Caffeine modulates pharmacokinetic and pharmacodynamic profiles of pioglitazone in diabetic rats: Impact on therapeutics

Caffeine in Hepatocellular Carcinoma: Cellular Assays, Animal Experiments, and Epidemiological Investigation

The use of caffeine in treating various liver diseases has made substantial progress in the past decade owing to advances in science, technology, and medicine. However, whether caffeine has a preventive effect on hepatocellular carcinoma (HCC) and its mechanism are still worth further investigation. In this review, we summarize and analyze the efficacy and safety of caffeine in the prevention of HCC. We conducted a review of articles published in PubMed and Web of Science in the past 2 decades until December 6, 2023, which were searched for using the terms "Caffeine" and "Hepatocellular Carcinoma." Studies have found that coffee intake is negatively correlated with HCC risk, especially caffeinated coffee. Recent studies have found that caffeine has beneficial effects on liver health, decreasing levels of enzymes responsible for liver damaging and slowing the progression of hepatic fibrosis and cirrhosis. Caffeine also acts against liver fibrosis through adenosine receptors (ARs), which promote tissue remodeling by inducing fibrin and collagen production. Additionally, new studies have found that moderate consumption of caffeinated beverages can decrease various the levels of various collagens in patients with chronic hepatitis C. Furthermore, polyphenolic compounds in coffee can improve fat homeostasis, reduce oxidative stress, and prevent liver steatosis and fibrosis. Moreover, many in vitro studies have shown that caffeine can protect liver cells and inhibit the activation and proliferation of hepatic stellate cells. Taken together, we describe the benefits of caffeine for liver health and highlight its potential values as a drug to prevent various hepatic diseases. As a protective agent of liver inflammation, non-selective AR inhibitor caffeine can inhibit the growth of HCC cells by inhibiting adenosine and AR binding to initiate immune response, providing a basis for the future development of caffeine as an adjuvant drug against HCC.

Cardiorespiratory and Neuroprotective Effects of Caffeine in Neonate Animal Models

Caffeine is widely used to improve neonatal health in animals with low vitality. Due to its pharmacokinetics and pharmacodynamics, caffeine stimulates the cardiorespiratory system by antagonism of adenosine receptors and alteration in Ca+2 ion channel activity. Moreover, the availability of intracellular Ca+2 also has positive inotropic effects by increasing heart contractibility and by having a possible positive effect on neonate vitality. Nonetheless, since neonatal enzymatic and tissular systems are immature at birth, there is a controversy about whether caffeine is an effective therapy for newborns. This review aims to analyze the basic concepts of caffeine in neonatal animal models (rat and mouse pups, goat kids, lambs, and piglets), and it will discuss the neuroprotective effect and its physiological actions in reducing apnea in newborns.

Synergistic Effects of Caffeine in Combination with Conventional Drugs: Perspectives of a Drug That Never Ages

Plants have been known since ancient times for their healing properties, being used as preparations against human diseases of different etiologies. More recently, natural products have been studied and characterized, isolating the phytochemicals responsible for their bioactivity. Most certainly, there are currently numerous active compounds extracted from plants and used as drugs, dietary supplements, or sources of bioactive molecules that are useful in modern drug discovery. Furthermore, phytotherapeutics can modulate the clinical effects of co-administered conventional drugs. In the last few decades, the interest has increased even more in studying the positive synergistic effects between plant-derived bioactives and conventional drugs. Indeed, synergism is a process where multiple compounds act together to exert a merged effect that is greater than that of each of them summed together. The synergistic effects between phytotherapeutics and conventional drugs have been described in different therapeutic areas, and many drugs are based on synergistic interactions with plant derivatives. Among them, caffeine has shown positive synergistic effects with different conventional drugs. Indeed, in addition to their multiple pharmacological activities, a growing body of evidence highlights the synergistic effects of caffeine with different conventional drugs in various therapeutic fields. This review aims to provide an overview of the synergistic therapeutic effects of caffeine and conventional drugs, summarizing the progress reported to date.

Caffeine in liver diseases: Pharmacology and toxicology

We have previously shown that adenosine A1AR antagonists, adenosine A2aAR antagonists, and caffeine have significant inhibitory effects on the activation and proliferation of hepatic stellate cells in alcoholic liver fibrosis. Many recent studies have found that moderate coffee consumption is beneficial for various liver diseases. The main active ingredient of coffee is caffeine, which is a natural non-selective adenosine receptor antagonist. Moreover, numerous preclinical epidemiological studies and clinical trials have examined the association between frequent coffee consumption and the risk of developing different liver diseases. In this review, we summarize and analyze the prophylactic and therapeutic effects of caffeine on various liver diseases, with an emphasis on cellular assays, animal experiments, and clinical trials. To review the prevention and treatment effects of caffeine on different liver diseases, we searched all literature before 19 July 2022, using “caffeine” and “liver disease” as keywords from the PubMed and ScienceDirect databases. We found that moderate coffee consumption has beneficial effects on various liver diseases, possibly by inhibiting adenosine binding to its receptors. Caffeine is a potential drug for the prevention and treatment of various liver diseases.

Antidiabetic and antioxidant potential of Gardenia latifolia in type-2 diabetic rats fed with high-fat diet plus low-dose streptozotocin

OBJECTIVES

To test the antidiabetic potential of Gardenia latifolia extract (GLE) in rats with type 2 diabetes mellitus (T2DM) induced by a high-fat diet (HFD) + streptozotocin (STZ).

METHODS

The study was carried out in June 2021. Gardenia latifolia powdered leaves were subjected to Soxhlet extraction using ethanol. Male rats were administered a low dose-40 mg/kg STZ by intraperitoneal route following 2 weeks of HFD to induce type-2 diabetic rats (T2DR). Rats were randomized into 5 groups (n=6). Group 1 (normal control; 10 ml/kg normal saline); Group 2 (diabetic control: DC); Group 3 (standard; DR + metformin, 100 mg/kg per oral); Group 4 (DR + GLE 250 mg/kg); Group 5 (DR + GLE 500 mg/kg). The treatment period extended for 2 weeks. Body weight and fasting blood glucose were determined on days 0, 7, and 14. Fasting serum insulin (FSI) levels, fasting blood glucose (FBG), HOMA-IR, antioxidant enzyme level, Insulin tolerance test (ITT), and intraperitoneal glucose tolerance test (IPGTT) tests were estimated.

RESULTS

Gardenia latifolia extract exhibited a marked decrease (p<0.001) in fasting blood glucose levels. T2DR receiving a higher dose of GLE showed a greater improvement in metabolic indices (FSI, FBG, Homeostatic Model Assessment of insulin resistance). The ITT and IPGTT results demonstrated that GLE could significantly enhance insulin tolerance, glucose tolerance, and antioxidant enzyme levels in T2DR.

CONCLUSION

Gardenia latifolia can be an ideal medicinal plant candidate for treating T2DM, and it should be investigated further for its therapeutic potential.

The inhibitory effects of Dulaglutide on cellular senescence against high glucose in human retinal endothelial cells

Diabetic nephropathy is one of the most important chronic microvascular complications of diabetes, and its main feature is diabetic glomerulosclerosis. Endothelial sirtuin 1 (SIRT1) expression is related to aging, and reducing SIRT1 expression promotes endothelial cell aging. Plasminogen activator inhibitor-1 (PAI-1) can be synthesized in a variety of cells, such as endothelial cells. Dulaglutide is a glucagon-like peptide-1 (GLP-1) drug, and it can activate the GLP-1 receptor and promote the conversion of intracellular adenosine triphosphate to adenylate cyclase, thereby activating phosphokinase A, and regulating blood glucose levels effectively in the body. We analyzed the effects of Dulaglutide on inhibiting cell senescence by studying the effects of its different concentrations on telomerase activity and senescence-related gene expression. Our results suggest that Dulaglutide can alleviate high-glucose-induced oxidative stress in human retinal endothelial cells by restoring the expressions of SIRT1 and endothelial nitric oxide synthase (eNOS), thereby inhibiting the expression of PAI-1, and restoring telomerase activity. This suggests that the activity of retinal endothelial cells can be controlled by regulating the expression of SIRT1, so as to achieve the effect of treating diabetic retinopathy.

Bee venom ameliorates cardiac dysfunction in diabetic hyperlipidemic rats

High levels of blood glucose and lipids are well-known risk factors for heart diseases. Bee venom is a natural product that has a potent hypoglycemic, hypolipidemic, anti-inflammatory, and antioxidant effects. The current study aimed to determine the bee venom effects on cardiac dysfunction compared to combined therapy of metformin and atorvastatin in diabetic hyperlipidemic rats. The median lethal dose of bee venom was estimated, and then 50 adult male albino rats were categorized into five groups. One group was fed a standard diet and served as a negative control, while the other groups were given nicotinamide and streptozotocin injections to induce type 2 diabetes. After confirming diabetes, the rats were fed a high-fat diet for four weeks. The four groups were divided as follows: one group served as a positive control, whereas the other three groups were treated with bee venom (0.5 mg/kg), bee venom (1.23 mg/kg), and combined therapy of metformin (60 mg/kg) and atorvastatin (10 mg/kg), respectively, for four weeks. Upon termination of the experiment, blood samples and heart tissue were obtained. Administration of bee venom using both doses (0.5 and 1.23 mg/kg) and combined therapy of metformin and atorvastatin revealed a significant decrease in the concentrations of glucose, total cholesterol, triacylglycerol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, troponin I, creatine kinase, and lactate dehydrogenase activities. Moreover, a significant decrease had been detedcted in malondialdehyde, nuclear factor-kappa-β levels, and relative mRNA expression of vascular cell adhesion molecule-1 and galectin-3 in heart tissue compared to the positive control (P < 0.0001). Furthermore, there was a significant increase in bodyweight levels of insulin, high-density lipoprotein cholesterol, and total antioxidant capacity in heart tissue compared to the positive control (P < 0.0001). The results indicate that bee venom can ameliorate cardiac dysfunction through attenuating oxidative stress and downregulating the NF-κβ signaling pathway.

Modulatory Effects of Caffeine and Pentoxifylline on Aromatic Antibiotics: A Role for Hetero-Complex Formation

Antimicrobial resistance is a major healthcare threat globally. Xanthines, including caffeine and pentoxifylline, are attractive candidates for drug repurposing, given their well-established safety and pharmacological profiles. This study aimed to analyze potential interactions between xanthines and aromatic antibiotics (i.e., tetracycline and ciprofloxacin), and their impact on antibiotic antibacterial activity. UV-vis spectroscopy, statistical-thermodynamical modeling, and isothermal titration calorimetry were used to quantitatively evaluate xanthine-antibiotic interactions. The antibacterial profiles of xanthines, and xanthine-antibiotic mixtures, towards important human pathogens Staphylococcus aureus, Enterococcus faecium, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, and Enterobacter cloacae were examined. Caffeine and pentoxifylline directly interact with ciprofloxacin and tetracycline, with neighborhood association constant values of 15.8-45.6 M^-1 and enthalpy change values up to -4 kJ·M^-1. Caffeine, used in mixtures with tested antibiotics, enhanced their antibacterial activity in most pathogens tested. However, antagonistic effects of caffeine were also observed, but only with ciprofloxacin toward Gram-positive pathogens. Xanthines interact with aromatic antibiotics at the molecular and in vitro antibacterial activity level. Given considerable exposure to caffeine and pentoxifylline, these interactions might be relevant for the effectiveness of antibacterial pharmacotherapy, and may help to identify optimal treatment regimens in the era of multidrug resistance.