Associaton of Retinol Binding Protein 4 (RBP4) Levels With Hyperuricemia: A Cross-Sectional Study in a Chinese Population.

Background: There are few studies on predictive biomarkers for hyperuricemia, and the predictive value of these biomarkers tends to be poor. Additionally, no reports have described the predictive value of retinol binding protein 4 (RBP4) for hyperuricemia. Purpose: This study was performed to evaluate the value of RBP4 for predicting the risk of hyperuricemia in a general population, determine whether RBP4 could be used alone or in combination with other factors to predict the risk of hyperuricemia in the general population, and establish an optimum predictive model. Methods: We conducted a population-based cross-sectional survey in 2018, involving a questionnaire, physical examination, and laboratory testing. We enrolled 2303 individuals by stratified random sampling, and 2075 were included in the data analysis after applying the eligibility criteria. Results: Serum RBP4 level had a highly significant association with hyperuricemia (P<0.001). After adjusting for potential confounders, logistic regression indicated that the risk of hyperuricemia was highest in the highest RBP4 quartile (odds ratio: 7.9, 95% confidence interval [CI]: 4.18-14.84, compared to the lowest quartile). The area under the receiver operating characteristic (ROC) curve (AUC) for RBP4 was 0.749 (95% CI: 0.725-0.774, P<0.001), which was higher than that for all the other predictors assessed. The optimum model for predicting hyperuricemia in the general population consisted of RBP4, sex (male), body mass index, serum creatinine, high-sensitivity C-reactive protein, fasting blood glucose, insulin, and alcohol consumption. The AUC was 0.804 (95% CI: 0.782-0.826, P<0.001). Conclusions: RBP4 is strongly associated with hyperuricemia, and its predictive value was higher than that of traditional predictors.

Tissue Inhibitor of Matrix Metalloproteinase 2-Loaded Polylactic Acid-Polyethylene Glycol Nanoparticles Directly Regulates Renal Tubular Epithelial Cell Proliferation via Protein Tyrosine Kinase KIT.

TIMP2 has been previously reported to be associated with acute kidney injury (AKI); however, the underlying mechanism remains unclear. Therefore, the present study investigated the regulation of TIMP2 in human tubular epithelial cells HK-2 cells. Proliferation of HK-2 cells treated by TIMP2 at normal expression level was detected. GST pulldown and mass spectrometry were performed to investigate the interacting protein of TIMP2 and immunofluorescence test was used to determine the location of the protein in HK-2 cells. Cell viability as well as the expression level of CCND1, C-FOS, MAPK1 and P-MAPK1 were detected in the samples treated by overexpressed TIMP2 and the inhibitor of the interacting protein KIT. TIMP2 significantly inhibited cell proliferation compared with the control and BB-94-treated groups (P < 0.05). KIT was identified as the interacting protein of TIMP2, and was located in both the cytoplasm and membrane of HK-2 cells. Inhibited KIT and the overexpressed of TIMP2 both significantly suppressed cell proliferation and decreased the expression levels of CCND1, MAPK1, and P-MAPK1 compared with the control (P < 0.05). No significant difference was observed in cell proliferation and the expression level of aforementioned proteins between overexpressed TIMP2 and KIT-inhibited group. The results revealed that TIMP2 regulates cell proliferation by reducing the expression levels of CCND1, MAPK1, and P-MAPK1 via KIT, indicating that TIMP2 directly regulates cell proliferation without inhibiting matrix metalloproteinases in AKI. Furthermore, PLA-PEG nanoparticles successfully transported TIMP2 to the target with no significant effect on cell proliferation.

High-Sensitivity C-Reactive Protein Leads to Increased Incident Metabolic Syndrome in Women but Not in Men: A Five-Year Follow-Up Study in a Chinese Population.

PURPOSE: Metabolic syndrome (MetS), characterized by a constellation of insulin resistance, central obesity, hypertension, and hyperlipidemia, is a global health threat. High-sensitivity C-reactive protein (hs-CRP) has been shown to be associated with type 2 diabetes and cardiovascular disease; however, its association with incident MetS is less known. Therefore, the aim of this study was to examine the prospective association between hs-CRP and MetS among a Chinese population in a 5-year follow-up study. PATIENTS AND METHODS: The levels of hs-CRP were measured using serum samples collected at baseline recruitment in 2012 from 886 participants without MetS. Follow-up interviews were conducted in 2018, and MetS was diagnosed by 2017 criteria from the Chinese Diabetes Society. Multivariate logistic regression models were used to assess the overall and sex-specific associations between hs-CRP and incident MetS. The odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed with adjustment for demographic, socioeconomic, clinical, and lifestyle factors. RESULTS: After a mean follow-up duration of 5.40 ± 0.56 years, 116 (13.3%) participants developed MetS. In the total study population, increased hs-CRP levels were associated with a higher risk of MetS (OR comparing extreme quartiles of hs-CRP: 4.06 [95% CI: 1.91-8.65]) in the fully-adjusted model. When stratified by sex, the positive association was only observed in women (OR: 4.82 [1.89-12.3]) but not in men (OR: 3.15 [0.82-12.1]; P-interaction = 0.039). CONCLUSION: In this study of a Chinese population, a positive association between hs-CRP and incident MetS was found only in women and not in men. Sex-specific prediction and intervention of MetS using hs-CRP as a target should be further evaluated.

tert-Butylhydroquinone Treatment Alleviates Contrast-Induced Nephropathy in Rats by Activating the Nrf2/Sirt3/SOD2 Signaling Pathway.

Oxidative stress plays a critical role in the pathophysiology of contrast-induced nephropathy (CIN). Since the specific treatment of CIN remains an unmet medical need, it is imperative to find an effective strategy against the clinical management of CIN. The transcription factor Nrf2 is known to regulate antioxidative stress response. The aim of the present study was to assess the effects of tert-butylhydroquinone (t-BHQ), an activator of Nrf2, in the prevention of CIN and elucidate the underlying mechanism of its action in vitro and in vivo. We established a rat model of CIN and treated the animals with t-BHQ (25 mg/kg). The effects of t-BHQ treatment on CIN rats were elucidated by assessing renal function, HE staining, immunohistochemistry, and western blotting. We also studied the activity of oxidative stress-related markers, such as intracellular ROS level, MDA level, SOD2 activity, and GSH/GSSG ratio. We validated our results by siRNA-mediated silencing of Nrf2 in HK-2 cells exposed to the radiocontrast agent. Treatment with t-BHQ significantly ameliorated the renal function and the histopathological lesions in CIN rats. Further, pretreatment with t-BHQ significantly increased the SOD2 activity and GSH/GSSG ratio and decreased the levels of ROS and MDA in animals subjected to ioversol exposure. In addition, t-BHQ treatment increased the expression of Nrf2, Sirt3, and SOD2 and concomitantly decreased the expression of acetylated-SOD2. When Nrf2-silenced HK-2 cells were exposed to radiocontrast agent, they suffered severe cell oxidative stress, exhibited lower expression of Sirt3 and SOD2, and expressed higher levels of acetylated-SOD2; however, t-BHQ treatment did not affect the protein expression of these indicators in si-Nrf2 HK-2 cells. Our findings suggested that Nrf2 plays an important role in the regulation of the Sirt3/SOD2 antioxidative pathway, and t-BHQ may be a potential agent to ameliorate radiocontrast-induced nephropathy via activating the Nrf2/Sirt3/SOD2 signaling pathway in vitro and in vivo.