High-Fat Diet-Induced Renal Proximal Tubular Inflammatory Injury: Emerging Risk Factor of Chronic Kidney Disease

Bicyclol alleviates obesity-induced renal injury by inhibiting JNK and NF-κB-mediated inflammation

Obesity is recognized as a major risk factor for chronic kidney disease (CKD), which is accompanied by increased renal lipid build-up, fibrosis, inflammation, apoptosis and pyroptosis. Bicyclol (BIC), a Chinese marketed hepatoprotective drug, has shown excellent anti-inflammatory, anti-fibrosis, anti-apoptotic, and lipid regulation effects in different animal models. In this study, we explored the role and mechanism of BIC in high-fat diet (HFD)-induced obesity-related nephropathy. Mice were fed with HFD for 24 weeks to develop obesity-related nephropathy, while mice in the BIC administration group were treated with BIC (50 mg/kg or 100 mg/kg, once every two days) at the last 12 weeks. We found that BIC treatment relieved the impairment of kidney structure and renal dysfunction caused by HFD. In addition, we found that BIC mitigated HFD-induced renal fibrosis, inflammation, apoptosis and pyroptosis by inhibiting JNK and NF-κB pathways. SV40-MES-13 cells treated with palmitate (PA) were used as the in vitro model. Our data show that BIC pre-administration relieved cellular damage caused by PA through suppressing JNK and NF-κB signaling pathways. In conclusion, we demonstrated that BIC attenuated obesity-induced renal injury by inhibiting chronic inflammation, fibrosis, apoptosis and pyroptosis via targeting JNK and NF-κB pathways. Our data suggested that BIC could be potentially used to prevent obesity-associated nephropathy, which warrants future investigation.

Cold-Pressed Sacha Inchi Oil: High in Omega-3 and Prevents Fat Accumulation in the Liver

The ability of oil supplementation to inhibit various metabolic syndromes has been recognized. However, there are currently no studies determining the effects of oil supplements on healthy conditions. Plukenetia volubilis L., also known as Sacha inchi, is a seed rich in essential unsaturated fatty acids that improves metabolic syndrome diseases, such as obesity and nonalcoholic fatty liver. However, the health benefits and effects of Sacha inchi oil (SIO) supplementation remain unclear. This study aims to evaluate the chemical effects and properties of Sacha inchi oil. The results of the chemical compound analysis showed that Sacha inchi is an abundant source of ω-3 fatty acids, with a content of 44.73%, and exhibits scavenging activity of 240.53 ± 11.74 and 272.41 ± 6.95 µg Trolox/g, determined via DPPH and ABTS assays, respectively, while both olive and lard oils exhibited lower scavenging activities compared with Sacha inchi. Regarding liver histology, rats given Sacha inchi supplements showed lower TG accumulation and fat droplet distribution in the liver than those given lard supplements, with fat areas of approximately 14.19 ± 6.49% and 8.15 ± 2.40%, respectively. In conclusion, our findings suggest that Sacha inchi oil is a plant source of ω-3 fatty acids and antioxidants and does not induce fatty liver and pathology in the kidney, pancreas, and spleen. Therefore, it has the potential to be used as a dietary supplement to improve metabolic syndrome diseases.

Canonical and non-canonical functions of NLRP3

BACKGROUND

Since its discovery, NLRP3 is almost never separated from its major role in the protein complex it forms with ASC, NEK7 and Caspase-1, the inflammasome. This key component of the innate immune response mediates the secretion of proinflammatory cytokines IL-1β and IL-18 involved in immune response to microbial infection and cellular damage. However, NLRP3 has also other functions that do not involve the inflammasome assembly nor the innate immune response. These non-canonical functions have been poorly studied. Nevertheless, NLRP3 is associated with different kind of diseases probably through its inflammasome dependent function as through its inflammasome independent functions.

AIM OF THE REVIEW

The study and understanding of the canonical and non-canonical functions of NLRP3 can help to better understand its involvement in various pathologies. In parallel, the description of the mechanisms of action and regulation of its various functions, can allow the identification of new therapeutic strategies.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

NLRP3 functions have mainly been studied in the context of the inflammasome, in myeloid cells and in totally deficient transgenic mice. However, for several year, the work of different teams has proven that NLRP3 is also expressed in other cell types where it has functions that are independent of the inflammasome. If these studies suggest that NLRP3 could play different roles in the cytoplasm or the nucleus of the cells, the mechanisms underlying NLRP3 non-canonical functions remain unclear. This is why we propose in this review an inventory of the canonical and non-canonical functions of NLRP3 and their impact in different pathologies.

Geniposide suppressed OX-LDL-induced osteoblast apoptosis by regulating the NRF2/NF-κB signaling pathway

BACKGROUND

Osteoporosis (OP), due to microarchitectural alterations, is associated with decreased bone mass, declined strength, and increased fracture risk. Increased osteoblast apoptosis contributes to the progression of OP. Natural compounds from herbs provide a rich resource for drug screening. Our previous investigation showed that geniposide (GEN), an effective compound from Eucommia ulmoides, could protect against the pathological development of OP induced by cholesterol accumulation.

METHODS

The rat OP models were duplicated. Dual-energy X-ray absorptiometry, hematoxylin and eosin staining, and immunohistochemistry were used to evaluate bone changes. TUNEL/DAPI staining assays were used for cell apoptosis detection. Protein expression was determined by western blotting assays.

RESULTS

A high-fat diet promoted OP development in vivo, and OX-LDL stimulated osteoblast apoptosis in vitro. GEN exhibited protective activities against OX-LDL-induced osteoblast apoptosis by increasing the NRF2 pathway and decreasing the NF-κB pathway. PDTC, an NF-κB inhibitor, could further promote the biological functions of GEN. In contrast, ML385, an NRF2 inhibitor, might eliminate GEN's protection.

CONCLUSION

GEN suppressed OX-LDL-induced osteoblast apoptosis by regulating the NRF2/NF-κB signaling pathway.

Lepidium sativum alleviates diabetic nephropathy in a rat model by attenuating glucose levels, oxidative stress, and inflammation with concomitant suppression of TGF-β1

In this research, the treatment of diabetic nephropathy in rats induced by streptozotocin with L. sativium whole-plant aqueous extract was examined, and the mechanism of action was proposed. Adult male rats were grouped into: control, L. sativum, T1DM, and T1DM + L. sativum-treated groups. For 8 weeks, L. sativum S was given to rats at a final dose of 250 mg/kg. Treatment with L. sativum reduced the amount of fasting glucose, increased the amount of fasting insulin, and diminished the increase in hepatic and serum cholesterol, free fatty acid, and triglyceride levels. The level of serum LDL-c was reduced. At the level of the kidney, L. sativum reduced urine volume and albumin excretion and spiked creatinine excretion. It also attenuated the tubular damage in the rats' kidneys and reduced the amounts of major inflammatory markers, including nuclear factor-kappaα (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). Interestingly, L. sativium reduced the amount of mRNA transforming growth factor-β1 (TGF-β1), stimulated mRNA superoxide dismutase (SOD) and catalase (CAT), reduced lipid peroxide levels (MDA), and increased the glutathione (GSH), SOD, and CAT in the rat kidneys of the control and T1DM-treated group. In conclusion, L. sativum is a novel therapy against DN owing to its hypoglycemic effect, insulin-releasing, and antioxidant potential.

Maternal High-Fat Diet Controls Offspring Kidney Health and Disease

A balanced diet during gestation is critical for fetal development, and excessive intake of saturated fats during gestation and lactation is related to an increased risk of offspring kidney disease. Emerging evidence indicates that a maternal high-fat diet influences kidney health and disease of the offspring via so-called renal programming. This review summarizes preclinical research documenting the connection between a maternal high-fat diet during gestation and lactation and offspring kidney disease, as well as the molecular mechanisms behind renal programming, and early-life interventions to offset adverse programming processes. Animal models indicate that offspring kidney health can be improved via perinatal polyunsaturated fatty acid supplementation, gut microbiota changes, and modulation of nutrient-sensing signals. These findings reinforce the significance of a balanced maternal diet for the kidney health of offspring.

Prognostic value of low-density lipoprotein cholesterol in IgA nephropathy and establishment of nomogram model

BACKGROUND

Dyslipidemia is closely related to kidney disease. We aimed to investigate the relationship between low-density lipoprotein cholesterol (LDL-C) and prognosis of IgA nephropathy (IgAN) and build a nomogram prognostic model.

METHODS

519 IgAN patients with 61 months median follow-up were enrolled and divided into two groups based on the cut-off value of baseline LDL-C (2.60 mmol/L): the high group (n=253) and the low group (n=266). Renal survival was assessed by Kaplan⁃Meier (KM) survival curve. Risk factors were identified by COX regression analysis. The area under the receiver operating characteristic (ROC) curves (AUC), concordance index (C-index), and calibration curves were applied to evaluate the nomogram model.

RESULTS

KM survival curve analysis showed that the high LDL-C group had worse renal survival than the low LDL-C group (χ2 = 8.555, p=0.003). After adjusting for confounding factors, Cox regression analysis showed the baseline LDL-C level was an independent risk factor of end-stage renal disease (ESRD) in IgAN (HR=3.135, 95% CI 1.240~7.926, p =0.016). LDL-C, segmental sclerosis, tubular atrophy/interstitial fibrosis, the prevalence of cardiovascular disease, 24-hour proteinuria were identified and entered into the nomogram models, with AUC of 0.864, 0.827, and 0.792 respectively to predict the 5-, 8-, and 10-year risk of ESRD in IgAN. The C-index of this prediction model was respectively 0.862, 0.838, and 0.800 and was well-calibrated.

CONCLUSION

Elevated LDL-C level is a predictive factor for the prognosis of IgAN. We developed a nomogram model that can predict the risk of ESRD in IgAN by using LDL-C ≥ 2.60 mmol/L.

Sesamol Attenuates Renal Inflammation and Arrests Reactive-Oxygen-Species-Mediated IL-1β Secretion via the HO-1-Induced Inhibition of the IKKα/NFκB Pathway In Vivo and In Vitro

Chronic nephritis leads to irreversible renal fibrosis, ultimately leading to chronic kidney disease (CKD) and death. Macrophage infiltration and interleukin 1β (IL-1β) upregulation are involved in inflammation-mediated renal fibrosis and CKD. Sesamol (SM), which is extracted from sesame seeds, has antioxidant and anti-inflammatory properties. We aimed to explore whether SM mitigates macrophage-mediated renal inflammation and its underlying mechanisms. ApoE^-/- mice were subjected to 5/6 nephrectomy (5/6 Nx) with or without the oral gavage of SM for eight weeks. Blood and urine samples and all the kidney remnants were collected for analysis. Additionally, THP-1 cells were used to explore the mechanism through which SM attenuates renal inflammation. Compared with the sham group, the 5/6 Nx ApoE^-/- mice exhibited a significant increase in the macrophage infiltration of the kidneys (nephritis), upregulation of IL-1β, generation of reactive oxygen species, reduced creatinine clearance, and renal fibrosis. However, the administration of SM significantly alleviated these effects. SM suppressed the H₂O₂-induced secretion of IL-1β from the THP-1 cells via the heme oxygenase-1-induced inhibition of the IKKα-NF-κB pathway. SM attenuated renal inflammation and arrested macrophage accumulation by inhibiting IKKα, revealing a novel mechanism of the therapeutic effects of SM on renal injury and offering a potential approach to CKD treatment.

Lycopene Effects on Metabolic Syndrome and Kidney Injury in Rats Fed a High-Fat Diet: An Experimental Study

The frequency of overweight and obesity is rising globally. These disorders are prevalent health problems. It has a substantial correlation with a number of health issues, including cardiovascular, metabolic, and diabetes mellitus disorders. Lycopene (Lyc) is an acyclic structural isomer of β-carotene and has powerful antioxidant properties with various promising therapeutic effects. In this study, rats fed a high-fat diet were examined to determine how lycopene affected metabolic syndrome and kidney damage. After being acclimated, rats were divided into 5 groups (n = 8/group) as follows: the first group served as the control and was fed on a normal pelleted diet (4.25% fat) until the end of the experiment. The second group (high-fat diet; HFD) was fed on a high-fat diet (45.5 kcal% fat) composed of 24% fat, 24% protein, and 41% carbohydrate. The third and fourth groups were fed on HFD and administered lycopene at 25 and 50 mg/kg bodyweight orally every day. The fifth group (standard drug group) received HFD and simvastatin (SVS; 10 mg/kg bodyweight orally daily) for 3 months. Tissue samples from the kidney were taken for determination of the biochemical parameters, lipid peroxidation (LPO), protein carbonyl (PC), reduced glutathione (GSH), total thiol group, antioxidant enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), in addition to renal mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2), renal levels of inflammatory markers [tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)], and apoptotic markers (BCL2 Associated X (Bax), B-cell lymphoma 2 (Bcl-2), and Bax/Bcl-2 ratio). When compared to the control group, the HFD group's food consumption, body weight, serum levels of glucose, uric acid, creatinine, LPO, PC, TNF-α, IL-1β, Bax, and the Bax/Bcl-2 ratio all increased significantly. In the kidney sample of HFD-fed rats, there was a downregulation of Nrf2 mRNA expression along with a significant reduction in the enzymatic activity of SOD, CAT, GR, and GPx. Lyc treatment was able to successfully reverse HFD-mediated changes as compared to the HFD group. Consuming lyc helps to prevent fat and renal damage in a positive way.

Good Adherence to the Mediterranean Diet Lowered Risk of Renal Glomerular Impairment in Children: A Longitudinal Study

Healthy diet patterns have a positive effect on chronic non-communicable diseases in the pediatric population, but the evidence is limited on the association between kidney impairment and adherence to a Mediterranean diet. We aim to determine the associations between Mediterranean diet adherence and longitudinal tubular and glomerular impairment in children. Based on four waves of urine assays conducted from October 2018 to November 2019, we assayed urinary β₂-microglobulin (β₂-MG) and microalbumin (MA) excretion to determine transient renal tubular and glomerular impairment during the follow-up of the child cohort (PROC) study in Beijing, China. We assessed Mediterranean diet adherence using the 16-item Mediterranean Diet Quality Index in children and adolescents (KIDMED) among 1914 primary school children. Poor, intermediate, and good adherence rates for the Mediterranean diet were 9.0% (KIDMED index 0–3), 54.4% (KIDMED index 4–7) and 36.5% (KIDMED index 8–12), respectively. A short sleep duration was more prevalent in children with lower Mediterranean diet adherence, with no significant differences presenting in the other demographic and lifestyle covariates. The results of linear mixed-effects models showed that a higher urinary MA excretion was inversely associated with a higher KIDMED score (β = −0.216, 95%CI: −0.358, −0.074, p = 0.003), after adjusting for sex, age, BMI z-score, SBP z-score, screen time, sleep duration and physical activity. Furthermore, in generalized linear mixed-effects models, consistent results found that transient renal glomerular impairment was less likely to develop in children with intermediate Mediterranean diet adherence (aOR = 0.68, 95%CI: 0.47, 0.99, p = 0.044) and in children with good Mediterranean diet adherence (aOR = 0.60, 95%CI: 0.40, 0.90, p = 0.014), taking poor Mediterranean diet adherence as a reference. We visualized the longitudinal associations between each item of the KIDMED test and kidney impairment via a forest plot and identified the main protective eating behaviors. Children who adhere well to the Mediterranean diet have a lower risk of transient glomerular impairment, underscoring the necessity of the early childhood development of healthy eating patterns to protect kidney health.