The influence of nicotine in healing of small bowel anastomoses in rats: angiogenesis and miofibroblasts

Is There a Smoking Gun for Nicotine? A Review of the Role of Nicotine in Dermatologic Surgery

BACKGROUND

Dermatologic surgeons are faced with a dilemma when counseling actively smoking patients who require dermatologic surgery: recommend total cessation of all nicotine that is associated with extremely high rates of cessation failure or recommend nicotine replacement therapy (NRT).

OBJECTIVE

To determine the safety of NRT in dermatologic surgery.

MATERIALS AND METHODS

PubMed was queried: [(nicotine OR electronic cigarettes) AND (flap OR wound healing)].

RESULTS

Smoking tobacco is detrimental to wound healing, supported by ample evidence (1A). Perioperative smoking cessation reduces risk (1B). Basic science demonstrates both a benefit and detriment of nicotine depending on the factor studied (2A). Human studies suggest no detrimental effect of nicotine on perioperative complications (1B). Nicotine may be detrimental to flaps, but evidence is limited to basic science (2A).

CONCLUSION

Dermatologists should consider recommending nicotine replacement for smokers in the perioperative period. Evidence is lacking to determine safety in flaps. It is presumed based on animal studies that nicotine has a negative effect on flaps; however, it is likely less than tobacco. Weighing the risk of cessation failure without nicotine replacement versus nicotine replacement after flap is challenging. Electronic cigarettes should be discouraged as a means of NRT.

α7-nAChRs-mediated therapeutic angiogenesis accounts for the advantageous effect of low nicotine doses against myocardial infarction in rats

Angiogenesis accelerates tissue regeneration in a variety of ischemic conditions including myocardial infarction (MI). Here we tested the hypothesis that angiogenesis induced by α7-nicotinic acetylcholine receptors (α7-nAChRs) mitigates histopathological, electrocardiographic, and molecular consequences of MI in rats. These profiles were evaluated in the isoprenaline (85 mg/kg/day i. p. For 2 days) MI rat model treated with or without nicotine or PHA-543613 (PHA, selective α7-nAChR agonist). Isoprenaline-insulted rats showed (i) ECG signs of MI such as significant ST-segment elevations and prolonged QT-intervals, (ii) deteriorated left ventricular histopathological scoring and elevated inflammatory cell infiltration, (iii) reduced immunohistochemical expression of cardiac CD34, a surrogate marker of capillary density, (iv) decreased cardiac expression of iNOS and α7-nAChRs, and (v) adaptive increases in cardiac HO-1 expression and plasma angiogenic markers such as vascular endothelial growth factor (VEGF) and nitric oxide (NO). These effects of isoprenaline, except cardiac iNOS and α7-nAChRs downregulation, were ameliorated in rats treated with a low dose (20 μg/kg/day s. c. For 16 days) of nicotine or PHA. We also show that concurrent α7-nAChR blockade by methyllycaconitine (MLA, 40 μg/kg/day, for 16 days) reversed the ECG, histopathological, and capillary density effects of nicotine, thereby reinforcing the advantageous cardioprotective and anti-ischemic roles of α7-nAChRs in this setting. The observed results showed promising effects on isoprenaline induced myocardial damage. In conclusion, the activation of α7-nAChRs by doses of nicotine or PHA in the microgram scale promotes neovascularization and offers a promising therapeutic strategy for MI. CATEGORY: Cardiovascular Pharmacology.