Acute Exposure to Cigarette Smoking Followed by Myocardial Infarction Aggravates Renal Damage in an In Vivo Mouse Model

Serum hydroxycotinine was associated with chronic kidney disease (CKD): a cross-sectional study based on NHANES

OBJECTIVE

Smoking has been suggested as a modifiable and cardiovascular risk factor for chronic kidney disease (CKD). Although long-term smoking has been associated with CKD, the potential relationship between its metabolite hydroxycotinine and CKD has not been clarified.

METHODS

A total of 8,544 participants aged 20 years and above from the National Health and Nutrition Examination Survey (NHANES) 2017 - March 2020 were enrolled in our study. CKD was defined by estimated glomerular filtration rate (eGFR) < 60 mL/(min*1.73 m2). Serum hydroxycotinine was measured by an isotope-dilution high-performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometric (ID HPLC-APCI MS/MS) method with a lower limit of detections (LLOD) at 0.015 ng/mL. The non-linear relationship was explored with restricted cubic splines (RCS). Pearson's correlation coefficient and a multivariate logistic regression model were used for correlation analysis.

RESULTS

Serum hydroxycotinine and eGFR were negatively correlated in both non-CKD group (r= -0.05, p < 0.001) and CKD group (r= -0.04, p < 0.001). After serum hydoxycotinine dichotominzed with LLOD, serum hydroxycotinine ≥ 0.015 ng/mL was negatively correlated with eGFR not only in non-CKD group (r = -0.05, p < 0.001) but also in CKD group (r = -0.09, p < 0.001). After adjusting for comprehensive confounders, results from the multivariate logistic regression analysis showed that participants with serum hydroxycotinine ≥ 0.015 ng/mL had increased odds of CKD (OR = 1.505, p < 0.001).

CONCLUSIONS

Serum hydroxycotinine might be positively associated with CKD. Further study is warranted to find the right concentration of hydroxycotinine to measure the CKD.

Sexual dimorphism in acute myocardial infarction-induced acute kidney injury: cardiorenal deteriorating effects of ovariectomy in premenopausal female mice

Acute kidney injury (AKI) is a common complication of cardiovascular diseases (CVDs) in both males and females, increasing mortality rate substantially. Premenopausal females appear to be more protected, suggesting a potential protective role of female sex hormones. Here, we tested the hypothesis that ovariectomy (OVX) eliminates the beneficial effect of female sex on renal protection following acute myocardial infarction (MI). Seven days post-MI, both sexes exhibited worsened kidney function and a substantial decrease in total kidney NAD levels. Unlike MI female mice, MI males showed exacerbated morphological alterations with increased proinflammatory, proapoptotic, and profibrotic biomarkers. The expression of NAD+ biosynthetic enzymes NAMPT and NMRK-1 was increased in MI females only, while males showed a substantial increase in NAD+ consuming enzyme PARP-1. OVX did not eliminate the female-sex protection of glomerular morphology but was associated with swelling of proximal convoluted tubules with MI as in males. With OVX, MI females had enhanced proinflammatory cytokine release, and a further decrease in creatinine clearance and urine output was observed. Our findings suggest that MI induced AKI in both sexes with pre-menopausal female mice being more protected. Ovariectomy worsens aspects of AKI in females after MI, which may portend increased risk for development of chronic kidney disease.

Sex differences in cardiac remodeling post myocardial infarction with acute cigarette smoking

Background

Whether cigarette smoking affects the heart post-myocardial infarction (MI) in a sex-dependent way remains controversial. Using a mouse model, we investigated cardiac remodeling under the influence of acute cigarette smoke (CS) exposure following ischemic injury in both sexes.

Methods

Ten cigarettes were smoked twice daily for 2 weeks followed by MI and then 1 additional week post permanent LAD ligation. Cardiac function, histology, and infarct size were assessed, and inflammatory markers quantified by RT–PCR. Statistical comparisons were performed using an unpaired t test or ANOVA followed by Tukey post hoc test.

Results

We observed that cigarette smoking exacerbated both left and right ventricular remodeling only in males at an early stage of post-MI. Females did not display a significant structural and/or functional alteration within 7 days of cardiac remodeling post-MI upon CS exposure. Worsened right ventricular remodeling in males was independent of pulmonary congestion. CS-exposed males exhibited enhanced increases in left ventricular end systolic and diastolic volumes, as well as reductions in ejection fraction and fractional area changes of left ventricular base. At day 7, infarct size was increased by cigarette smoking in males only, which was accompanied by enhanced collagen deposition in both the infarcted and peri-infarcted areas. Both IL-6 and TNF-α mRNA expression significantly increased in CS-exposed MI male group only at day 7 post-MI suggestive of prolonged inflammation.

Conclusions

These findings indicate that CS exposure worsens the progression of cardiac remodeling post-MI in male sex in a significant manner compared to female sex at least at early stages.

Smoking and Risk of Urolithiasis: Meta-Analysis of Observational Studies

Background

Earlier studies have warned about the effects of smoking on urolithiasis. Some studies have deemed that smoking has a promoting effect on urolithiasis, whereas others have considered that no inevitable association exists between the two. Therefore, we conducted a meta-analysis to estimate whether smoking is associated with urolithiasis risk.

Methods

To identify publications from related observational studies, we performed a search on PubMed, Web of Science, Embase, and the Cochrane Library databases from inception until October 1, 2021. According to the heterogeneity, random-effect model was used to calculate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

Results

Five articles were included in the meta-analysis, representing data for 20,402 subjects, of which 1,758 (8.62%) had urolithiasis as defined according to the criteria. Three articles are concerned with analysis between ex-smokers and non-smokers, in which a significant difference was observed (OR = 1.73, 95% CI: 1.48–2.01). Our comparison of current smokers with non-smokers in another meta-analysis of three articles revealed no significant difference between them (OR = 1.08, 95% CI: 0.94–1.23). Finally, we separated subjects into ever-smokers and never-smokers and found a significant difference between the two groups in the analysis of three articles (OR = 1.31, 95% CI: 1.17–1.47). Sensitivity analysis confirmed the stability of the current results.

Conclusion

Combined evidence from observational studies demonstrates a significant relation between smoking and urolithiasis. The trend of elevated urolithiasis risk from smoking was found in ever-smokers vs. never-smokers.

Gender-biased kidney damage in mice following exposure to tobacco cigarette smoke: More protection in premenopausal females

Multiple clinical studies documented renal damage in chronic cigarette smokers (CS) irrespective of their age and gender. Premenopausal female smokers are known to exert a certain cardiovascular and renal protection with undefined mechanisms. Given the multiple demographic variables within clinical studies, this experimental study was designed to be the first to assess whether gender‐biased CS‐induced kidney damage truly exists between premenopausal female and age‐matched C57Bl6J male mice when compared to their relative control groups. Following 6 weeks of CS exposure, cardiac function, inflammatory marker production, fibrosis formation, total and glomerular ROS levels, and glomerulotubular homeostasis were assessed in both genders. Although both CS‐exposed male and female mice exhibited comparable ROS fold change relative to their respective control groups, CS‐exposed male mice showed a more pronounced fibrotic deposition, inflammation, and glomerulotubular damage profile. However, the protection observed in CS‐exposed female group was not absolute. CS‐exposed female mice exhibited a significant increase in fibrosis, ROS production, and glomerulotubular alteration but with a pronounced anti‐inflammatory profile when compared to their relative control groups. Although both CS‐exposed genders presented with altered glomerulotubular homeostasis, the alteration phenotype between genders was different. CS‐exposed males showed a significant decrease in Bowman's space along with reduced tubular diameter consistent with an endocrinization pattern of chronic tubular atrophy, suggestive of an advanced stage of glomerulotubular damage. CS‐exposed female group, on the other hand, displayed glomerular hypertrophy with a mild tubular dilatation profile suggestive of an early stage of glomerulotubular damage that generally precedes collapse. In conclusion, both genders are prone to CS‐induced kidney damage with pronounced female protection due to a milder damage slope.

Sex-based differences in myocardial infarction-induced kidney damage following cigarette smoking exposure: more renal protection in premenopausal female mice

The impact of cigarette smoking (CS) on kidney homeostasis in the presence of myocardial infarction (MI) in both males and females remains poorly elucidated. C57BL6/J mice were exposed to 2 weeks of CS prior to MI induction followed by 1 week of CS exposure in order to investigate the impact of CS on kidney damage in the presence of MI. Cardiac hemodynamic analysis revealed a significant decrease in ejection fraction (EF) in CS-exposed MI male mice when compared with the relative female subjects, whereas cardiac output (CO) comparably decreased in CS-exposed MI mice of both sexes. Kidney structural alterations, including glomerular retraction, proximal convoluted tubule (PCT) cross-sectional area, and total renal fibrosis were more pronounced in CS-exposed MI male mice when compared with the relative female group. Although renal reactive oxygen species (ROS) generation and glomerular DNA fragmentation significantly increased to the same extent in CS-exposed MI mice of both sexes, alpha-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) significantly increased in CS-exposed MI male mice, only. Metabolically, nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide riboside-1 (NMRK-1) substantially increased in CS-exposed MI female mice only, whereas sirtuin (SIRT)-1 and SIRT-3 substantially decreased in CS-exposed MI male mice compared with their relative female group. Additionally, renal NAD levels significantly decreased only in CS-exposed MI male mice. In conclusion, MI female mice exhibited pronounced renal protection following CS when compared with the relative male groups.

Tobacco cigarette smoking exacerbates aortic calcification in an early stage of myocardial infarction in a female mouse model

Despite increased social awareness, marketing restraints, tobacco taxation, and available smoking cessation rehab programs, active and passive smoking remain a worldwide challenging epidemic and a key risk factor for cardiovascular diseases development. Although cardiovascular (CV) protection is more pronounced in women than in men due to estrogenic effects, tobacco cigarette smoking exposure seems to alter this protection by modulating estrogen actions via undefined mechanisms. Premenopausal cigarette smoking women are at higher risk of adverse CV effects than non-smokers. In this study, we investigated the impact of cigarette smoking on early CV injury after myocardial infarction (MI) in non-menopausal female mice. Aortic arch calcification, fibrosis, reactive oxygen species, and gene expression of inflammatory and calcification genes were exaggerated in mice exposed to cigarette smoke (CS). These findings suggest that aortic injury following MI, characterized by vascular smooth muscle cells transdifferentiation, calcification, inflammation, and collagen deposition but not cardiac dysfunction is exacerbated with CS exposure. The novel findings of this study highlight the importance of aortic injury on short and long-term prognosis in CS-exposed MI females. Linking those findings to estrogen alteration is probable and entails investigation.

Cerebral blood flow alteration following acute myocardial infarction in mice

Heart failure is associated with low cardiac output (CO) and low brain perfusion that imposes a significant risk for accelerated brain ageing and Alzheimer’s disease (AD) development. Although clinical heart failure can emerge several years following acute myocardial infarction (AMI), the impact of AMI on cerebral blood flow (CBF) at early stages and up to 30 days following MI is unknown. Sixteen months old male mice underwent left anterior descending (LAD) coronary artery ligation. Hemodynamics analyses were performed at baseline and at days 1, 7, and 30 post-MI. Left ventricular (LV) ejection fraction (EF), LV volumes, CO, and right common carotid artery (RCCA) diameter were recorded by echocardiography. RCCA flow (RCCA FL) was measured by Doppler echocardiography. LV volumes consistently increased (P<0.0012) and LV systolic function progressively deteriorated (P<0.0001) post-MI. CO and RCCA FL showed a moderate but significant decrease over the course of MI with similar fluctuation pattern such that both variables were decreased at day 1, increased at day 7, and decreased at 30 days post-MI. Correlation and regression analyses between CO and RCCA FL showed a strong correlation with significance at baseline and day 30 post-MI (R = 0.71, P=0.03, and R = 0.72, P=0.03, respectively). Days 1 and 7 analyses between CO and RCCA FL showed moderate correlation with non-significance post-MI (R = 0.51, P=0.2, and R = 0.56, P=0.12, respectively). In summary, CBF significantly decreased following AMI and remained significantly decreased for up to 30 days, suggesting a potential risk for brain damage that could contribute to cognitive dysfunction later in life.