Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease in adults and children worldwide. NAFLD has become a severe health issue and it can progress towards a more severe form of the disease, the non-alcoholic steatohepatitis (NASH). A combination of environmental factors, host genetics, and gut microbiota leads to excessive accumulation of lipids in the liver (steatosis), which may result in lipotoxicity and trigger hepatocyte cell death, liver inflammation, fibrosis, and pathological angiogenesis. NASH can further progress towards liver cirrhosis and cancer. Over the last few years, cell-derived extracellular vesicles (EVs) have been identified as effective cell-to-cell messengers that transfer several bioactive molecules in target cells, modulating the pathogenesis and progression of NASH. In this review, we focused on recently highlighted aspects of molecular pathogenesis of NASH, mediated by EVs via their bioactive components. The studies included in this review summarize the state of art regarding the role of EVs during the progression of NASH and bring novel insight about the potential use of EVs for diagnosis and therapeutic strategies for patients with this disease.
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Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.
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Fibroblast growth factor 21 (FGF21) is a metabolic hormone with pleiotropic effects on energy metabolism and insulin sensitivity. Besides its antiobese and antidiabetic activity, FGF21 also possesses the protective effects against atherosclerosis. Circulating levels of FGF21 are elevated in patients with atherosclerosis, macrovascular and microvascular complications of diabetes, possibly due to a compensatory upregulation. In apolipoprotein E-deficient mice, formation of atherosclerotic plaques is exacerbated by genetic depletion of FGF21, but is attenuated upon replenishment with recombinant FGF21. However, the blood vessel is not the direct target of FGF21, and the antiatherosclerotic activity of FGF21 is attributed to its actions in adipose tissues and liver. In adipocytes, FGF21 promotes secretion of adiponectin, which in turn acts directly on blood vessels to reduce endothelial dysfunction, inhibit proliferation of smooth muscle cells and block conversion of macrophages to foam cells. Furthermore, FGF21 suppresses cholesterol biosynthesis and attenuates hypercholesterolemia by inhibiting the transcription factor sterol regulatory element-binding protein-2 in hepatocytes. The effects of FGF21 on elevation of adiponectin and reduction of hypercholesterolemia are also observed in a phase-1b clinical trial in patients with obesity and diabetes. Therefore, FGF21 exerts its protection against atherosclerosis by fine-tuning the interorgan crosstalk between liver, brain, adipose tissue, and blood vessels.
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The aim of this study was to estimate the prevalence and incidence of type 1 diabetes mellitus (T1DM) in Korea. In addition, we planned to do a performance analysis of the Registration Project of Type 1 diabetes for the reimbursement of consumable materials.
To obtain nationwide data on the incidence and prevalence of T1DM, we extracted claims data from July 2011 to August 2013 from the Registration Project of Type 1 diabetes on the reimbursement of consumable materials in the National Health Insurance (NHI) Database. For a more detailed analysis of the T1DM population in Korea, stratification by gender, age, and area was performed, and prevalence and incidence were calculated.
Of the 8,256 subjects enrolled over the 26 months, the male to female ratio was 1 to 1.12, the median age was 37.1 years, and an average of 136 new T1DM patients were registered to the T1DM registry each month, resulting in 1,632 newly diagnosed T1DM patients each year. We found that the incidence rate of new T1DM cases was 3.28 per 100,000 people. The average proportion of T1DM patients compared with each region's population was 0.0125%. The total number of insurance subscribers under the universal compulsory NHI in Korea was 49,662,097, and the total number of diabetes patients, excluding duplication, was 3,762,332.
The prevalence of T1DM over the course of the study was approximately 0.017% to 0.021% of the entire population of Korea, and the annual incidence of T1DM was 3.28:100,000 overall and 3.25:100,000 for Koreans under 20 years old.
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Diabetic cardiomyopathy is an important causal factor in morbidity and mortality among diabetic patients, and currently, no effective means are available to reverse its pathological progress. The purpose of the present study was to investigate the effect of ginger extract on apolipoproteins (apo) A and B, hyperhomocysteinemia, cathepsin G and leptin changes, as well as cardiac fibrosis and heart muscle cell proliferation under hyperglycemic conditions
Twenty-four male Wistar rats were divided into three groups, namely: control, non-treated diabetic, and ginger extract-treated diabetic groups. The ginger extract-treated diabetic group received a 50 mg daily dose of ginger extract intragastrically for 6 weeks.
The results revealed concurrent significant increases in plasma C-reactive protein (CRP), homocysteine (Hcy), cathepsin G and apoB levels and decreases in apoA and leptin levels in the non-treated diabetic group compared to the control group. Moreover, heart structural changes, including fibrosis and heart muscle cell proliferation, were observed in non-treated diabetic rats compared to the control rats. Significant amelioration of changes in the heart structure together with restoration of the elevated levels of Hcy and CRP, leptin, cathepsin G, and apoA and B were found in the ginger extract-treated diabetic group compared to the non-treated diabetic group.
The findings indicated that ginger extract significantly reduces heart structural abnormalities in diabetic rats and that these effects might be associated with improvements in serum apo, leptin, cathepsin G, and Hcy levels and with the antioxidant properties of ginger extract.
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The waist-to-height ratio (WHtR) is an easy and inexpensive adiposity index that reflects central obesity. In this study, we examined the association of baseline WHtR and progression of coronary artery calcification (CAC) over 4 years of follow-up in apparently healthy Korean men.
A total of 1,048 male participants (mean age, 40.9 years) in a health-screening program in Kangbuk Samsung Hospital, Seoul, Korea who repeated a medical check-up in 2010 and 2014 were recruited. Baseline WHtR was calculated using the value for the waist in 2010 divided by the value for height in 2010. The CAC score (CACS) of each subject was measured by multi-detector computed tomography in both 2010 and 2014. Progression of CAC was defined as a CACS change over 4 years greater than 0.
During the follow-up period, progression of CAC occurred in 278 subjects (26.5%). The subjects with CAC progression had slightly higher but significant baseline WHtR compared to those who did not show CAC progression (0.51±0.04 vs. 0.50±0.04,
Increased baseline WHtR was associated with increased risk for CAC progression. WHtR might be a useful screening tool to identify individuals at high risk for subclinical atherosclerosis.
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Cystatin C has been known to be associated not only with early renal impairment but also with the incidence of diabetic conditions (prediabetes plus diabetes). However, it is not clear whether cystatin C levels are associated with the prevalence of diabetic conditions in Asian populations. We evaluated this association using glycosylated hemoglobin (HbA1c) levels as the definition of diabetes in Korean adults.
We analyzed data from 1,559 Korean adults (937 men and 622 women) with available serum cystatin C and HbA1c values.
The serum cystatin C levels in subjects with prediabetes and diabetes were significantly increased (0.91±0.14 mg/L in prediabetes and 0.91±0.17 mg/L in diabetes vs. 0.88±0.13 mg/L in patients with normal glucose levels,
Higher levels of serum cystatin C are associated with an increased prevalence of diabetic conditions in Korean adults. Our findings may extend the positive association of cystatin C with diabetes incidence to an Asian population.
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Elevated serum levels of growth differentiation factor-15 (GDF-15) are associated with type 2 diabetes. Therefore, the effects of atorvastatin on metabolic parameters and GDF-15 levels in patients with type 2 diabetes and dyslipidemia were evaluated.
In this prospective randomized trial from February 2013 to March 2014, 50 consecutive type 2 diabetic patients with a low density lipoprotein cholesterol (LDL-C) levels ≥100 mg/dL were enrolled. The patients were divided into two groups based on the amount of atorvastatin prescribed, 10 mg/day (
The baseline metabolic parameters and GDF-15 levels were not significantly different between the two groups. After 8 weeks of treatment, the total cholesterol (TC) and LDL-C levels were significantly decreased in both groups. The mean changes in TC and LDL-C levels were more significant in the 40 mg atorvastatin group. The GDF-15 level was decreased in the 10 mg atorvastatin group, from 1,460.6±874.8 to 1,451.0±770.8 pg/mL, and was increased in the 40 mg atorvastatin group, from 1,271.6±801.0 to 1,341.4±855.2 pg/mL. However, the change in the GDF-15 level was not statistically significant in the 10 or 40 mg atorvastatin group (
The GDF-15 levels were not significantly changed after an 8-week treatment with atorvastatin in type 2 diabetic patients.
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In 2014, the National Health Insurance Service (NHIS) signed a memorandum of understanding with the Korean Diabetes Association to provide limited open access to its databases for investigating the past and current status of diabetes and its management. NHIS databases include the entire Korean population; therefore, it can be used as a population-based nationwide study for various diseases, including diabetes and its complications. This report presents how we established the analytic system of nation-wide population-based studies using the NHIS database as follows: the selection of database study population and its distribution and operational definition of diabetes and patients of currently ongoing collaboration projects.
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