Unveiling the role of hypoxia-inducible factor 2alpha in osteoporosis: Implications for bone health.

BACKGROUND: Osteoporosis (OP) has become a major public health problem worldwide. Most OP treatments are based on the inhibition of bone resorption, and it is necessary to identify additional treatments aimed at enhancing osteogenesis. In the bone marrow (BM) niche, bone mesenchymal stem cells (BMSCs) are exposed to a hypoxic environment. Recently, a few studies have demonstrated that hypoxia-inducible factor 2alpha (HIF-2α) is involved in BMSC osteogenic differentiation, but the molecular mechanism involved has not been determined. AIM: To investigate the effect of HIF-2α on the osteogenic and adipogenic differentiation of BMSCs and the hematopoietic function of hematopoietic stem cells (HSCs) in the BM niche on the progression of OP. METHODS: Mice with BMSC-specific HIF-2α knockout (Prx1-Cre;Hif-2αfl/fl mice) were used for in vivo experiments. Bone quantification was performed on mice of two genotypes with three interventions: Bilateral ovariectomy, semilethal irradiation, and dexamethasone treatment. Moreover, the hematopoietic function of HSCs in the BM niche was compared between the two mouse genotypes. In vitro, the HIF-2α agonist roxadustat and the HIF-2α inhibitor PT2399 were used to investigate the function of HIF-2α in BMSC osteogenic and adipogenic differentiation. Finally, we investigated the effect of HIF-2α on BMSCs via treatment with the mechanistic target of rapamycin (mTOR) agonist MHY1485 and the mTOR inhibitor rapamycin. RESULTS: The quantitative index determined by microcomputed tomography indicated that the femoral bone density of Prx1-Cre;Hif-2αfl/fl mice was lower than that of Hif-2αfl/fl mice under the three intervention conditions. In vitro, Hif-2αfl/fl mouse BMSCs were cultured and treated with the HIF-2α agonist roxadustat, and after 7 d of BMSC adipogenic differentiation, the oil red O staining intensity and mRNA expression levels of adipogenesis-related genes in BMSCs treated with roxadustat were decreased; in addition, after 14 d of osteogenic differentiation, BMSCs treated with roxadustat exhibited increased expression of osteogenesis-related genes. The opposite effects were shown for mouse BMSCs treated with the HIF-2α inhibitor PT2399. The mTOR inhibitor rapamycin was used to confirm that HIF-2α regulated BMSC osteogenic and adipogenic differentiation by inhibiting the mTOR pathway. Consequently, there was no significant difference in the hematopoietic function of HSCs between Prx1-Cre;Hif-2αfl/fl and Hif-2αfl/fl mice. CONCLUSION: Our study showed that inhibition of HIF-2α decreases bone mass by inhibiting the osteogenic differentiation and increasing the adipogenic differentiation of BMSCs through inhibition of mTOR signaling in the BM niche.

Diabetes patients with comorbidities had unfavorable outcomes following COVID-19: A retrospective study.

BACKGROUND: Previous studies have shown that diabetes mellitus is a common comorbidity of coronavirus disease 2019 (COVID-19), but the effects of diabetes or anti-diabetic medication on the mortality of COVID-19 have not been well described. AIM: To investigate the outcome of different statuses (with or without comorbidity) and anti-diabetic medication use before admission of diabetic after COVID-19. METHODS: In this multicenter and retrospective study, we enrolled 1422 consecutive hospitalized patients from January 21, 2020, to March 25, 2020, at six hospitals in Hubei Province, China. The primary endpoint was in-hospital mortality. Epidemiological material, demographic information, clinical data, laboratory parameters, radiographic characteristics, treatment and outcome were extracted from electronic medical records using a standardized data collection form. Most of the laboratory data except fasting plasma glucose (FPG) were obtained in first hospitalization, and FPG was collected in the next day morning. Major clinical symptoms, vital signs at admission and comorbidities were collected. The treatment data included not only COVID-19 but also diabetes mellitus. The duration from the onset of symptoms to admission, illness severity, intensive care unit (ICU) admission, and length of hospital stay were also recorded. All data were checked by a team of sophisticated physicians. RESULTS: Patients with diabetes were 10 years older than non-diabetic patients [(39 - 64) vs (56 - 70), P < 0.001] and had a higher prevalence of comorbidities such as hypertension (55.5% vs 21.4%, P < 0.001), coronary heart disease (CHD) (9.9% vs 3.5%, P < 0.001), cerebrovascular disease (CVD) (3% vs 2.2%, P < 0.001), and chronic kidney disease (CKD) (4.7% vs 1.5%, P = 0.007). Mortality (13.6% vs 7.2%, P = 0.003) was more prevalent among the diabetes group. Further analysis revealed that patients with diabetes who took acarbose had a lower mortality rate (2.2% vs 26.1, P < 0.01). Multivariable Cox regression showed that male sex [hazard ratio (HR) 2.59 (1.68 - 3.99), P < 0.001], hypertension [HR 1.75 (1.18 - 2.60), P = 0.006), CKD [HR 4.55 (2.52-8.20), P < 0.001], CVD [HR 2.35 (1.27 - 4.33), P = 0.006], and age were risk factors for the COVID-19 mortality. Higher HRs were noted in those aged ≥ 65 (HR 11.8 [4.6 - 30.2], P < 0.001) vs 50-64 years (HR 5.86 [2.27 - 15.12], P < 0.001). The survival curve revealed that, compared with the diabetes only group, the mortality was increased in the diabetes with comorbidities group (P = 0.009) but was not significantly different from the non-comorbidity group (P = 0.59). CONCLUSION: Patients with diabetes had worse outcomes when suffering from COVID-19; however, the outcome was not associated with diabetes itself but with comorbidities. Furthermore, acarbose could reduce the mortality in diabetic.

Anthocyanin extract from Lycium ruthenicum enhanced production of biomass and polysaccharides during submerged fermentation of Agaricus bitorquis (Quél.) Sacc. Chaidam.

Agaricus bitorquis (Quél.) Sacc. Chaidam (ABSC) is a wild edible fungus uniquely found in the Tibet Plateau. ABSC is rich in polysaccharides that are considered biologically active. This study aimed to determine the feasibility of enhancing exopolysaccharide (EPS) production by ABSC in shake flask culture by supplementing the fermentation medium with anthocyanin extract. Different concentrations of Lycium ruthenicum Murr. (LRM) anthocyanin crude extract were tested on ABSC fermentation. The activity of phosphoglucose isomerase (PGI), phosphoglucose mutase (PGM), and phosphomannose isomerase (PMI), enzymes presumably involved in EPS synthesis by ABSC, was determined. ABSC transcriptomic profile in response to the presence of anthocyanins during fermentation was also investigated. LRM anthocyanin crude extract (0.06 mg/mL) was most effective in increasing EPS content and mycelial biomass (by 208.10% and 105.30%, respectively, P < 0.01). The activity of PGI, PGM, and PMI was increased in a medium where LRM anthocyanin extract and its main components (proanthocyanidins and petunia anthocyanin) were added. RNA-Seq analysis showed that 349 genes of ABSC were differentially expressed during fermentation in the medium containing anthocyanin extract of LRM; 93 genes were up-regulated and 256 genes down-regulated. From gene ontology enrichment analysis, differentially expressed genes were mostly assigned to carbohydrate metabolism and signal transduction categories. Collectively, LRM anthocyanins extract positively affected EPS production and mycelial biomass during ABSC fermentation. Our study provides a novel strategy for improving EPS production and mycelial growth during ABSC liquid submerged fermentation.

Liraglutide and Insulin Have Contrary Effects on Adipogenesis of Human Adipose-Derived Stem Cells via Wnt Pathway.

BACKGROUND: Glucagon-like peptide-1 (GLP-1) has been reported to have beneficial impacts on improving human's metabolism and ameliorating insulin resistance. While insulin is another important and conventional drug in diabetes treatment, but it has an adverse effect on weight gain. PURPOSE: To make sure whether GLP-1 and insulin play different roles in human adipose-derived stem cells (hADSCs). METHODS: We examined the in vitro roles and molecular mechanisms of liraglutide, a GLP-1 analogue, and human insulin on hADSCs isolated from subcutaneous adipose tissue. Different concentrations (0, 0.1, 1, 10, 100nM) of liraglutide and insulin were added to proliferation and differentiation medium of hADSCs, respectively. RESULTS: Liraglutide inhibits while insulin promotes the proliferation and differentiation at the concentration of 100nM. Moreover, the levels of GSK-3 increase during differentiation and liraglutide could down-regulate it when compared with insulin. We also find that the activation of phosphorylated GSK-3α and GSK-3ß is involved in the differentiation roles. And classical and non-classical Wnt pathways all play roles in the differentiation, which are characterized with the up/down-regulation of the expression of adipogenesis genes such as PPAR-γ and CEBP-α. CONCLUSION: Liraglutide and insulin have contrary effects on the proliferation and adipogenesis via Wnt pathway in primary cultured ADSCs. Those effects could partly explain the different roles of GLP-1 and insulin on weight gain and insulin resistance.

Saxagliptin is similar in glycaemic variability more effective in metabolic control than acarbose in aged type 2 diabetes inadequately controlled with metformin.

This study compared the effects on glycaemic variability and glucose control between saxagliptin and acarbose as add-on therapies for aged T2DM inadequately controlled with metformin alone. The results showed that compared with acarbose-metformin, saxagliptin-metformin was more effective in glucose control with similar glycaemic variability.

Nonalcoholic fatty liver disease and cardiovascular disease.

Nonalcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD) are two diseases that are common in the general population. To date, many studies have been conducted and demonstrate a direct link between NAFLD and CVD, but the exact mechanisms for this complex relationship are not well established. A systematic search of the PubMed database revealed that several common mechanisms are involved in many of the local and systemic manifestations of NAFLD and lead to an increased cardiovascular risk. The possible mechanisms linking NAFLD and CVD include inflammation, oxidative stress, insulin resistance, ectopic adipose tissue distribution, dyslipidemia, endothelial dysfunction, and adiponectin, among others. The clinical implication is that patients with NAFLD are at an increased risk of CVD and should undergo periodic cardiovascular risk assessment.

[Assessment and analysis of risks of realizing schistosomiasis transmission control in Jiangxi Province].

OBJECTIVE: To evaluate the situation of realizing schistosomiasis transmission control in Jiangxi Province. METHODS: The situation of reaching the criteria of schistosomiasis transmission control was evaluated by using the method of field surveys combined with retrospective investigations. RESULTS: The schistosome infection in human was kept at a stable low level, and the infection rate in residents was below 1% in 90.24% (536/594) of whole epidemic controlled villages. There were 45 spots with schistosome infected Oncomelania hupensis snails in 38 pieces of marshland. The epidemic situation in livestock showed less optimistic than that in human, and the infection rate in bovine was higher than 1% in 19.87% (118/594) of the whole epidemic controlled villages. CONCLUSIONS: Currently, the prevalence of schistosomiasis is at a low level in 9 infection-controlled counties of Jiangxi Province. More favorable situation has emerged to the realization of schistosomiasis transmission control. However, it is necessary to strengthen the infectious sources control with emphasis on bovine so as to achieve the goal of transmission control in whole province in 2015.

[Primary culturing and effects of insulin glargine on proliferation, differentiation of human preadipocytes from subcutaneous and omental adipose tissue].

OBJECTIVE: To compare the morphological and functional differences of human primary preadipocytes from different fat depots and explore the effects of insulin glargine on their proliferation and differentiation. METHODS: Primary preadipocytes isolated from human subcutaneous and omental adipose tissue by collagenase I were passaged in vitro.Inverted phase contrast microscope was used to observe the morphological differences of two kinds of preadipocytes. Then two kinds of preadipocytes were cultured or induced to differentiation with different doses of insulin glargine. The methyl thiazolyl tetrazolium (MTT) assay was used to detect their proliferative differences.Reverse transcription-polymerase chain reaction (RT-PCR) was used to observe the effects of insulin on adipogenic gene expression. RESULTS: (1) Both preadipocytes could be successfully cultured from adipose tissue and amplified in vitro.Subcutaneous preadipocytes were more slender and proliferated more quickly while omental preadipocytes were polygonal and aged easily.(2) MTT results showed that insulin glargine could inhibit the proliferation of omental preadipocytes in a dose-dependent fashion. After 72 h incubation, compared with negative control, the absorbance (A) value of 1000 nmol/L insulin glargine group decreased greatly (0.144 ± 0.021 vs 0.267 ± 0.040, P < 0.01). But it had no effect on subcutaneous preadipocytes (0.305 ± 0.045 vs 0.350 ± 0.037, P > 0.05). (3) Insulin at 500 nmol/L was a suitable concentration for inducing differentiation.RT-PCR analysis showed that, for subcutaneous adipocytes, adipogenic genes such as peroxisome proliferator-activated receptor gamma (PPARγ) (F = 31.31, P < 0.01) and CCAAT enhancer binding protein α (C/EBPα) (F = 9.86, P < 0.05) had the highest mRNA expression while preadipocytes gene Pref-1 had the lowest expression at this concentration. But insulin dose had no obvious effect on PPARγ or C/EBPα mRNA (P > 0.05) for omental adipocytes. CONCLUSION: Insulin glargine could inhibit the proliferation of omental preadipocytes, and enhance the differentiation of subcutaneous and omental preadipocytes.

[Depot-specific expression of caveolin-1 in human adipose tissue and their relationship with obesity and insulin resistance].

OBJECTIVE: To explore the depot-specific mRNA and protein expression of caveolin-1 (CAV-1) in human subcutaneous and omental adipose tissues and analyze their relationship with obesity and insulin resistance. METHODS: A total of 41 subjects with normal glucose regulation were recruited. Among them, there were 29 cases with normal body mass index (BMI) and 12 cases with BMI ≥ 24 kg/m(2). All were scheduled to undergone selective abdominal operations. The levels of fasting insulin (FINS) were measured by chemiluminescence enzyme-linked immunosorbent assay (ELISA) kit. Fasting plasma glucose (FPG) was tested by glucose oxidase and home model insulin resistance index (HOMA-IR) calculated. Real-time polymerase chain reaction (RT-PCR) and Western blotting were employed to assess the relative mRNA and protein expression of caveolin-1 in subcutaneous and omental adipose tissues. And the mRNA and protein expression of caveolin-1 from different fat depots were compared and their correlations with BMI and HOMA-IR analyzed. RESULTS: (1) FINS and HOMA-IR were significantly higher in the overweight and obesity group than those in the normal BMI group (FINS: (8.82 ± 3.79) mU/L vs (6.43 ± 4.38) mU/L, P < 0.05, HOMA-1R: 1.91 ± 0.85 vs 1.36 ± 0.72, P < 0.05). (2) The normal BMI group patients had the higher expression levels of caveolin-1 mRNA in omental adipose tissue than overweight counterparts (2.84 ± 0.86 vs 1.02 ± 0.36, P < 0.01). But the difference in subcutaneous adipose tissue was not significant (P > 0.05). (3) The caveolin-1 protein expression in omental adipose tissue of the normal BMI group was higher than that of overweight patients (1.68 ± 0.67 vs 0.73 ± 0.29, P < 0.05). And the difference between two groups was not significant (P > 0.05). (4)The expressions of caveolin-1 mRNA in omental adipose tissue were negatively correlated with BMI, waist circumstance, triglyceride and HOMA-IR (r = -0.441, -0.615, -0.539, -0.688, P < 0.05). No correlations were found between the expressions of caveolin-1 mRNA in subcutaneous adipose tissue with BMI, waist circumstance and HOMA-IR (P > 0.05). CONCLUSION: Differential depot-specific expressions of caveolin-1 are present in human subcutaneous and omental adipose tissues. A low expression of caveolin-1 in omental adipose tissue may contribute to the pathogenesis of obesity and insulin resistance.

Effects of a combination of oral anti-diabetes drugs with basal insulin therapy on ß-cell function and glycaemic control in patients with newly diagnosed type 2 diabetes.

BACKGROUND: Oral anti-diabetes drugs plus basal insulin (OAD + insulin) therapy in patients with newly diagnosed type 2 diabetes might improve ß-cell function and result in extended glycaemic remission. This randomised trial compared the effect on ß-cell function and diabetes remission rate between oral drug alone or with addition of basal insulin. METHODS: One hundred and twenty-nine patients, aged 35-50 years, were enrolled between June 2005 and June 2009. For initial correction of hyperglycaemia, patients with fasting plasma glucose ≥9.0 mmol/L and HbA(1c) ≥ 9.0%, were randomly assigned to therapy with oral drugs + insulin or oral drugs alone. Treatment was stopped after normoglycaemia was maintained for 3 months. Patients were then followed-up with diet and physical exercise. Blood glucose, HbA(1c) and insulin were measured prior to treatment and at 1-year follow-up. RESULTS: More patients achieved target glycaemic control in the oral drugs + insulin group [98.3% (58 of 59)] in less time [(10.4 ± 2.5) days] than those in the oral drug group [95.7% (67 of 70) and (12.4 ± 3.4) days]. At 1-year follow-up, more patients maintained target glycaemia without any drugs in the oral drug + insulin group than in the oral drug group [37.9% (22 of 58) vs 20.9% (14 of 67)]. Both treatments improved homeostasis model assessment-ß (HOMA-ß) and homeostasis model assessment-insulin resistance (HOMA-IR) significantly. They had similar effects on insulin resistance [lg(HOMA-IR): (0.50 ± 0.09) vs (0.48 ± 0.09), p = 0.23]. However, oral drugs + insulin could recover ß-cell function much more than OAD alone could [lg(HOMA-ß): (2.17 ± 0.14) vs (2.11 ± 0.13), p = 0.03]. CONCLUSION: In newly diagnosed type 2 diabetes, therapy with oral drugs + insulin has had favourable outcomes on recovery and maintenance of ß-cell function and protracted glycaemic remission compared with treatment with oral drugs alone.

[Effects of drynaria total flavonoid on osteogenic differentiation of bone marrow mesenchymal stem cells at different glucose concentrations: experiment with rats].

OBJECTIVE: To study the effects of drynaria total flavonoid on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) at different glucose concentrations. METHODS: BMSCs of SD rats were isolated, cultivated in vitro, and divided into 6 groups to be induced to differentiate into osteoblasts under different conditions: (1) low glucose control group, (2) high glucose control group, (3) low glucose classical induction group (sodium glycerophosphate+vitamin C+dexamethasone), (4) high glucose classical induction group (sodium glycerophosphate+vitamin C+dexamethasone), (5) low glucose+drynaria total flavonoid group, and (6) high glucose with drynaria total flavonoid group. Alkaline phosphate (ALP) test kit was used to examine the level of ALP. The ALP staining positive rate was examined with modified calcium cobalt method. Alizarin red staining was adopted to observe the number of calcium nodes. Immunohistochemistry was used to detect type I collagen level. Advanced glycosylation end products (AGEs) were tested by ELISA. RESULTS: The A value indicating the ALP activity, ALP staining positive rate, calcium node number, and type I collagen expression score of the low glucose+drynaria total flavonoid group were (0.439±0.024), 48.7%, (9.75±1.71) nodes/HP, and (2.21±0.07) respectively, all significantly higher than those of the sodium glycerophosphate+vitamin C+dexamethasone [(0.385±0.029), 35.0%, (6.25±0.96) nodes/HP, and (1.93±0.13) respectively, all P<0.05]. The A value, ALP staining positive rate, calcium node number, and type I collagen expression score of the high glucose with drynaria total flavonoid group were (0.352±0.022), 25.3%, (4.50±1.29)/HP, and (1.70±0.03) respectively, all significantly higher than those of the sodium glycerophosphate+vitamin C+dexamethasone [(0.139±0.013), 22.7%, (3.25±1.50)/HP, and (1.28±0.27) respectively, all P<0.05]. The AGE expression levels of the high glucose classical induction group and high glucose+drynaria total flavonoid group were both significantly higher than those of the low glucose classical induction group and low glucose+drynaria total flavonoid group (both P<0.05). There were no significant differences in the AGE level among the low glucose control, low glucose classical induction, and low glucose+drynaria total flavonoid groups (all P<0.05); and among the high glucose control, high glucose classical induction, and high glucose+drynaria total flavonoid groups (all P<0.05). However, the AGE levels of the high glucose groups were all significantly higher than those of the corresponding low glucose groups (all P<0.05). Glucose increased the AGE levels dose- and time-dependently. The concentrations of AGEs were significantly negatively correlated with the expression of type I collagen (r=-0.410, P<0.05). CONCLUSIONS: Drynaria total flavonoid promotes the osteogenic differentiation of BMSCs and relieves the inhibitory effect of osteogenic differentiation by glucose at high concentration. Thus drynaria total flavonoid may provide a potential therapy for diabetic osteoporosis.

[In vitro studies on the growth and proliferation characteristics of rat bone mesenchymal stem cells].

OBJECTIVE: This study was to investigate the growth and proliferation characteristics of rat bone mesenchymal stem cells (BMSCs) isolated by the method of whole bone marrow culture and to explore the effect of cell inoculation density and incubation period on cell proliferation, with an aim to provide multipotential seed cells for preventing from degenerative disease. METHODS: Bone mesenchymal stem cells were isolated by the method of whole bone marrow culture and then cultured in vitro. The cell morphologic features were observed by inverted microscope. The cell surface antigens were identified by flow cytometry. The effect of cell inoculation density and culture period on cell growth and proliferation was explored by analyzing the characteristics of a ten-day cell growth curve in 96-well plates. RESULTS: Flow cytometry results showed the detection rates for CD29, CD34 and CD45 were 97.68% (7607/7788), 7.93% (661/8340) and 2.76% (215/7788) respectively, which was consistent with the expression characteristics of BMSCs surface antigens. BMSCs became uniform after three cell passages, existing in a typical shape of whirlpool or radial colony. The senescent cells started to appear at 7(th) passage, and more senescent cells were found at 10(th) passage. The growth curve for moderate inoculation density was typically S-shaped. Lag phase was found during the first two days, and logarithm growth phase was in the following three days. Plateau phase started from the 6(th) day and cell numbers decreased slightly from the 8(th) day. CONCLUSION: The whole bone marrow culture is an effective way to obtain BMSCs. A moderate inoculation density was more advantageous to cell proliferation, by which more seed cells could be obtained.

[Depot-specific expression of retinol-binding protein 4 in human adipose tissue and their relationship with obesity and insulin resistance].

OBJECTIVE: To explore the depot-specific mRNA and protein expression of retinol-binding protein 4 (RBP4) in human subcutaneous and omental adipose tissue and investigate their relationship with the serum RBP4 levels, obesity and insulin resistance. METHODS: A total of 41 subjects with normal glucose regulation were recruited. Among them, there were 29 cases with normal body mass index (BMI) and 12 cases with BMI ≥ 24 kg/m(2). All were prepared to undergone a selective abdominal surgery. The levels of serum RBP4 and fasting insulin (FINS) were measured by ELISA (enzyme-linked immunosorbent assay) and chemiluminescence ELISA kit respectively. Fasting plasma glucose (FPG) was tested by glucose oxidase and the home model insulin resistance index (HOMA-IR) calculated. Real-time PCR (RT-PCR) and Western blot were employed to assess the relative mRNA and protein expression of RBP4 in subcutaneous and omental adipose tissues. The mRNA and protein expression of RBP4 from different fat depots were compared and their correlations with BMI, the serum RBP4 concentrations and HOMA-IR analyzed. RESULTS: (1) The serum concentrations of RBP4, FINS and HOMA-IR were significantly higher in overweight and obesity group than those in the normal BMI group [RBP4: (39.61 ± 1.57) mg/L vs (33.40 ± 1.28) mg/L, P < 0.01; FINS: (8.82 ± 3.79) mU/L vs (6.43 ± 4.38) mU/L, P < 0.05; HOMA-IR: 1.91 ± 0.85 vs 1.36 ± 0.72, P < 0.05]. (2) The expression levels of RBP4 mRNA and protein were significantly higher in omental adipose tissues than those in subcutaneous adipose tissue [mRNA: (5.88 ± 2.37) vs (2.07 ± 1.66), P < 0.01; protein: (0.76 ± 0.18 vs 0.15 ± 0.07, P < 0.05] and these depots difference in both groups (P < 0.05). Moreover, the overweight patients had the higher expression levels of RBP4 mRNA and protein in omental adipose tissue than normal BMI group (mRNA: 7.52 ± 0.58 vs 4.37 ± 0.45, P < 0.01; protein: 0.92 ± 0.23 vs 0.57 ± 0.13, P < 0.05). (3) The expressions of both RBP4 mRNA and protein in the omental adipose tissue were positively correlated with BMI, waist circumstance, serum concentrations of RBP4, FINS and HOMA-IR. The expression of was negatively correlated with HOMA-IR (r = -0.635, P < 0.05) in subcutaneous adipose tissue. No correlations were found between the expressions of RBP4 mRNA and protein in subcutaneous adipose tissue with BMI, waist circumstance, serum RBP4 and FINS concentrations. CONCLUSIONS: There is depot-specific expression of RBP4 in human subcutaneous and omental adipose tissues. A high expression of RBP4 in omental adipose tissue and an elevated level of serum RBP4 may contribute to the pathogenesis of obesity and IR.