Purpose: Muscles play an important role in energy metabolism. Several studies have investigated the association between muscle mass and metabolic syndrome (MetS), reporting conflicting results. However, studies concerning the association between muscle strength and MetS are limited. We aimed to investigate the association between relative handgrip strength (HGS) and MetS in Korean adults. Participants and methods: We analyzed data from 5,014 Korean adults aged ≥20 years (2,472 men and 2,542 women) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) VI (2014–2015). Results: The increasing quartiles of relative HGS (defined as the sum of both hands’ HGS divided by body mass index) were inversely associated with the risk of MetS in both men and women (OR, 0.37; 95% CI, 0.30–0.45, vs OR, 0.19; 95% CI, 0.14–0.27, respectively) after multivariable adjustment for age, region of residence, smoking status, heavy alcohol consumption, regular exercise, family income, and education level. On multivariable logistic regression analyses, participants with the highest relative HGS had a significant decrease in relative risk of MetS, compared with those with the lowest relative HGS. The multivariable-adjusted ORs (with 95% CIs) for MetS in quartiles 1, 2, 3, and 4 were 1.00, 0.72 (0.55–0.94), 0.34 (0.26–0.46), and 0.22 (0.15–0.32) in men and 1.00, 0.50 (0.36–0.68), 0.26 (0.17–0.40), and 0.16 (0.09–0.27) in women, respectively. Conclusion: Relative HGS showed a highly significant inverse association with the risk of MetS in Korean adults, and it can be a novel biomarker for assessing the risk of MetS.

Purpose: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and it is the hepatic manifestation of metabolic syndrome (MetS). We aimed to estimate the prevalence of NAFLD defined by the fatty liver index (FLI), in order to investigate the association between FLI and metabolic disorders and to determine the cutoff value of FLI to screen for MetS. Subjects and methods: This study utilized a national representative sample of Korean adults (the Korean National Health and Nutrition Examination Surveys) which was conducted in 2010–2011. A total of 10,107 adults aged 19 years or older were selected. NAFLD was diagnosed on the basis of an increased FLI (≥60) after the exclusion of alcohol or viral liver disease. Results: NAFLD was identified in 1,134 subjects (age-standardized prevalence, 10.0%). When subjects were categorized into three groups by FLI (<20, 20–59, and ≥60), the higher FLI group showed a higher prevalence of hypertension (49.7% vs 14.4%), diabetes mellitus (DM; 20.4% vs 3.8%), and MetS (74.9% vs 7.4%). FLI was positively associated with age, body mass index, blood pressure, hemoglobin A1c, and homeostasis model assessment of insulin resistance (P for trend <0.001). In the multivariate analysis, the higher FLI group had a significantly higher risk for hypertension (OR =2.92, 95% CI =2.18–3.90, P<0.001), DM (OR =4.38, 95% CI =2.96–6.49, P<0.001), and MetS (OR =24.85, 95% CI =17.33–35.64, P<0.001). However, no increase was observed for cardiovascular disease after adjustment of other risk factors. The cutoff value of the FLI estimated to predict the presence of MetS was 20 (area under the curve 0.849, sensitivity 0.828, and negative predictive value 91.9%). Conclusion: NAFLD prevalence using FLI is significantly higher in subjects with metabolic disorder including MetS. FLI might be a useful screening tool to detect subjects who may require early management of MetS and who have a high cardiovascular risk.

Background: Reactive oxygen species (ROS) and inflammation are reported to have a fundamental role in the pathogenesis of ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury. The present study investigated the role of pyruvate dehydrogenase kinase 4 (PDK4) in ROS production and inflammation following IR injury.Methods: We used a streptozotocin-induced diabetic C57BL6/J mouse model, which was subjected to IR by clamping both renal pedicles. Cellular apoptosis and inflammatory markers were evaluated in NRK-52E cells and mouse primary tubular cells after hypoxia and reoxygenation using a hypoxia work station.Results: Following IR injury in diabetic mice, the expression of PDK4, rather than the other PDK isoforms, was induced with a marked increase in pyruvate dehydrogenase E1α (PDHE1α) phosphorylation. This was accompanied by a pronounced ROS activation, as well as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1) production. Notably, sodium dichloroacetate (DCA) attenuated renal IR injury-induced apoptosis which can be attributed to reducing PDK4 expression and PDHE1α phosphorylation levels. DCA or shPdk4 treatment reduced oxidative stress and decreased TNF-α, IL-6, IL-1β, and MCP-1 production after IR or hypoxia-reoxygenation injury.Conclusion: PDK4 inhibition alleviated renal injury with decreased ROS production and inflammation, supporting a critical role for PDK4 in IR mediated damage. This result indicates another potential target for reno-protection during IR injury; accordingly, the role of PDK4 inhibition needs to be comprehensively elucidated in terms of mitochondrial function during renal IR injury.

이해정, et al. Korean J Adult Nurs. 2022 Feb;34(1):39-50. https://doi.org/10.7475/kjan.2022.34.1.39

Background: The ratio of estimated glomerular filtration rate (eGFR) based on cystatin C and creatinine (eGFRcystatin C/eGFRcreatinine ratio) is related to accumulating atherosclerosis-promoting proteins and increased mortality in several cohorts.Methods: We assessed whether the eGFRcystatin C/eGFRcreatinine ratio is a predictor of arterial stiffness and sub-clinical atherosclerosis in type 2 diabetes mellitus (T2DM) patients, who were followed up during 2008 to 2016. GFR was estimated using an equation based on cystatin C and creatinine.Results: A total of 860 patients were stratified according to their eGFRcystatin C/eGFRcreatinine ratio (i.e., 1.1). Intima-media thickness was comparable among the groups; however, presence of carotid plaque was frequent in the <0.9 group (1.1 group, 17.2%, P<0.001). Brachial-ankle pulse wave velocity (baPWV) was faster in the <0.9 group (1.1 group, 1,494.0±252.2 cm/sec, P<0.001). On comparing the <0.9 group with the 0.9–1.1 group, the multivariate-adjusted odds ratios of prevalence of high baPWV and carotid plaque were 2.54 (P=0.007) and 1.95 (P=0.042), respectively. Cox regression analysis demonstrated near or over 3-fold higher risks of the prevalence of high baPWV and carotid plaque in the <0.9 group without chronic kidney disease (CKD).Conclusion: We concluded that eGFRcystatin C/eGFRcreatinine ratio <0.9 was related to an increased risk of high baPWV and carotid plaque in T2DM patients, especially, those without CKD. Careful monitoring of cardiovascular disease is needed for T2DM patients with low eGFRcystatin C/eGFRcreatinine ratio.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors regulate blood glucose levels in patients with type 2 diabetes mellitus and may also exert anti-inflammatory and anti-atherosclerotic effects by promoting M2 macrophage polarization. Although SGLT2 is expressed in brain regions that influence glucose balance and cognitive function, its roles in the central nervous system are unclear. This study investigated the effects of empagliflozin (EMPA), an SGLT2 inhibitor, on hypothalamic inflammation associated with metabolic diseases. Mice were subjected to a high-fat diet (HFD) for varying durations (3 d, 3 weeks, and 16 weeks) and treated with EMPA for 3 weeks (NFD, NFD + EMPA, HFD, HFD + EMPA; n = 5/group). EMPA regulated the expression of astrocyte markers and pro-inflammatory cytokine mRNA in the hypothalamus of HFD-induced mice, which was linked to regulation of the NF-κB pathway. Under hyperglycemic conditions, EMPA may mitigate hypothalamic inflammation by modulating astrocyte activation via the NF-κB pathway. Our findings demonstrated that EMPA possesses therapeutic potential beyond merely lowering blood glucose levels, opening new avenues for addressing inflammation and providing neuroprotection in metabolic disease management.