Oxidative Stress and Nonalcoholic Fatty Liver Disease in Hemodialysis Patients

Non-alcoholic fatty liver disease in diabetes mellitus patients on chronic hemodialysis – A case series addressing cardiovascular and mortality risks

Non-alcoholic fatty liver disease (NAFLD) has an important role in the pathogenesis of cardiovascular diseases in the population with diabetes and it is highly prevalent in end-stage renal disease (ESRD) patients. This case series describes NAFLD associated factors and survival in type 2 diabetes patients (T2DM) who have ESRD treated with hemodialysis. NAFLD prevalence in patients with T2DM and ESRD is 69.2%. A high number of patients (15 out of 18) have obesity evaluated by calculating body mass index (BMI) and bioimpedance measurements. Patients with NAFLD have higher cardiovascular mortality risk, 13 of 18 patients were already diagnosed with coronary heart disease, 6 of 18 had cerebrovascular disease, and 6 of 18 had peripheral artery disease. Fourteen patients were treated with insulin, two patients with sitagliptin (renal adjusted dose of 25mg/day) and two patients with medical nutrition therapy, with an HbA1c ranging from 4.4 to 9.0%. After one-year follow-up 7 of 18 patients died, the causes having roughly equal proportions: myocardial infarction, SARS-CoV2 infection, and pulmonary edema. In conclusion, our population of type 2 diabetic patients with ESRD in hemodialysis had a prevalence of ultrasound-diagnosed NAFLD of 69.2%. Also, this population had a high death rate at one-year follow-up, cardiovascular causes being among the most common.

Postnatal persistence of nonhuman primate sex-dependent renal structural and molecular changes programmed by intrauterine growth restriction

BACKGROUND

Poor nutrition during fetal development programs postnatal kidney function. Understanding postnatal consequences in nonhuman primates (NHP) is important for translation to our understanding the impact on human kidney function and disease risk. We hypothesized that intrauterine growth restriction (IUGR) in NHP persists postnatally, with potential molecular mechanisms revealed by Western-type diet challenge.

METHODS

IUGR juvenile baboons were fed a 7-week Western diet, with kidney biopsies, blood, and urine collected before and after challenge. Transcriptomics and metabolomics were used to analyze biosamples.

RESULTS

Pre-challenge IUGR kidney transcriptome and urine metabolome differed from controls. Post-challenge, sex and diet-specific responses in urine metabolite and renal signaling pathways were observed. Dysregulated mTOR signaling persisted postnatally in female pre-challenge. Post-challenge IUGR male response showed uncoordinated signaling suggesting proximal tubule injury.

CONCLUSION

Fetal undernutrition impacts juvenile offspring kidneys at the molecular level suggesting early-onset blood pressure dysregulation.

Emergence of SGLT2 Inhibitors as Powerful Antioxidants in Human Diseases

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of oral glucose-lowering agents. Apart from their glucose-lowering effects, large clinical trials assessing certain SGLT2 inhibitors have revealed cardiac and renal protective effects in non-diabetic patients. These excellent outcomes motivated scientists and clinical professionals to revisit their underlying mechanisms. In addition to the heart and kidney, redox homeostasis is crucial in several human diseases, including liver diseases, neural disorders, and cancers, with accumulating preclinical studies demonstrating the therapeutic benefits of SGLT2 inhibitors. In the present review, we aimed to update recent advances in the antioxidant roles of SGLT2 inhibitors in common but debilitating human diseases. We anticipate that this review will guide new research directions and novel therapeutic strategies for diabetes, cardiovascular diseases, nephropathies, liver diseases, neural disorders, and cancers in the era of SGLT2 inhibitors.

Circulating vascular endothelial growth factor receptor 2 levels and their association with lipid abnormalities in patients on hemodialysis

The aim of the present study was to examine the association between the levels of circulating vascular endothelial growth factor receptor (VEGFR)2 levels, serum lipid composition and plasma receptor for advanced glycation end-products (RAGE) expression in patients undergoing hemodialysis (HD). A total of 50 patients on HD (27 men and 23 women; median age, 66 years; age range 28-88 years; HD mean time, 29.0, 3.9-157.0 months) were enrolled. Age-matched healthy subjects (n=26) were used as the control group. Plasma VEGFR2 and RAGE levels were determined using ELISA. Dyslipidemia (D) in patients on HD was diagnosed according to the Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Managing Dyslipidemias in Chronic Kidney Disease. Circulating VEGFR2, RAGE and serum lipids were compared between dyslipidemic and non-dyslipidemic patients on HD and controls. In patients on HD, the plasma VEGFR2 levels were lower compared with those in the healthy population. D was associated with high plasma VEGFR2 levels. The triglyceride/HDL-cholesterol ratio was strongly associated with plasma VEGFR2 levels. The plasma VEGFR2 concentration was associated with circulating RAGE levels. Therefore, circulating VEGFR2 levels may be partly associated with lipid abnormalities and plasma RAGE levels in patients receiving HD.

Association Between Leukocyte Mitochondrial DNA Copy Number and Non-alcoholic Fatty Liver Disease in a Chinese Population Is Mediated by 8-Oxo-2'-Deoxyguanosine

Background: Alterations in mitochondrial DNA are potentially associated with oxidative stress and may be involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). However, the association between mitochondrial DNA copy number (mtDNAcn) and NAFLD was not consistent. In addition, the association between inflammation and NAFLD has not been established yet. The present study, based on a Chinese population of individuals with different glucose statuses, aimed to explore the association between leukocyte mtDNAcn, markers of oxidative stress, and inflammation and NAFLD.

Methods: A total of 318 participants from a diabetes project were included. NAFLD was diagnosed by ultrasonography. Leukocyte mtDNAcn was determined by PCR assay. The levels of the inflammation markers tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) and the oxidative stress markers glutathione reductase (GR), superoxide dismutase (SOD), and 8-oxo-2′-deoxyguanosine (8-oxo-dG) were also measured.

Results: Participants with NAFLD (n = 105) exhibited significantly higher leukocyte mtDNAcn, IL-6, and 8-oxo-dG (all P < 0.05). Pearson correlation analysis indicated mtDNAcn was negatively associated with age, uric acid, SOD, and TNF-α, but was positively associated with 8-oxo-dG (all P < 0.05). Univariate logistic regression analysis revealed that mtDNAcn was positively associated with NAFLD [odds ratio (OR) = 1.617, 95% confidence interval (CI) = 1.036–2.525; P = 0.034]. However, after adjustment for 8-oxo-dG, this association was no longer statistically significant (OR = 1.534, 95% CI = 0.979–2.403, P = 0.062). Moreover, the stress marker 8-oxo-dG was independently associated with NAFLD after adjustment for mtDNAcn, IL-6, glucose tolerance status, and other conventional NAFLD risk factors (OR = 1.707, 95% CI =1.142–2.550, P = 0.009). Mediation analysis indicated that 8-oxo-dG fully mediated the effect of mtDNAcn on the incidence of NAFLD (direct effect β = 0.5221, 95% CI = −0.0648 to 1.2504; indirect effect β = 0.0946, 95% CI = 0.0049–0.2463).

Conclusions: In a Chinese population, the association between leukocyte mtDNAcn and NAFLD was fully mediated by high levels of 8-oxo-dG. Thus, oxidative stress may be an important driver of NAFLD, and clinical interventions aimed at decreasing oxidative stress to improve NAFLD warrant further research.

The Systemic Redox Status Is Maintained in Non-Smoking Type 2 Diabetic Subjects Without Cardiovascular Disease: Association with Elevated Triglycerides and Large VLDL

Decreased circulating levels of free thiols (R-SH, sulfhydryl groups) reflect enhanced oxidative stress, which plays an important role in the pathogenesis of cardiometabolic diseases. Since hyperglycemia causes oxidative stress, we questioned whether plasma free thiols are altered in patients with type 2 diabetes mellitus (T2DM) without cardiovascular disease or renal function impairment. We also determined their relationship with elevated triglycerides and very low density lipoproteins (VLDL), a central feature of diabetic dyslipidemia. Fasting plasma free thiols (colorimetric method), lipoproteins, VLDL (nuclear magnetic resonance spectrometry), free fatty acids (FFA), phospholipid transfer protein (PLTP) activity and adiponectin were measured in 79 adult non-smoking T2DM subjects (HbA1c 51 ± 8 mmol/mol, no use of insulin or lipid lowering drugs), and in 89 non-smoking subjects without T2DM. Plasma free thiols were univariately correlated with glucose (r = 0.196, p < 0.05), but were not decreased in T2DM subjects versus non-diabetic subjects (p = 0.31). Free thiols were higher in subjects with (663 ± 84 µmol/L) versus subjects without elevated triglycerides (619 ± 91 µmol/L; p = 0.002). Age- and sex-adjusted multivariable linear regression analysis demonstrated that plasma triglycerides were positively and independently associated with free thiols (β = 0.215, p = 0.004), FFA (β = 0.168, p = 0.029) and PLTP activity (β = 0.228, p = 0.002), inversely with adiponectin (β = −0.308, p < 0.001) but not with glucose (β = 0.052, p = 0.51). Notably, the positive association of free thiols with (elevated) triglycerides appeared to be particularly evident in men. Additionally, large VLDL were independently associated with free thiols (β = 0.188, p = 0.029). In conclusion, circulating free thiols are not decreased in this cohort of non-smoking and generally well-controlled T2DM subjects. Paradoxically, higher triglycerides and more large VLDL particles are likely associated with higher plasma levels of thiols, reflecting lower systemic oxidative stress.

Lactobacillus paracasei Jlus66 extenuate oxidative stress and inflammation via regulation of intestinal flora in rats with non alcoholic fatty liver disease

The nonalcoholic fatty liver disease (NAFLD) is a progressive liver disease that affects the health of people in an increasing rate. In the current research, we investigated the beneficial effect of a novel probiotic strain L. paracasei Jlus66 (Jlus66) on rats with high-fat diet (HFD)-induced NAFLD. The intestinal flora of rats was analyzed based on V3-V4 region 16S rDNA sequencing. Moreover, we measured the oxidative stress and inflammation factors in the liver using commercial ELISA kit, and the lipopolysaccharide (LPS) in serum with chromogenic end-point tachypheus amebocyte lysate. Compared with the HFD-induced group, Jlus66 treatment significantly decreased the malondialdehyde (MDA) level in the serum (p < 0.05). Additionally, Jlus66 significantly enhanced the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the liver and serum (p < 0.05). Jlus66 administration also reduced the levels of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), and inversely increased the interleukin-10 (IL-10) level in serum (p < 0.05). Intestinal flora analysis results showed that Jlus66 can improve intestinal flora structure by increasing the abundance of gram-positive flora such as Firmicutes, and decreasing gram-negative flora such as Bacteroidetes, Proteobacteria, and Fusobacteria, and then reduced LPS concentration in the serum. So we concluded that Jlus66 can improve NAFLD by modulating the intestinal flora and followed reduction of oxidative stress (OxS) and inflammation.