Elevated nicotine levels in patients undergoing hemodialysis. A role in cardiovascular mortality and morbidity?

Medicinal nicotine in COVID-19 acute respiratory distress syndrome, the new corticosteroid

The cholinergic anti-inflammatory pathway (CAP) refers to the anti-inflammatory effects mediated by the parasympathetic nervous system. Existence of this pathway was first demonstrated when acetylcholinesterase inhibitors showed benefits in animal models of sepsis. CAP functions via the vagus nerve. The systemic anti-inflammatory effects of CAP converges on the α7 nicotinic acetylcholine receptor on splenic macrophages, leading to suppression of pro-inflammatory cytokines and simultaneous stimulation of anti-inflammatory cytokines, including interleukin 10. CAP offers a novel mechanism to mitigate inflammation. Electrical vagal nerve stimulation has shown benefits in patients suffering from rheumatoid arthritis. Direct agonists like nicotine and GTS-1 have also demonstrated anti-inflammatory properties in models of sepsis and acute respiratory distress syndrome, as have acetylcholinesterase inhibitors like Galantamine and Physostigmine. Experience with coronavirus disease 2019 (COVID-19) induced acute respiratory distress syndrome indicates that immunomodulators have a protective role in patient outcomes. Dexamethasone is the only medication currently in use that has shown to improve clinical outcomes. This is likely due to the suppression of what is referred to as a cytokine storm, which is implicated in the lethality of viral pneumonia. Nicotine transdermal patch activates CAP and harvests its anti-inflammatory potential by means of an easily administered depot delivery mechanism. It could prove to be a promising, safe and inexpensive additional tool in the currently limited armamentarium at our disposal for management of COVID-19 induced acute hypoxic respiratory failure.

How to manage cigarette smoking in kidney transplant candidates and recipients?

Tobacco smoking is a frequent problem affecting many kidney transplant (KT) candidates and recipients. The negative impact of active smoking on KT outcomes has been demonstrated. Consequently, most guidelines strongly recommend quitting smoking before considering kidney transplantation. However, nicotine addiction is a complex multifactorial disease and only 3-5% of the patients who try to quit by themselves achieve prolonged abstinence. Smoking cessation programmes (SCPs) have proven their efficacy in the general population to increase the rate of quitting and should therefore be proposed to all smoking KT candidates and recipients. Nevertheless, SCPs have not been evaluated in the KT field and not all KT centres have easy access to these programmes. In this work, we aim to review the current knowledge on the subject and provide an overview of the available interventions to help smoking patients quit. We detail non-pharmaceutical and pharmaceutical approaches and discuss their use in KT candidates and recipients.

Active Smoking is Associated with Lower Dialysis Adequacy in Prevalent Dialysis Patients

BACKGROUND:

Dialysis adequacy measured by single pool Kt/V (spKt/V) lower than 1.2 or urea reduction rate (URR) lower than 65% is associated with a significant increase in patient mortality rate. Patients’ adherence to the medical treatment is crucial to achieve recommended targets for spKt/V. Smoking is a recognized factor of non-adherence.

AIM:

In this study we sought to assess the association of active smoking and dialysis adequacy.

METHODS:

A total of 134 prevalent dialysis patients from one dialysis center were included in an observational cross-sectional study. Clinical, laboratory and dialysis data were obtained from medical charts in previous 6 months. The number of missed, on purpose interrupted or prematurely terminated dialysis sessions was obtained. Dialysis adequacy was calculated as spKt/V and URR. Patients were questioned about current active smoking status. T-test and Chi-Square test were used for comparative analysis of dialysis adequacy with regard to smoking status.

RESULTS:

The majority of patients declared a non-smoking status (100 (75%)) and 34 (25%) were active smokers. Male gender, younger age and shorter dialysis vintage were significantly more often present in the active smokers ((9 (26%) vs 25 (73%), p = 0.028; 57.26 ± 12.59 vs 50.15 ± 14.10, p = 0.012; 118.59 ± 76.25 vs 88.82 ± 57.63, p = 0.030)), respectively. spKt/V and URR were significantly lower and Kt/V target was less frequently achieved in smokers ((1.46 ± 0.19 vs. 1.30 ± 0.021, p = 0.019; 67.14 ± 5.86 vs. 63.64 ± 8.30, p = 0.002; 14 (14%) vs. 11 (32%), p = 0.023), respectively. Shorter dialysis sessions, larger ultra filtrations and higher percentage of missed/interrupted dialysis session on patients’ demand were observed in smokers (4.15 ± 0.30 vs. 4.05 ± 0.17, p = 0.019; 3.10 ± 0.78 vs. 3.54 ± 0.92, p = 0.017; 25 (0.3%) vs. 48 (1.8%), p = 0.031), respectively.

CONCLUSION:

Active smokers, especially younger men, achieve lower than the recommended levels for dialysis adequacy. Non-adherence to treatment prescription in smokers is a problem to be solved. Novel studies are recommended in patients on dialysis, to further elucidate the association of dialysis adequacy with the active smoking status.

Targeting glutamate homeostasis for potential treatment of nicotine dependence

Several studies demonstrated that impairment in glutamatergic neurotransmission is linked to drug dependence and drug-seeking behavior. Increased extracellular glutamate concentration in mesocorticolimbic regions has been observed in animals developing nicotine dependence. Changes in glutamate release might be associated with stimulatory effect of nicotinic acetylcholine receptors (nAChRs) via nicotine exposure. We and others have shown increased extracellular glutamate concentration, which was associated with down regulation of the major glutamate transporter, glutamate transporter 1 (GLT-1), in brain reward regions of animals exposed to drug abuse, including nicotine and ethanol. Importantly, studies from our laboratory and others showed that upregulation of GLT-1 expression in the mesocorticolimbic brain regions may have potential therapeutic effects in drug dependence. In this review article, we discussed the effect of antagonizing presynaptic nAChRs in glutamate release, the upregulatory effect in GLT-1 expression and the role of glutamate receptors antagonists in the treatment of nicotine dependence.

[Smoking cessation in case of chronic kidney disease]

Smoking is one of the main causes of morbidity and mortality around the world. In France, despite increase of cost of cigarettes and exclusion of smoking in public places, daily smoking consummation remains high, particularly in women and young. Now, smoking is considered as a compartmental and/or psychologic and/or physic addiction. There are many categories of smokers and smoking cessation strategies must be tailored to individual level. Whatever the etiology of chronic kidney disease, in dialysis patient as transplanted, hypertension and vascular diseases are strong determinants of prognosis. In this way, there is a need for stronger involvement of nephrologists in the process of smoking cessation of their patients. Therapeutics and strategies are reviewed.

Association of smoking with cardiovascular and infection-related morbidity and mortality in chronic hemodialysis

BACKGROUND AND OBJECTIVES

Smoking is common in the hemodialysis population and is associated with increased all-cause mortality and development of cardiovascular disease. Cause-specific outcomes have not yet been examined in detail. This study investigated the association of baseline smoking status with all-cause, cardiovascular, and infection-related morbidity and mortality in patients undergoing long-term hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Post hoc analysis of the HEMO Study in patients with available comorbidity, clinical, and nutritional data. Cox proportional hazards regression models were fit to estimate the association of smoking status with mortality. Poisson and negative binomial regression models were fit to estimate the association of smoking status with hospitalization rate.

RESULTS

Complete data were available for 1842 individuals (44% male, 63% black, 45% diabetic). Mean age was 58 ± 14 years. At baseline, 17% were current smokers and 32% were former smokers. After case-mix adjustment, compared with never smoking, current smoking was associated with greater infection-related mortality (hazard ratio [HR], 2.04; 95% confidence interval [CI], 1.32-3.10) and all-cause mortality (HR, 1.44; 95% CI, 1.16-1.79) and greater cardiovascular (incidence rate ratio [IRR], 1.49; 95% CI, 1.22-1.82), infection-related (IRR, 1.35; 95% CI, 1.11-1.64) and all-cause (IRR, 1.43; 95% CI, 1.24-1.65) hospitalization rates. The population attributable fraction (i.e., fraction of observed deaths that may have been avoided) was 5.3% for current smokers versus never-smokers and 2.1% for current versus former smokers.

CONCLUSIONS

Active smoking is prevalent in the chronic hemodialysis population and is associated with greater all-cause, cardiovascular, and infection-related morbidity and mortality.

Nicotine chemistry, metabolism, kinetics and biomarkers

Nicotine underlies tobacco addiction, influences tobacco use patterns, and is used as a pharmacological aid to smoking cessation. The absorption, distribution and disposition characteristics of nicotine from tobacco and medicinal products are reviewed. Nicotine is metabolized primarily by the liver enzymes CYP2A6, UDPglucuronosyltransferase (UGT), and flavin-containing monooxygenase (FMO). In addition to genetic factors, nicotine metabolism is influenced by diet and meals, age, sex, use of estrogen-containing hormone preparations, pregnancy and kidney disease, other medications, and smoking itself. Substantial racial/ethnic differences are observed in nicotine metabolism, which are likely influenced by both genetic and environmental factors. The most widely used biomarker of nicotine intake is cotinine, which may be measured in blood, urine, saliva, hair, or nails. The current optimal plasma cotinine cut-point to distinguish smokers from non-smokers in the general US population is 3 ng ml(-1). This cut-point is much lower than that established 20 years ago, reflecting less secondhand smoke exposure due to clear air policies and more light or occasional smoking.

Metabolism and Disposition Kinetics of Nicotine

Nicotine is of importance as the addictive chemical in tobacco, pharmacotherapy for smoking cessation, a potential medication for several diseases, and a useful probe drug for phenotyping cytochrome P450 2A6 (CYP2A6). We review current knowledge about the metabolism and disposition kinetics of nicotine, some other naturally occurring tobacco alkaloids, and nicotine analogs that are under development as potential therapeutic agents. The focus is on studies in humans, but animal data are mentioned when relevant to the interpretation of human data. The pathways of nicotine metabolism are described in detail. Absorption, distribution, metabolism, and excretion of nicotine and related compounds are reviewed. Enzymes involved in nicotine metabolism including cytochrome P450 enzymes, aldehyde oxidase, flavin-containing monooxygenase 3, amine N-methyltransferase, and UDP-glucuronosyltransferases are represented, as well as factors affecting metabolism, such as genetic variations in metabolic enzymes, effects of diet, age, gender, pregnancy, liver and kidney diseases, and racial and ethnic differences. Also effects of smoking and various inhibitors and inducers, including oral contraceptives, on nicotine metabolism are discussed. Due to the significance of the CYP2A6 enzyme in nicotine clearance, special emphasis is given to the effects and population distributions of CYP2A6 alleles and the regulation of CYP2A6 enzyme.

Smoking, blood glucose control, and locus of control beliefs in people with type 1 diabetes mellitus

The relations between blood glucose control (HbA(1c)), smoking, and health-related diabetes locus of control beliefs were studied in a consecutive adult sample of 187 patients with Type 1 diabetes who were free of diabetes complications. Those who were smokers (n=32) had poorer HbA(1c) values than non-smokers [7.5+/-1.4 (S.D.) vs 6. 8+/-1.2%, P=0.017]. When the patients were compared according to HbA(1c) quartiles, 17 of the smokers (53%) were found among those with worst blood glucose control. The smokers showed a lesser belief than the non-smokers in powerful others such as physicians and diabetes nurses in regards as diabetes control and the course of the disease [23.5+/-4.4 (S.D.) vs 25.8+/-5.5 (S.D.), P=0.05]. The group as a whole exhibited strong beliefs that their own behaviour was important for diabetes control. This belief appears incongruent with smoking behaviour. The results have implications for possible coping and defence strategies used by the smokers. Due to their worse blood glucose control, weaker beliefs in health care professionals, and possible denial-like coping strategies, smokers clearly need special attention in diabetes care, particularly in the view of their risk of developing long-term complications.

Acute effects of nicotine infusion on platelets in nicotine users with normal and impaired renal function

The role of platelets in cardiovascular disease associated with smoking is becoming more established, but the effects of nicotine on platelets are unclear. Nicotine therapy is used for smoking cessation in both health and disease. Consequently, the effects of nicotine on platelets are of particular significance in disorders such as renal disease, which is associated with defective platelet function, increased cardiovascular morbidity, and altered nicotine metabolism. Thus, the aim of the present study was to investigate the acute effects of nicotine infusion (NI) on platelets in seven healthy subjects (HS) and seven patients with renal failure (RF). All subjects were nicotine users and had refrained from using nicotine for 36 h before NI. Blood was collected before, immediately after, and 2 h after NI. The plasma concentrations of nicotine and its main metabolite cotinine were determined by gas chromatography. Platelet responsiveness was assessed by aggregometry and flow cytometry in whole blood (P-selectin surface expression, fibrinogen- and von Willebrand factor-binding), P-selectin expression in isolated platelets, and immunoassays of platelet release (beta-thromboglobulin, platelet factor 4, and soluble P-selectin) and nitric oxide (NO) products. The plasma levels of cotinine, but not nicotine, were significantly higher in RF compared to HS at all time points. In both groups, collagen-induced platelet aggregation was restrained immediately after NI, when the plasma concentration of nicotine was maximal, and was restored after 2 h. Two hours after NI, activation-dependent P-selectin surface expression in isolated platelets increased in both groups. This increased platelet responsiveness occurred simultaneously with a significant increase of plasma cotinine and a decrease of NO products. Thus, the present study suggests that nicotine, directly or through some secondary mechanism or metabolite, only slightly potentiates some of the platelet responses. Renal failure appears not to influence the effects of nicotine on platelets.

Cigarette smoking and diabetes: an update

The article provides an overview of recent scientific information on the role of cigarette smoking in the prognosis of diabetes. Data sources included an English-language MEDLINE search for 1989 through 6/1993, supplemented by manual search of bibliographies of pertinent articles. Only studies of humans were considered. Cigarette smoking is related to the development and progression of diabetic nephropathy. Therefore, smoking status has to be taken into account in clinical studies on the course of nephropathy. The association between smoking and retinopathy is less consistent. Evidence is accumulating that cigarette smoking influences insulin action. Several large prospective cohort studies have shown that the relative risk for all-cause mortality is about twice as high for smoking compared to non-smoking diabetic patients. Strong associations are consistently found between cigarette-pack years and complications. It has been calculated that the theoretical benefit of stopping smoking is the most (cost-)effective risk factor intervention for diabetic patients. However, available programmes to help diabetic patients to stop smoking are unsuccessful.

Smoking and diabetes

The frequency of smoking in diabetic patients is not appreciably different from that in the general population. As in non-diabetic subjects, smoking is a major cardiovascular risk factor in diabetic patients. For young diabetic patients, smoking has been identified as a risk for macroproteinuric nephropathy. In respect of retinopathy, study results are more controversial. Recent studies also suggest smoking as a risk indicator for extra-articular connective tissue changes and neuropathy. Patients who already present with vascular complications, pregnant women, and women who use oral contraceptive drugs appear to run a particularly high risk by smoking. Stopping smoking reduces the risk of vascular morbidity and mortality in non-diabetic subjects. Although no comparable studies are available for diabetic populations, it should be assumed that the beneficial effects of stopping smoking are applicable to diabetic patients as well. Programmes to encourage diabetic patients to stop smoking are scarce and have not been successful.