Cigarette smoking reduced renal function deterioration in hypertensive patients may be mediated by elevated homocysteine

Metabolomic Insights into Smoking-Induced Metabolic Dysfunctions: A Comprehensive Analysis of Lipid and Amino Acid Metabolomes

BACKGROUND

Cigarette smoking is a leading cause of preventable mortality, largely due to the absence of effective, non-invasive biomarkers for early disease detection. Profiling serum metabolomics to identify metabolic changes holds the potential to accelerate the detection process and identify individuals at risk of developing smoking-related diseases.

OBJECTIVES

This study investigated the biochemical and metabolomic changes induced by nicotine exposure, with a focus on disruptions in amino acid, lipid, and carbohydrate metabolism.

METHODS

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed to observe significant disruptions in lipid and amino acid metabolism, along with alterations in key metabolic pathways. A total of 400 smokers and 100 non-smokers were included to evaluate the biomarkers related to insulin resistance, blood lipid profile, inflammation, and kidney and liver function.

RESULTS

The results demonstrated significantly elevated (p < 0.05) levels of glycemic markers in smokers, including fasting blood glucose; glycated hemoglobin (HbA1c); and inflammatory markers such as interleukin-6 (IL-6) and C-reactive protein (CRP). Smokers also exhibited dyslipidemia, with increased total cholesterol (154.888 ± 35.565) and LDL levels (117.545 ± 24.138). Impaired liver and kidney function was evident, with significantly higher levels (p < 0.05) of AST, ALP, ALT, blood urea nitrogen, and creatinine in smokers. A total of 930 metabolites were identified, of which 343 exhibited significant alterations (p < 0.05) in smokers compared to non-smokers. Among these, 116 metabolites were upregulated, and 127 were downregulated. Metabolomic pathway analysis revealed eight significant pathways. The study also identified three lipid metabolites specific to smokers and seven unique to non-smokers. Through LC-MS/MS, fragments of phenylalanine, tryptophan, valine, histidine, carnitine, and sphinganine were detected. Several lipidomic changes associated with insulin resistance and cardiovascular complications were observed. Cadmium (Cd) levels were higher in smokers than non-smokers (1.264 ppb vs. 0.624 ppb) and showed a strong negative correlation (R2 = 0.8061, p-value = 0.015) with serum zinc (Zn), likely due to Cd displacing Zn in proteins and causing nephrotoxicity through accumulation.

CONCLUSIONS

This study highlights the distinct metabolic disruptions caused by smoking that could serve as potential biomarkers for the early detection of metabolic diseases. It emphasizes the importance of metabolomics in identifying systemic indicators of smoking-related health issues, providing new opportunities for preventive and therapeutic interventions.

Smoking and Health Profiles of Hypertensive Patients with COVID-19: An Exploratory Study of Key Physiological Markers

Background/Objectives: Smoking and hypertension are major contributors to cardiovascular diseases, with smoker hypertensives typically presenting with exacerbated health risks. These factors are associated with COVID-19 aggravation, but their cumulative impact in the context of this disease remains understudied. Our hypothesis was that hypertensive smokers display a more vulnerable health profile (versus non-smokers) upon hospital admission for COVID-19. Methods: This exploratory observational study compared the clinical profiles of hypertensive COVID-19 patients depending on their smoking status. Focusing on key cardiometabolic, blood, renal, hepatic, and inflammatory markers, this investigation included 100 hypertensive COVID-19 patients (50 smokers and 50 non-smokers) aged 50 and above. Logistic regression and Spearman's correlations were used to identify significant predictors and relationships among variables. Results: Hypertensive smokers with COVID-19 were significantly more likely to exhibit higher heart rate (p = 0.047), left atrial size (p = 0.013) and diameter (p = 0.040), left ventricular end-systolic volume (p = 0.036), and interventricular septal thickness (p ≤ 0.001). These patients were also much more prone to display elevated CRP (p = 0.035) and hemoglobin (p = 0.011). The renal profiles of the smokers and non-smokers differed, with the smokers showing a significantly greater likelihood to have high serum urea (p = 0.036), but normal-to-low serum potassium (p = 0.011) and sodium (p ≤ 0.001). Their lipid profile was less favorable, with higher triglycerides (p ≤ 0.001), but lower HDL (p = 0.008). The strongest predictors of smoking status were interventricular septal thickness, triglycerides, and serum sodium. Conclusions: Hypertensive smokers admitted to the hospital with COVID-19 tend to exhibit a more adverse clinical profile, particularly in terms of cardiovascular remodeling, lipid imbalances, renal profile, and inflammation. These findings suggest that smoking exacerbates the effects of hypertension in the context of COVID-19, highlighting the need for more aggressive monitoring and management in this patient group.

Anti-atherogenic role of green tea (Camellia sinensis) in South Indian smokers

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea (Camellia sinensis) is a popular beverage consumed all over the world due to its health benefits. Many of these beneficial effects of green tea are attributed to polyphenols, particularly catechins.

AIM OF THE STUDY

The present study focuses on underlying anti-platelet aggregation, anti-thrombotic, and anti-lipidemic molecular mechanisms of green tea in South Indian smokers.

MATERIALS AND METHODS

We selected 120 South Indian male volunteers for this study to collect the blood and categorised them into four groups; control group individuals (Controls), smokers, healthy control individuals consuming green tea, and smokers consuming green tea. Smokers group subjects have been smoking an average 16-18 cigarettes per day for the last 7 years or more. The subjects (green tea consumed groups) consumed 100 mL of green tea each time, thrice a day for a one-year period.

RESULTS

LC-MS analysis revealed the presence of multiple phytocompounds along with catechins in green tea extract. Increased plasma lipid peroxidation (LPO), protein carbonyls, cholesterol, triglycerides, and LDL-cholesterol with decreased HDL-cholesterol levels were observed in smokers compared to the control group and the consumption of green tea showed beneficial effect. Furthermore, docking studies revealed that natural compounds of green tea had high binding capacity with 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) when compared to their positive controls, whereas (-) epigallocatechin-3-gallate (EGCG) and (-) epicatechin-gallate (ECG) had high binding capacity with sterol regulatory element-binding transcription factor 1 (SREBP1c). Further, our ex vivo studies showed that green tea extract (GTE) significantly inhibited platelet aggregation and increased thrombolytic activity in a dose dependent manner.

CONCLUSION

In conclusion, in smokers, catechins synergistically lowered oxidative stress, platelet aggregation and modified the aberrant lipid profile. Furthermore, molecular docking studies supported green tea catechins' antihyperlipidemic efficacy through strong inhibitory activity on HMG-CoA reductase and SREBP1c. The mitigating effects of green tea on cardiovascular disease risk factors in smokers that have been reported can be attributed majorly to catechins or to their synergistic effects.

Prophylactic role of olive fruit extract against cigarette smoke-induced oxidative stress in Sprague-Dawley rats

Cigarette smoke exposure increases the production of free radicals leading to initiation of several pathological conditions by triggering the oxidative stress and inflammatory cascade. Olive fruit owing to its unique phytochemical composition possesses antioxidant, immune modulatory, and anti-inflammatory potential. Considering the compositional alterations in olive fruits during ripening, the current experimental trail was designed to investigate the prophylactic role of green and black olives against the oxidative stress induced by cigarette smoke exposure in rats. Purposely, rats were divided into five different groups: NC (negative control; normal diet), PC [positive control; normal diet + smoke exposure (SE)], drug (normal diet + SE + citalopram), GO (normal diet + SE + green olive extract), and BO (normal diet + SE + black olive extract). Rats of all groups were exposed to cigarette smoke except "NC" and were sacrificed for collection of blood and organs after 28 days of experimental trial. The percent reduction in total oxidative stress by citalopram and green and black olive extracts in serum was 29.72, 58.69, and 57.97%, respectively, while the total antioxidant capacity increased by 30.78, 53.94, and 43.98%, accordingly in comparison to PC. Moreover, malondialdehyde (MDA) was reduced by 29.63, 42.59, and 45.70% in drug, GO, and BO groups, respectively. Likewise, green and black olive extracts reduced the leakage of hepatic enzymes in sera, alkaline phosphatase (ALP) by 23.44 and 25.80% and 35.62 and 37.61%, alanine transaminase (ALT) by 42.68 and 24.39% and 51.04 and 35.41%, and aspartate transaminase (AST) by 31.51 and 16.07% and 40.50 and 27.09% from PC and drug group, respectively. Additionally, olive extracts also maintained the antioxidant pool, i.e., superoxide dismutase, catalase, and glutathione in serum. Furthermore, histological examination revealed that olive extracts prevented the cigarette smoke-induced necrosis, pyknotic alterations, and congestion in the lung, hepatic, and renal parenchyma. Besides, gene expression analysis revealed that olive extracts and citalopram decreased the brain and lung damage caused by stress-induced upregulation of NRF-2 and MAPK signaling pathways. Hence, it can be concluded that olives (both green and black) can act as promising antioxidant in alleviating the cigarette smoke-induced oxidative stress.

Effect of hyperhomocysteinemia on a murine model of smoke-induced pulmonary emphysema

Hyperhomocysteinemia was reported to enhance endoplasmic reticulum (ER) stress and subsequent apoptosis in several cells. However, the precise mechanisms of smoking susceptibility associated with hyperhomocysteinemia has not been fully elucidated. This study included 7- to 9-week-old C57BL6 male mice induced with hyperhomocysteinemia and were exposed to cigarette smoke (CS). A549 cells (human alveolar epithelial cell line) were cultured with homocysteine and were exposed to cigarette smoke extract (CSE) to observe cell viability and expression of proteins related to the ER stress. After 6 months of CS exposure, pulmonary emphysema was more severely induced in the group under the condition of hyperhomocysteinemia compared to that in the control group. The apoptotic A549 cells increased as homocysteine concentration increased and that was enhanced by CSE. Protein expression levels of ER stress markers were significantly increased after simultaneous stimulation. Notably, vitamin B12 and folate supplementation improved ER stress after simultaneous stimulation of A549 cells. In this study, we showed that hyperhomocysteinemia exacerbates CS exposure-induced emphysema in mice, suggesting that hyperhomocysteinemia and CS stimulation enhance ER stress and subsequent induced apoptosis in alveolar epithelial cells. It was suggested that there is a synergistic effect between homocysteine and CS.

Continuous Positive Airway Pressure Improves Renal Function in Obese Patients With Obstructive Sleep Apnea Syndrome

Background: Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for cardiovascular morbidity and mortality, and it has a detrimental effect on renal function. Obesity is the major risk factor for OSAS, and represents a risk factor for chronic kidney disease. Continuous positive airway pressure (CPAP) is the suggested therapy for moderate-to-severe OSAS. We designed this study to evaluate the effect of CPAP on estimated glomerular filtration rate (e-GFR) in a cohort of obese patients with moderate-to-severe OSAS and normal renal function. Methods: We enrolled 198 obese subjects, divided into two groups (OSAS+ and OSAS-), on the basis of cardiorespiratory monitoring; mild OSAS patients (n = 33) were excluded from the study, thus the analyses were conducted on 165 patients. Comparisons between groups were made by Student t-test or χ² test as appropriate. Linear regression analyses were used to assess the relationship between baseline e-GFR and different covariates and, in the OSAS+ group, between Δe-GFR and different covariates. A multivariate regression analysis was performed to determinate the independent predictor of the Δe-GFR. Results: OSAS+ subjects showed significantly increased values of systolic blood pressure, HOMA, pulse wave velocity, high-sensitivity C reactive protein and uric acid compared with OSAS- group. OSAS+ group showed significantly lower values of e-GFR and increased values of microalbuminuria. At linear regression analysis e-GFR resulted significantly and inversely related to AHI in the whole study population and in the two groups. After 6 months of CPAP therapy, OSAS+ subjects showed an improvement in respiratory parameters, as well as a significant increase in e-GFR values (104.2 + 19.0 vs. 84.0 + 13.1 ml/min/1.73 m², P < 0.0001). At multiple regression analysis, Δ apnea/hypopnea index (AHIa) resulted the main independent predictor of Δe-GFR explaining 22% of its variation. Conclusions: Obese OSAS patients show significantly lower values of e-GFR, even if in the normal range, compared with obese non-OSAS subjects. After 6 months of CPAP, e-GFR significantly improved (+20 ml/min/1.73 m²) and ΔAHIa resulted the most important independent predictor of Δe-GFR.

Associations between hyperhomocysteinemia and the presence and severity of acute coronary syndrome in young adults ≤ 35 years of age

Background

The prevalence of acute coronary syndrome (ACS) continues to increase among young Chinese adults. Homocysteine (HCY) has been suggested as a promoter of atherosclerosis leading to coronary artery disease (CAD). Yet, it remains uncertain whether HCY is associated with the ACS and the severity of coronary artery stenosis in young adults.

Methods

Young patients (18–35 years of age) diagnosed with ACS who underwent coronary angiography (CAG) at Anzhen Hospital between January 2013 and June 2019 were assigned to the ACS group. As confirmed by CAG during the same period, an equivalent age-matched population without CAD was assigned to the non-CAD group. A serum HCY level > 15 µmol/L was defined as hyperhomocysteinemia (HHCY). The Gensini score assessed the severity of coronary artery stenosis.

Results

A total of 1103 participants, including 828 ACS patients and 275 non-CAD subjects, were enrolled in this study. Young ACS patients had higher level of serum HCY and greater prevalence of HHCY compared with non-CAD subjects [for HCY, 16.55 (11.93–29.68) vs 12.50 (9.71–17.42), P < 0.001; for HHCY prevalence, 62.08% vs 26.18%, P < 0.001]. Multivariate logistic regression analysis with the stepwise method indicated that HHCY was an independent predictor associated with the presence of ACS, after adjusting for traditional confounders (OR, 4.561; 95% CI, 3.288–6.327; P < 0.001). Moreover, young ACS patients with HHCY had increased prevalence of ST-segment elevation myocardial infarction (STEMI) (P = 0.041), multi-vessel disease (P = 0.036), and decreased value of left ventricular ejection fraction (LVEF) (P = 0.01). Also, the HCY level was significantly correlated with Gensini Score in ACS patients (r = 0.142, P < 0.001).

Conclusion

HHCY is significantly associated with the presence of ACS and the severity of coronary artery stenosis in young adults ≤ 35 years of age.

Polymorphism of MTHFR C677T Gene and the Associations with the Severity of Essential Hypertension in Northern Chinese Population

Objective

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of homocysteine metabolism and is closely related to the occurrence of hypertension. The aim of this study was to investigate the polymorphism of the (MTHFR) C677T and the factors influencing the severity of hypertension. Material and Methods. A total of 985 subjects were enrolled to analyze the polymorphisms of the MTHFR C677T gene by polymerase chain reaction (PCR). 306 people with essential hypertension were selected from 985 subjects to estimate the severity of hypertension by the ordinal multivariate logistical regression model.

Results

The frequencies of CC, CT, and TT genotypes were 19.5%, 49.95%, and 30.46%, respectively. The allelic frequency of mutant T was 55.43%. The plasma homocysteine level of the homozygous TT in individuals was significantly higher than in those with CC or CT (P < 0.01). MTHFR677CT genotype, MTHFR677TT genotype, smoking, family history of hypertension, Hcy, and triglycerides (TG) were independent risk factors for the severity of hypertension (OR = 2.29, 2.24, 2.04, 1.81, 1.04, 1.26).

Conclusion

MTHFR gene, smoking, family history of hypertension, Hcy, and triglycerides could be important genetic and high-risk factors of the development of severe hypertension in northern Chinese. These factors will contribute to the identification of high-risk populations of hypertension and facilitate the development of hypertension control strategies.