Relations between toxicity and altered tissue distribution and urinary excretion of nicotine, cotinine, and hydroxycotinine after chronic oral administration of nicotine in rats

Active smoking in urban households: An association between urinary cotinine metabolite level and serum eGFR concentration

INTRODUCTION

Smoking stands as a primary contributor to preventable deaths globally and is linked to an increased risk of developing kidney failure and other diseases. A few studies have focused on the negative correlation between serum cotinine and estimated glomerular filtration rate (eGFR), indicating decreased kidney function. This study investigated the associations between urinary cotinine metabolite concentration and serum eGFR among active smokers in urban households.

METHODS

This was a cross-sectional study of active smokers in urban households' community Bangkok, Thailand from January to April 2023. The study involved 85 participants aged ≥18 years who were active smokers. Both urinary cotinine and serum eGFR concentrations were used as biomarkers. Independent sample t-tests were used to compare the urinary cotinine metabolite based on differences in the characteristic variable. We used multiple linear regression to test the association between cotinine metabolite and characteristics variables. Spearman's analysis was used to test the correlation between cotinine metabolite and eGFR concentration.

RESULTS

The association between urinary cotinine metabolite and serum eGFR concentration decreased with increasing cotinine concentrations (r= -0.223, p=0.041), suggesting a decline in kidney function. However, this study found no significant difference between urinary cotinine metabolite and characteristic variables (p>0.05). Additionally, those who smoked for ≥10 years (117.40 ± 89.80 ng/mL), smoked ≥10 cigarettes per day (117.40 ± 89.80 ng/mL) and used conventional cigarettes (124.53 ± 115.10 ng/mL). The results of the multiple linear regression models analysis indicated that those who were smokers for ≥10 years (β=0.076; 95% CI: -31.575-59.715) and those who were smoked ≥10 cigarettes/day (β=0.126; 95% CI: -65.636-18.150) were not associated with urinary cotinine metabolite level.

CONCLUSIONS

This study shows that the urinary cotinine metabolite level is associated with serum eGFR concentration among active smokers in urban households. The current study suggests that clinical identification and a prospective cohort study are needed before robust conclusions about how tobacco affects kidney efficiency.

Effect of occupational exposure to petrol and gasoline components on liver and renal biochemical parameters among gas station attendants, a review and meta-analysis

OBJECTIVES

Kidney and liver are of the most affected organs during permanent exposure to petrol and gasoline components in gas stations. This study aims to investigate the renal and liver involvements in these workers using meta-analysis.

METHODS

PubMed, Scopus, Science direct, ISI web of science, and Google scholar motor engine were searched using Mesh terms of the relevant keywords. Screening of titles, abstracts and full texts was continued until the eligible articles meeting the inclusion/exclusion criteria were selected. Quality assessment was conducted using NOS (Newcastle-Ottawa Quality score). The pooled standard mean difference of the renal and liver indices between exposed/unexposed groups was estimated using Stata ver. 11 software.

RESULTS

In this systematic review, 22 papers were entered. The pooled standard mean difference (95% confidence interval) between exposed and unexposed groups was estimated as of 0.74 (0.28, 1.21) for alkaline phosphatase (ALP), 2.44 (1.80, 3.08) for aspartate transaminase (AST), 2.06 (1.42, 2.69) for alanine transaminase (ALT), 0.10 (-0.09, 0.29) for total Bilirubin (TB), 0.74 (-0.42, -1.90) for total protein (TP), -0.49 (-0.82, -0.15) for albumin, 0.88 (-0.10, 1.87) for uric acid, 1.02 (0.45, 1.59) for creatinine and 1.44 (0.75, 2.13) for blood urea nitrogen (BUN).

CONCLUSION

Our meta-analysis showed that the serum AST, ALT, ALP, total protein, total bilirubin, BUN, uric acid and creatinine levels were higher among workers exposed to petrol and gasoline than control group, while albumin was lower in the serum of the exposed workers. Therefore, occupational exposure to gasoline stations can create adverse effects on kidney and liver function.

Age-dependent sensitivity of the mouse kidney to chronic nicotine exposure

BackgroundMany adolescents are exposed to nicotine via smoking, e-cigarette use, or second-hand smoke. Nicotine-induced renal oxidative stress and its long-term consequences may be higher in adolescents than in adults because of intrinsic factors in the adolescent kidney.MethodsAdolescent and adult male C57Bl/6J mice were subjected to 2 or 200 μg/ml nicotine, which closely emulates passive or active smoking, respectively, for 4 weeks. Extent of nicotine exposure (cotinine content), oxidative stress (HNE), renal function (creatinine), tubular injury (KIM-1), and pretreatment renal levels of select pro-oxidant (p66shc) and antioxidant (Nrf2/MnSOD) genes were determined. Impact of p66shc overexpression or Nrf2/MnSOD knockdown on low-/high-dose nicotine-induced oxidative stress was determined in cultured renal proximal tubule cells.ResultsDespite similar plasma/renal cotinine levels, renal HNE and KIM-1 contents were higher in adolescents compared with those in adults, whereas renal function was unaltered after passive or active smoking-equivalent nicotine exposure. Pretreatment levels of p66shc were higher, whereas Nrf2/MnSOD levels were lower in the adolescent kidney. In agreement with this, overexpression of p66shc or knockdown of Nrf2/MnSOD augmented nicotine-induced ROS production in renal proximal tubule cells.ConclusionChronic nicotine exposure incites higher oxidative stress in the adolescent than in adult kidney because of a pre-existent pro-oxidant milieu.

The multiple bottle effect is overridden in male and female rats by simultaneous presentation of two oral nicotine solutions

BACKGROUND

Studies on the oral route of nicotine administration in rodents make important contributions to our understanding of human nicotine use, and alternative approaches to smoking cessation. While environmental availability of oral nicotine contributes to voluntary intake and appears to drive consumption initially, solution concentration may exert more control over intake with continued exposure. Further, it is believed that female rodents consume more nicotine and show greater motivation to obtain it than males.

OBJECTIVES

The purpose of our study was to determine voluntary oral nicotine intake patterns following continuous exposure to relatively high concentrations in male and female rats, employing a multiple bottle approach, and to describe the relationship between oral nicotine consumption and sera cotinine.

METHODS

Using five bottles, adult Sprague-Dawley rats were given continuous access to water and 15 μg/ml nicotine solutions or water and 15 and 30 μg/ml nicotine solutions for 2 weeks; blood serum was analyzed for cotinine.

RESULTS

Rats consistently consumed oral nicotine and female rats ingested more nicotine than males, even at relatively high concentrations. Yet, when both concentrations were presented simultaneously, oral nicotine intake did not exceed that of water, thus overriding an environmental, or multiple-bottle, effect. Cotinine was systemically circulated following first-pass hepatic metabolism of nicotine at early, but not at later stages of nicotine exposure.

CONCLUSIONS

Our findings suggest rats will readily and voluntarily ingest considerably higher doses of nicotine than previously reported resulting in initial systemic cotinine, and trends toward sex differences are mitigated by solution concentration.

Preclinical in vivo ADME studies in drug development: a critical review

INTRODUCTION

The last two decades have brought many fundamental changes to the drug development process. One such change is the importance of preclinical pharmacokinetics, which has become an essential part of early drug discovery. Furthermore, bioanalytical methods have become more sensitive and the identification and quantitation of metabolites can now be carried out on limited amount of biological material. There has also been a change in regulatory expectations, which are now particularly focused on the safety of human metabolites.

AREAS COVERED

The focus of this paper is on some 'traditional' in vivo ADME studies: excretion balance, metabolic profile and WBA in the toxicological species. These studies, performed with radiolabeled material, have a long history: and are a regular presence in submission dossiers. This paper reviews their value in the perspective of the contemporary drug development process.

EXPERT OPINION

These experiments may sometimes still be relevant to explain toxicological findings or for other special purposes but should not be considered required pieces of the registration dossiers. An appropriate investigation of samples coming from safety evaluation and human Phase I studies and the knowledge generated during the lead optimization phase provide, in most instances, all the DMPK information needed to take decisions in the drug development process.

Simultaneous quantification of nicotine and metabolites in rat brain by liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of nicotine (NIC), cotinine (COT), nornicotine (NNIC), norcotinine (NCOT), nicotine-N-β-D-glucuronide (NIC GLUC), cotinine-N-β-D-glucuronide (COT GLUC), nicotine-1'-oxide (NNO), cotinine-N-oxide (CNO), trans-3'-hydroxycotinine (3-HC), anabasine (AB) and anatabine (AT) was modified and validated for quantification of these selected analytes in rat brain tissue. This analytical method provides support for preclinical NIC pharmacokinetic and toxicological studies after controlled dosing protocols. After brain homogenization and solid-phase extraction, target analytes and corresponding deuterated internal standards were chromatographically separated on a Discovery(®) HS F5 HPLC column with gradient elution and analyzed by LC-MS/MS in positive electrospray ionization (ESI) mode with multiple reaction monitoring (MRM) data acquisition. Method linearity was assessed and calibration curves were determined over the following ranges: 0.1-7.5 ng/mg for NIC, COT GLUC and AB; and 0.025-7.5 ng/mg for COT, NNIC, NCOT, NIC GLUC, NNO, CNO, 3-HC and AT (R(2)≥0.99 for all analytes). Extraction recoveries ranged from 64% to 115%, LC-MS/MS matrix effects were ≤21%, and overall process efficiency ranged from 57% to 93% at low and high quality control concentrations. Intra- and inter-assay imprecisions and accuracy for all analytes were ≤12.9% and ≥86%, respectively. The method was successfully applied to quantification of NIC and metabolites in the brain of post-natal day 90 rats that were sacrificed 2-h after a single 0.8 mg/kg s.c. administration of (-)NIC. In these tissues, striatal concentrations were 204.8±49.4, 138.2±14.2 and 36.1±6.1 pg/mg of NIC, COT and NNIC, respectively. Concentrations of NIC, COT and NNIC in the remaining whole brain (RWhB) were 183.3±68.0, 130.0±14.1 and 46.7±10.3 pg/mg, respectively. Quantification of these same analytes in plasma was also performed by a previously validated method. NIC, COT, NNIC, NCOT, NNO and CNO were detected in plasma with concentrations comparable to those reported in previous studies. However, and in contrast to brain tissues, COT concentrations in plasma were significantly higher than were those of NIC (194.6±18.6 ng/mL versus 52.7±12.9 ng/mL). Taken together, these results demonstrate that a sensitive and selective method has been developed for the determination of NIC biomarkers in rat brain.

Chronic nicotine exposure exacerbates acute renal ischemic injury

Recent epidemiological reports showed that smoking has a negative impact on renal function and elevates the renal risk not only in the renal patient but perhaps also in the healthy population. Studies suggested that nicotine, a major tobacco alkaloid, links smoking to renal dysfunction. While several studies showed that smoking/chronic nicotine exposure exacerbates the progression of chronic renal diseases, its impact on acute kidney injury is virtually unknown. Here, we studied the effects of chronic nicotine exposure on acute renal ischemic injury. We found that chronic nicotine exposure increased the extent of renal injury induced by warm ischemia-reperfusion as evidenced by morphological changes, increase in plasma creatinine level, and kidney injury molecule-1 expression. We also found that chronic nicotine exposure elevated markers of oxidative stress such as nitrotyrosine as well as malondialdehyde. Interestingly, chronic nicotine exposure alone increased oxidative stress and injury in the kidney without morphological alterations. Chronic nicotine treatment not only increased reactive oxygen species (ROS) production and injury but also exacerbated oxidative stress-induced ROS generation through NADPH oxidase and mitochondria in cultured renal proximal tubule cells. The resultant oxidative stress provoked injury through JNK-mediated activation of the activator protein (AP)-1 transcription factor in vitro. This mechanism might exist in vivo as phosphorylation of JNK and its downstream target c-jun, a component of the AP-1 transcription factor, is elevated in the ischemic kidneys exposed to chronic nicotine. Our results imply that smoking may sensitize the kidney to ischemic insults and perhaps facilitates progression of acute kidney injury to chronic kidney injury.