Capsaicin and Zinc Signalling Pathways as Promising Targets for Managing Insulin Resistance and Type 2 Diabetes

The role of Chinese herbal medicine in the regulation of oxidative stress in treating hypertension: from therapeutics to mechanisms

BACKGROUND

Although the pathogenesis of essential hypertension is not clear, a large number of studies have shown that oxidative stress plays an important role in the occurrence and development of hypertension and target organ damage.

PURPOSE

This paper systematically summarizes the relationship between oxidative stress and hypertension, and explores the potential mechanisms of Chinese herbal medicine (CHM) in the regulation of oxidative stress in hypertension, aiming to establish a scientific basis for the treatment of hypertension with CHM.

METHODS

To review the efficacy and mechanism by which CHM treat hypertension through targeting oxidative stress, data were searched from PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, the Chinese National Knowledge Infrastructure, the VIP Information Database, the Chinese Biomedical Literature Database, and the Wanfang Database from their inception up to January 2024. NPs were classified and summarized by their mechanisms of action.

RESULTS

In hypertension, the oxidative stress pathway of the body is abnormally activated, and the antioxidant system is inhibited, leading to the imbalance between the oxidative and antioxidative capacity. Meanwhile, excessive production of reactive oxygen species can lead to endothelial damage and vascular dysfunction, resulting in inflammation and immune response, thereby promoting the development of hypertension and damaging the heart, brain, kidneys, blood vessels, and other target organs. Numerous studies suggested that inhibiting oxidative stress may be the potential therapeutic target for hypertension. In recent years, the clinical advantages of traditional Chinese medicine (TCM) in the treatment of hypertension have gradually attracted attention. TCM, including active ingredients of CHM, single Chinese herb, TCM classic formula and traditional Chinese patent medicine, can not only reduce blood pressure, improve clinical symptoms, but also improve oxidative stress, thus extensively affect vascular endothelium, renin-angiotensin-aldosterone system, sympathetic nervous system, target organ damage, as well as insulin resistance, hyperlipidemia, hyperhomocysteinemia and other pathological mechanisms and hypertension related risk factors.

CONCLUSIONS

CHM display a beneficial multi-target, multi-component, overall and comprehensive regulation characteristics, and have potential value for clinical application in the treatment of hypertension by regulating the level of oxidative stress.

Association between dietary antioxidant levels and diabetes: a cross-sectional study

Background

The onset and progression of diabetes mellitus (DM) is strongly linked to oxidative stress. Previous studies have highlighted the protective effects of individual dietary antioxidants against diabetes. However, the relationship between a comprehensive combination of dietary antioxidants and diabetes has rarely been examined. Therefore, this study assessed the association between various dietary antioxidant intake levels and diabetes among US adults and further investigated potential associations using the Composite Dietary Antioxidant Index (CDAI).

Methods

The study employed data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2018 for cross-sectional analysis. Dietary information was obtained from two 24-h dietary recall interviews. The CDAI was calculated using intakes of six dietary antioxidants from the dietary information. Multifactorial logistic regression models were employed to investigate the association of different dietary antioxidants and CDAI with DM. The relationship between CDAI and DM was further explored using subgroup analyses and restricted cubic spline curves.

Results

A total of 7,982 subjects (mean age 47.32 ± 16.77 years; 48.50% male and 51.50% female) were included in this study. In the multivariate-adjusted single antioxidant model, vitamin C intake was significantly and negatively associated with diabetes prevalence (P for trend = 0.047), while zinc intake demonstrated a potential trend toward reduced diabetes risk (P for trend = 0.088). This association was similarly observed in the multivariate-adjusted model for the Composite Dietary Antioxidant Index (CDAI) in the female population (p = 0.046).

Conclusion

Intake of vitamin C was negatively associated with DM prevalence. Additionally, CDAI was found to reduce the risk of DM in the female population.

Ratiometric electrochemical aptasensor with strand displacement for insulin detection in blood samples

BACKGROUND

Diabetes patients suffer either from insulin deficiency or resistance with a high risk of severe long-term complications, thus the quantitative assessment of insulin level is highly desired for diabetes surveillance and management. Utilizing insulin-capturing aptamers may facilitate the development of affordable biosensors however, their rigid G-quadruplex structures impair conformational changes of the aptamers and diminish the sensor signals.

RESULTS

Here we report on a ratiometric, electrochemical insulin aptasensor which is achieved by hybridization of an insulin-capturing aptamer and a partially complementary ssDNA to break the rigid G-quadruplex structures. To improve the durability of the aptasensor, the capturing aptamer was immobilized on gold electrodes via two dithiol-phosphoramidite functional groups while methoxy-polyethylene glycol thiol was used as a blocking molecule. The exposure of the sensor to insulin-containing solutions induced the dissociation of the hybridized DNA accompanied by a conformational rearrangement of the capturing aptamer back into a G-quadruplex structure. The reliability of sensor readout was improved by the adoption of an AND logic gate utilizing anthraquinone and methylene blue redox probes associated to the aptamer and complementary strand, respectively. Our aptasensor possessed an improved detection limit of 0.15 nM in comparison to aptasensors without strand displacement.

SIGNIFICANCE

The sensor was adapted for detection in real blood and is ready for future PoC diagnostics. The capability of monitoring the insulin level in an affordably manner can improve the treatment for an increasing number of patients in developed and developing nations. The utilization of low-cost and versatile aptamer receptors together with the engineering of ratiometric electrochemical signal recording has the potential to considerably advance the current insulin detection technology toward multi-analyte diabetes sensors.

Zinc and Diabetes: A Connection between Micronutrient and Metabolism

Diabetes mellitus is a global health problem and a major contributor to mortality and morbidity. The management of this condition typically involves using oral antidiabetic medication, insulin, and appropriate dietary modifications, with a focus on macronutrient intake. However, several human studies have indicated that a deficiency in micronutrients, such as zinc, can be associated with insulin resistance as well as greater glucose intolerance. Zinc serves as a chemical messenger, acts as a cofactor to increase enzyme activity, and is involved in insulin formation, release, and storage. These diverse functions make zinc an important trace element for the regulation of blood glucose levels. Adequate zinc levels have also been shown to reduce the risk of developing diabetic complications. This review article explains the role of zinc in glucose metabolism and the effects of its inadequacy on the development, progression, and complications of diabetes mellitus. Furthermore, it describes the impact of zinc supplementation on preventing diabetes mellitus. The available information suggests that zinc has beneficial effects on the management of diabetic patients. Although additional large-scale randomized clinical trials are needed to establish zinc's clinical utility further, efforts should be made to increase awareness of its potential benefits on human health and disease.

Capsaicin: A chili pepper bioactive phytocompound with a potential role in suppressing cancer development and progression

Cancer profoundly influences morbidity and fatality rates worldwide. Patients often have dismal prognoses despite recent improvements in cancer therapy regimens. However, potent biomolecules derived from natural sources, including medicinal and dietary plants, contain biological and pharmacological properties to prevent and treat various human malignancies. Capsaicin is a bioactive phytocompound present in red hot chili peppers. Capsaicin has demonstrated many biological effects, including antioxidant, anti-inflammatory, antimicrobial, and anticarcinogenic capabilities. This review highlights the cellular and molecular pathways through which capsaicin exhibits antineoplastic activities. Our work also depicts the synergistic anticancer properties of capsaicin in conjunction with other natural bioactive components and approved anticancer drugs. Capsaicin inhibits proliferation in various cancerous cells, and its antineoplastic actions in numerous in vitro and in vivo carcinoma models impact oncogenesis, tumor-promoting and suppressor genes, and associated signaling pathways. Capsaicin alone or combined with other phytocompounds or approved antineoplastic drugs triggers cell cycle progression arrest, generating reactive oxygen species and disrupting mitochondrial membrane integrity, ultimately stimulating caspases and promoting death. Furthermore, capsaicin alone or in combination can promote apoptosis in carcinoma cells by enhancing the p53 and c-Myc gene expressions. In conclusion, capsaicin alone or in combination can have enormous potential for cancer prevention and intervention, but further high-quality studies are needed to firmly establish the clinical efficacy of this phytocompound.

Dysregulated miRNA-375, IL-17, TGF-β, and Microminerals Are Associated with Calpain-10 SNP 19 in Diabetic Patients: Correlation with Diabetic Nephropathy Stages

Zinc (Zn) and copper (Cu) have been shown to have the potential to improve glucose metabolism through interactions with cytokines and signaling events with multiple genes. miRNA-375 and the Calpin-10 gene are potential genetic biomarkers for the early prediction of diabetic nephropathy (DN). 128 healthy controls and 129 type 2 diabetic (T2DM) participants were matched for age and sex. Three subgroups were identified from the T2DM group: 39 patients had microalbuminuria, 41 had macroalbuminuria, and 49 patients had renal problems. Circulating miR-375 expression levels were measured via qPCR. Calpain-10 SNP 19 (rs3842570) genotyping was assessed with allele-specific PCR in all the included participants. Spectrophotometry was used to measure the concentrations of serum copper, zinc, and magnesium, while ELISA was used to measure the levels of TGF-β and IL-17. There was significant up-regulation in the expression of miR-375 and serum levels of TGF-β, IL-17, Cu, and the Cu/Zn ratio, whereas, in contrast to the control group, the Zn and Mg levels were lower in the T2DM group. The DN groups had significantly lower miR-375, TGF-β, IL-17, Mg, and Zn levels compared with the T2DM without nephropathy group. Furthermore, between TGF-β, IL-17, and miRNA-375, there were notable correlations. Calpain-10 SNP 19 genotype 22 and allele 2 were linked to a higher incidence of T2DM and DN. Significant TGF-β, Cu, Cu/Zn ratio, HbAc1, and creatinine levels, but insignificant miRNA-375 levels, were associated with genotype 22 of Calpain-10 SNP 19. interactions between the Calpain-10 SNP 19 genotype 22 and IL-17, TGF-β, mineral levels, and miRNA-375 might contribute to the aetiology of DN and T2DM and may have clinical implications for diagnosis and management.

Dietary Intake of Capsaicin and Its Association with Markers of Body Adiposity and Fatty Liver in a Mexican Adult Population of Tijuana

Background: Capsaicin (CAP) is the main chemical component responsible for the pungency (burning pain) of the chili plant (capsicum spp.), whose metabolic functions include energy balance and fatty acid oxidation. The aim of this study is to analyze the association of dietary capsaicin consumption with markers of adiposity and fatty liver in a Mexican adult population. Methods: This cross-sectional/analytical study recruited 221 subjects aged 18 to 65 years who were resident in the city of Tijuana, Baja California, Mexico. The daily CAP intake was analyzed through a validated chili/CAP consumption questionnaire. Anthropometric and biochemical measurements were performed following standardized protocols. Adjusted Pearson's correlations were applied to analyze the association of CAP with adiposity and fatty liver markers. Results: In this study, the daily average consumption of CAP was 152.44 mg. The dietary CAP consumption positively correlated with BMI (r = 0.179, p = 0.003), hip circumference (r = 0.176, p = 0.004) and body adiposity index (r = 0.181, p = 0.001. Likewise, the daily CAP intake positively correlated with hepatic steatosis index (r = 0.158, p = 0.004), fatty liver index (r = 0.141, p = 0.003) and lactate dehydrogenase (r = 0.194, p = 0.016) after statistical settings. Conclusions: The results of this study suggest positive associations between dietary CAP consumption and the markers of body adiposity and fatty liver in a Mexican adult population.

Relationship between Copper, Zinc, and Copper-to-Zinc Ratio in Hair and Severity of Coronary Artery Disease according to the SYNTAX Score

Coronary artery disease (CAD) continues to be a foremost contributor to global mortality, and the quest for modifiable risk factors could improve prophylactic strategies. Recent studies suggest a significant role of zinc (Zn) and copper (Cu) deficiency in atheromatous plaque formation. Furthermore, hair was previously described as a valuable source of information on elemental burden during the 6-8 week period before sampling. The aim of this study was to investigate the possibility of correlation between the extent of CAD evaluated with the SYNergy Between PCI With TAXUS and the Cardiac Surgery (SYNTAX) score with Cu and Zn content in hair samples, as well as with the Cu/Zn ratio in a cohort of 130 patients. Our findings describe a statistically significant inverse correlation between Cu content and the Cu/Zn ratio in hair samples and the extent of CAD. In contrast, no significant correlation was found between Zn content and the extent of CAD. Considering the scarcity of existing data on the subject, the analysis of hair samples could yield a novel insight into elemental deficiencies and their potential influence on CAD extent.

Diabetic cardiomyopathy - Zinc preventive and therapeutic potentials by its anti-oxidative stress and sensitizing insulin signaling pathways

Oxidative stress and insulin resistance are two key mechanisms for the development of diabetic cardiomyopathy (DCM, cardiac remodeling and dysfunction). In this review, we discussed how zinc and metallothionein (MT) protect the heart from type 1 or type 2 diabetes (T1D or T2D) through its anti-oxidative function and insulin-mediated PI3K/Akt signaling activation. Both T1D and T2D-induced DCM, shown by cardiac structural remodeling and dysfunction, in wild-type mice, but not in cardiomyocyte-specific overexpressing MT mice. In contrast, mice with global MT gene deletion were more susceptible to the development of DCM. When we used zinc to treat mice with either T1D or T2D, cardiac remodeling and dysfunction were significantly prevented along with increased cardiac MT expression. To support the role of zinc homeostasis in insulin signaling pathways, treatment of diabetic mice with zinc showed the preservation of phosphorylation levels of insulin-mediated glucose metabolism-related Akt2 and GSK-3β and even rescued cardiac pathogenesis induced by global deletion of Akt2 gene in a MT-dependent manner. These results suggest the protection by zinc from DCM is through both the induction of MT and sensitization of insulin signaling. Combined our own and other works, this review comprehensively summarized the roles of zinc homeostasis in the development and progression of DCM and its therapeutic implications. At the end, we provided pre-clinical and clinical evidence for the preventive and therapeutic potential of zinc supplementation through its anti-oxidative stress and sensitizing insulin signaling actions. Understanding the intricate connections between zinc and DCM provides insights for the future interventional approaches.