Dietary vinegar prevents kidney stone recurrence via epigenetic regulations

Cell death‑related molecules and targets in the progression of urolithiasis (Review)

Urolithiasis is a high‑incidence disease caused by calcium oxalate (mainly), uric acid, calcium phosphate, struvite, apatite, cystine and other stones. The development of kidney stones is closely related to renal tubule cell damage and crystal adhesion and aggregation. Cell death, comprising the core steps of cell damage, can be classified into various types (i.e., apoptosis, ferroptosis, necroptosis and pyroptosis). Different crystal types, concentrations, morphologies and sizes cause tubular cell damage via the regulation of different forms of cell death. Oxidative stress caused by high oxalate or crystal concentrations is considered to be a precursor to a variety of types of cell death. In addition, complex crosstalk exists among numerous signaling pathways and their key molecules in various types of cell death. Urolithiasis is considered a metabolic disorder, and tricarboxylic acid cycle‑related molecules, such as citrate and succinate, are closely related to cell death and the inhibition of stone development. However, a literature review of the associations between kidney stone development, metabolism and various types of cell death is currently lacking, at least to the best of our knowledge. Thus, the present review summarizes the major advances in the understanding of regulated cell death and urolithiasis progression.

Oxalates: Dietary Oxalates and Kidney Inflammation: A Literature Review

This literature review explores the role of dietary oxalate in the development of chronic inflammatory kidney disease in middle-aged and older individuals. The authors pose the following questions: Is oxalate produced endogenously? If food sources contribute to chronic kidney disease and inflammation, what are those foods? What role do cultural food preparation and cooking play in denaturing food oxalates? The concentration of oxalates found within the body at any particular time is not limited to edible plants; normal human metabolic processes of breaking down ascorbic acid may create up to 30 mg of oxalate daily. Research supports urolithiasis as a common urologic disease in industrialized societies. Approximately 80% of kidney stones are composed of calcium oxalate, resulting in hyperoxaluria. Exogenous (originating outside the cell or organism) oxalate sources include ascorbic acid, amino acids, and glyoxal metabolism. Additional research estimates the daily endogenous (produced within the cell or organism) production of oxalate to be 10-25 mg. Suboptimal colonization of oxalate-degrading bacteria and malabsorptive disease are also contributing factors to the development of chronic kidney disease. Oxalate transcellular processes, though poorly understood, rely on multifunctional anion exchangers, and are currently being investigated. A review of research showed that normal human metabolic processes, including the breakdown of ascorbic acid, account for 35-55% of circulating oxalates and can create ≤30 mg of circulating serum oxalate daily. Glyoxylic acid accounts for 50-70% of circulating urinary oxalate in compromised individuals with liver glycation, bacterial insufficiencies, malabsorption, and anion exchange challenges. For persons with a family history of kidney stones, consumption of foods high in oxalates may be consumed in moderation, provided there is adequate calcium intake in the diet to decrease the absorption of oxalates from the meal ingested.

Lycopene from tomatoes and tomato products exerts renoprotective effects by ameliorating oxidative stress, apoptosis, pyroptosis, fibrosis, and inflammatory injury in calcium oxalate nephrolithiasis: the underlying mechanisms

Several mechanisms underlying nephrolithiasis, one of the most common urological diseases, involve calcium oxalate formation, including oxidative stress, inflammatory reactions, fibrosis, pyroptosis, and apoptosis. Although lycopene has strong antioxidant activity, its protective effects against CaOx-induced injury have not yet been reported. This study aimed to systematically investigate the protective effects of lycopene and explore its mechanisms and molecular targets. Crystal deposition, renal function, oxidative stress, inflammatory response, fibrosis, pyroptosis, and apoptosis were assessed to evaluate the renoprotective effects of lycopene against crystal formation in a CaOx rat model and oxalate-stimulated NRK-52E and HK-2 cells. Lycopene markedly ameliorated crystal deposition, restored renal function, and suppressed kidney injury by reducing oxidative stress, apoptosis, inflammation, fibrosis, and pyroptosis in the rats. In cell models, lycopene pretreatment reversed reactive oxygen species increase, apoptotic damage, intracellular lactate dehydrogenase release, cytotoxicity, pyroptosis, and extracellular matrix deposition. Network pharmacology and proteomic analyses were performed to identify lycopene target proteins under CaOx-exposed conditions, and the results showed that Trappc4 might be a pivotal target gene for lycopene, as identified by cellular thermal shift assay and surface plasmon resonance analyses. Based on molecular docking, molecular dynamics simulations, alanine scanning mutagenesis, and saturation mutagenesis, we observed that lycopene directly interacts with Trappc4 via hydrophobic bonds, which may be attributed to the PHE4 and PHE142 residues, preventing ERK1/2 or elevating AMPK signaling pathway phosphorylation events. In conclusion, lycopene might ameliorate oxalate-induced renal tubular epithelial cell injury via the Trappc4/ERK1/2/AMPK pathway, indicating its potential for the treatment of nephrolithiasis.

Histone deacetylase 6 suppression of renal tubular epithelial cell promotes interstitial mineral deposition via alpha-tubulin acetylation

Randall's plaque (RP) is derived from interstitial mineral deposition and is highly prevalent in renal calcium oxalate (CaOx) stone disease, which is predictive of recurrence. This study shows that histone deacetylase 6 (HDAC6) levels are suppressed in renal tubular epithelial cells in RP samples, in kidney tissues of hyperoxaluria rats, and in hyper-oxalate-treated or mineralized cultured renal tubular epithelial (MDCK) cells in vitro. Mineral deposition in MDCK cells was exacerbated by HDAC6 inhibition but alleviated by HDAC6 overexpression. Surprisingly, the expression of some osteogenic-associated proteins, were not increased along with the increasing of mineral deposition, and result of single-cell RNA sequencing of renal papillae samples revealed that epithelial cells possess lower calcific activity, suggesting that osteogenic-transdifferentiation may not have actually occurred in tubular epithelial cells despite mineral deposition. The initial mineral depositions facilitated by HDAC6 inhibitor were localized in extracellular dome rather than inside the cells, moreover, suppression of HDAC6 significantly increased the calcium content of co-cultured renal interstitial fibroblasts (NRK49F) and enhanced mineral deposition of indirectly co-cultured NRK49F cells, suggesting that HDAC6 may influence trans-MDCK monolayer secretion of mineral. Further experiments revealed that this regulatory role was partially alpha-tubulinLys40 acetylation dependent. Collectively, these results suggest that hyper-oxalate exposure led to HDAC6 suppression in renal tubular epithelial cells, which may contribute to interstitial mineral deposition by promoting alpha-tubulinLys40 acetylation. Therapeutic agents that influence HDAC6 activity may be beneficial in preventing RP and CaOx stone formation.

Mechanism of Porphyra Yezoensis Polysaccharides in Inhibiting Hyperoxalate-Induced Renal Injury and Crystal Deposition

Oxidative damage to the kidneys is a primary factor in the occurrence of kidney stones. This study explores the inhibitory effect of Porphyra yezoensis polysaccharides (PYP) on oxalate-induced renal injury by detecting levels of oxidative damage, expression of adhesion molecules, and damage to intracellular organelles and revealed the molecular mechanism by molecular biology methods. Additionally, we validated the role of PYP in vivo using a crystallization model of hyperoxalate-induced rats. PYP effectively scavenged the overproduction of reactive oxygen species (ROS) in HK-2 cells, inhibited the adhesion of calcium oxalate (CaOx) crystals on the cell surface, unblocked the cell cycle, restored the depolarization of the mitochondrial membrane potential, and inhibited cell death. PYP upregulated the expression of antioxidant proteins, including Nrf2, HO-1, SOD, and CAT, while decreasing the expression of Keap-1, thereby activating the Keap1/Nrf2 signaling pathway. PYP inhibited CaOx deposition in renal tubules in the rat crystallization model, significantly reduced high oxalate-induced renal injury, decreased the levels of the cell surface adhesion proteins, improved renal function in rats, and ultimately inhibited the formation of kidney stones. Therefore, PYP, which has crystallization inhibition and antioxidant properties, may be a therapeutic option for the treatment of kidney stones.

Exploring diversity and functional traits of lactic acid bacteria in traditional vinegar fermentation: A review

Vinegar has been used for centuries as a food preservative, flavor enhancer, and medicinal agent. While commonly known for its sour taste and acidic properties due to acetic acid bacteria metabolism, vinegar is also home to a diverse community of lactic acid bacteria (LAB). The main genera found during natural fermentation include Lactobacillus, Lacticaseibacillus, Lentilactobacillus, Limosilactbacillus, Leuconostoc, and Pedicoccus. Many of the reported LAB species fulfill the probiotic criteria set by the World Health Organization (WHO). However, it is crucial to acknowledge that LAB viability undergoes a significant reduction during vinegar fermentation. While containing LAB, none of the analyzed vinegar met the minimum viable amount required for probiotic labeling. To fully unlock the potential of vinegar as a probiotic, investigations should be focused on enhancing LAB viability during vinegar fermentation, identifying strains with probiotic properties, and establishing appropriate dosage and consumption guidelines to ensure functional benefits. Currently, vinegar exhibits substantial potential as a postbiotic product, attributed to the high incidence and growth of LAB in the initial stages of the fermentation process. This review aims to identify critical gaps and address the essential requirements for establishing vinegar as a viable probiotic product. It comprehensively examines various relevant aspects, including vinegar processing, total and LAB diversity, LAB metabolism, the potential health benefits linked to vinegar consumption, and the identification of potential probiotic species.

Non-Coding RNAs in Kidney Stones

Nephrolithiasis is a major public health concern associated with high morbidity and recurrence. Despite decades of research, the pathogenesis of nephrolithiasis remains incompletely understood, and effective prevention is lacking. An increasing body of evidence suggests that non-coding RNAs, especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play a role in stone formation and stone-related kidney injury. MiRNAs have been studied quite extensively in nephrolithiasis, and a plethora of specific miRNAs have been implicated in the pathogenesis of nephrolithiasis, involving remarkable changes in calcium metabolism, oxalate metabolism, oxidative stress, cell-crystal adhesion, cellular autophagy, apoptosis, and macrophage (Mp) polarization and metabolism. Emerging evidence suggests a potential for miRNAs as novel diagnostic biomarkers of nephrolithiasis. LncRNAs act as competing endogenous RNAs (ceRNAs) to bind miRNAs, thereby modulating mRNA expression to participate in the regulation of physiological mechanisms in kidney stones. Small interfering RNAs (siRNAs) may provide a novel approach to kidney stone prevention and treatment by treating related metabolic conditions that cause kidney stones. Further investigation into these non-coding RNAs will generate novel insights into the mechanisms of renal stone formation and stone-related renal injury and might lead to new strategies for diagnosing and treating this disease.

Identification of biomarkers and potential therapeutic targets of kidney stone disease using bioinformatics

PURPOSE

Kidney stone disease (KSD) is a common urological disease, but its pathogenesis remains unclear. In this study, we screened KSD-related hub genes using bioinformatic methods and predicted the related pathways and potential drug targets.

METHODS

The GSE75542 and GSE18160 datasets in the Gene Expression Omnibus (GEO) were selected to identify common differentially expressed genes (DEGs). We conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to identify enriched pathways. Finally, we constructed a hub gene-miRNA network and drug-DEG interaction network.

RESULTS

In total, 44 upregulated DEGs and 1 downregulated DEG were selected from the GEO datasets. Signaling pathways, such as leukocyte migration, chemokine activity, NF-κB, TNF, and IL-17, were identified in GO and KEGG. We identified 10 hub genes using Cytohubba. In addition, 21 miRNAs were predicted to regulate 4 or more hub genes, and 10 drugs targeted 2 or more DEGs. LCN2 expression was significantly different between the GEO datasets. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses showed that seven hub gene expressions in HK-2 cells with CaOx treatment were significantly higher than those in the control group.

CONCLUSION

The 10 hub genes identified, especially LCN2, may be involved in kidney stone occurrence and development, and may provide new research targets for KSD diagnosis. Furthermore, KSD-related miRNAs may be targeted for the development of novel drugs for KSD treatment.

Analysis of Dietary Patterns Associated with Kidney Stone Disease Based on Data-Driven Approaches: A Case-Control Study in Shanghai

The main objective of this study was to analyze dietary patterns using data-driven approaches and to explore preventive or risk dietary factors for kidney stone disease (KSD). A case-control matching study was conducted in adults (n = 6396) from a suburb of Shanghai. A food frequency questionnaire was used to assess the consumption of various types of food, and B-ultrasound was used to identify kidney stones. Principal component analysis and regression were used to generate dietary patterns and further explore the relationship between dietary patterns and KSD. LASSO regression and post-selection inference were used to identify food groups most associated with KSD. Among males, the "balanced but no-sugary-beverages pattern" (OR = 0.78, p < 0.05) and the "nuts and pickles pattern" (OR = 0.84, p < 0.05) were protective dietary patterns. Among females, "high vegetables and low-sugary-beverages pattern" (OR = 0.83, p < 0.05) and "high-crustaceans and low-vegetables pattern" (OR = 0.79, p < 0.05) were protective dietary patterns, while the "comprehensive pattern with a preference for meat" (OR = 1.06, p < 0.05) and "sugary beverages pattern" (OR = 1.16, p < 0.05) were risk dietary patterns. We further inferred that sugary beverages (p < 0.05) were risk factors and pickles (p < 0.05) and crustaceans (p < 0.05) were protective factors.

Association between N, N-diethyl-m-toluamide exposure and the odds of kidney stones in US adults: a population-based study

Background

Currently, there is limited research on the specific relationship between N, N-diethyl-m-toluamide (DEET) exposure and the odds of kidney stones. We aimed to investigate the relationship between DEET exposure and the prevalence of kidney stones.

Methods

We included 7,567 qualified participants in our research from the 2007-2016 NHANES survey. We carried out three logistic regression models to explore the potential association between DEET exposure and the odds of kidney stones. Spline smoothing with generalized additive models (GAM) was utilized to assess the non-linear relationship and restricted cubic spline (RCS) curves was to determine the dose-response association. Multivariate regression models were used to conduct stratified analysis and sensitivity analysis.

Results

Baseline characteristics of study participants presented the distribution of covariables. Regression analysis revealed that the odds of kidney stones were positively associated with the main metabolites of 3-diethyl-carbamoyl benzoic acid (DCBA) (log2) (OR = 1.05, 95% CI 1.02 to 1.08). The fourth quartile of urine DCBA showed a greater risk of kidney stones in the fully adjusted model (OR = 1.36, 95% CI 1.08 to 1.72). Another DEET metabolite of N, N-diethyl-3-hydroxymethylbenzamide (DHMB) was used to confirm the accuracy and stability of the results. The spline smoothing curve represented two main DEET metabolites had similar no-linear relationships and a positive trend with kidney stones proportion. RCS implied that the incidence of kidney stones rose with increasing levels of DEET exposure. High-risk groups on kidney stones were exhibited by stratified analysis under DEET exposure.

Conclusion

Our study suggests that DEET exposure is positively associated with odds of kidney stones. Further investigation into the underlying processes of this association is required to guide the prevention and treatment of kidney stones.

Predictive value of single-nucleotide polymorphism signature for nephrolithiasis recurrence: a 5-year prospective study

Background

Genetic variations are linked to kidney stone formation. However, the association of single nucleotide polymorphism (SNPs) and stone recurrence has not been well studied. This study aims to identify genetic variants associated with kidney stone recurrences and to construct a predictive nomogram model using SNPs and clinical features to predict the recurrence risk of kidney stones.

Methods

We genotyped 49 SNPs in 1001 patients who received surgical stone removal between Jan 1 and Dec 31 of 2012. All patients were confirmed stone-free by CT scan and then received follow-up at least 5 years. SNP associations with stone recurrence were analyzed by Cox proportion hazard model. A predictive nomogram model using SNPs and clinical features to predict the recurrence risk of kidney stones was developed by use of LASSO Cox regression.

Results

The recurrence rate at 3, 5, 7 years were 46.8%, 71.2%, and 78.4%, respectively. 5 SNPs were identified that had association with kidney stone recurrence risk. We used computer-generated random numbers to assign 500 of these patients to the training cohort and 501 patients to the validation cohort. A nomogram that combined the 14-SNPs-based classifier with the clinical risk factors was constructed. The areas under the curve (AUCs) at 3, 5 and 7 years of this nomogram was 0.645, 0.723, and 0.75 in training cohort, and was 0.631, 0.708, and 0.727 in validation cohort, respectively. Results show that the nomogram presented a higher predictive accuracy than those of the SNP classifier or clinical factors alone.

Conclusion

SNPs are significantly associated with kidney stone recurrence and should add prognostic value to the traditional clinical risk factors used to assess the kidney stone recurrence. A nomogram using clinical and genetic variables to predict kidney stone recurrence has revealed its potential in the future as an assessment tool during the follow-up of kidney stone patients.

Protective mechanism of fruit vinegar polyphenols against AGEs-induced Caco-2 cell damage

Accumulation of advanced glycation end products (AGEs) is linked with development or aggravation of many degenerative processes or disorders. Fruit vinegars are rich in polyphenols that can be a good dietary source of AGEs inhibitors. In this study, eight kinds of vinegars were prepared. Among them, the highest polyphenol and flavonoid content were orange vinegar and kiwi fruit vinegar, respectively. Ferulic acid, vanillic acid, chlorogenic acid, p-coumaric acid, caffeic acid, catechin, and epicatechin were main polyphenols in eight fruit vinegars. Then, we measured the inhibitory effect of eight fruit vinegars on fluorescent AGEs, and found that orange vinegar had the highest inhibitory rate. Data here suggested that orange vinegar and its main components catechin, epicatechin, and p-coumaric acid could effectively reduce the level of ROS, RAGE, NADPH and inflammatory factors in Caco-2 cells. Our research provided theoretical basis for the application of orange vinegar as AGEs inhibitor.

Development of innovative fermented products by exploiting the diversity of immunomodulatory properties and fermentative activity of lactic and propionic acid bacteria

Many consumers nowadays demand plant-based milk analogs for reasons related to lifestyle, health, diet and sustainability. This has led to the increasing development of new products, fermented or not. The objective of the present study was to develop a plant-based fermented product (based on soy milk analog or on hemp milk analog), as well as mixes, using lactic acid bacteria (LAB) and propionic acid bacteria (PAB) strains, as well as consortia thereof. We screened a collection of 104 strains, from nine LAB species and two PAB species, based on their ability to ferment plant or milk carbohydrates, to acidify goat milk, soy milk analog and hemp milk analog, as well as to hydrolyze proteins isolated from these three products. Strains were also screened for their immunomodulatory ability to induce secretion of two interleukins, i.e., IL-10 and IL-12, in human Peripheral Blood Mononuclear Cells. We selected five strains: Lactobacillus delbrueckii subsp. lactis Bioprox1585, Lactobacillus acidophilus Bioprox6307, Lactococcus lactis Bioprox7116, Streptococcus thermophilus CIRM-BIA251, and Acidipropionibacterium acidipropionici CIRM-BIA2003. We then assembled them in 26 different bacterial consortia. Goat milk and soy milk analog fermented by each of the five strains or by the 26 consortia were tested in vitro, for their ability to modulate inflammation in cultured Human Epithelial Intestinal Cells (HEIC) stimulated by pro-inflammatory Lipopolysaccharides (LPS) from Escherichia coli. Plant-based milk analogs, fermented by one consortium composed of L.delbrueckii subsp. lactis Bioprox1585, Lc.lactis Bioprox7116, and A.acidipropionici CIRM-BIA2003, reduced the secretion of the proinflammatory cytokine IL-8 in HIECs. Such innovative fermented vegetable products thus open perspectives as functional foods targeting gut inflammation.

Acetate attenuates hyperoxaluria-induced kidney injury by inhibiting macrophage infiltration via the miR-493-3p/MIF axis

Hyperoxaluria is well known to cause renal injury and end-stage kidney disease. Previous studies suggested that acetate treatment may improve the renal function in hyperoxaluria rat model. However, its underlying mechanisms remain largely unknown. Using an ethylene glycol (EG)-induced hyperoxaluria rat model, we find the oral administration of 5% acetate reduced the elevated serum creatinine, urea, and protected against hyperoxaluria-induced renal injury and fibrosis with less infiltrated macrophages in the kidney. Treatment of acetate in renal tubular epithelial cells in vitro decrease the macrophages recruitment which might have reduced the oxalate-induced renal tubular cells injury. Mechanism dissection suggests that acetate enhanced acetylation of Histone H3 in renal tubular cells and promoted expression of miR-493-3p by increasing H3K9 and H3K27 acetylation at its promoter region. The miR-493-3p can suppress the expression of macrophage migration inhibitory factor (MIF), thus inhibiting the macrophages recruitment and reduced oxalate-induced renal tubular cells injury. Importantly, results from the in vivo rat model also demonstrate that the effects of acetate against renal injury were weakened after blocking the miR-493-3p by antagomir treatment. Together, these results suggest that acetate treatment ameliorates the hyperoxaluria-induced renal injury via inhibiting macrophages infiltration with change of the miR-493-3p/MIF signals. Acetate could be a new therapeutic approach for the treatment of oxalate nephropathy.

Kidney Stone Prevention

Kidney stone disease (KSD) (alternatively nephrolithiasis or urolithiasis) is a global health care problem that affects almost people in developed and developing countries. Its prevalence has been continuously increasing with a high recurrence rate after stone removal. Although effective therapeutic modalities are available, preventive strategies for both new and recurrent stones are required to reduce physical and financial burdens of KSD. To prevent kidney stone formation, its etiology and risk factors should be first considered. Low urine output and dehydration are the common risks of all stone types, whereas hypercalciuria, hyperoxaluria, and hypocitraturia are the major risks of calcium stones. In this article, up-to-date knowledge on strategies (nutrition-based mainly) to prevent KSD is provided. Important roles of fluid intake (2.5-3.0 L/d), diuresis (>2.0-2.5 L/d), lifestyle and habit modifications (for example, maintain normal body mass index, fluid compensation for working in high-temperature environment, and avoid cigarette smoking), and dietary management [for example, sufficient calcium at 1000-1200 mg/d, limit sodium at 2 or 3-5 g/d of sodium chloride (NaCl), limit oxalate-rich foods, avoid vitamin C and vitamin D supplements, limit animal proteins to 0.8-1.0 g/kg body weight/d but increase plant proteins in patients with calcium and uric acid stone and those with hyperuricosuria, increase proportion of citrus fruits, and consider lime powder supplementation] are summarized. Moreover, uses of natural bioactive products (for example, caffeine, epigallocatechin gallate, and diosmin), medications (for example, thiazides, alkaline citrate, other alkalinizing agents, and allopurinol), bacterial eradication, and probiotics are also discussed. Adv Nutr 2023;x:xx-xx.

Network pharmacology and experimental validation to elucidate the pharmacological mechanisms of Bushen Huashi decoction against kidney stones

INTRODUCTION

Kidney stone disease (KS) is a complicated disease with an increasing global incidence. It was shown that Bushen Huashi decoction (BSHS) is a classic Chinese medicine formula that has therapeutic benefits for patients with KS. However, its pharmacological profile and mechanism of action are yet to be elucidated.

METHODS

The present study used a network pharmacology approach to characterize the mechanism by which BSHS affects KS. Compounds were retrieved from corresponding databases, and active compounds were selected based on their oral bioavailability (≥30) and drug-likeness index (≥0.18). BSHS potential proteins were obtained from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, whereas KS potential genes were obtained from GeneCards and OMIM, TTD, and DisGeNET. Gene ontology and pathway enrichment analysis were used to determine potential pathways associated with genes. The ingredients of BSHS extract were identified by the ultra-high-performance liquid chromatography coupled with quadrupole orbitrap mass spectrometry (UHPLC-Q/Orbitrap MS). The network pharmacology analyses predicted the potential underlying action mechanisms of BSHS on KS, which were further validated experimentally in the rat model of calcium oxalate kidney stones.

RESULTS

Our study found that BSHS reduced renal crystal deposition and improved renal function in ethylene glycol(EG)+ammonium chloride(AC)-induced rats, and also reversed oxidative stress levels and inhibited renal tubular epithelial cell apoptosis in rats. BSHS upregulated protein and mRNA expression of E2, ESR1, ESR2, BCL2, NRF2, and HO-1 in EG+AC-induced rat kidney while downregulating BAX protein and mRNA expression, consistent with the network pharmacology results.

DISCUSSION

This study provides evidence that BSHS plays a critical role in anti-KS via regulation of E2/ESR1/2, NRF2/HO-1, and BCL2/BAX signaling pathways, indicating that BSHS is a candidate herbal drug for further investigation in treating KS.

Association between urine cobalt and prevalence of kidney stones in Americans aged ≥ 20 years old

To determine whether urine cobalt (Co) is associated with the prevalence of kidney stones, we conducted a cross-sectional study of participants (≥ 20 years) involved in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. The urine Co level was divided into four groups: 0.02-0.22, 0.22-0.36, 0.36-0.58, and 0.58-37.40 μg/L. The independent correlation between urine Co and prevalence of kidney stones was determined by logistic regression analyses. A total of 10,744 participants aged over 20 years that were not pregnant were eligible. Among them, 1041 participants reported ever having developed kidney stones. Patients with kidney stones developed significantly higher urine Co than the non-stone participants. The kidney stone patients were more likely to have been smoking ≥ 100 cigarettes in life; have hypertension, diabetes, and cancer; and engage in heavy activity. Multivariate logistic regression indicated a significantly positive relationship between the urine Co level and occurrence of kidney stones (OR 1.059, 95% CI 1.018-1.102, P = 0.00430). Moreover, the outcome remained unchanged after some sophisticated factors were adjusted (OR 1.059, 95% CI 1.001-1.120, P = 0.04635), and kidney stones were significantly related to a higher level of Co (OR (95% CI) = 0.22-0.36 μg/L: 1.111 (0.869, 1.421); 0.36-0.58 μg/L: 1.392 (1.095, 1.770); 0.58-37.40 μg/L: 1.712 (1.351, 2.170), and P for trend < 0.00001). So, urine Co concentration is positively associated with the prevalence of kidney stones. However, more high-quality prospective studies are needed to elucidate the causal correlation between Co level and kidney stones.

Unravelling the Complex Relationship between Diet and Nephrolithiasis: The Role of Nutrigenomics and Nutrigenetics

Nephrolithiasis is an increasingly prevalent condition, especially in high income countries, and is associated with high morbidity. Extraordinary progress in genetics made the identification of genetic forms of nephrolithiasis possible. These genetic diseases are usually rare and do not account for the most common forms of nephrolithiasis that are the result of several factors such as environment, dietary habits, and predisposing genes. This knowledge has shaped what we classify as nephrolithiasis, a condition that is now recognized as systemic. How and to what extent all these factors interact with one another and end in kidney stone formation, growth, and recurrence is not completely understood. Two new research fields have recently been trying to give some answers: nutrigenomics and nutrigenetics. These fields have the aim of understanding the intricate diet/genome interface that influences gene expression regulation mainly through epigenetic mechanisms and results in specific medical conditions such as cancer, metabolic syndrome, and cardiovascular diseases. Epigenetics seems to play a crucial role and could represent the link between environmental factors, that we are constantly exposed to, and risk factors for nephrolithiasis. In this systematic review, we summarize all the available evidence of proven or hypothesized epigenetic mechanisms related to nephrolithiasis.

Vinegar: A functional ingredient for human health

Vinegar is a well-known natural food product derived from alcoholic and subsequently acetous fermentation of carbohydrate-rich foods. Vinegar is widely used in the food industry; domestically for pickling vegetables and fruits, and as an ingredient in condiments like salad dressings, ketchups, and mayonnaise; and traditionally as a food seasoning and preservative. Historically, vinegar has been used for medicinal purposes such as a cure for stomach aches, wounds, burns, rashes, and oedema conditions. Different types of vinegar are found worldwide such as rice, black, balsamic, grain, and fruit vinegars. These are produced from different raw materials, and using different fermentation methods to give unique tastes and flavours. Vinegar, while enhancing physiological functions such as lipid metabolism, blood glucose level control, and body weight management, also possesses anticancer, antibacterial, antioxidant, and anti-infection properties. It is considered as a good source material for many bioactive compounds including organic acids, melanoidins, polyphenols, ligustrazine, and tryptophol. The pharmacological and metabolic benefits of vinegar are believed to be due to these bioactive compounds present in vinegar. Acetic acid (CH3COOH) is the essential component of vinegar; it is slightly volatile and has a strong and sour aroma and flavour. Regular consumption of vinegar-containing foods is considered important for keeping many life-style related diseases like diabetes, hypertension, hyperlipidaemia, cancers, and obesity in check. Therefore, the present review aims at highlighting the health benefits associated with vinegar consumption for the physiological well-being of an individual.

Effect of a Combination of Rosa canina Fruits and Apple Cider Vinegar against Hydrogen Peroxide-Induced Toxicity in Experimental Animal Models

Oxidative stress is the trigger of several diseases. It is an imbalance between the production of free radicals and antioxidants. This study aims to evaluate the antioxidant capacity and the protective property of Rosa canina fruits and apple cider vinegar combined or not against hydrogen peroxide (H2O2)-induced toxicity in Wistar rats. The experiment included five groups: group 1 received distilled water (10 mL/kg b.wt), group 2 received H2O2 10% (10 mL/kg b.wt), group 3 received H2O2 10% (10 mL/kg b.wt) and apple vinegar (2 mL/kg b.wt); group 4 received H2O2 10% (10 mL/kg b.wt) and apple vinegar supplemented with Rosa canina fruits extract (300 mg/kg b.wt); group 5 received H2O2 10% (10 mL/kg b.wt) and extract of Rosa canina fruits (300 mg/kg b.wt). The doses were given once daily via a gavage. The antioxidant capacity of apple vinegar and Rosa canina extract was analyzed, and AST, ALT, PAL, urea, and creatinine were determined on day 22 of the experiment. In addition, the kidney and the liver tissues were analyzed. The results showed that H2O2 caused a significant elevation of blood urea, blood creatinine, and transaminases. The histopathology examination revealed that H2O2 caused congestion, hemorrhage, and Bowman’s space enlarged. On the other hand, the results clearly showed that apple vinegar and Rosa canina fruits counterbalance the biochemical and histological changes induced by H2O2. In conclusion, the two natural products studied in this work are effective against the harmful effect of oxidative stress, which explains their use in traditional medicine.

Inhibition of EZH2 ameliorates hyperoxaluria-induced kidney injury through the JNK/FoxO3a pathway

AIMS

Enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27 methyltransferase, has been shown to play a role in kidney diseases. However, its role in hyperoxaluria-induced renal tubular epithelial cells (TECs) injury remains unclear.

MATERIALS AND METHODS

A hyperoxaluria rat model was established by providing 0.5% ammonium chloride and drinking water containing 1% ethylene glycol. TECs were exposed to oxalate stress. The 3-DZNeP, a selective EZH2 inhibitor, was administered in vivo and in vitro. Cell viability, ROS production, and apoptosis ratio were evaluated. Crystal deposition was detected by Von Kossa staining and kidney tissue injury was detected by HE staining and TUNEL. EZH2, H3K27me3, cleaved-caspase3, IL-6, and MCP-1 were examined by western blot or immunohistochemistry.

KEY FINDINGS

Inhibition of EZH2 by 3-DZNeP significantly attenuated hyperoxaluria-induced oxidative and inflammatory injury and CaOx crystal deposition in vivo. Similarly, inhibition of EZH2 using 3-DZNeP or shRNA restored cell viability, suppressed LDH release and the production of intracellular ROS in vitro. Furthermore, the MAPK signaling pathway and FoxO3a levels were activated or elevated in TECs exposed to oxalate. EZH2 inhibition using 3-DZNeP blocked these effects. CC90003 (ERK inhibitor) or SB203580 (p38 inhibitor) did not significantly affect the expression of FoxO3a in TECs treated with 3-DZNeP and oxalate; only SP600125 (JNK inhibitor) significantly decreased FoxO3a expression.

SIGNIFICANCE

EZH2 inhibition protects against oxalate-induced TECs injury and reduces CaOx crystal deposition in the kidney may by modulating the JNK/FoxO3a pathway; EZH2 may be a promising therapeutic target in TECs injury.

Short-Chain Fatty Acids Reduced Renal Calcium Oxalate Stones by Regulating the Expression of Intestinal Oxalate Transporter SLC26A6

Renal calcium oxalate (CaOx) stone is a common urologic disease with a high prevalence and recurrence rate. However, short-chain fatty acids (SCFAs) are less often reported in the prevention of urolithiasis. This study aimed to explore the effect of SCFAs on the renal CaOx stone formation and the underlying mechanisms. Ethylene glycol was used to induce renal CaOx crystals in rats. SCFAs (acetate, propionate, or butyrate) were added as supplements to the drinking water with or without antibiotics. Because intestinal oxalate transporters SLC26A6 and SLC26A3 regulate the excretion and absorption of oxalate in the intestine, we injected adeno-associated virus 9 (AAV9)-SLC26A6-shRNA (short hairpin RNA) and AAV9-SLC26A3 into the tail vein of rats to suppress SLC26A6 and overexpress SLC26A3 expression in the intestine, respectively, to explore the role of SLC26A3 and SLC26A6 (SLC26A3/6) in the reduction of renal CaOx crystals induced by SCFAs. Results showed that SCFAs reduced renal CaOx crystals and urinary oxalate levels but, however, increased the abundance of SCFA-producing bacteria and cecum SCFA levels. SCFA supplements still reduced renal crystals and urinary oxalate after gut microbiota depletion. Propionate and butyrate downregulated intestinal oxalate transporter SLC26A3 expression, while acetate and propionate upregulated SLC26A6 expression, both in vivo and in vitro. AAV9-SLC26A3 exerted a protective effect against renal crystals, while AAV9-SLC26A6-shRNA contributed to the renal crystal formation even though the SCFAs were supplemented. In conclusion, SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones. IMPORTANCE Some studies found that the relative abundances of short-chain-fatty-acid (SCFA)-producing bacteria were lower in the gut microbiota of renal stone patients than healthy controls. Our previous study demonstrated that SCFAs could reduce the formation of renal calcium oxalate (CaOx) stones, but the mechanism is still unknown. In this study, we found that SCFAs (acetate, propionate, and butyrate) reduced the formation of renal calcium oxalate (CaOx) crystals and the level of urinary oxalate. Depleting gut microbiota increased the amount of renal crystals in model rats, and SCFA supplements reduced renal crystals and urinary oxalate after gut microbiota depletion. Intestinal oxalate transporter SLC26A6 was a direct target of SCFAs. Our findings suggested that SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones.

Complementary and Alternative Medicine Use in First-time and Recurrent Kidney Stone Formers

OBJECTIVE

To describe the patterns of complementary and alternative medicine (CAM) among patients with kidney stones and analyze the alkali content of commonly used CAM therapies.

METHODS

We prospectively conducted structured interviews with patients who presented to a specialty stone clinic for the management of kidney stones. Open-ended questions were used to elicit information regarding CAM knowledge, formulation/dosing, and patterns of use. Several common CAM therapies were then analyzed for their alkali, organic anion, and sugar content.

RESULTS

Of 103 subjects, 82 (80%) patients reported knowledge of CAM and 52 (50%) reported using CAM. Patients with recurrent kidney stones were more likely to report using CAM than patients with first-time episodes (56% vs 26%, P = 0.04). Some respondents reported their condition decreased in severity or frequency since starting CAM therapy (17%) and improvements in pain (12%). Total alkali content per serving of the tested supplements was 0 mEq (Stonebreaker), 1.5 mEq (Ocean Spray Cranberry Juice Cocktail), 4.7 mEq (Lakewood Pure Cranberry Juice), 0.6 mEq (Braggs Apple Cider Vinegar), 11.9 mEq (LithoBalance), 9.5 mEq (Simply Grapefruit Juice), 19.8 mEq (KSP-Key Lime), and 20.2 mEq (KSP-Very Berry).

CONCLUSION

Patients with kidney stones may use CAM to alleviate symptoms or prevent recurrence. Commercially available CAM therapies may contain comparable alkali content to commonly prescribed citrate therapy. These data suggest that providers should be prepared to discuss the role of CAM with their patients.

The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods

An expert panel was convened in September 2019 by The International Scientific Association for Probiotics and Prebiotics (ISAPP) to develop a definition for fermented foods and to describe their role in the human diet. Although these foods have been consumed for thousands of years, they are receiving increased attention among biologists, nutritionists, technologists, clinicians and consumers. Despite this interest, inconsistencies related to the use of the term 'fermented' led the panel to define fermented foods and beverages as "foods made through desired microbial growth and enzymatic conversions of food components". This definition, encompassing the many varieties of fermented foods, is intended to clarify what is (and is not) a fermented food. The distinction between fermented foods and probiotics is further clarified. The panel also addressed the current state of knowledge on the safety, risks and health benefits, including an assessment of the nutritional attributes and a mechanistic rationale for how fermented foods could improve gastrointestinal and general health. The latest advancements in our understanding of the microbial ecology and systems biology of these foods were discussed. Finally, the panel reviewed how fermented foods are regulated and discussed efforts to include them as a separate category in national dietary guidelines.

A high basal metabolic rate is an independent predictor of stone recurrence in obese patients

Purpose

Basal metabolic rate (BMR) is an indicator of overall body metabolism and may portend unique aberrations in urine physico-chemistry and stone recurrence. The present study examined the effect of predicted BMR on 24 hours urinary metabolic profiles and stone recurrence in obese stone patients.

Materials and Methods

Data from 308 obese patients (body mass index [BMI] ≥30 kg/m²) diagnosed with urinary stone disease between 2003 and 2015 were analyzed retrospectively. BMR was calculated using the Harris–Benedict equation, and patients were classified into two predicted BMR categories (<1,145 kcal/day, ≥1,145 kcal/day). Urinary metabolic parameters and risk of stone recurrence were compared between the two groups.

Results

The high BMR group was more likely to be younger and female, and to have a high BMI and lower incidence of diabetes than the low BMR group (each p<0.05). There was a positive correlation between BMR and 24 hours urinary sodium, uric acid, and phosphate excretion. The amounts of stone-forming constituents such as calcium and uric acid were significantly higher in the high BMR group. Kaplan–Meier estimates showed that the high BMR group had a significantly shorter stone recurrence-free period than the low BMR group (log-rank test, p<0.001). Multivariate Cox regression analyses revealed that predicted BMR was an independent factor of stone recurrence (hazard ratio, 2.759; 95% confidence interval, 1.413–5.386; p=0.003).

Conclusions

BMR may be an easily measured parameter that can be used to identify risk of stone recurrence in obese stone patients.

Hepatoprotective Effect and Molecular Mechanisms of Hengshun Aromatic Vinegar on Non-Alcoholic Fatty Liver Disease

Aromatic vinegar with abundant bioactive components can be used as a food additive to assist the treatment of various diseases. However, its effect on non-alcoholic fatty liver disease (NAFLD) is still unknown. The purpose of this study was to investigate the mechanism of Hengshun aromatic vinegar in preventing NAFLD in vivo and in vitro. Aromatic vinegar treatment was applied to rats fed with a high-fat diet (HFD) and HepG2 cells challenged with palmitic acid (PA). Our results showed that aromatic vinegar markedly improved cell viabilities and attenuated cell damage in vitro. The levels of TC, TG, FFA, AST, ALT, and malondialdehyde (MDA) in HFD-induced rats were significantly decreased by aromatic vinegar. Mechanism investigation revealed that aromatic vinegar markedly up-regulated the level of silent information regulator of transcription 1 (Sirt1), and thereby inhibited inflammation of the pathway through down-regulating the expressions of high mobility group box 1, toll-likereceptor-4, nuclear transcription factor-κB, tumor necrosis factor receptor-associated factor-6, and inflammatory factors. Aromatic vinegar simultaneously increased the expression of farnesoid X receptor and suppressed expressions of lipogenesis related proteins, including fatty acid synthase, acetyl-CoA carboxylase-1, sterol regulatory element binding transcription factor 1, and stearoyl-CoA desaturase-1. These results were further validated by knockdown of Sirt1 using siRNAs silencing in vitro. In conclusion, Hengshun aromatic vinegar showed protective effects against NAFLD by enhancing the activity of SIRT1 and thereby inhibiting lipogenesis and inflammation pathways, which is expected to become a new assistant strategy for NAFLD therapy in the future.

Short-term Cudrania tricuspidata fruit vinegar administration attenuates obesity in high-fat diet-fed mice by improving fat accumulation and metabolic parameters

Previous studies have suggested that vinegar intake can help to reduce body fat and hyperglycemia. Therefore, this study aimed to evaluate the anti-obesity efficacy of vinegar fermented using Cudrania tricuspidata fruits (CTFV) and its main phenolic constituents and to analyze its molecular mechanism and changes in obesity-related metabolizing enzymatic activities. We found that HFD significantly caused hepatic steatosis; increases in body fats, feed efficiency, liver mass, lipids, insulin, oxidative parameters, cardiovascular-associated risk indices, lipase and α-amylase activities, whereas CTFV efficaciously attenuated HFD-induced oxidant stress, fat accumulation, obesity-related enzymatic activity, and the activation or reduction of obesity-related molecular reactions via improving metabolic parameters including phosphorylated insulin receptor substrate 1, protein tyrosine phosphatase 1B, phosphorylated phosphoinositide 3-kinase/protein kinase B, phosphorylated mitogen-activated protein kinases, sterol regulatory element-binding protein 1c, CCAAT/enhancer-binding protein, and fatty acid synthase; and decreases in adiponectin receptor 1, leptin receptor, adenosine monophosphate-activated protein kinase, acetyl-CoA carboxylase, and peroxisome proliferator-activated receptor, subsequently ameliorating HFD-induced obesity. Therefore, CTFV might provide a functional food resource or nutraceutical product for reducing body fat accumulation.

Science and Healthy Meals in the World: Nutritional Epigenomics and Nutrigenetics of the Mediterranean Diet

The Mediterranean Diet (MD), UNESCO Intangible Cultural Heritage of Humanity, has become a scientific topic of high interest due to its health benefits. The aim of this review is to pick up selected studies that report nutrigenomic or nutrigenetic data and recapitulate some of the biochemical/genomic/genetic aspects involved in the positive health effects of the MD. These include (i) the antioxidative potential of its constituents with protective effects against several diseases; (ii) the epigenetic and epigenomic effects exerted by food components, such as Indacaxanthin, Sulforaphane, and 3-Hydroxytyrosol among others, and their involvement in the modulation of miRNA expression; (iii) the existence of predisposing or protective human genotypes due to allelic diversities and the impact of the MD on disease risk. A part of the review is dedicated to the nutrigenomic effects of the main cooking methods used in the MD and also to a comparative analysis of the nutrigenomic properties of the MD and other diet regimens and non-MD-related aliments. Taking all the data into account, the traditional MD emerges as a diet with a high antioxidant and nutrigenomic modulation power, which is an example of the “Environment-Livings-Environment” relationship and an excellent patchwork of interconnected biological actions working toward human health.

The Role of Acetate in the Antagonization of Oxalate: A Potential Causative Molecule for Heart Disease and Cancer Death

Previous reports demonstrated the anticancer effects and the protective effects on cardiovascular diseases of vinegar products. The molecular mechanism underlying these phenomena is not well elucidated. It was proposed that carcinogenesis is triggered by the formation of local strong acids such as HCl. Cancer cells may overproduce weak or moderate organic acids such as oxalate to antagonize strong acids, and calcium oxalate may cause organ failure and death. This study aimed at elucidating the underlying mechanism on the antagonism of apoptosis by acetate on oxalate. Quantitation of cell apoptosis of HEK293T cells in the presence of sodium oxalate and compounds with similar structures to oxalate was conducted by using Annexin V-fluorescein isothiocyanate/propidium iodide staining via flow cytometry. The data indicate that acetate could attenuate the proapoptotic functions of oxalate. This study yields insight into the anticancer and antidisease functions of vinegar products and opens up a new path in the use of weak acetic acid in the prevention and treatment of cancer.

Alteration of the gut microbiota by vinegar is associated with amelioration of hyperoxaluria-induced kidney injury

Hyperoxaluria is well known to cause renal injury and end-stage kidney disease. Previous studies suggested that the renal function of rats with hyperoxaluria was improved after dietary vinegar intake. However, its underlying mechanisms remain largely unknown. The aim of the present study was to examine changes of gut microbiota and blood and urinary metabolites that associate with changes in kidney function to identify mechanisms involved with vinegar induced amelioration of hyperoxaluria-induced kidney injury. Using an ethylene glycol (EG)-induced hyperoxaluria rat model, we evaluated the effects of the vinegar on renal injury. Oral administration of vinegar (2 ml kg^-1 day^-1) reduced the elevated serum creatinine, BUN, and protected against hyperoxaluria-induced renal injury, renal fibrosis, and inflammation. Gut microbiota analysis of 16S rRNA gene in the hyperoxaluria-induced renal injury rats showed that vinegar treatment altered their microbial composition, especially the recovery of the levels of the Prevotella, Ruminiclostridium, Alistipes and Paenalcaligenes genus, which were significantly increased in the hyperoxaluria-induced renal injury rats. Additionally, liquid chromatography-mass spectrometry (LC-MS)-based metabolome analysis showed that total of 35 serum and 42 urine metabolites were identified to be associated with protective effects of vinegar on hyperoxaluria-induced renal injury rats. Most of these metabolites were involved in thiamine metabolism, glycerol phosphate shuttle, biotin metabolism, phosphatidylcholine biosynthesis and membrane lipid metabolism. Importantly, the effects of vinegar against renal injury were weakened after depletion of gut microbiota by antibiotic treatment. These results suggest that vinegar treatment ameliorates the hyperoxaluria-induced renal injury by improving the gut microbiota and metabolomic profiles.