Coffee Consumption May Mitigate the Risk for Acute Kidney Injury: Results from the Atherosclerosis Risk in Communities (ARIC) Study

Metabolomic and proteomic analyses of renal function after liver transplantation

Background

Renal dysfunction is a common and serious complication in patients with end-stage liver diseases. While some patients recover renal function after liver transplantation (LT), others do not. Additionally, patients with normal kidney function (Normal-KF) before LT may develop post-transplant renal dysfunction. Early identification of patients at risk for impaired kidney function (Impaired-KF) post-LT is critical to improving outcomes. This study integrated metabolomic and proteomic analyses to investigate molecular profiles distinguishing Normal-KF from Impaired-KF post-LT.

Methods

Nine LT recipients were classified into Normal-KF (n = 5) and Impaired-KF (n = 4) groups. One additional recipient with pre-transplant renal function impairment who recovered renal function after LT, was analyzed separately. Serum samples were collected at 2- and 5-weeks post-LT. The metabolomic and proteomic profiles were assessed by untargeted liquid chromatography-tandem mass spectrometry.

Results

Metabolomic analysis identified 29 significantly altered metabolites between Normal-KF and Impaired-KF (fold change > 2, p < 0.05). Proteomic analysis revealed 45 differentially expressed proteins (fold change > 1.25, p < 0.05). For the recovered patient, the metabolomic profile closely resembled Normal-KF, whereas the proteomic profile remained aligned with Impaired-KF at both 14- and 35-days post-LT. From week 2 to week 5, both the metabolomic and proteomic profiles of the recovered patient showed trends toward the Normal-KF.

Conclusion

This study revealed distinct metabolomic and proteomic signatures associated with renal dysfunction post-LT. Proteomic profiles indicated a delayed recovery compared to metabolomic profiles, suggesting a dynamic and muti-layered renal recovery process. Further research is warranted to elucidate the functional implications of the differential proteins and metabolites for improved monitoring and therapeutic strategies.

Non-oliguric acute renal failure secondary to a potentially lethal dose of caffeine with acute intoxication: a case report

BACKGROUND

Recently, the incidence of caffeine intoxication has been on an upward trend, with severe outcomes. However, acute kidney injury (AKI) resulting from renal pathologies secondary to caffeine intoxication is rare, and the pathophysiological mechanisms underlying AKI are unclear.

CASE PRESENTATION

A female patient in her 20s ingested an over-the-counter drug containing caffeine. The patient was diagnosed with secondary non oliguric AKI caused by acute intoxication due to ingestion of a lethal dose of caffeine. On day 19 of hospitalization, a renal biopsy was performed to determine the etiology of her prolonged renal dysfunction. Light microscopy revealed normal glomeruli, mild inflammatory cell infiltration, and acute tubular damage. Myoglobin staining was positive within the tubules, with scattered myoglobin columns. Electron microscopy revealed loss of glomerular epithelial foot processes and inflated tubular mitochondria. After undergoing hemodialysis and continuous hemodiafiltration, the patient's overall condition stabilized. After a consultation with a psychiatrist, on her 34th day of hospitalization, she was discharged home.

CONCLUSIONS

Caffeine antagonizes adenosine receptors, stimulates ryanodine receptors, and elevates catecholamines. The onset of AKI is hypothesized to result from a combination of these mechanisms, resulting in tubular ischemia and injury, as well as renal artery constriction. The development of AKI was thought to be caused by the following factors: (1) disruption of the tubular oxygen supply-demand ratio and consequent ischemia due to adenosine receptor antagonism by caffeine, (2) tubular damage due to rhabdomyolysis and consequent ryanodine receptor stimulation, and (3) increased catecholamine levels and consequent renal artery constriction.

Neuroprotective effects of chlorogenic acid against oxidative stress in rats subjected to lithium-pilocarpine-induced status epilepticus

Epilepsy is a condition marked by sudden, self-sustained, and recurring brain events, showcasing unique electro-clinical and neuropathological phenomena that can alter the structure and functioning of the brain, resulting in diverse manifestations. Antiepileptic drugs (AEDs) can be very effective in 30% of patients in controlling seizures. Several factors contribute to this: drug resistance, individual variability, side effects, complexity of epilepsy, incomplete understanding, comorbidities, drug interactions, and no adherence to treatment. Therefore, research into new AEDs is important for several reasons such as improved efficacy, reduced side effects, expanded treatment options, treatment for drug-resistant epilepsy, improved safety profiles, targeted therapies, and innovation and progress. Animal models serve as crucial biological tools for comprehending neuronal damage and aiding in the discovery of more effective new AEDs. The utilization of antioxidant agents that act on the central nervous system may serve as a supplementary approach in the secondary prevention of epilepsy, both in laboratory animals and potentially in humans. Chlorogenic acid (CGA) is a significant compound, widely prevalent in numerous medicinal and food plants, exhibiting an extensive spectrum of biological activities such as neuroprotection, antioxidant, anti-inflammatory, and analgesic effects, among others. In this research, we assessed the neuroprotective effects of commercially available CGA in Wistar rats submitted to lithium-pilocarpine-induced status epilepticus (SE) model. After 72-h induction of SE, rats received thiopental and were treated for three consecutive days (1st, 2nd, and 3rd doses). Next, brains were collected and studied histologically for viable cells in the hippocampus with staining for cresyl-violet (Nissl staining) and for degenerating cells with Fluoro-Jade C (FJC) staining. Moreover, to evaluate oxidative stress, the presence of malondialdehyde (MDA) and superoxide dismutase (SOD) was quantified. Rats administered with CGA (30 mg/kg) demonstrated a significant decrease of 59% in the number of hippocampal cell loss in the CA3, and of 48% in the hilus layers after SE. A significant reduction of 75% in the cell loss in the CA3, shown by FJC+ staining, was also observed with the administration of CGA (30 mg/kg). Furthermore, significant decreases of 49% in MDA production and 72% in the activity of SOD were seen, when compared to animals subjected to SE that received vehicle. This study introduces a novel finding: the administration of CGA at a dosage of 30 mg/kg effectively reduced oxidative stress induced by lithium-pilocarpine, with its effects lasting until the peak of neural damage 72 h following the onset of SE. Overall, the research and development of new AEDs are essential for advancing epilepsy treatment, improving patient outcomes, and ultimately enhancing the quality of life for individuals living with epilepsy.

Caffeine and kidney function at two years in former extremely low gestational age neonates

BACKGROUND

Extremely low gestational age neonates (ELGANs) are at risk for chronic kidney disease. The long-term kidney effects of neonatal caffeine are unknown. We hypothesize that prolonged caffeine exposure will improve kidney function at 22-26 months.

METHODS

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial of neonates <28 weeks' gestation. Participants included if any kidney outcomes were collected at 22-26 months corrected age. Exposure was post-menstrual age of caffeine discontinuation.

PRIMARY OUTCOMES

'reduced eGFR' <90 ml/min/1.73 m2, 'albuminuria' (>30 mg albumin/g creatinine), or 'elevated blood pressure' (BP) >95th %tile. A general estimating equation logistic regression model stratified by bronchopulmonary dysplasia (BPD) status was used.

RESULTS

598 participants had at least one kidney metric at follow up. Within the whole cohort, postmenstrual age of caffeine discontinuation was not associated with any abnormal measures of kidney function at 2 years. In the stratified analysis, for each additional week of caffeine, the no BPD group had a 21% decreased adjusted odds of eGFR <90 ml/min/1.73m2 (aOR 0.78; CI 0.62-0.99) and the BPD group had a 15% increased adjusted odds of elevated BP (aOR 1.15; CI: 1.05-1.25).

CONCLUSIONS

Longer caffeine exposure during the neonatal period is associated with differential kidney outcomes at 22-26 months dependent on BPD status.

IMPACT

In participants born <28 weeks' gestation, discontinuation of caffeine at a later post menstrual age was not associated with abnormal kidney outcomes at 22-26 months corrected age. When assessed at 2 years of age, later discontinuation of caffeine in children born <28 weeks' gestation was associated with a greater risk of reduced eGFR in those without a history of BPD and an increased odds of hypertension in those with a history of BPD. More work is necessary to understand the long-term impact of caffeine on the developing kidney.

Inflammatory Bowel Disease With Chronic Kidney Disease and Acute Kidney Injury

INTRODUCTION

It remains unclear whether inflammatory bowel disease is associated with long-term risk of chronic kidney disease (CKD) and acute kidney injury (AKI) in the general population.

METHODS

A total of 417,302 participants, including 2,940 patients with ulcerative colitis and 1,261 patients with Crohn's disease, without previous CKD and AKI at baseline (2006-2010) from the UK Biobank were included. The study outcomes included incident CKD and AKI, ascertained by self-report data and data linkage with primary care, hospital admissions, and death registry records. Analysis was conducted in 2022.

RESULTS

During a median follow-up of 12.5 years, 13,564 and 14,331 participants developed CKD and AKI, respectively. Compared with the hazard ratio for non-inflammatory bowel diseases, the hazard ratios for CKD and AKI related to inflammatory bowel diseases were 1.57 (95% CI=1.37, 1.79) and 1.96 (95% CI=1.74, 2.20) after adjustments for age, sex, and race and were 1.32 (95% CI=1.15, 1.51) and 1.70 (95% CI=1.51, 1.91) after further adjustments for biological, behavioral, and socioeconomic factors in addition to mental health and self-rated health. Similar results were found for patients with Crohn's disease (adjusted hazard ratio=1.38 (95% CI=1.09, 1.75) for CKD and 1.62 [95% CI=1.30, 2.02] for AKI) and those with ulcerative colitis (adjusted hazard ratio=1.29 (95% CI=1.09, 1.51) for CKD and 1.71 [95% CI=1.49, 1.97] for AKI) in the fully adjusted models. Genetic risks of kidney diseases did not significantly affect the association of inflammatory bowel disease with incident CKD and AKI (both p-interactions>0.05). The association between inflammatory bowel disease and the risk of incident CKD (p-interaction=0.010) and AKI (p-interaction<0.001) were stronger in younger participants than in older participants.

CONCLUSIONS

Inflammatory bowel disease was associated with higher risks for CKD and AKI, independent of genetic risks of kidney diseases.

Current therapeutic targets and multifaceted physiological impacts of caffeine

Caffeine, which shares consubstantial structural similarity with purine adenosine, has been demonstrated as a nonselective adenosine receptor antagonist for eliciting most of the biological functions at physiologically relevant dosages. Accumulating evidence supports caffeine's beneficial effects against different disorders, such as total cardiovascular diseases and type 2 diabetes. Conversely, paradoxical effects are also linked to caffeine ingestion in humans including hypertension-hypotension and tachycardia-bradycardia. These observations suggest the association of caffeine action with its ingested concentration and/or concurrent interaction with preferential molecular targets to direct explicit events in the human body. Thus, a coherent analysis of the functional targets of caffeine, relevant to normal physiology, and disease pathophysiology, is required to understand the pharmacology of caffeine. This review provides a broad overview of the experimentally validated targets of caffeine, particularly those of therapeutic interest, and the impacts of caffeine on organ-specific physiology and pathophysiology. Overall, the available empirical and epidemiological evidence supports the dose-dependent functional activities of caffeine and advocates for further studies to get insights into the caffeine-induced changes under specific conditions, such as asthma, DNA repair, and cancer, in view of its therapeutic applications.

Long-term outcomes from the UK Biobank on the impact of coffee on cardiovascular disease, arrhythmias, and mortality: Does the future hold coffee prescriptions?

INTRODUCTION

Coffee is a popular beverage and the most used psychostimulant worldwide. Habitual coffee consumption has been linked to a growing list of health benefits; however, coffee consumption has been a source of longstanding debate. Recent observational studies have challenged the misconception of caffeine and reported the safety and beneficial effects of coffee intake on a range of cardiovascular (CV) conditions, including coronary artery disease, arrhythmias, heart failure, and stroke, leading to a decreased risk of CVD, all-cause and CVD mortality, and being associated with favorable CV outcomes. However, the mechanisms underlying the protective effects of caffeine remain speculative, and there is a lack of dedicated studies aimed at addressing the impact of different coffee subtypes on clinical outcomes such as CVD, arrhythmia, and mortality. Study and Results: The study included 449,563 UK Biobank participants, free of cardiovascular problems at enrollment (median age 58 years; 55.3% females). The median follow-up time was 12.5 years. Drinking 4 to 5 cups/day of ground (HR 0.83; 95% CI [0.76-0.91];  P  < .0001) or 2 to 3 cups/day of instant (HR, 0.88; 95% CI [0.85-0.92];  P  < .0001) coffee (but not decaffeinated coffee) was associated with a significant reduction in incident arrhythmia, including AF. Habitual coffee intake of up to 5 cups/day was associated with significant reductions in the risk of incident CVD, CHD (HR 0.89, CI [0.86-0.91], P < 0.0001), CCF (HR 0.83, CI [0.79-0.87], P < 0.0001), and ischemic stroke (HR 0.84, CI [0.78-0.90], P < 0.0001). Coffee consumption led to significant reductions in all-cause mortality (HR 0.86, CI [0.83-0.89], P < 0.0001) and CV mortality (HR 0.82, CI [0.74-0.90], P < 0.0001). Consumption of ground coffee at all levels significantly reduced the risk of all-cause and CV mortality. There was no significant difference in the incidence of CVD among all intake categories or across all coffee subtypes.

LESSONS LEARNED

The results from the UK Biobank indicate that mild-to-moderate consumption of all types of coffee is linked to improved CV outcomes and a lower risk of cardiovascular disease and death, with caffeinated coffee significantly reducing the risk of arrhythmias, including AF. Daily coffee intake should not be discouraged by physicians, even in the presence of a newly developed cardiovascular disease. Whether coffee will be prescribed in the future to prevent CVD and improve cardiovascular health depends on further evaluation of the physiological mechanisms and elucidation of the specific protective effects of coffee consumption.

Tea Consumption and New-Onset Acute Kidney Injury: The Effects of Milk or Sweeteners Addition and Caffeine/Coffee

Aims: To explore the relationship between tea consumption and the risk of incident acute kidney injury (AKI) and examine the effects of coffee consumption, genetic variation in caffeine metabolism, and the use of tea additives (milk and sweeteners) on this association. Methods: Using data from the UK Biobank, 498,621 participants who were free of AKI and had information on tea intake were included. Black tea is the main type consumed in this population. Dietary information was collected from standardized and validated Food-Frequency Questionnaire (FFQ). Outcome was incident AKI, determined via primary care data, hospital inpatient data, death register records, or self-reported data at follow-up visits. Results: After a median follow-up period of 12.0 years, 21,202 participants occurred AKI. Overall, there was a reversed J-shaped relation between tea consumption and incident AKI, with an inflection point at 3.5 cup/d (p for nonlinearity < 0.001). The relation was similar among participants with different genetically predicted caffeine metabolism (p-interaction = 0.684), while a more obvious positive association was found between heavy tea consumption and AKI when more coffee was consumed (p-interaction < 0.001). Meanwhile, there was a reversed J-shaped relationship for drinking tea with neither milk nor sweeteners, and a L-shaped association for drinking tea with milk (with or without sweeteners) with incident AKI. However, no significant association was found between drinking tea with sweeteners only and incident AKI. Conclusions: There was a reversed J-shaped relation between tea consumption and incident AKI, suggesting that light to moderate tea consumption, especially adding milk, can be part of a healthy diet.

The Epigenetic Effects of Coffee

In this review, we discuss the recent knowledge regarding the epigenetic effects of coffee extract and the three essential active ingredients in coffee (caffeine, chlorogenic acid, and caffeic acid). As a popular beverage, coffee has many active ingredients which have a variety of biological functions such as insulin sensitization, improvement of sugar metabolism, antidiabetic properties, and liver protection. However, recent researches have shown that coffee is not only beneficial for human, but also bad, which may be due to its complex components. Studies suggest that coffee extract and its components can potentially impact gene expression via alteration of DNA methylation, histone modifications, and ncRNA expression; thus, exert long lasting impacts on the epigenome. More importantly, coffee consumption during pregnancy has been linked to multiple negative effects on offspring due to epigenetic modifications; on the other hand, it has also been linked to improvements in many diseases, including cancer. Therefore, understanding more about the epigenetic effects associated with coffee components is crucial to finding ways for improving human health.

Mitigative effect of caffeine against diclofenac-induced hepato-renal damage and chromosomal aberrations in male albino rats

BACKGROUND

Among the most commonly consumed non-steroidal anti-inflammatory drugs (NSAID) is Diclofenac (Dic), especially in low-income countries due to its high efficiency and affordable price. However, the continuous administration of Diclofenac may induce toxic effects on various body organs including the liver and kidney. Caffeine (Caf) (1,3,7-trimethylxanthine) is a pharmacologically active alkaloid type with antioxidant and anti-inflammatory actions.

AIM

The current study aims to evaluate the ameliorative effect of Caffeine against Dic-induced hepato-renal toxicity and damage.

METHODS

Twenty-four male albino rats type were assigned randomly into four groups (n = 6): (Group 1): Control group, (Group 2): Six male rats were exposed to Dic 10 mg/kg intraperitoneally (I.P) for 28 days, (Group 3): Six male rats were exposed to Caf (15 mg/kg orally) for 28 days; (Groups 4): Six male rats were exposed to Dic (10 mg/kg, i.p) + Caf (15 mg/kg, orally) for 28 days. Histopathological study and various biological parameters were estimated among the four groups including hemoglobin (Hb%) red blood cells (RBCs), Hematocrit (HT%), total leucocyte count (WBCs), lipid peroxidation (LPO), glutathione peroxidase (GPx), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, tumor necrosis factor-α (TNF-α), and nitric oxide (NO).

RESULTS

The administration of Diclofenac resulted in significant deteriorations in the histopathological findings and estimated biological parameters. Whereas, daily Caffeine administration ameliorated Diclofenac-induced toxicity in the kidney and liver by three mechanisms including antioxidant, anti-inflammatory, and DNA damage inhibition.

CONCLUSION

The current study demonstrated the promising ameliorative and protective effects of Caffeine against Diclofenac-induced hepatic and renal injury.