Impact of cigarette smoking on kidney inflammation and fibrosis in diabetic rats

Smoking as a causative factor in chronic kidney disease: a two-sample Mendelian randomization study

Smoking is widely acknowledged for its harmful effects on multiple organs. However, its specific causal relationship with chronic kidney disease (CKD) remains uncertain. This study applied bivariate causal analysis and two-sample Mendelian randomization (MR) methods to examine the association between various smoking behaviors - initiation, cessation, age at initiation, cigarettes smoked per day, and lifetime smoking - and CKD, using genome-wide data. The inverse variance weighted (IVW) method was the primary analytical tool, supported by sensitivity analyses, pleiotropy assessments, and mediation analyses. External validation was conducted using independent datasets. The results revealed positive associations between CKD and smoking initiation (Pivw = 1.8 × 10-2, OR = 1.192), earlier age at initiation (Pivw = 2.3 × 10-3, OR = 1.481), cigarettes smoked per day (Pivw = 8.8 × 10-3, OR = 1.216), and lifetime smoking (Pivw = 2.3 × 10-7, OR = 2.445). In contrast, smoking cessation demonstrated a protective effect against CKD (Pivw = 4.0 × 10-12, OR = 0.791). External validation results aligned with the primary findings, and the absence of significant heterogeneity confirmed the robustness of the MR analysis. Additionally, the effect of smoking on CKD was mediated by factors such as body mass index, cardiovascular disease, hypertension, and type 2 diabetes. These findings identify smoking as a contributing factor to CKD and suggest that reducing smoking prevalence could significantly lower the incidence of CKD in the population.

The association between anti-inflammatory therapies and renal outcomes in patients with established cardiovascular disease or high cardiovascular risks: a meta-analysis of randomised controlled trials

BACKGROUND

To assess the relationship between anti-inflammatory therapy and renal events risk in participants with cardiovascular risks or diagnosed cardiovascular disease (CVD).

METHODS

Literature searches were carried out in PubMed, Embase, clinicaltrial.gov and the Cochrane Central Register of Controlled Trials. Randomised controlled trials that were published from January 1995 to July 2024, compared anti-inflammatory therapy and placebo in participants at cardiovascular risks or with diagnosed CVD and with reports of renal outcomes were included. The results were shown as risk ratio (RR) and 95% confidence interval (CI).

RESULTS

In comparison to placebo, therapies targeting inflammation did not exhibit a significant association with the risk of composite renal outcomes (worsening of renal function, death due to kidney disease and end-stage renal disease) (RR = 0.89, 95% CI 0.40 to 1.99, I2 = 0%). The risk of worsening of renal function (RR = 0.81, 95% CI 0.21 to 3.07, I2 = NA), end-stage renal disease (RR = 0.94, 95% CI 0.31 to 2.85, I2 = 0%), death due to kidney disease (RR = 3.00, 95% CI 0.12 to 73.56, I2 = NA), chronic kidney disease (RR = 1.77, 95% CI 0.74 to 4.23, I2 = 0%), chronic renal failure (RR = 1.70, 95% CI 0.56 to 5.15, I2 = 61%) and acute kidney injury (RR = 1.16, 95% CI 0.95 to 1.42, I2 = 0%) showed no significant difference between patients receiving anti-inflammatory therapy and placebo.

CONCLUSION

Current evidence did not indicate associations between anti-inflammatory therapies and adverse renal events risks in patients with cardiovascular risks or established CVD. Future researches are needed to explore the renal effects of anti-inflammatory therapy.

Association between endocrine disrupting chemicals exposure and diabetic kidney disease in adults: A national cross-sectional NHANES study

BACKGROUND

Diabetic kidney disease (DKD) is a global public health concern. Environmental factors are increasingly recognized as significant risk factors that cannot be overlooked, and certain environmental pollutants exhibit endocrine-disrupting properties. Previous research on the association between endocrine-disrupting chemicals (EDCs) and DKD has been notably limited.

METHODS

This study investigated the association between exposure to 25 EDC metabolites and DKD in 1421 U.S. adults from the 2015-2018 National Health and Nutrition Examination Survey (NHANES). We used logistic regression, restricted cubic spline regression, weighted quantile sum (WQS) regression, and bayesian kernel machine regression (BKMR) models to assess the association between individual and co-exposure to multiple EDCs and DKD. Subgroup analyses and interaction tests were performed to investigate whether this association was stable across the population. Additionally, mediation analysis was used to explore the mediating role of serum globulins in the association between Pb exposure and DKD.

RESULTS

In logistic regression models, N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA), N-Acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine (MHBMA3), Phenylglyoxylic acid (PGA), and lead (Pb) were significantly positively associated with diabetes. Restricted cubic spline (RCS) analyses also revealed significant non-linear positive associations between 2HPMA, MHBMA3, and DKD. Perfluorohexane sulfonic acid (PFHxS), n-perfluorooctanoic acid (n-PFOA), n-perfluorooctane sulfonic acid (n-PFOS), and Perfluoromethylheptane sulfonic acid isomers (Sm-PFOS) were significantly negatively associated with DKD. Furthermore, co-exposure to metals and metalloid was positively associated with DKD in both the WQS regression and the BKMR models, with Pb as the primary contributing factor. Mediation analysis showed that globulin mediated the association between Pb exposure and DKD, with a mediation proportion of 7.25 % (P = 0.046). Co-exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) was negatively correlated with DKD, and subgroup analyses revealed that this correlation was more pronounced in the obese group (BMI ≥30 kg/m²). The BKMR analysis revealed potential interactions among various chemical compounds, such as N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA), 2-Methylhippuric acid (2MHA), N-Acetyl-S-(4-hydroxy-2-methyl-2-butenyl)-L-cysteine (IPM3), mercury (Hg), and cadmium (Cd), in a model simulating co-exposure to metals and metalloid, as well as to volatile organic compound metabolites (mVOCs).

CONCLUSION

The findings suggest an association between individual or co-exposure to EDC metabolites and DKD, providing valid evidence for DKD prevention from the perspective of EDCs exposure. However, more prospective studies are needed to elucidate the potential mechanisms underlying these findings.

High mobility group box 1 (HMGB1) mediates nicotine-induced podocyte injury

Introduction

Cigarette smoking is a well-established risk factor for renal dysfunction. Smoking associated with renal damage bears distinct physiological correlations in conditions such as diabetic nephropathy and obesity-induced glomerulopathy. However, the cellular and molecular basis of such an association remains poorly understood. High mobility group box 1(HMGB1) is a highly conserved non-histone chromatin associated protein that largely contributes to the pathogenesis of chronic inflammatory and autoimmune diseases such as sepsis, atherosclerosis, and chronic kidney diseases. Hence, the present study tested whether HMGB1 contributes to nicotine-induced podocyte injury.

Methods and Results

Biochemical analysis showed that nicotine treatment significantly increased the HMGB1 expression and release compared to vehicle treated podocytes. However, prior treatment with glycyrrhizin (Gly), a HMGB1 binder, abolished the nicotine-induced HMGB1 expression and release in podocytes. Furthermore, immunofluorescent analysis showed that nicotine treatment significantly decreased the expression of podocyte functional proteins- podocin and nephrin as compared to control cells. However, prior treatment with Gly attenuated the nicotine-induced nephrin and podocin reduction. In addition, nicotine treatment significantly increased desmin expression and cell permeability compared to vehicle treated podocytes. However, prior treatment with Gly attenuated the nicotine-induced desmin expression and cell permeability. Mechanistic elucidation revealed that nicotine treatment augmented the expression of toll like receptor 4 (TLR4) and pre-treatment with Gly abolished nicotine induced TLR4 upregulation. Pharmacological inhibition of TLR4 with Resatorvid, a TLR4 specific inhibitor, also attenuated nicotine induced podocyte damage.

Conclusion

HMGB1 is one of the important mediators of nicotine-induced podocyte injury through TLR4 activation.

Vaping/e-cigarette-induced pulmonary extracellular vesicles contribute to exacerbated cardiomyocyte impairment through the translocation of ERK5

AIMS

The impact of e-cigarettes/vaping on cardiac function remains contradictory owing to insufficient direct evidence of interorgan communication. Extracellular vesicles (EVs) have protective or detrimental effects depending on pathological conditions, making it crucial to understand their role in lung-cardiac cell interactions mediated by vaping inhalation.

METHODS AND KEY FINDINGS

Pulmonary EVs were characterized from animals that underwent 12 weeks of nicotine inhalation (vaping component) (EVsNicotine) or vehicle control (EVsVehicle). EVsNicotine significantly increased in size and abundance compared with EVsVehicle. The direct effect of EVs Nicotine and EVs Vehicle on cardiomyocytes was then assessed in vitro and in vivo. EVs Nicotine led to a decrease in cardiac function as manifested by reduced cardiac contractility and impaired relaxation. EVs Nicotine induced increased levels of cleaved caspase-1 and cleaved caspase-11 in cardiomyocytes, indicating the promotion of pyroptosis. Meanwhile, EVsNicotine stimulated the secretion of fibrotic factors. Further analysis revealed that nicotine inhalation stimulated EVs Nicotine enriched with high levels of ERK5 (EVs Nicotine-ERK5). It was discovered that these EVs derived from pulmonary epithelial cells. Furthermore, inhibiting cardiac ERK5 blunted the EVs Nicotine-induced pyroptosis and fibrotic factor secretion. We further identified GATA4, a pro-pyroptosis transcription factor, as being activated through ERK5-dependent phosphorylation.

SIGNIFICANCE

Our research demonstrates that nicotine inhalation exacerbates cardiac injury through the activation of EVs derived from the lungs during e-cigarettes/vaping. Specifically, the EVs containing ERK5 play a crucial role in mediating the detrimental effects on cardiac function. This research provides new insights into the cardiac toxicity of vaping and highlights the role of EVs Nicotine-ERK5 in this process.

Prospective study on the joint effect of persistent organic pollutants and glucose metabolism on chronic kidney disease: Modifying effects of lifestyle interventions

There is no evidence on the associations between persistent organic pollutants (POPs) and the incidence of chronic kidney disease (CKD) in the Chinese rural population. We aimed to investigate the individual and mixed effects of 22 POPs on the prevalence and incidence of CKD, and the joint effects of POPs and abnormal glucose metabolism as well as the modification effects of healthy lifestyle on these associations. A total of 2775 subjects, including 925 subjects with normal plasma glucose (NPG) and 925 subjects with prediabetes (PDM) and type 2 diabetes mellitus (T2DM), were enrolled from the Henan Rural Cohort Study. Logistic regression and quantile g-computation were performed to assess the individual and mixed effects of POPs on the risk of CKD. Joint effects of POPs and abnormal glucose metabolism status, as well as the modification effects of lifestyle on CKD were assessed. After 3-year follow-up, an increment of ln-o,p'-DDT was related to an elevated risk of CKD prevalence. Positive associations of p,p'-DDE and β-BHC with CKD incidence were observed (P < 0.05). In addition, participants with high levels of ∑POPs were associated elevated incidence risk of CKD (OR: 1.217, 95%CI: 1.008-1.469). One quartile increase in POPs mixture was associated with the increased incidence of CKD among T2DM patients (P < 0.05). Further, a higher risk of CKD was observed among PDM and T2DM patients with high levels of o,p'-DDT, p,p'-DDE, β-BHC, and ∑POPs than NPG subjects with low levels of pollutants. In addition, interactive effects of ∑POPs and lifestyle score on CKD incidence were found. Individual and mixed exposure to POPs increased the prevalence and incidence of CKD, and glucose metabolic status exacerbated the risk of CKD resulting from such exposures. Further, the modifying effects of lifestyle were observed, highlighting the importance of precision prevention for high-risk CKD population and healthy lifestyle intervention measures.

Positive correlation between hypertensive retinopathy and albuminuria in hypertensive adults

PURPOSE

We investigated the association between albuminuria and hypertensive retinopathy (HR) in hypertensive adults.

METHODS

This was a cross-sectional subgroup analysis of data from the China Stroke Primary Prevention Trial. We enrolled 2,964 hypertensive adults in this study. Keith-Wagener-Barker stages was used to assess HR. The urinary albumin to creatinine ratio (UACR) was calculated to evaluate albuminuria.

RESULTS

HR was found in 76.6% (n = 2, 271) of the participants, albuminuria was found in 11.1% (n = 330). The UACR levels were significantly higher in subjects with HR than in those without HR (grade 1, β = 1.42, 95% confidence intervals [CI]: -0.12, 2.95, p = 0.070; grade 2, β = 2.62, 95% CI: 0.56, 4.67, p = 0.013; grade 3, β = 5.17, 95% CI: 1.13, 9.20, p = 0.012). In the subgroup analyses, the association between HR and UACR was stronger in current smokers (p for interaction = 0.014). The correlation between HR grades 1 and 2 and UACR was stronger in subjects with higher triglyceride levels (≥ 1.7 mmol/L), but for grade 3 HR, this correlation was stronger in subjects with lower triglycerides levels (< 1.7 mmol/L, p for interaction = 0.023). The odds of albuminuria were significantly higher in subjects with HR than in those without HR (grade 1, odds ratio [OR] = 1.57, 95% CI: 1.08, 2.29, p = 0.019; grade 2, OR = 2.02, 95% CI: 1.28, 3.18, p = 0.002; grade 3, OR = 2.12, 95% CI: 0.99, 4.55, p = 0.053). In the subgroup analyses, the association between HR grades 1 and 2 and albuminuria was stronger in subjects with higher triglycerides levels (≥ 1.7 mmol/L), but for grade 3 HR, this correlation was stronger in subjects with lower triglyceride levels (< 1.7 mmol/L, p for interaction = 0.014).

CONCLUSION

HR was positively correlated with albuminuria in hypertensive Chinese adults. This correlation was more remarkable when the population was stratified by triglycerides levels and smoking status. HR can be used as an indicator of early renal injury.

Association of Blood Urea Nitrogen with Cardiovascular Diseases and All-Cause Mortality in USA Adults: Results from NHANES 1999-2006

In the general population, there is little evidence of a link between blood urea nitrogen (BUN) and long-term mortality. The goal of this study was to explore whether higher BUN concentration is a predictor of cardiovascular disease (CVD) and all-cause mortality. From 1999 to 2006, the National Health and Nutrition Examination Survey (NHANES) included 17,719 adult individuals. Death outcomes were ascertained by linkage to the database records through 31 December 2015. The Cox proportional hazard regression model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD and all-cause mortality in individuals. We also performed stratified analyses based on age, gender, drinking, smoking, history of hypertension and diabetes. During a mean follow-up 11.65 years, a total of 3628 deaths were documented, of which 859 were due to CVD. Participants with higher BUN had a higher risk of CVD and all-cause death compared to those with lower BUN. After multifactor adjustment for demographics, major lifestyle factors, and hypertension and diabetes history, higher BUN levels compared with lower levels were significantly associated with higher risk of CVD (HR: 1.48 [1.08, 2.02], P-trend < 0.001) and all-cause mortality (HR: 1.48 [1.28, 1.72], P-trend < 0.001). In subgroup analyses, we found that the trend in the association of BUN with the risk of death remained strong in female subjects. Greater BUN levels were linked to higher CVD and all-cause mortality in the NHANES of American adults. The importance of BUN in predicting death is supported by our research.

Effects of Smoking on Diabetic Nephropathy

Diabetes is a systemic metabolic disease with serious complications that cause significant stress on the healthcare system. Diabetic kidney disease is the primary cause of end stage renal disease globally and its progression is accelerated by various factors. Another major healthcare hazard is tobacco consumption and smoking has deleterious effects on renal physiology. Prominent factors are defined as sympathetic activity, atherosclerosis, oxidative stress and dyslipidemia. This review aims to enlighten the mechanism underlying the cumulative negative effect of simultaneous exposure to hyperglycemia and nicotine.

Predictors for Submucosal Fibrosis in Patients With Superficial Squamous Esophageal Neoplasia Undergoing Endoscopic Submucosal Dissection

INTRODUCTION

Submucosal fibrosis greatly hinders the success of endoscopic submucosal dissection (ESD). This study determined ESD outcomes in patients with esophageal submucosal fibrosis and further explored the predictors.

METHODS

We retrospectively analyzed 163 patients with superficial squamous esophageal neoplasia. The degree of submucosal fibrosis was classified as follows: F0, none; F1, mild; and F2, severe. ESD outcomes as a function of the degree of submucosal fibrosis and biopsy were determined. The potential predictors of submucosal fibrosis were analyzed.

RESULTS

En bloc resection, R0 resection, and procedure time were significantly different between the F0-F2 groups (P = 0.009, P = 0.002, and P < 0.001, respectively). Perforation and immediate bleeding rates of F2 were significantly higher than the F0/F1 groups (P < 0.001 and P < 0.001, respectively). However, the nonbiopsy group vs the biopsy group and the delayed ESD group (postbiopsy >21 days) vs the early ESD group (postbiopsy ≤21 days) showed no statistical differences regarding the en bloc resection, R0 resection, and ESD complications (all P > 0.05). Further analysis indicated that it was not the biopsy history and delayed ESD (both P > 0.05), rather submucosal invasion vs intramucosal tumor (odds ratio = 4.534, P = 0.003) and current smoker vs nonsmoker (odds ratio = 2.145, P = 0.043) were independent risk factors for endoscopic submucosal fibrosis.

DISCUSSION

Esophageal submucosal fibrosis was shown to be closely related to unsatisfactory ESD outcomes. Biopsy history and delayed ESD had no adverse effect on submucosal fibrosis and ESD outcomes. Submucosal invasion and current cigarette smoking were predictors of submucosal fibrosis.

Role of the IL-33/ST2 axis in cigarette smoke-induced airways remodelling in chronic obstructive pulmonary disease

BACKGROUND

Efficient therapy and potential prophylaxis are confounded by current ignorance of the pathogenesis of airway remodelling and blockade in COPD.

OBJECTIVE

To explore the role of the IL-33/ST2 axis in cigarette smoke (CS) exposure-induced airways remodelling.

METHODS

C57BL/6, BALB/c and IL-1RL1 -/- mice exposed to CS were used to establish an animal surrogate of COPD (air-exposed=5~8, CS-exposed=6~12). Hallmarks of remodelling were measured in mice. Cigarette smoke extract (CSE)-induced proliferation and protein production in vitro by fibroblasts in the presence of anti-interleukin-33 (anti-IL-33) or hST2 antibodies were measured. Expression of IL-33 and ST2 and other remodelling hallmarks were measured, respectively, in bronchoalveolar lavage fluid (BALF) (controls=20, COPD=20), serum (controls=59, COPD=90) and lung tissue sections (controls=11, COPD=7) from patients with COPD and controls.

RESULTS

Wild-type mice exposed to CS elevated expression of hallmarks of tissue remodelling in the lungs and also in the heart, spleen and kidneys, which were significantly abrogated in the IL-1RL1 -/- mice. Fibroblasts exposed to CSE, compared with control, exhibited early cellular translocation of IL-33, accompanied by proliferation and elevated protein synthesis, all inhabitable by blockade of IL-33/ST2 signalling. Expression of IL-33 and ST2 and hallmarks of tissue remodelling were significantly and proportionally elevated in BALF, serum and tissue samples from patients with COPD.

CONCLUSIONS

Exposure to CS induces remodelling changes in multiple organs. The data support the hypothesis that CS-induced lung collagen deposition is at least partly a result of CS-induced IL-33 translocation and release from local fibroblasts.

Effect of alcohol consumption on kidney function: population-based cohort study

The association between alcohol consumption and kidney function is intriguing, but study results are mixed and controversial. We examined the association of alcohol consumption with the overall change in kidney function over 12 years. We analyzed data from a population-based cohort that was part of the Korean Genome and Epidemiology Study. Primary exposure was total alcohol intake (non-drinkers, 0 to < 10 g/day, 10 to < 30 g/day, and ≥ 30 g/day). Main outcome was decline in kidney function over 12 years. Our study included 5729 participants (mean [SD] age, 51 [8] years; 46% males). Compared to non-drinkers, higher alcohol intake groups had lesser reduction in estimated glomerular filtration rate (eGFR) over 12 years; fully adjusted beta coefficients and 95% confidence intervals were 0.45 (− 0.27, 1.18), 1.87 (0.88, 2.87), and 3.08 (1.93, 4.24) for participants with alcohol intake of < 10, 10 to < 30, and ≥ 30 g/day, respectively. However, this association was attenuated among women, smoker, and age ≥ 60 year. Compared with not drinking, more frequent alcohol consumption and binge drinking were associated with lesser reduction in eGFR. Our findings suggest that alcohol consumption may have a favorable effect on kidney function among the general population.

Smoking and risk of incident end-stage kidney disease in general population: A Nationwide Population-based Cohort Study from Korea

We analyzed data from the Korean National Health Insurance Service (NHIS) to investigate whether smoking increases the risk of end-stage kidney disease (ESKD). This retrospective nationwide population-based cohort study included the data of 23,232,091 participants who underwent at least one health examination between 2009 and 2012. Smoking status was recorded at baseline. The incidence of ESKD was identified via ICD-10 codes and special medical aid codes from the Korean National Health Insurance Service database till December 2016. A Cox proportional-hazards model with multivariable adjustment was used to evaluate the association between smoking and ESKD incidence. Overall, 24.6% of participants were current smokers; 13.5% and 61.9%, were ex- and non-smokers, respectively. Overall, 45,143 cases of ESKD developed during the follow-up period. Current smokers (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.35-1.43) and ex-smokers (HR, 1.09; 95% CI, 1.06-1.12) demonstrated a significant increase in the adjusted risk of ESKD compared to non-smokers. The risk of ESKD was directly proportional to the smoking duration, number of cigarettes smoked daily, and pack-years. In conclusion, smoking is associated with a greater risk of ESKD in the general Korean population; the risk increases with an increase in the smoking duration, number of cigarettes smoked daily, and pack-years.

The influence of tobacco smoke exposure on selected markers of oxidative stress, kidneys and liver function in the serum of rats with streptozotocin-induced diabetes

BACKGROUND

The significance of the free radicals is emphasized in the pathophysiology of diabetes and the progression of chronic diabetic complications. Smoking cigarettes increases the risk of developing type II diabetes and intensifies pathophysiological processes during the development of type I diabetes. Tobacco smoke is also additional source of free radicals. Moreover, smoking causes variety of adverse effects on organs, that have no direct contact with the tobacco smoke itself. The objective of the study was to examine the effects of tobacco smoke on the serum concentrations of relevant oxidative stress markers such as total protein (TP), reduced glutathione (GSH), glutathione S-transferase (GST) and thiobarbituric acid reactive substances (TBARS), as well as renal (creatinine, urea) and liver function (alkaline phosphatase, ALP; alanine aminotransferase, ALT; aspartate aminotransferase, AST) among animals with induced diabetes after administration of a single dose of streptozotocin (65 mg/kg, ip).

METHODS

The markers of oxidative stress and biochemical parameters were determined using spectrophotometric methods. As a biomarker of exposure to tobacco smoke, cotinine was determined using high-performance liquid chromatography with diode array detection (HPLC-DAD).

RESULTS

Tobacco smoke exposure of diabetic rats was manifested by significantly elevated liver enzymes activity - ALT (p < 0.05) and ALP (p < 0.01), higher creatinine and urea concentration (p < 0.01), lower GSH amount (p < 0.05), and higher GST activity (p < 0.05).

CONCLUSIONS

Tobacco smoking induce liver and renal damage through the mechanisms including increased oxidative stress.