Objective. Adiponectin is an adipocytokine that displays insulin-sensitizing and immunoregulatory properties. Adipocyte development in association with fibrosis is frequently detected in primary Sjögren's syndrome lesions, connoting a healing process. The aim of this study was to examine the expression of adiponectin in minor salivary gland biopsy specimens obtained from patients with primary SS and controls.Methods. The expression of adiponectin in minor salivary gland biopsy specimens and in long-termcultured non-neoplastic salivary gland epithelial cell (SGEC) lines obtained from patients with primary SS and control subjects was examined, using immunohistochemistry and immunoblotting, respectively. The expression of adiponectin, adiponectin receptor 1 (AdipoR1), and AdipoR2 messenger RNA (mRNA) by SGECs was investigated by reverse transcriptionpolymerase chain reaction.Results. Immunohistochemical analysis for adiponectin revealed positive staining of adipocytes from primary SS lesions as well as ductal epithelial cells from both patients with primary SS and controls. All of the SGEC lines tested were shown to express adiponectin, AdipoR1, and AdipoR2 mRNA, whereas adiponectin protein expression was detected by immunoblotting in SGECs from patients with primary SS but not in those from controls. The analysis of concentrated culture supernatants also revealed increased adiponectin expression by SGECs from patients with SS compared with controls.Conclusion. Our findings provide novel evidence that adiponectin is produced by SGECs. The high constitutive expression of adiponectin by SGECs from patients with primary SS is likely attributable to aberrant activation of these cells. Although the significance of adiponectin expression remains unknown, it is possible that adiponectin functions in an autocrine manner, as suggested by concurrent expression of the relevant receptors.Adiponectin is an adipocytokine that was independently discovered by several groups of investigators, using different approaches (1). Although adiponectin was considered to be synthesized and secreted exclusively by adipocytes, recent data suggest that it is also produced by cells other than adipocytes (2-4).Adiponectin protein belongs to the soluble defense collagen superfamily and has structural homology with type VIII collagen, type X collagen, and complement factor C1q (1). This hormone has been shown to possess several biologic properties, ranging from an insulin-sensitizing function to an immunomodulatory function. Indeed, results of several studies suggest that the protein acts as an inflammation-modulating factor (1-6). In addition, a regulatory role of adiponectin in the apoptotic death of many types of cells has been suggested (7).

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The aim of this study was to investigate the effect of anti-tumor necrosis factor alpha (anti-TNF) treatment on body composition and serum adiponectin levels of women with rheumatoid arthritis (RA). Nineteen women with RA starting anti-TNF treatment were included in the study. Disease activity, body composition, lumbar spine bone mineral density (BMD) and serum adiponectin concentrations were measured at baseline and after 1 year of follow-up. No important changes on body composition and lumbar spine BMD were observed, while the serum levels of adiponectin levels increased after 1 year of anti-TNF treatment (p = 0.02). Anti-TNF treatment in women with RA does not have any significant effect on body composition; however, it is associated with increase in adiponectin levels which may ameliorate the systemic inflammatory response state associated with RA.

SummaryThe aim of this study was to examine the levels of endoplasmic reticulum (ER) stress in minor salivary glands, to investigate the interplay between ER stress-induced autophagy and apoptosis in human salivary gland (HSG) cells and to test the effect of ER stress-induced apoptosis on the cellular redistribution of the two major Sj€ ogren's syndrome (SS) autoantigens Ro/ Sj€ ogren's syndrome-related antigen A (SSA) and La/Sj€ ogren's syndromerelated antigen B (SSB). Minor salivary gland biopsies from SS patients and sicca controls were examined by immunohistochemistry for the expression of 78 kDa glucose-regulated protein/binding immunoglobulin protein (GRP78/BiP) as an indicator of unfolded protein response (UPR). HSG cells were treated with thapsigargin (TG) and cell viability, autophagy and apoptosis were assessed. Immunoblot was applied to detect the conversion of LC3I to LC3II and the protein levels of GRP78/BiP and X-box binding protein-1 (XBP-1). Apoptosis was evaluated by a single-stranded DNA enzyme-linked immunosorbent assay (ELISA). Ro/SSA and La/SSB localization was visualized using immunofluorescence. GRP78/BiP was expressed by acinar and ductal epithelial cells in salivary glands of patients and sicca controls. TG treatment induced autophagy, as indicated by enhanced protein expression of LC3II. The protein levels of UPR marker XBP-1 were increased after TG treatment, while GRP78/BiP levels were decreased. TG treatment resulted in induction of HSG apoptosis. Ro/SSA and La/SSB autoantigens were localized predominantly to the cytoplasm in resting cells, while they were redistributed to cell membrane and blebs in the apoptotic cells. In conclusion, ER stress is activated in minor salivary gland epithelial cells from SS patients and controls. ER stress-induced apoptosis in HSG cells leads to cell surface and apoptotic blebs relocalization of Ro/SSA and La/SSB autoantigens.

Dietary ALA has no effect on plasma adiponectin concentration in dyslipidemic men.