Effects of a diet enriched with polyunsaturated, saturated, or trans fatty acids on cytokine content in the liver, white adipose tissue, and skeletal muscle of adult mice

The role of exosome derived miRNAs in inter-cell crosstalk among insulin-related organs in type 2 diabetes mellitus

Exosomes are small extracellular vesicles secreted by almost all cell types, and carry diverse cargo including RNA, and other substances. Recent studies have focused exosomal microRNAs (miRNAs) on various human diseases, including type 2 diabetes mellitus (T2DM) and metabolic syndrome (METS) which accompany the occurrence of insulin resistance. The regulation of insulin signaling has connected with some miRNA expression which play a significant regulatory character in insulin targeted cells or organs, such as fat, muscle, and liver. The miRNAs carried by exosomes, through the circulation in the body fluids, mediate all kinds of physiological and pathological process involved in the human body. Studies have found that exosome derived miRNAs are abnormally expressed and cross-talked with insulin targeted cells or organs to affect insulin pathways. Further investigations of the mechanisms of exosomal miRNAs in T2DM will be valuable for the diagnostic biomarkers and therapeutic targets of T2DM. This review will summarize the molecular mechanism of action of the miRNAs carried by exosomes which are secreted from insulin signaling related cells, and elucidate the pathogenesis of insulin resistance to provide a new strategy for the potential diagnostic biomarkers and therapeutic targets for the type 2 diabetes.

Effects of a Ketogenic Diet on the Assessment of Biochemical and Clinical Parameters in Duchenne Muscular Dystrophy: A Preclinical Investigation

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder characterized by progressive skeletal muscle degeneration and systemic effects, including the central nervous system (CNS). This study aimed to assess the impact of a 14-day ketogenic diet (DCet) on biochemical and clinical parameters in a DMD mouse model. Young adult mice (50 days old) were fed DCet, while control groups received a standard diet. On the 14th day, memory and behavior tests were conducted, followed by biochemical evaluations of oxidative stress, inflammatory biomarkers, body weight, feed intake, and brain-derived neurotrophic factor (BDNF) levels. mdx + DCet mice showed reduced mass (0.2 g ± 2.49) and improved memory retention (p < 0.05) compared to controls. Oxidative damage in muscle tissue and CNS decreased, along with a significant cytokine level reduction (p <0.05). The protocol led to an increase in hippocampal BDNF and mitochondrial respiratory complex activity in muscle tissue and the central nervous system (CNS), while also decreasing creatine kinase activity only in the striatum. Overall, a 14-day DCet showed protective effects by improving spatial learning and memory through reductions in oxidative stress and immune response, as well as increases in BDNF levels, consistent with our study's findings.

Plant-sourced cooking oil consumption is associated with lower total mortality in a longitudinal nationwide cohort study

BACKGROUND & AIMS

Evidence linking individual cooking oil consumption with total mortality is limited in China. The aim of this study was to examine the associations of intakes of plant-sourced and animal-sourced cooking oils with total mortality in a Chinese nationwide cohort.

METHODS

We analyzed data from 14,305 adults aged ≥20 y at entry in the China Health and Nutrition Survey (CHNS). The 3-day 24-h dietary records were used to collect dietary information. Cox proportional hazards regression models were established to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause death.

RESULTS

Overall 1006 deaths were documented during a median of 14 years (199,091 person-years) of follow-up. Multivariate-adjusted HRs (95% CIs) of total mortality via comparing the highest tertile of cooking oil consumption with no consumption were 0.86 (0.70-1.06) for lard, 0.59 (0.47-0.74) for peanut oil, 0.71 (0.54-0.93) for soybean oil, 0.76 (0.61-0.94) for canola oil, 0.71 (0.50-0.99) for salad oil, and 0.59 (0.44-0.79) for other plant cooking oils. Replacing animal cooking oils with 1 tablespoon/d of total plant cooking oils or other plant cooking oils was related to 4% or 17% lower total mortality, respectively, while consumption of peanut oil or salad oil in replacement of animal cooking oils had a marginal inverse association with total mortality.

CONCLUSIONS

Intakes of plant-sourced cooking oils, including peanut oil, soybean oil, canola oil, salad oil, and other plant cooking oils and substituting plant cooking oils for animal cooking oils were associated with lower total mortality among general Chinese population (NCT03259321).

Adipocyte-Derived Exosomal MiR-27a Induces Insulin Resistance in Skeletal Muscle Through Repression of PPARγ

The mechanism by which adipocyte-derived endocrine factors promote insulin resistance in skeletal muscle are not fully understood. MiR-27a is highly expressed in sera of obese individuals with prediabetes and T2DM, and mainly derived by adipose tissues. Thus, miR-27a secreted into circulation by adipose tissue may regulate insulin resistance in skeletal muscle.

Methods: The association between miR-27a and insulin resistance in skeletal muscle was determined in obese children, high-fat diet-induced miR-27a knockdown obese mice, db/db mice and C2C12 cells overexpressing miR-27a. The crosstalk mediated by exosomal miR-27a between adipose tissue and skeletal muscle was determined in C2C12 cells incubated with conditioned medium prepared from palmitate-treated 3T3-L1 adipocytes.

Results: We showed that serum miR-27a level correlated positively with obesity and insulin resistance in obese children, and that elevated serum miR-27a levels correlated with insulin resistance in leptin receptor-deficient db/db mice, and with obesity and insulin resistance in high-fat diet-fed C57BL/6J mice. MiR-27a released from adipocytes of high-fat diet-fed C57BL/6J mice was associated with triglyceride accumulation. MiR-27a derived from these adipocytes induced insulin resistance in C2C12 skeletal muscle cells through miR-27a-mediated repression of PPARγ and its downstream genes involved in the development of obesity.

Conclusions: These results identify a novel crosstalk signaling pathway between adipose tissue and skeletal muscle in the development of insulin resistance, and indicate that adipose tissue-derived miR-27a may play a key role in the development of obesity-triggered insulin resistance in skeletal muscle.

Effect of a trans fatty acid-enriched diet on mitochondrial, inflammatory, and oxidative stress parameters in the cortex and hippocampus of Wistar rats

PURPOSE

Previously showed that dietary trans fatty acids (TFAs) may cause systemic inflammation and affect the central nervous system (CNS) in Wistar rats by increased levels of cytokines in the cerebrospinal fluid (CSF) and serum (Longhi et al. Eur J Nutr 56(3):1003-1016, 1). Here, we aimed to clarifying the impact of diets with different TFA concentrations on cerebral tissue, focusing on hippocampus and cortex and behavioral performance.

METHODS

Wistar rats were fed either a normolipidic or a hyperlipidic diet for 90 days; diets had the same ingredients except for fat compositions, concentrations, and calories. We used lard in the cis fatty acid (CFA) group and PHSO in the TFA group. The intervention groups were as follows: (1) low lard (LL), (2) high lard (HL), (3) low partially hydrogenated soybean oil (LPHSO), and (4) high partially hydrogenated soybean oil (HPHSO). Mitochondrial parameters, tumor necrosis factor alpha (TNF-α), 2'7'-dichlorofluorescein (DCFH) levels in brain tissue, and open field task were analyzed.

RESULTS

A worse brain tissue response was associated with oxidative stress in cortex and hippocampus as well as impaired inflammatory and mitochondrial parameters at both PHSO concentrations and there were alterations in the behavioral performance. In many analyses, there were no significant differences between the LPHSO and HPHSO diets.

CONCLUSIONS

Partially hydrogenated soybean oil impaired cortical mitochondrial parameters and altered inflammatory and oxidative stress responses, and the hyperlipidic treatment caused locomotor and exploratory effects, but no differences on weight gain in all treatments. These findings suggest that quality is more important than the quantity of fat consumed in terms of CFA and TFA diets.

Effect of a trans fatty acid-enriched diet on biochemical and inflammatory parameters in Wistar rats

PURPOSE

Recent data regarding trans fatty acids (TFAs) have implicated these lipids as particularly deleterious to human health, causing systemic inflammation, endothelial dysfunction and possibly inflammation in the central nervous system (CNS). We aimed to clarify the impact of partially hydrogenated soybean oil (PHSO) with different TFA concentrations on cerebrospinal fluid (CSF), serum and hepatic parameters in adult Wistar rats.

METHODS

Wistar rats (n = 15/group) were fed either a normolipidic diet or a hyperlipidic diet for 90 days. The normolipidic and hyperlipidic diets had the same ingredients except for fat compositions, concentrations and calories. We used lard in the cis fatty acid group and PHSO in the trans fatty acid group. The intervention groups were as follows: (1) low lard (LL), (2) high lard (HL), (3) low partially hydrogenated soybean oil (LPHSO) and (4) high partially hydrogenated soybean oil (HPHSO). Body weight, lipid profiles and the inflammatory responses in the CSF, serum and liver tissue were analyzed.

RESULTS

Surprisingly, with the PHSO diet we observed a worse metabolic response that was associated with oxidative stress in hepatic tissue as well as impaired serum and CSF fluid parameters at both PHSO concentrations. In many analyses, there were no significant differences between the LPHSO and HPHSO diets.

CONCLUSIONS

Dietary supplementation with PHSO impaired inflammatory parameters in CSF and blood, induced insulin resistance, altered lipid profiles and caused hepatic damage. Overall, these findings suggest that fat composition is more important than the quantity of fat consumed in terms of cis and trans fatty acid diets.

A Hyperlipidic Diet Combined with Short-Term Ovariectomy Increases Adiposity and Hyperleptinemia and Decreases Cytokine Content in Mesenteric Adipose Tissue

Four-week-old female Wistar rats were divided into two groups and fed a control diet (C) or a hyperlipidic diet (H) for 4 weeks. Rats from each group underwent ovariectomy (OVX) or sham surgery (SHAM). They received C or H for the next four weeks. The body weight gain (BW), food efficiency (FE), and carcass lipid content were higher in the OVX H than in the SHAM H. The OVX H exhibited a higher serum leptin level than other groups. IL-6, TNF-α, and IL-10 content of mesenteric (MES) adipose tissue was lower in the OVX H than in the OVX C. IL-6, TNF-α, and IL-10 content of retroperitoneal (RET) adipose tissue was lower in the SHAM H than in the SHAM C. The SHAM H showed decreased TG relative to the SHAM C. Similar results were obtained in relation to IL-6Rα, TNFR1, TLR-4, and MyD88 contents in the MES and RET white adipose tissue among the groups. A hyperlipidic diet for 8 weeks combined with short-term ovariectomy decreases the cytokine content of MES adipose tissues but increases BW, enhancing FE and elevating serum leptin levels. These suggest that the absence of estrogens promotes metabolic changes that may contribute to installation of a proinflammatory process induced by a hyperlipidic diet.

Probiotics (Lactobacillus rhamnosus R0011 and acidophilus R0052) reduce the expression of toll-like receptor 4 in mice with alcoholic liver disease

OBJECTIVE

The role of lipopolysaccharide (LPS) and toll-like receptor 4 (TLR 4) in the pathogenesis of alcoholic liver disease (ALD) has been widely established. We evaluated the biological effects of probiotics (Lactobacillus rhamnosus R0011 and acidophilus R0052), KRG (Korea red ginseng), and urushiol (Rhus verniciflua Stokes) on ALD, including their effects on normal and high-fat diet in mice.

METHODS

One hundred C57BL/6 mice were classified into normal (N) and high-fat diet (H) groups. Each group was divided into 5 sub-groups: control, alcohol, alcohol+probiotics, alcohol+KRG, and alcohol+urushiol. A liver function test, histology, electron-microscopy, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-10, and TLR 4 were evaluated and compared.

RESULTS

In the N group, probiotics, KRG, and urushiol significantly reduced levels of TNF-α (12.3±5.1, 13.4±3.9, and 12.1±4.3 vs. 27.9±15.2 pg/mL) and IL-1β (108.4±39.4, 75.0±51.0, and 101.1±26.8 vs. 162.4±37.5 pg/mL), which were increased by alcohol. Alcohol-induced TLR 4 expression was reduced by probiotics and urushiol (0.7±0.2, and 0.8±0.1 vs. 1.0±0.3, p<0.001). In the H group, IL-10 was significantly increased by probiotics and KRG, compared with alcohol (25.3±15.6 and 20.4±6.2 vs. 7.6±5.6 pg/mL) and TLR 4 expression was reduced by probiotics (0.8±0.2 vs. 1.0±0.3, p = 0.007).

CONCLUSIONS

Alcohol-induced TLR 4 expression was down-regulated by probiotics in the normal and high-fat diet groups. Probiotics, KRG, and urushiol might be effective in the treatment of ALD by regulating the gut-liver axis.