cytokines. SOCS3 expression suppresses inflammation and arthritis (7-9).In this study, we showed that oral administration of high molecular weight HA (HA900) up-regulated suppressor of cytokine signaling 3 (SOCS3). In large intestinal epithelial cells, HA900 bound to TLR-4 on the cell surface and was not systemically absorbed.Furthermore, HA900 suppressed pleiotrophin expression, which is implicated in inflammation, in intestinal tissue and in arthritis. Pleiotrophin mRNA in the spinal cord is significantly up-regulated after induction of experimental autoimmune encephalomyelitis (10, 11), and pleiotrophin is expressed in adults with inflammatory diseases, particularly in rheumatoid arthritis (12). These findings suggest that HA900 controls the immune system through up-regulation of SOCS3 and downregulation of pleiotrophin. This ...

Intestinal metaplasia (IM) of the stomach is associated with an increased risk of differentiated gastric cancer. While it is important to diagnose IM endoscopically, it can be difficult to observe by white-light endoscopy. In magnifying endoscopy with narrow-band imaging (M-NBI) of the stomach, a light-blue crest (LBC) is widely known to be a useful marker in the endoscopic diagnosis of IM. However, IM that exhibits only white opaque substance (WOS) without an LBC can also occur. The aim of this study was to elucidate whether the presence of WOS on M-NBI of the stomach could serve as a marker of IM in the same way that an LBC does. The subjects were 40 consecutive patients who underwent M-NBI between July and December 2014. The primary endpoint in this study was to evaluatethe diagnostic performance of M-NBI for histologically observed IM in WOS- and LBC-positive mucosa. The sensitivity and specificity of WOS for histologically diagnosed IM were 50.0 % (95 % confidence interval [CI] 40.0 % - 50.0 %) and 100.0 % (95 %CI 85.0 % - 100.0 %), respectively. Meanwhile, the sensitivity and specificity of LBC were 62.5 % (95 %CI 51.1 % - 65.9 %) and 93.8 % (95 %CI 76.7 % - 98.9 %), respectively. The sensitivity and specificity of WOS and/or LBC (WOS positive and LBC positive, WOS positive and LBC negative, or WOS negative and LBC positive) for histologically diagnosed IM were 87.5 % (95 %CI 76.9 % - 90.9 %) and 93.8 % (95 %CI 77.9 % - 98.9 %), respectively. LBC and WOS are both useful markers for endoscopic diagnosis of IM. Combining both markers improves the sensitivity.Clinical trial number: UMINCTR000014453.

Similar to UC patients in Western countries, a bimodal distribution of onset age was also observed in Japanese UC patients, and smoking cessation may partly contribute to the increase in late-onset UC patients in recent years in Japan.

Hyaluronic acid is a constituent of the skin and helps to maintain hydration. The oral intake of hyaluronic acid increases water in the horny layer as demonstrated by human trials, but in vivo kinetics has not been shown. This study confirmed the absorption, migration, and excretion of 14C-labeled hyaluronic acid (14C-hyaluronic acid). 14C-hyaluronic acid was orally or intravenously administered to male SD rats aged 7 to 8 weeks. Plasma radioactivity after oral administration showed the highest level 8 hours after administration, and orally administered 14C-hyaluronic acid was found in the blood. Approximately 90% of 14C-hyaluronic acid was absorbed from the digestive tract and used as an energy source or a structural constituent of tissues based on tests of the urine, feces, expired air, and cadaver up to 168 hours (one week) after administration. The autoradiographic results suggested that radioactivity was distributed systematically and then reduced over time. The radioactivity was higher in the skin than in the blood at 24 and 96 hours after administration. The results show the possibility that orally administered hyaluronic acid migrated into the skin. No excessive accumulation was observed and more than 90% of the hyaluronic acid was excreted in expired air or urine.