Anti-inflammatory effects of differential molecular weight Hyaluronic acids on UVB-induced calprotectin-mediated keratinocyte inflammation.

BACKGROUND: The biological functions of Hyaluronic acid are related to its molecular weight and binding to its receptor, Toll-like receptor4 (TLR4) or CD44. Recent studies have shown that low-molecular-weight Hyaluronic acid (LMW-HA) exhibits proinflammatory effects, while high-molecular-weight Hyaluronic acid (HMW-HA) functions as an anti-inflammatory factor. UVB-induced epidermal inflammation is mainly mediated by endogenous molecules, such as damage-associated molecular patterns (DAMPs), that cause severe skin damage by activating TLR signaling pathways. OBJECTIVE: Since both LMW- and HMW-HA have inhibitory functions on TLR-mediated macrophage inflammation, HA is assumed to suppress UVB-induced DAMP-mediated inflammation in the skin. In this study, both Ultra- low-molecular-weight Hyaluronic acid (uLMW-HA) and HMW-HA were found to inhibit UVB-induced keratinocyte inflammation. METHODS: HaCaT cells were treated with medium containing Hyaluronic acid at the appropriate concentration after 15 mJ/cm2 irradiation. Secreted protein levels were determined with ELISA kits. Expression levels of proteins downstream of TLR4 were detected by Simple Western system. RESULTS: By competitively binding to TLR4, uLMW-HA downregulated Calprotectin-induced TRAF6 expression, which might be the direct process by which uLMW-HA decreased UVB-induced IL-6 secretion. Reduced　CD44 variant (CD44v) expression in keratinocytes attenuated the inhibitory effect of both uLMW-HA and HMW-HA on UVB-induced inflammation, which indicated the involvement of CD44v in HA-regulated anti-inflammatory activity. CONCLUSION: Overall, this research indicates that Hyaluronic acid is more than a moisturizer; it is also a biologically effective material that can prevent the excessive skin inflammation caused in daily life, especially in the late stages after sunburn.

Keratinocyte Proline-Rich Protein Deficiency in Atopic Dermatitis Leads to Barrier Disruption.

Atopic dermatitis is a common inflammatory skin disease caused by the interaction of genetic and environmental factors. By allelic copy number analysis at missense single-nucleotide polymorphisms on 26 genes with copy number variation, we identified a significant association between atopic dermatitis and human KPRP. Human KPRP expression, which was localized to the upper granular layer of epidermis, was significantly decreased in atopic dermatitis compared with normal skin. KPRP was histologically colocalized with loricrin and was mainly detected in cytoskeleton fractions of human keratinocytes. To further investigate the role of KPRP in skin, Kprp-knockout mice were generated. Heterozygous knockout (Kprp+/-) mice exhibited reduced KPRP expression to level a similar to that of human AD lesional skin. Kprp+/- mice showed abnormal desmosome structure and detachment of lower layers of the stratum corneum. Percutaneous inflammation by topical application of croton oil or oxazolone was enhanced, and epicutaneous immunization with ovalbumin induced a high level of IgE in Kprp+/- mice. Our study, started from allelic copy number analysis in human AD, identified the importance of KPRP, the decrease of which leads to barrier dysfunction.

Clinicalpathological analysis of risk factors for the development of hepatocellular carcinoma after surgery for esophageal varices due to underlying cirrhosis or pre-cirrhosis in the 397 patients.

Risk factors for the development of hepatocellular carcinoma (HCC) were investigated in 397 patients who underwent non-shunt operation for esophageal varices due to underlying cirrhosis or pre-cirrhosis between September 1979 and May 1995. Ninety-five of these patients developed HCC. The clinical characteristics of patients at the time of surgery for varices, stages (F0-F4) of the progression of fibrosis, and grades (A0-A3) of necroinflammatory activity in liver biopsy tissue obtained at surgery in 170 patients based on the New Inuyama Classification (Int. Hepatol. Commun. 6 (1996) 112), were analyzed to investigate their relationship with the development of HCC. In addition, the levels of AST and ALT were followed every 3 months after surgery in 116 patients, and were divided into 2 groups at 80 IU/ml to compare the level of risk for the development of HCC. In liver biopsy tissue, group F4 (n=68/152, 45%) showed a significantly higher (P=0.0224) rate of appearance of HCC than group F3 (n=3/18, 17%). Group F4 also tended to show a higher cumulative HCC appearance rate of 55% compared with 37% for group F3 at 10 years after surgery (P=0.097). In regard to activity, the appearance rate of HCC in group A2+A3 (n=52/112, 51%) was significantly higher (P=0.0008) than that of HCC in group A1 (n=14/58, 25%). The cumulative appearance rate (60%) of HCC in group A2+A3 was significantly higher than that (31%) in group A1 at 10 years after surgery (P=0.0003). The appearance rate of HCC was significantly higher in the group (n=33/44, 75%) with a mean AST level >/=80 IU/ml than in the group (n=41/72, 57%) with a mean AST level <80 IU/ml (P=0.0496). A multivariate analysis of the risk factors for the development of HCC showed that necroinflammatory activity was a risk factor. These results suggested that the histopathologic classification (the New Inuyama Classification) of liver biopsy tissue from patients who underwent non-shunt operation for esophageal varices due to underlying cirrhosis or pre-cirrhosis is useful for predicting the development of HCC, to which the grades of necroinflammatory activity in particular are more closely related.