Environmental tobacco smoke furthers progression of diabetic nephropathy

Association Between Life's Essential 8 and Diabetic Kidney Disease in Patients With Diabetes Mellitus: Evidence From National Health and Nutrition Examination Survey 2005-2018

BACKGROUND

Diabetic kidney disease (DKD) is often connected with an elevated cardiovascular disease risk. A novel index, the Life's Essential 8 (LE8), was developed with the American Heart Association to ascertain cardiovascular health. In people with diabetes mellitus, we aimed to estimate if LE8 possessed a connection with DKD risk.

METHODS

We implemented data from the National Health and Nutrition Examination Survey from 2005 to 2018. The correlation between LE8 and DKD was evaluated with weighted multivariate logistic regression models and restricted cubic spline models with covariate adjustments. In addition, we performed subgroup analyses and interaction tests.

RESULTS

After taking into account relevant confounding factors, the findings indicated that higher levels of LE8 was linked to a decreased probability of developing DKD (per 10-point increase in LE8, OR = 0.75, 95%CI = 0.68-0.84, P < .001). The subscales of the LE8 similarly demonstrated negative associations with DKD risk. After grouping the LE8 scores, it was found that individuals with high LE8 were significantly less likely to develop DKD compared to those with low LE8 (OR = 0.32, 95%CI = 0.15-0.70, P = .005). The association between LE8 and DKD was consistent across different subgroups.

CONCLUSION

LE8 scores were shown to have a significantly negative association with the risk of DKD in people with diabetes mellitus. By concentrating on the state of cardiovascular health, it may be possible to lessen the impact of DKD.

The Influence of Smoking on Renal Functions Among Apparently Healthy Smokers

Background

Cigarette smoking is an important modifiable risk factor in kidney disease progression. Although long-term smoking has been associated with chronic kidney disease (CKD), its effect on kidney function in early stages has not been clarified.

Objective

To detect the early effects of smoking either active or passive on kidney functions.

Methodology

The current study was comparative cross sectional study conducted on 280 participants, 140 were non‑smokers and 140 were smokers (70 passive smokers and 70 active smokers). The two groups were comparable in terms of all parameters. We investigated the possible effects of smoking on kidney functions using both serum kidney function tests especially; serum urea, serum creatinine, serum cotinine levels and detection of albumin in urine. Smoking history, full Laboratory investigations, Ventilatory function test including (FEV1/FVC, FEV1, FEF 25-75%, VC and FVC) were done.

Results

Serum urea, serum creatinine, serum cotinine levels and urinary albumin were statistically significant higher in smokers group in comparison to nonsmokers, also the serum cotinine levels and urinary albumin were statistically significant in active smokers in comparison to passive smokers. There were positive correlations between the level of urinary albumin and pack/year (r = 0.9, p<0.05), smoking index (r = 0.9, p<0.05), smoking duration (r = 0.4, p<0.05), and serum cotinine (r = 0.6, p<0.050) with good statistical significance. The most significant predictive risk factors of microalbuminuria among smokers group in descending orders were active smoking, passive smoking, age and serum cotinine level.

Conclusion

Both active and passive smoking, especially among heavy smokers, is a significant risk factor for microalbuminuria. This finding increase the importance of early cessation of smoking in order to minimize early renal affection among healthy smokers that may not be discovered by routine renal function tests.

Emerging role of air pollution in chronic kidney disease

Chronic kidney disease (CKD), a global disease burden related to high rates of incidence and mortality, manifests as progressive and irretrievable nephron loss and decreased kidney regeneration capacity. Emerging studies have suggested that exposure to air pollution is closely relevant to increased risk of CKD, CKD progression and end-stage kidney disease (ESKD). Inhaled airborne particles may cause vascular injury, intraglomerular hypertension, or glomerulosclerosis through non-hemodynamic and hemodynamic factors with multiple complex interactions. The mechanisms linking air pollutants exposure to CKD include elevated blood pressure, worsening oxidative stress and inflammatory response, DNA damage and abnormal metabolic changes to aggravate kidney damage. In the present review, we will discuss the epidemiologic observations linking air pollutants exposure to the incidence and progression of CKD. Then, we elaborate the potential roles of several air pollutants including particulate matter and gaseous co-pollutants, environmental tobacco smoke, and gaseous heavy metals in its pathogenesis. Finally, this review outlines the latent effect of air pollution in ESKD patients undergoing dialysis or renal transplant, kidney cancer and other kidney diseases. The information obtained may be beneficial for further elucidating the pathogenesis of CKD and making proper preventive strategies for this disease.

COX-2-derived prostaglandins as mediators of the deleterious effects of nicotine in chronic kidney disease

Tobacco smoking has been identified as a risk factor in the progression of chronic kidney disease (CKD). In previous studies, we showed that nicotine induces cyclooxygenase (COX)-2 expression in vivo and in vitro and that the administration of nicotine in vivo worsens the severity of renal injury in a model of subtotal renal ablation. In the present study, we tested the role of COX-2-derived prostaglandins on the deleterious effects of nicotine in CKD. Sham and 5/6 nephrectomy (5/6Nx) rats received tap water or nicotine (100 μg/mL) in the drinking water for 12 wk. Additional groups also systemically received the COX-2 inhibitor NS-398 (1.5 mg·kg^-1·day^-1 via osmotic minipump). The administration of nicotine worsened renal injury and proteinuria in 5/6Nx rats and increased proteinuria in sham rats. 5/6Nx rats had increased cortical production of the prostaglandins PGE₂, PGI₂, PGD₂, and PGF_2α and of thromboxane A₂. In these rats, nicotine reduced the production of all prostaglandins examined except thromboxane A₂. Treatment with the COX-2 inhibitor NS-398 resulted in complete inhibition of all prostaglandins studied and ameliorated renal injury and proteinuria in 5/6Nx rats on nicotine but not in 5/6 Nx rats on tap water. Nicotine also reduced the expression of megalin in all groups examined, and this was partially prevented by COX-2 inhibition. In the present study, we showed that in CKD, nicotine worsens renal injury at least in part by producing an imbalance in the production of prostaglandins. This imbalance in the production of prostaglandins likely plays a role in the deleterious effects of smoking on the progression of CKD.

Cigarette smoke inhalation aggravates diabetic kidney injury in rats

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. Epidemiological studies have demonstrated that cigarette smoke or nicotine is a risk factor for the progression of chronic kidney injury. The present study analyzed the kidney toxicity of cigarette smoke in experimental rats with DKD. Experimental diabetes was induced in 7-week-old Sprague-Dawley rats by a single intraperitoneal injection of streptozotocin (60 mg kg^-1). Four weeks after the induction of diabetes, rats were exposed to cigarette smoke (200 μg L^-1), 4 h daily, and 5 days per week for 4 weeks. Cigarette smoke did not affect the levels of plasma glucose, hemoglobin A1c, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol or non-esterified fatty acids in both control and diabetic rats under the experimental conditions. Cigarette smoke, however, significantly increased diabetes-induced glomerular hypertrophy and urinary kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) excretion, suggesting exacerbation of diabetic kidney injury. Cigarette smoke promoted macrophage infiltration and fibrosis in the diabetic kidney. As expected, cigarette smoke increased oxidative stress in both control and diabetic rats. These data demonstrated that four weeks of exposure to cigarette smoke aggravated the progression of DKD in rats.

Air pollution and kidney disease: review of current evidence

Along with amazing technological advances, the industrial revolution of the mid-19th century introduced new sources of pollution. By the mid-20th century, the effects of these changes were beginning to be felt around the world. Among these changes, health problems due to environmental air pollution are increasingly recognized. At the beginning, respiratory and cardiovascular diseases were emphasized. However, accumulated data indicate that every organ system in the body may be involved, and the kidney is no exception. Although research on air pollution and kidney damage is recent, there is now scientific evidence that air pollution harms the kidney. In this holistic review, we have summarized the epidemiology, disease states and mechanisms of air pollution and kidney damage.

Maternal Smoking during Pregnancy, Household Smoking after the Child's Birth, and Childhood Proteinuria at Age 3 Years

BACKGROUND AND OBJECTIVES

Smoking is a well known risk factor of proteinuria in adults; however, clinical studies in children are limited. The purpose of this study is to clarify the associations of maternal smoking during pregnancy and household smoking after the child's birth with the risk of proteinuria at age 3 years old.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a population-based retrospective cohort study on 44,595 children using data on prenatal health checkups, home visit neonatal health checkups, and health checkups at 4, 9, and 18 months and 3 years of age in Kobe City, Japan. Maternal smoking status (nonsmoker, past smoker, or current smoker) was collected with standardized questionnaires. The outcome of interest was the presence of proteinuria at 3 years of age defined as urinary protein ≥1+. To evaluate the association between child proteinuria and smoking status, we performed multivariate logistic regression model analyses adjusted for confounding factors.

RESULTS

The prevalence rates of children in the maternal smoking groups (none, past, and current) were 78.9%, 4.4%, and 16.7%, respectively. The frequencies of child proteinuria defined as ≥1+ urinary protein were 1.7% in the current smoking group, 1.6% in the past smoking group, and 1.3% in the nonsmoking group. Maternal smoking during pregnancy was associated with child proteinuria (odds ratio, 1.24; 95% confidence interval, 1.00 to 1.52; P=0.05) in the multiple logistic regression model, although nonmaternal family smoking during pregnancy was not significantly associated with child proteinuria (odds ratio, 0.97; 95% confidence interval, 0.79 to 1.19; P=0.77). We also found a similar association with household smoking after the child's birth (odds ratio, 1.23; 95% confidence interval, 0.99 to 1.54; P=0.06), although this observation was not significant.

CONCLUSIONS

Maternal smoking during pregnancy was one of the risk factors of childhood proteinuria. We also found a similar association with household smoking after the child's birth, although this observation was not significant.

Clinical predictive factors in diabetic kidney disease progression

Diabetic kidney disease (DKD) represents a major component of the health burden associated with type 1 and type 2 diabetes. Recent advances have produced an explosion of ‘novel’ assay‐based risk markers for DKD, though clinical use remains restricted. Although many patients with progressive DKD follow a classical albuminuria‐based pathway, non‐albuminuric DKD progression is now well recognized. In general, the following clinical and biochemical characteristics have been associated with progressive DKD in both type 1 and type 2 diabetes: increased hemoglobin A1c, systolic blood pressure, albuminuria grade, early glomerular filtration rate decline, duration of diabetes, age (including pubertal onset) and serum uric acid; the presence of concomitant microvascular complications; and positive family history. The same is true in type 2 diabetes for male sex category, in patients following an albuminuric pathway to DKD, and also true for the presence of increased pulse wave velocity. The following baseline clinical characteristics have been proposed as risk factors for DKD progression, but with further research required to assess the nature of any relationship: dyslipidemia (including low‐density lipoprotein, total and high‐density lipoprotein cholesterol); elevated body mass index; smoking status; hyperfiltration; decreases in vitamin D, hemoglobin and uric acid excretion (all known consequences of advanced DKD); and patient test result visit‐to‐visit variability (hemoglobin A1c, blood pressure and high‐density lipoprotein cholesterol). The development of multifactorial ‘renal risk equations’ for type 2 diabetes has the potential to simplify the task of DKD prognostication; however, there are currently none for type 1 diabetes‐specific populations. Significant progress has been made in the prediction of DKD progression using readily available clinical data, though further work is required to elicit the role of several variables, and to consolidate data to facilitate clinical implementation.

Hypoxia: The Force that Drives Chronic Kidney Disease

In the United States the prevalence of end-stage renal disease (ESRD) reached epidemic proportions in 2012 with over 600,000 patients being treated. The rates of ESRD among the elderly are disproportionally high. Consequently, as life expectancy increases and the baby-boom generation reaches retirement age, the already heavy burden imposed by ESRD on the US health care system is set to increase dramatically. ESRD represents the terminal stage of chronic kidney disease (CKD). A large body of evidence indicating that CKD is driven by renal tissue hypoxia has led to the development of therapeutic strategies that increase kidney oxygenation and the contention that chronic hypoxia is the final common pathway to end-stage renal failure. Numerous studies have demonstrated that one of the most potent means by which hypoxic conditions within the kidney produce CKD is by inducing a sustained inflammatory attack by infiltrating leukocytes. Indispensable to this attack is the acquisition by leukocytes of an adhesive phenotype. It was thought that this process resulted exclusively from leukocytes responding to cytokines released from ischemic renal endothelium. However, recently it has been demonstrated that leukocytes also become activated independent of the hypoxic response of endothelial cells. It was found that this endothelium-independent mechanism involves leukocytes directly sensing hypoxia and responding by transcriptional induction of the genes that encode the β2-integrin family of adhesion molecules. This induction likely maintains the long-term inflammation by which hypoxia drives the pathogenesis of CKD. Consequently, targeting these transcriptional mechanisms would appear to represent a promising new therapeutic strategy.

Tobacco and the pediatric chronic kidney disease population

Tobacco use and exposure are preventable causes of morbidity and mortality. Whereas the impact of this public health issue is well described in adults with kidney disease, its role in the pediatric chronic kidney disease (CKD) population is largely unknown. This review discusses the prevalence of tobacco use and exposure in children with CKD, updates the reader on how tobacco affects the kidney, and presents intervention strategies relevant to this patient population.

A case of "hidden" diabetic nephropathy diagnosed by a combination of renal biopsy findings and continuous glucose monitoring system

Although diabetic nephropathy is a microvascular complication of diabetes mellitus, some reports suggest that renal biopsy often shows this pathological change without a diagnosis of diabetes mellitus. Here, we report a case of a 65-year-old man who presented with proteinuria, hypoalbuminemia and hypertension without a diagnosis of diabetes mellitus. He drank alcohol regularly and was a heavy smoker. Renal biopsy revealed a diffuse increase in the mesangial area, mesangial nodules or well-developed hyalinosis, interstitial fibrosis, and arteriosclerosis consistent with the changes of diabetic nephropathy. Although we had initially diagnosed him with idiopathic nodular glomerulosclerosis, use of a continuous glucose monitoring system (CGMS) revealed that the changes in his daily blood glucose concentrations met with the diagnostic criteria of diabetes mellitus. Accordingly, we diagnosed him with diabetic nephropathy and initiated treatment for diabetes mellitus. This case suggests that some cases of diabetic nephropathy may be hidden among patients with impaired glucose tolerance, who are not diagnosed with diabetes mellitus. Use of a CGMS may be helpful in diagnosing this type of "hidden" diabetes mellitus. In addition to diet therapy, smoking control, treatment for hypertension, and strict control of hyperglycemia may be important for these patients.

Tobacco exposure in children and adolescents with chronic kidney disease: parental behavior and knowledge. A study from the Midwest Pediatric Nephrology Consortium

AIM

The incidence of cardiovascular disease (CVD) in children with chronic kidney disease (CKD) is high. Exposure to second hand smoke (SHS) is a known risk factor for CVD. Due to a recent report of high incidence of SHS in children with CKD, we sought to investigate via questionnaire the smoking behaviors of caregivers of children with CKD.

MATERIAL AND METHODS

A cross sectional study was conducted in which caregivers of children and adolescents with CKD were asked to complete a single anonymous self-administered survey.

RESULTS

Almost 40% of children and adolescents lived with one or more smokers. Over half of smokers smoked in the presence of their children and in the car. Smokers were significantly less aware of the detrimental effect of SHS exposure on the renal health of their children. Among smokers, almost 70% reported they had not been advised by their child's nephrologist to quit tobacco use.

CONCLUSION

There is a high prevalence of SHS exposure among children and adolescents with CKD, which may contribute to CVD. Caregivers are not fully aware of the detrimental effects of SHS exposure on the renal health of their children.

Dioxins, furans and dioxin-like PCBs in human blood: causes or consequences of diabetic nephropathy?

Nephropathy, or kidney disease, is a major, potential complication of diabetes. We assessed the association of 6 chlorinated dibenzo-p-dioxins, 9 chlorinated dibenzofurans and 8 polychlorinated biphenyls (PCBs) in blood with diabetic nephropathy in the 1999-2004 National Health and Nutrition Examination Survey (unweighted N=2588, population estimate=117,658,357). Diabetes was defined as diagnosed or undiagnosed (glycohemoglobin ≥ 6.5%) and nephropathy defined as urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria or macroalbuminuria. For the 8 chemicals analyzed separately, values above the 75th percentile were considered elevated, whereas for the other 15 compounds values above the maximum limit of detection were considered elevated. Seven of 8 dioxins and dioxin-like compounds, analyzed separately, were found to be associated with diabetic nephropathy. The chemicals associated with diabetic nephropathy were: 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin; 2,3,4,7,8-Pentachlorodibenzofuran; PCB 126; PCB 169; PCB 118; and PCB 156. Three of the 8 dioxins and dioxin-like compounds; 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin; 2,3,4,7,8-Pentachlorodibenzofuran and PCB 118; expressed as log-transformed continuous variables; were associated with diabetes without nephropathy. When 4 or more of the 23 chemicals were elevated the odds ratios were 7.00 (95% CI=1.80-27.20) for diabetic nephropathy and 2.13 (95% CI=0.95-4.78) for diabetes without nephropathy. Log-transformed toxic equivalency (TEQ) was associated with both diabetic nephropathy, and diabetes without nephropathy, the odds ratios were 2.35 (95% CI=1.57-3.52) for diabetic nephropathy, and 1.44 (95% CI=1.11-1.87) for diabetes without nephropathy. As the kidneys function to remove waste products from the blood, diabetic nephropathy could be either the cause or the consequence (or both) of exposure to dioxins, furans and dioxin-like PCBs.

Secondhand smoke exposure is associated with proteinuria in children with chronic kidney disease

BACKGROUND

In adults with chronic kidney disease (CKD), cigarette smoking is associated with an increased risk for CKD progression and transplant failure. In children, secondhand smoke (SHS) exposure has been associated with elevated blood pressure. There are no studies on the prevalence and effect of SHS exposure in CKD.

METHODS

Subjects were enrolled in the Chronic Kidney Disease in Children (CKiD) Study, an observational cohort of 366 children aged 1 to 16 years with CKD. Secondhand smoke exposure was obtained via questionnaire. SHS exposure was also determined based on urine cotinine (Ucot) measurements (1 ng/mL ≤ Ucot < 75 ng/mL). The cross-sectional association of SHS exposure with proteinuria was assessed.

RESULTS

Using Ucot, 22 % of subjects were exposed to SHS. SHS exposure was significantly associated with lower maternal education and African American race, and a greater prevalence of nephrotic range proteinuria and left ventricular hypertrophy. In a multivariate model (including sex, age, race, maternal education, income level, private insurance status, abnormal birth history and CKD diagnosis), the prevalence odds of nephrotic range proteinuria was 2.64, (95 % confidence interval 1.08, 6.42) higher in children exposed to SHS compared to those unexposed.

CONCLUSIONS

In our cohort of children with CKD, SHS exposure was common (22 %) and independently associated with nephrotic range proteinuria. Exposure to SHS may be an important factor to consider in CKD progression.

Nicotine signaling and progression of chronic kidney disease in smokers

The deleterious health effects of cigarette smoking are far reaching, and it remains the most important modifiable risk factor for improving overall morbidity and mortality. In addition to being a risk factor for cancer, cardiovascular disease and lung disease, there is strong evidence, both from human and animal studies, demonstrating a role for cigarette smoking in the progression of chronic kidney disease (CKD). Clinical studies have shown a strong correlation between cigarette smoking and worsening CKD in patients with diabetes, hypertension, polycystic kidney disease, and post kidney transplant. Nicotine, in addition to its role in the addictive properties of cigarette smoking, has other biological effects via activation of non-neuronal nicotinic acetylcholine receptors (nAChRs). Several nAChR subunits are expressed in the normal kidney and blockade of the α7-nAChR subunit ameliorates the effects of nicotine in animal models of CKD. Nicotine increases the severity of renal injury in animal models including acute kidney injury, diabetes, acute nephritis and subtotal nephrectomy. The renal effects of nicotine are also linked to increased generation of reactive oxygen species and activation of pro-fibrotic pathways. In humans, nicotine induces transitory increases in blood pressure accompanied by reductions in glomerular filtration rate and effective renal plasma flow. In summary, clinical and experimental evidence indicate that nicotine is at least in part responsible for the deleterious effects of cigarette smoking in the progression of CKD. The mechanisms involved are the subject of active investigation and may result in novel strategies to ameliorate the effects of cigarette smoking in CKD.

Smoking in diabetic nephropathy: sparks in the fuel tank?

Diabetic nephropathy is associated with high morbidity and mortality and the prevalence of this disease is continuously increasing worldwide. Long-term diabetes increases the likelihood of developing secondary complications like nephropathy, the most common cause of end stage renal disease. Usually, other factors like hypertension, alcoholism and smoking also partly contribute to the progression of diabetic nephropathy. Among this, cigarette smoking in diabetes has been repeatedly confirmed as an independent risk factor for the onset and progression of diabetic nephropathy. Various studies suggest that smoking is a major fuel in the development of high oxidative stress and subsequently hyperlipidemia, accumulation of advanced glycation end products, activation of the renin angiotensin system and Rho-kinase, which are observed to play a pathogenic role in the progression of diabetic nephropathy. Furthermore, cigarette smoking in diabetic patients with vascular complications produces a variety of pathological changes in the kidney, such as thickening of the glomerular basement membrane and mesangial expansion with progression in glomerulosclerosis and interstitial fibrosis, which ultimately results in end stage renal failure. Strong associations are consistently found between chronic cigarette smoking and diabetic microvascular complications. A diverse group of studies unveil potential mechanisms that may explain the role of cigarette smoking in the progression of diabetic nephropathy. Tremendous efforts are being made to control smoking mediated progression of diabetic nephropathy, but no promising therapy is yet available. The present review critically discusses the possible detrimental role of chronic cigarette smoking in the progression of diabetic nephropathy and various possible pharmacological interventions to attenuate the exacerbation of diabetic nephropathy.