Combined long-term caffeine intake and exercise inhibits the development of diabetic nephropathy in OLETF rats

Inverse association between caffeine intake and albuminuria in US adults: an analysis of NHANES 2005-2016

OBJECTIVES

Albuminuria is a significant biomarker of various kidney diseases and is associated with renal outcome. Recently, caffeine intake has shown potential renoprotective effects. However, the relationship between caffeine intake and albuminuria remains profoundly elusive.

METHODS

We conducted a cross-sectional study aimed to explore the association between caffeine intake and albuminuria in the American adult population using the data acquired from the National Health and Nutrition Examination Survey (NHANES) 2005-2016. Caffeine intake was assessed by 24-h dietary recalls, and albuminuria was assessed by albumin-to-creatinine ratio. Multivariate logistic regression was performed to explore the independent association between caffeine intake and albuminuria. Subgroup analysis and interaction tests were also conducted.

RESULTS

Among 23,060 participants, 11.8% of the individuals exhibited albuminuria, and the prevalence of albuminuria decreased with higher caffeine intake tertiles (Tertile 1: 13%; Tertile 2: 11.9%; Tertile 3: 10.5%; P < 0.001). After adjusted potential confounders, the results of logistic regression indicated that a higher caffeine intake was associated with a decreased risk of albuminuria (OR = 0.903; 95% CI: 0.84, 0.97; P = 0.007), especially in females and the participants aged <60 years and chronic kidney disease stage II.

CONCLUSION

The present study first indicated an inverse correlation between caffeine intake and albuminuria, which further confirmed the potentially protective effects of caffeine on the kidney.

Early growth response factor 1 upregulates pro-fibrotic genes through activation of TGF-β1/Smad pathway via transcriptional regulation of PAR1 in high-glucose treated HK-2 cells

Tubulointerstitial fibrosis (TIF) makes a key role in diabetic kidney disease (DKD). In this study, we revealed that the expressions of Egr1 and protease-activated receptor 1 (PAR1) were increased in renal tissues of DKD rats. In vitro experiments demonstrated that both Egr1 overexpression and high glucose (HG) condition could promote the expressions of PAR1, fibronectin (FN) and collagen I (COL I). Furthermore, HG stimulation enhanced the binding capacity of Egr1 to PAR1 promoter. Both HG condition and Egr1 upregulation could increase, and thrombin inhibitor did not affect activity of TGF-β1/Smad pathway via PAR1. Collectively, Egr1 is involved in TIF of DKD partly through activating TGF-β1/Smad pathway via transcriptional regulation of PAR1 in HG treated HK-2 cells.

Systematic review of the effect of caffeine therapy effect on cardiometabolic markers in rat models of the metabolic syndrome

This systematic review aimed to study caffeine's effect on the cardiometabolic markers of the metabolic syndrome and to evaluate caffeine's application as a potential therapeutic agent in rat models. The systematic review was structured and synthesized according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Population, Intervention, comparator, outcome (PICO) framework. A literature search was conducted in PubMed, Scopus, and ScienceDirect to identify studies that used caffeine as an intervention in the rat model of the metabolic syndrome or any of its components compared with no treatment or controls. Studies that did not mention the disease manifestations from the experimental model used, without rat subjects, and which induced renovascular hypertension were excluded. The risk of bias in the included studies was assessed using the Systematic Review Center for Laboratory Animal Experimentation risk-of-bias tool. The main outcomes assessed were caffeine's effect on obesity, dyslipidemia, hepatic steatosis, hepatic dysfunction, insulin resistance, and hypertension. Out of 228 studies retrieved from the search, 18 met our inclusion criteria and were included in the systematic review. Caffeine was found to favorably reduce obesity and insulin resistance in the rat model of the metabolic syndrome. The effects of caffeine on dyslipidemia, hepatic steatosis, hepatic dysfunction, and hypertension remain inconclusive. The main limitations of this study are the heterogeneity of the included studies in terms of the disease model used, experimental duration, methods to assess outcomes, including studies that were only published in English, measurement units used, and graphical data without and numerical mention in the results section. As a result, quantitative synthesis was unfeasible, and a qualitative descriptive synthesis was conducted; this might have led to the under characterization of caffeine's effect on metabolic syndrome and its potential as an adjuvant therapy in metabolic syndrome. Caffeine has favorable effects on the metabolic syndrome, chiefly reducing obesity and insulin resistance. Future research is encouraged to delve into caffeine's effect on dyslipidemia, hepatic steatosis, hepatic dysfunction, and hypertension, which is necessary if caffeine is to be used as a potential clinical adjuvant therapy to treat the metabolic syndrome.

CYP1A2 Genetic Variation, Coffee Intake, and Kidney Dysfunction

IMPORTANCE

Caffeine is detoxified by cytochrome P450 1A2 (CYP1A2), and genetic variation in CYP1A2 impacts the rate of caffeine clearance. Factors that may modify the association between coffee intake and kidney disease remain unclear.

OBJECTIVE

To assess whether CYP1A2 genotype modifies the association between coffee intake and kidney dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

The Hypertension and Ambulatory Recording Venetia Study (HARVEST) was a prospective cohort study of individuals with stage 1 hypertension in Italy; HARVEST began on April 1, 1990, and follow-up is ongoing. The current study used data from April 1, 1990, to June 30, 2006, with follow-up of approximately 10 years. Blood pressure and biochemical data were collected monthly during the first 3 months, then every 6 months thereafter. Data were analyzed from January 2019 to March 2019. Participants were screened and recruited from general practice clinics. The present study included 1180 untreated participants aged 18 to 45 years with stage 1 hypertension; those with nephropathy, diabetes, urinary tract infection, and cardiovascular disease were excluded.

EXPOSURES

Coffee intake and CYP1A2 genotype rs762551 were exposures analyzed over a median follow-up of 7.5 (IQR, 3.1-10.9) years.

MAIN OUTCOMES AND MEASURES

Albuminuria (defined as an albumin level of ≥30 mg/24 h) and hyperfiltration (defined as an estimated glomerular filtration rate of ≥150 mL/min/1.73 m2) were the primary outcomes as indicators of kidney dysfunction.

RESULTS

Among 1180 participants, genotyping, lifestyle questionnaires, and urine analysis data were obtained from 604 individuals (438 [72.5%] male) with a mean (SD) age of 33.3 (8.5) years and a mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 25.4 (3.4). A total of 158 participants (26.2%) consumed less than 1 cup of coffee per day, 379 (62.7%) consumed 1 to 3 cups per day, and 67 (11.1%) consumed more than 3 cups per day. Genotype frequencies for rs762551 (260 participants [43.1%] with genotype AA, 247 participants [40.8%] with genotype AC, and 97 participants [16.1%] with genotype CC) did not differ between coffee intake categories. The level of risk of developing albuminuria, hyperfiltration, and hypertension, assessed by Cox regression and survival analyses, was not associated with coffee intake in the entire group or among fast metabolizers. The risks of albuminuria (adjusted hazard ratio [aHR], 2.74; 95% CI, 1.63-4.62; P < .001), hyperfiltration (aHR, 2.11; 95% CI, 1.17-3.80; P = .01), and hypertension (aHR, 2.81; 95% CI, 1.51-5.23; P = .001) increased significantly among slow metabolizers who consumed more than 3 cups per day.

CONCLUSIONS AND RELEVANCE

In this study, the risks of albuminuria, hyperfiltration, and hypertension increased with heavy coffee intake only among those with the AC and CC genotypes of CYP1A2 at rs762551 associated with slow caffeine metabolism, suggesting that caffeine may play a role in the development of kidney disease in susceptible individuals.

The magical smell and taste: Can coffee be good to patients with cardiometabolic disease?

Coffee is a beverage consumed globally. Although few studies have indicated adverse effects, it is typically a beneficial health-promoting agent in a range of diseases, including depression, diabetes, cardiovascular disease, and obesity. Coffee is rich in caffeine, antioxidants, and phenolic compounds, which can modulate the composition of the gut microbiota and mitigate both inflammation and oxidative stress, common features of the burden of lifestyle diseases. This review will discuss the possible benefits of coffee on complications present in patients with diabetes, cardiovascular disease and chronic kidney disease, outwith the social and emotional benefits attributed to caffeine consumption.

Subproteomic profiling from renal cortices in OLETF rats reveals mutations of multiple novel genes in diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is a serious threat to human health, but its pathogenesis is not fully understood. Otsuka Long-Evans Tokushima Fatty (OLETF) rats are very similar to human DN in many aspects such as pathological changes and processes, and are deemed to be an ideal rodent model.

OBJECTIVE

This study was aimed to explore the pathogenesis of DN by analyzing the protein expression profile from renal cortices in OLETF rats.

METHODS

Thirty-six-week-old diabetic OLETF rats and normal control Long-Evans Tokushima Otsuka (LETO) rats were nephrectomized, and the renal cortices were isolated. The proteins were separated by soluble and insoluble high-resolution subproteomics methods for the analysis and identification of differential proteins.

RESULTS

Thirty-six differentially expressed proteins were found. Among them, 11 proteins had different isoelectric points and molecular weights between OLETF and LETO rats. Further sequencing identified point mutations in genes encoding eight of these proteins, which are involved in many biological processes closely related to DN, including oxidative stress and inflammation. Five of these eight proteins have not been reported in DN.

CONCLUSION

This study reveals mutations of multiple novel genes in diabetic OLETF rats, providing some new potential targets for the pathogenesis of DN and helping to better understand the pathogenesis of DN.

Identification of a Novel Oligosaccharide in Maple Syrup as a Potential Alternative Saccharide for Diabetes Mellitus Patients

The incidence of diabetes mellitus (DM) is increasing rapidly and is associated with changes in dietary habits. Although restrictions in the use of sweeteners may prevent the development of DM, this might reduce the quality of life of patients with DM. Therefore, there has been a great deal of research into alternative sweeteners. In the search for such sweeteners, we analyzed the carbohydrate content of maple syrup and identified a novel oligosaccharide composed of fructose and glucose, linked at the C-4 of glucose and the C-6 of fructose. This oligosaccharide inhibited the release of fructose from sucrose by invertase (IC₅₀: 1.17 mmol/L) and the decomposition of maltose by α-(1-4) glucosidase (IC₅₀: 1.72 mmol/L). In addition, when orally administered together with sucrose to rats with DM, the subsequent plasma glucose concentrations were significantly lower than if the rats had been administered sucrose alone, without having any effect on the insulin concentration. These findings suggest that this novel oligosaccharide might represent a useful alternative sweetener for inclusion in the diet of patients with DM and may also have therapeutic benefits.

Chronic Consumption of a Commercial Energy Drink Reduces Blood Pressure in Normotensive Wild-Type Mice

Objective: Studies report that acute consumption of energy drinks transiently increases blood pressure (BP). However, few studies report the effect of chronic energy drink consumption on BP. In this study, we investigated the effects of long-term energy drink ingestion on BP in C57BL/6J normotensive wild-type mice.

Research Methods and Procedures: Groups of mice were randomized to no treatment (water) (Control group), or to Mother^™ provided as a decarbonated 30% (v/v) drinking solution (Energy Drink group), sugar-free Mother^™ at 30% (Sugar-free group), Coca Cola^™ at 30% (Coke group) for a total intervention period of 13 weeks.

Results: After 13 weeks of intervention, the control mice showed a modest increase in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) by 7.1 ± 8.8, 5.8 ± 9.4, and 6.3 ± 9.1 mmHg, respectively. However, the Energy Drink significantly decreased the DBP and MAP by 18.8 ± 9.9 and 15.3 ± 9.8 mmHg, respectively. Similarly, Sugar-free group mice showed significant decrease of the SBP, DBP, and MAP by 10.85 ± 5.6, 18.7 ± 6.7, and 15.6 ± 6.1 mmHg, respectively. The SBP, DBP, and MAP in Coke mice showed no significant changes. The estimated cumulative intake of caffeine, taurine, and vitamin B3 and B5 was significantly higher in the mice of Energy Drink and Sugar-free groups compared to the Control and Coke mice.

Conclusion: Collectively, the data suggest that the long-term chronic consumption of energy drinks may significantly lower the BP in normotensive mice through the actions of caffeine, taurine, and/or B-vitamins. The study findings do not support consideration of energy drinks for BP management, but rather demonstrate no long-term amplification of BP in normotensive preclinical models.