Nicotine, as a novel tolerogenic adjuvant, enhances the efficacy of immunotherapy in a mouse model of allergic asthma

Nicotine in Inflammatory Diseases: Anti-Inflammatory and Pro-Inflammatory Effects

As an anti-inflammatory alkaloid, nicotine plays dual roles in treating diseases. Here we reviewed the anti-inflammatory and pro-inflammatory effects of nicotine on inflammatory diseases, including inflammatory bowel disease, arthritis, multiple sclerosis, sepsis, endotoxemia, myocarditis, oral/skin/muscle inflammation, etc., mainly concerning the administration methods, different models, therapeutic concentration and duration, and relevant organs and tissues. According to the data analysis from recent studies in the past 20 years, nicotine exerts much more anti-inflammatory effects than pro-inflammatory ones, especially in ulcerative colitis, arthritis, sepsis, and endotoxemia. On the other hand, in oral inflammation, nicotine promotes and aggravates some diseases such as periodontitis and gingivitis, especially when there are harmful microorganisms in the oral cavity. We also carefully analyzed the nicotine dosage to determine its safe and effective range. Furthermore, we summarized the molecular mechanism of nicotine in these inflammatory diseases through regulating immune cells, immune factors, and the vagus and acetylcholinergic anti-inflammatory pathways. By balancing the “beneficial” and “harmful” effects of nicotine, it is meaningful to explore the effective medical value of nicotine and open up new horizons for remedying acute and chronic inflammation in humans.

Protective effect of gallic acid on nicotine-induced testicular toxicity in mice

Background and purpose

Nicotine is an alkaloid found in many nutrients and tobacco that can cause infertility in men. Gallic acid is a powerful antioxidant that possesses antimutagenic and anticancer activities. This study aimed to determine the potential protective effect of gallic acid against nicotine-induced testicular toxicity in male mice.

Experimental approach

In this in vivo study, forty-eight mice were equally divided into eight groups intraperitoneally receiving normal saline (control), nicotine (0.6 mg/kg), gallic acid (5, 10, and 15 mg/kg), and gallic acid (5, 10, and 15 mg/kg) plus nicotine. Nicotine was injected intraperitoneally for 14 days and gallic acid was administered concomitantly with nicotine and continued for 7 days later. Then, body and testicular weights, the sperm parameters (viability, number, motility, and morphology of sperm), and testicular histology were evaluated. Also, serum levels of nitric oxide, total antioxidant, superoxide dismutase, malondialdehyde, and testosterone were measured.

Findings/Results

The results showed that the administration of nicotine significantly reduced testis and body weight, sperm count, viability, normal morphology and motility, seminiferous tubules diameter, testosterone levels, serum levels of total antioxidants, and superoxide dismutase compared to the control group (P < 0.05). It also significantly increased the level of nitric oxide and malondialdehyde (P < 0.05). Increasing the dose of gallic acid along with nicotine significantly increased body weight, sperm count, viability, normal morphology and motility, the diameter of seminiferous, testosterone concentration, total antioxidant levels (P < 0.05). This combination also significantly decreased malondialdehyde and nitric oxide levels compared to the nicotine-receiving group (P < 0.05).

Conclusion and implications

Gallic acid had a protective effect on nicotine-induced testicular toxicity in mice. It can neutralize the harmful effect of nicotine on male fertility in smokers.

Serum levels of TGF-β1, cytokines, angiogenic, and anti-angiogenic factors in pregnant women who smoke

INTRODUCTION

Women who smoke during pregnancy have a reduced risk of preeclampsia. The mechanism of this association is poorly understood. Preeclampsia is an anti-angiogenic and inflammatory state. Transforming growth factor beta 1 (TGF-β1) is a multi-functional anti-inflammatory cytokine that activates membrane bound endoglin on endothelial cells causing a myriad of vascular actions including vasorelaxation. The objective of the study was to determine serum levels of cytokines, angiogenic factors, placental growth factor (PlGF), TGF-β-1 and anti-angiogenic factors, soluble endoglin (sEng) and soluble vascular endothelial growth factor 1 (sVEGFR1) in smoking and non-smoking pregnant women.

METHODS

Using enzyme-linked immunosorbent and multiplex assays we prospectively analyzed serum levels of PIGF, TGF-β1, sEng, sVEGFR1 and cytokines in normotensive pregnant smokers and non-smokers. Exclusion criteria included maternal hypertension, autoimmune disorders, rupture of membranes, evidence of labor and drug use.

RESULTS

There were 59 women in the smoking and 66 in the non-smoking group. Compared to non-smoking mothers. maternal age was lower in smoking mothers with no significant difference in other demographic variables. There was no difference in levels of cytokines, anti-angiogenic factors and PlGF between the two groups. Median TGF-β1 levels were significantly higher in the smoking group (8120 pg/mL vs 6040 pg/mL, p < 0.001) and remained significant after controlling for confounders. TGF-β1 levels correlated positively with cotinine levels in the smoking group.

CONCLUSIONS

We speculate that higher TGF-β1 levels may explain the reduced incidence of preeclampsia in mothers who smoke by being available for action on maternal endothelium even after inactivation by circulating maternal sEng.