Effect of nicotine on vasoconstrictor and vasodilator responses in human skin vasculature

What Is the Fate of Total Joint Arthroplasty Patients Who Are Asked to Quit Smoking Prior to Surgery?

Background

Smoking is a known risk factor for complications following primary total joint arthroplasty (TJA). Little is known regarding the fate of patients who are asked to quit smoking before surgery. The purpose of this study was to evaluate the success of smoking cessation prior to primary TJA and the impact of smoking cessation on perioperative outcomes.

Methods

This is a retrospective review of patients who presented between 2008 and 2020 to a single academic medical center with a documented smoking history and were asked to quit smoking prior to receiving a date for primary TJA. The cohort was surveyed about smoking cessation, smoking history, use of quit aids, seeking surgery elsewhere due to the cessation policy, and postoperative complications. Descriptive statistics evaluated the relationship between demographics, smoking cessation, and postoperative complications.

Results

A total of 101 patients completed the survey with an overall response rate of 48%. Sixty-two percent of patients quit smoking before surgery, and 51% of these patients reported remaining smoke-free at 6 months postoperatively. The average time to quit before TJA was 45 days (range: 1-365 days), and 62% quit without quit aids. The wound complication/infection rate was significantly higher for patients who did not stop smoking prior to TJA (4 of 16; 27%) than for those who did quit prior to surgery (3 of 63; 5%; P = .02).

Conclusions

This study demonstrates that most patients (62%) will stop smoking, if required, prior to primary TJA. Furthermore, 51% of patients reported abstinence from smoking at 6 months following TJA. TJA appears to be an effective motivator for smoking cessation.

Level of Evidence

III (retrospective cohort study).

Smoking and microvascular free flap perfusion in head and neck reconstruction: radial free forearm flaps and anterolateral thigh flaps

Head and neck reconstruction with microvascular free flaps is frequently performed in smokers. Smoking causes various alterations in the cardiovascular system. The aim of this study was to investigate the effects of smoking on flap perfusion as a critical factor for flap survival. A total of 370 patients reconstructed with a radial free forearm flap (RFFF) or anterolateral thigh flap (ALTF) in the head and neck region between 2011 and 2020 were retrospectively analyzed. Flap perfusion measurements with the O2C tissue oxygen analysis system were compared between nonsmokers, light smokers (< 20 pack-years), and heavy smokers (≥ 20 pack-years). The blood flow was intraoperatively equal in RFFFs (84.5 AU vs. 84.5 AU; p = 0.900) and increased in ALTFs (80.5 AU vs. 56.5 AU; p = 0.001) and postoperatively increased in RFFFs (114.0 AU vs. 86.0 AU; p = 0.035) and similar in ALTFs (70.5 AU vs. 71.0 AU; p = 0.856) in heavy smokers compared to nonsmokers. The flap survival rate was similar in nonsmokers, light smokers, and heavy smokers (97.3%, 98.4%, and 100.0%). Smoking partially increases rather than decreases microvascular free flap perfusion, which may contribute to similar flap survival rates in smokers and nonsmokers.

Evaluation of periodontal indices among non-smokers, tobacco, and e-cigarette smokers: a systematic review and network meta-analysis

OBJECTIVES

The detrimental effect of tobacco smoking on periodontal health is well known, while the effect of electronic cigarette on periodontal parameters has been less investigated. The aim of the present systematic review was to compare periodontal indices in three categories of patients: traditional cigarette smokers (TS), e-cigarette smokers (ES), and non-smokers (NS).

MATERIALS AND METHODS

An electronic search was conducted for studies published until December 2021 on MEDLINE (PubMed), ISI Web of Science, and Scopus. A hand search was additionally conducted. Clinical observational and cross-sectional trials investigating periodontal indices among tobacco smokers (TS), electronic cigarette smokers (ES) and non-smokers (NS) were included and selected by 2 independent reviewers. Data on probing depth (PD), plaque index (PI), and bleeding on probing (BOP) were collected. The risk of bias was evaluated according to the NIH quality assessment tool and a network meta-analysis (NMA) was undertaken.

RESULTS

Five relevant studies, from 707 identified, were included. Overall, 512 patients were included, of them 170 were NS, 176 were TS, and 166 were ES. A significant difference in the comparison among TS vs NS: effect size (ES) = 3.297 (95%CI: [2.142-4.454], p = 0.001) and TS and ES ES = 2.507 (95%CI: [1.351-3.663], p = 0.001) was identified for PD. A significant difference in the comparison among TS and NS, ES = 21.34 (95%CI: [13.41-29.27], p = 0.001) and between TS and ES ES = 15.67 (95%CI: [7.73-23.62], p = 0.001) was identified for PI. The analysis of BOP values shows a significant difference in the comparison among ES and NS: ES = - 16.22 (95%CI: [- 22.85 to - 9.59], p < 0.001) and between TS and NS: ES = - 14.47 (95%CI: [- 21.103 to - 7.848], p < 0.001). Based on the SUCRA ranking, NS showed the most favorable outcome for PD and PI, followed by ES. Tobacco smokers were clearly in the last position. Dealing with BoP ES showed the most favorable outcome, followed by TS. NS were in the last position.

CONCLUSIONS

Periodontal parameters were similar among NS and ES, while TS presented the worst indices. BoP was reduced both in ES and in TS.

CLINICAL RELEVANCE

Results of the present review suggest a reduced effect on periodontal tissue of e-cig smoking compared to traditional cigarettes, despite recent studies proved that e-cig smoking increases oxidative stress, inflammatory responses, change in pulmonary cellular behavior, and stimulates DNA injury.

Role of smoking in androgenetic alopecia: A systematic review

Smoking and its role in Androgenetic Alopecia has long been debated. Smoking may lead to hair loss by vasoconstriction, by forming DNA adducts, free radical damage to hair follicle, by enhancing senescence and hormonal effects. We have reviewed the available literature on AGA and smoking. Data available show that there is a significant association between smoking and AGA. However, studies demonstrating the benefit of avoidance of smoking in improving hair loss are lacking. Furthermore, large controlled studies with histological documentation are still unavailable to affirm the findings.

Association of vaping with decreased vascular endothelial growth factor expression and decreased microvessel density in cutaneous wound healing tissue in rats

Vaping is suggested to be a risk factor for poor wound healing akin to smoking. However, the molecular and histologic mechanisms underlying this postulation remain unknown. Our study sought to compare molecular and histologic changes in cutaneous flap and non-flap tissue between vaping, smoking and control cohorts. Animal study of 15 male Sprague-Dawley rats was randomized to three cohorts: negative control (n = 5), e-cigarette (n = 5) and cigarette (n = 5) and exposed to their respective treatments with serum cotinine monitoring. After 30 days, random pattern flaps were raised and healed for 2 weeks after which skin punch biopsies of flap and non-flap tissues were collected for quantitative-reverse transcription-polymerase chain reaction of three selected wound healing genes (transforming growth factor β [TGF-β], vascular endothelial growth factor [VEGF], matrix metalloproteinase-1 [MMP-1]); then, immunohistochemistry for CD68 expression, α-smooth muscle actin looking at microvessel density (MVD) and in situ hybridization to localize VEGF production were undertaken. In flap tissue, vaping (mean[SEM]) (0.61[0.07]) and smoking (0.70[0.04]) were associated with decreased fold change of VEGF expression compared with controls (0.91[0.03]) (p < 0.05, p < 0.05, respectively). In non-flap tissue, only vaping was associated with decreased VEGF expression (mean[SEM]) (0.81[0.07]), compared with controls (1.17[0.10]) (p < 0.05) with expression primarily localized to basal keratinocytes and dermal capillaries. Immunohistochemistry showed decreased MVD in smoking (0.27[0.06]) and vaping (0.26[0.04]) flap tissue compared to matched controls (0.65[0.14]) (p < 0.05, p < 0.05, respectively) and decreased areas of fibrosis compared with controls on gross histology. Vaping and smoking were similarly associated with decreased VEGF expression, MVD and fibrotic changes in flap tissue. The results suggest attenuated angiogenesis via decreased VEGF expression as a mechanism for poor wound healing in vaping-exposed rats.

The Impact of Smoking on Early Postoperative Complications in Hand Surgery

PURPOSE

Smoking is a prevalent modifiable risk factor that has been associated with adverse postoperative outcomes across numerous surgical specialties. We examined the impact of smoking on 30-day complications in patients undergoing hand surgery procedures.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program data sets were queried for patients who underwent common hand surgery procedures from 2011 to 2016. Cohorts were divided into smoking and nonsmoking and compared in terms of demographic characteristics, comorbidities, and postoperative complications. Multivariable logistic regression models were used to control for demographic characteristics and comorbidities in assessing the association between smoking and postoperative infections as well as other major and minor complications.

RESULTS

We identified a cohort of 48,370 patients in the National Surgical Quality Improvement Program who underwent certain outpatient and inpatient hospital facility-based hand surgery procedures from 2011 to 2016. Up to 22% of these patients reported active smoking. Compared with nonsmokers, smokers were more likely to be younger and male and to have a lower body mass index. In addition, they were more likely to have a higher American Society of Anesthesiologists classification and to report dyspnea and chronic obstructive pulmonary disease. Multivariable logistic regression identified an independent association between smoking and major complications. Smoking was not significantly associated with minor complications. When regrouped by complication type, smoking was associated with infectious and wound healing complications. In subgroup analysis, smokers undergoing elective hand surgery had increased odds of wound healing complications but not major, minor, or infectious complications.

CONCLUSIONS

Smokers may be at a significantly higher odds of certain complications compared with nonsmokers. For patients undergoing the elective procedures evaluated in this study, perioperative smoking may increase the risk of wound-healing complications.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Nicotine and vascular dysfunction

Cigarette smoking is the single most important risk factor for the development of cardiovascular diseases (CVDs). However, the role of nicotine, the addictive component of all tobacco products, in the development of CVD is incompletely understood. Although increased public awareness of the harms of cigarette smoking has successfully led to a decline in its prevalence, the use of electronic cigarettes (e-cig) or electronic nicotine delivery system has increased dramatically in recent years because of the perception that these products are safe. This review summarizes our current knowledge of the expression and function of the nicotinic acetylcholine receptors in the cardiovascular system and the impact of nicotine exposure on cardiovascular health, with a focus on nicotine-induced vascular dysfunction. Nicotine alters vasoreactivity through endothelium-dependent and/or endothelium-independent mechanisms, leading to clinical manifestations in both cigarette smokers and e-cig users. In addition, nicotine induces vascular remodelling through its effects on proliferation, migration and matrix production of both vascular endothelial and vascular smooth muscle cells. The purpose of this review is to identify critical knowledge gaps regarding the effects of nicotine on the vasculature and to stimulate continued nicotine research.

Non-microsurgical Composite Grafting for Acute Management of Fingertip Amputation

Following a fingertip amputation, if vessels are present and of adequate condition, microsurgical replantation is the preferred technique for management. Composite grafting has a limited role in the management of fingertip amputations due to its unreliable nature but can be an option when an amputated fingertip is not replantable and the patient desires restoration of fingertip length and aesthetics. When composite grafting is selected as the treatment of choice for a particular patient, there are methods of optimizing the chances of graft revascularization and survival, including early grafting, graft cooling, and a moist wound healing environment.

Anatabine ameliorates intestinal inflammation and reduces the production of pro-inflammatory factors in a dextran sulfate sodium mouse model of colitis

Background

Inflammatory bowel disease (IBD) is the collective term for chronic immune-mediated diseases of unknown, multifactorial etiology, arising from the interplay between genetic and environmental factors and including two main disease manifestations: ulcerative colitis (UC) and Crohn’s disease. In the last few decades, naturally occurring alkaloids have gained interest because of their substantial anti-inflammatory effects in several animal models of disease. Studies on mouse models of IBD have demonstrated the anti-inflammatory action of the main tobacco alkaloid, nicotine. In addition, anatabine, a minor tobacco alkaloid also present in peppers, tomato, and eggplant presents anti-inflammatory properties in vivo and in vitro. In this study, we aimed to evaluate the anti-inflammatory properties of nicotine and anatabine in a dextran sulfate sodium (DSS) mouse model of UC.

Results

Oral administration of anatabine, but not nicotine, reduced the clinical symptoms of DSS-induced colitis. The result of gene expression analysis suggested that anatabine had a restorative effect on global DSS-induced gene expression profiles, while nicotine only had limited effects. Accordingly, MAP findings revealed that anatabine reduced the colonic abundance of DSS-associated cytokines and increased IL-10 abundance.

Conclusions

Our results support the amelioration of inflammatory effects by anatabine in the DSS mouse model of UC, and suggest that anatabine constitutes a promising therapeutic agent for IBD treatment.

Perioperative complications of abdominal surgery in smokers

Purpose

This study examined the association between smoking and perioperative complications of laparoscopic abdominal surgery and whether these complications were reduced with ≥ 4 weeks of preoperative smoking cessation.

Methods

A total of 555 patients who underwent gastric and colorectal cancer surgeries under general anesthesia were divided into the following groups retrospectively: 290 individuals without smoking history (NS group), 144 previous smokers (stopped smoking more than 8 weeks before surgery, PS group), and 121 current smokers (CS group) divided to two groups according to preoperative smoking cessation for < 4 (CS1, n = 76) and 4–8 weeks (CS2, n = 45).

Results

When compared with the NS group, postoperative hospitalization duration was significantly longer in the CS1 group (p < 0.01), whereas differences between the CS2 or PS groups and NS group were not significant. The total number of postoperative complications was higher in all groups of smoking than in NS group, independent on preoperative smoking cessation; however, suture failure was significantly more frequent only in CS1 group. Although pack-years did not significantly affect complication rates in smokers, duration of smoking cessation time in PS group was a negative predictor of postoperative complications.

Conclusion

Providing more than 4 weeks of smoking cessation before gastrointestinal surgery can reduce the duration of hospitalization and rate of suture failure.

A case report of acute hypothermia during initial inpatient clozapine titration with review of current literature on clozapine-induced temperature dysregulations

BACKGROUND

Here we describe a unique case of clozapine-associated hypothermia during initial titration of this medication in an acute inpatient psychiatry setting. Only a handful of cases on this topic have been published. We discuss possible pharmacologic mechanisms supporting or refuting the propensity of clozapine to induce hypothermia, as well as risk factors for clozapine-induced hypothermia, and a comparison to clozapine-induced hyperthermia.

CASE PRESENTATION

A 70 year-old African American female with treatment-refractory schizoaffective disorder developed hypothermia with a nadir temperature of 89 °F (31.7 °C) after 7 days on clozapine, on a total dose of 50 mg twice daily. Accompanying symptoms included bradycardia, hypotension, QTc prolongation, tachypnea, hypoxemia, and an absence of shivering. The patient was transferred to the ICU, and rewarmed within 10 h with the discontinuation of her clozapine, ziprasidone, and carvedilol. Broad spectrum antibiotics were initiated, but discontinued shortly after, as the patient had no leukocytosis, and blood cultures were negative.

DISCUSSION

While hypoglycemia, hypothyroidism, sepsis, and stroke were effectively ruled out, alternative drug-disease (including chronic kidney disease), and drug-drug interactions were considered possible contributing features. Benzodiazepines, valproic acid, ziprasidone, and the numerous antihypertensive agents the patient was taking were considered as either primary or compounding factors for hypothermia. After exclusion or inclusion of these alternative causes, we calculated a score of 4 (possible) for clozapine-induced hypothermia on the Naranjo Scale.

CONCLUSIONS

Clozapine-induced hypothermia may occur more commonly than clinicians believe. Practitioners should be cognizant of this potentially fatal phenomenon, and monitor for temperature dysregulations while on clozapine, especially during initial titration, in those with multiple comorbid factors, and on additional medications that may contribute to hypothermia.

The Effects of Sildenafil and/or Nitroglycerin on Random-pattern Skin Flaps After Nicotine Application in Rats

Smoking aggravates skin necrosis as a complication of random-pattern flap ischaemia. Sildenafil and nitroglycerin (NTG) are vasodilator agents that may affect skin flap survival. Fifty rats were subjected to a dorsal random-pattern flap operation and randomly divided into 5 groups. The control group received no treatment. The ischaemic group were administered local nicotine injections. The sildenafil group were administered oral sildenafil treatment in addition to the same intervention as the ischaemic group. The NTG group received topical NTG ointment application instead of sildenafil. The combined group were given both sildenafil and NTG treatments. After 7 days, all rats were sacrificed for flap assessment. Flap survival percentages at the 3^rd and 7^th days were significantly higher in the combined group than in the other study groups. Histologically, the ischaemic group exhibited dermal disorganization and inflammatory cell infiltration, which were improved in the 3 treated groups; however, the combined group presented the most relevant effect. The epidermal thickness showed a decrease in the ischaemic group (23.1 μm) that was significantly increased in the sildenafil (28.4 μm), NTG (28.8 μm) and combined (35.8 μm) groups. Immunohistochemically, the combined group exhibited a significant decrease in the apoptotic index and an increase in the proliferative index (2.3 and 56.9%, respectively) compared to those in the ischaemic (63.2 and 3%), sildenafil (41.7 and 28.1%) and NTG (39.3 and 30.4%) groups. Transmission electron microscopy (TEM) showed that the combined group displayed improvement in most of the ischaemic changes. Our analyses suggest that the combined use of sildenafil and NTG is more efficacious than using only one of these treatments for skin flap survival.

The Presence of Sinus Tract Adversely Affects the Outcome of Treatment of Periprosthetic Joint Infections

BACKGROUND

A sinus tract may be encountered in patients with periprosthetic joint infection (PJI) and constitutes a major criterion for diagnosis. The aim of this study is to identify associated factors for the presence of sinus tract and outcome of 2-stage exchange arthroplasty in these patients.

METHODS

We retrospectively reviewed all patients with PJI following hip and knee arthroplasty from 2000 to 2017. Of them, 161 patients with a sinus tract had a minimum follow-up of 1 year following 2-stage exchange arthroplasty. These patients were matched 1:2 with those without sinus tract by using propensity score matching. Treatment success was assessed using the modified Delphi criteria. A multiple logistic regression analysis was performed to determine the effect of sinus tract on the outcome and associated factors for the presence of sinus tract.

RESULTS

Factors significantly associated with sinus tract included smoking (odds ratio [OR] = 1.83), hypothyroidism (OR = 1.62), hypoalbuminemia (OR = 1.52), hip joint involvement (OR = 1.43), and prior revision surgery (OR = 1.37). Patients with sinus tract had a significantly higher rate of failure compared to those without sinus tract (OR = 2.94).

CONCLUSION

This study demonstrates that the presence of sinus tract in patients with PJI adversely affects the outcome of treatment of these patients. The presence of sinus tract may be a proxy for other issues such as poor periarticular soft tissue, the poor nutritional status of the host, and multiple prior operations. These findings need to be borne in mind when treating patients with PJI and a concomitant sinus tract.

Chronic exposure to e-cig aerosols during early development causes vascular dysfunction and offspring growth deficits

Increasing popularity of electronic cigarettes (e-cigs), including among women of reproductive age, is attributed to its perceived safety compared to conventional tobacco. However, there is a major knowledge gap surrounding the effects of e-cig aerosols on pregnancy and fetal development. We aimed to evaluate the effects of vaping e-cigs during gestation on offspring growth and to asses if growth deficits are accompanied by altered maternal and fetal vascular hemodynamics. Sprague-Dawley dams were assigned to Pair-Fed Control, Pair-Fed Juice, or Juice+Nicotine groups, and then underwent either a prenatal or prenatal+postnatal exposure paradigm in a custom-engineered vaping system. Mass spectrometry identified major aerosolized constituents from e-cig vaping. The Juice+Nicotine group exhibited significantly decreased fetal weight and crown-rump length (↓46.56%, and ↓23.83%, respectively). Pre- and postnatal exposure to Juice+Nicotine resulted in decreased pup weight at postnatal day (PND) 4-10. Crown-rump length was decreased by 24.71% on PND 10. Blood flow in the Juice+Nicotine group was decreased in the maternal uterine and fetal umbilical circuits by 49.50% and 65.33%, respectively. We conclude that chronic exposure to e-cig aerosols containing nicotine during early development can have deleterious health effects on the exposed offspring. Vaping e-cigs containing nicotine during pregnancy lead to a reduction in offspring weight and crown-rump length, associated with a marked decrease in blood flow in both the maternal uterine and fetal umbilical circulation (a strong indicator of growth restriction). Thus, chronic exposure to e-cig aerosols containing nicotine can lead to potentially harmful developmental effects in early life.

Nicotine impairs intra-substance tendon healing after full thickness injury in a rat model

Nicotine is harmful to many bodily systems; however, the effects of nicotine on intra-substance tendon healing remain largely unexplored. The purpose of this study was to examine the functional, structural, and biomechanical effects of nicotine on the healing of Achilles tendons in rats after an acute full-thickness injury. Sixty Sprague-Dawley rats were enrolled in this study. Half were exposed to 0.9% saline and half to 61 ng/mL of nicotine for 3 months via subcutaneous osmotic pumps. At 3 months, all rats underwent blunt full thickness transection of the left Achilles tendon and were immobilized for one week in plantarflexion. In-vivo assays were conducted prior to injury, at 21 days, and at 42 days post-injury and included the following: Functional limb assessment, passive joint mechanics, and vascular evaluation. Rats were sacrificed at 21 and 42 days for biomechanical testing and histologic evaluation. Rats exposed to nicotine demonstrated decreased vascularity, greater alteration in gait mechanics, and increased passive ROM of the ankle joint. Biomechanically, the nicotine tendons failed at lower maximum loads, were less stiff, had smaller cross-sectional areas and had altered viscoelastic properties. Histologically, nicotine tendons demonstrated decreased vessel density at the injury site. This study demonstrates that nicotine leads to worse functional outcomes and biomechanical properties in tendons. The decreased vascularity in the nicotine group may suggest an underlying mechanism for inferior tendon healing. Patients should be counseled that using nicotine products increase their risk of poor tendon healing and may predispose them to tendon re-rupture. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Beyond photoaging: additional factors involved in the process of skin aging

Studies assessing the impact of extrinsic factors on skin aging have increased during the last with the increase in life expectancy. Although most of the studies are about the sun radiation impact, many factors should be considered in elderly people, beyond environmental conditions. Lifestyle factors, like diet, sleeping, smoking, should be analyzed carefully, as common age-related conditions (menopause, diabetes, pulmonary diseases, etc.). All these factors could accelerate the natural decline of skin structure and functions, possibly affecting the responses to treatments and drugs. This review demonstrates that growing evidence regarding environmental factors that are associated with lifestyle and comorbidities deserve greater attention from researchers and dermatologists and may require new approaches in the management of skin aging.

Interaction of obesity with smoking and inflammatory arthropathies increases the risk of periprosthetic joint infection: a propensity score matched study in a Chinese Han population

BACKGROUND

Although a large number of studies have identified obesity as an independent risk factor for the development of periprosthetic joint infection (PJI), the synergistic impacts of obesity with other factors on PJI remain unknown. Additionally, few studies have specifically explored the risk factors of PJI within a Chinese population.

AIMS

To investigate the association between obesity and PJI in a Chinese population, and identify synergistic impacts of obesity with other risk factors on the development of PJI.

METHODS

Three hundred and seven patients at a single institution with a diagnosis of PJI following primary total hip or knee arthroplasty, treated from 2008 to 2015, were identified. Each case was matched with two controls who did not develop PJI after primary total hip or knee arthroplasty in the study period using propensity score matching for several important parameters. Multi-variable logistic regression models were used to estimate the association between body mass index (BMI) and the risk of developing PJI. Interaction and stratified analyses were conducted according to age, sex, type of surgery, smoking status, alcohol use, diabetes, inflammatory arthritis, liver disease and renal disease.

FINDINGS

The multiple logistic analyses showed that obesity was associated with increased risk of PJI [odds ratio (OR) 2.48; 95% confidence interval (CI) 1.66-3.69]. When analysed as a continuous variable, BMI was also associated with increased risk of PJI (OR per 1 kg/m² increase in BMI 1.08; 95% CI 1.02-1.14). In the interaction analysis, patients who were obese and smoked had a higher OR of developing PJI than non-smokers who were obese (OR 3.54 vs 1.55, P-value for interaction=0.031). Similarly, the OR was much higher for patients with both obesity and inflammatory arthritis than for patients who were obese with no history of inflammatory arthritis (OR 3.9 vs 1.55, P-value for interaction=0.029). No other significant interactions were found in the association between obesity and PJI.

CONCLUSION

Obesity is an independent risk factor for the development of PJI in the Chinese Han population. Surgeons should be aware that obese patients who smoke or have inflammatory arthritis are at additional increased risk of PJI.

Infection and Rerupture After Surgical Repair of Achilles Tendons

Background:

Surgical repair of an Achilles tendon rupture has been shown to decrease rerupture rates. However, surgery also increases the risk of complications, including infection.

Purpose:

To determine the risk factors for infection and rerupture after primary repair of Achilles tendon ruptures.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective review was performed on 423 patients who underwent operative treatment of Achilles tendon ruptures between the years 2008 and 2014. The primary outcome of interest was the total rate of infection, and the secondary outcome of interest was the incidence of rerupture within 2 years of operation.

Results:

A total of 423 patients were analyzed, with a mean age of 46 years (range, 16-83 years) and a mean body mass index of 31.4 kg/m² (range, 17-55 kg/m²). The overall infection rate was 2.8%, and the rerupture rate was 1%. The median time between surgery and superficial surgical site infection was 30 days, and the median time between surgery and rerupture was 38 days. Longer tourniquet times (100.3 ± 34.7 minutes vs 69.9 ± 21.4 minutes; P = .04) and greater estimated blood loss (15.0 ± 9.1 mL vs 5.1 ± 12.0 mL; P = .01) were associated with an increased rate of deep surgical site infections. Patients who had longer operation and tourniquet times trended toward higher rerupture rates (P = .06 and .08, respectively). When compared with nonsmokers, current and previous smokers had an increased incidence of superficial or deep surgical site infections (6.25% vs 1.42%; P = .02). Age, sex, race, body mass index, alcohol use, diabetes, past steroid injections, and mechanism of injury did not contribute to complication rates.

Conclusion:

Achilles tendon repairs were associated with a low risk of infection and rerupture. Patients with longer tourniquet times, higher estimated blood loss, and a history of smoking were at increased risk for surgical site infections. Patients with longer operative times had increased rates of rerupture.

Body fat rather than body mass index is associated with gingivitis - A southern Brazilian cross-sectional study

BACKGROUND

This cross-sectional study aimed to evaluate the association between body mass index (BMI) and body fat with gingivitis in 613 adults of Porto Alegre, Brazil.

METHODS

Individuals with at least four teeth were included in this study. They were identified through a multi-stage probability sampling, considering the city distribution of sex and age. Structured interviews were conducted by trained researchers in order to collect sociodemographic characteristics, behavioral habits, and systemic impaired conditions. Visible plaque and modified gingival index were assessed by a trained and calibrated examiner. Additionally, weight, height, and body fat percentage were measured. Body fat percentage was determined by bioelectrical-impedance analysis using a portable electrical micro-current monitor. The median sites with marginal bleeding was 20%, and used as a cutoff point for gingivitis. Crude and adjusted prevalence ratio by mean Poisson regression with robust variance were calculated. Two multivariable models were performed in order to associate both independent and dependent variables.

RESULTS

In the multivariable analysis that included BMI, no significant association with gingivitis was detected. On the other hand, the multivariable model that included body fat showed that very high body fat category (PR 1.22; 95% CI: 1.01 to 1.49) was significantly associated with higher marginal gingival bleeding.

CONCLUSION

Very high body fat category rather than BMI was significantly associated with higher positive marginal gingival bleeding in adults.

Impact of alcohol & smoking on the surgical management of gastrointestinal patients

Alcohol and smoking are repeatedly described as modifiable risk factors in clinical studies across all surgical specialities. These lifestyle choices impart a sub-optimal physiology via multiple processes and play an important role in the surgical management of the gastrointestinal patient. Cessation is imperative to optimise the patient's fitness for surgery with surgery itself being a prime opportunity for sustained cessation. A consistent, planned and integrated management involving surgical, anaesthetic, medical, and primary care facets will aid in successful cessation and perioperative care. This review highlights the pathological processes which contribute to perioperative complications and details the current practices to detect, predict and appropriately manage the perioperative gastrointestinal patient who smokes and consumes alcohol.

How Does Chronic Cigarette Smoke Exposure Affect Human Skin? A Global Proteomics Study in Primary Human Keratinocytes

Cigarette smoking has been associated with multiple negative effects on human skin. Long-term physiological effects of cigarette smoke are through chronic and not acute exposure. Molecular alterations due to chronic exposure to cigarette smoke remain unclear. Primary human skin keratinocytes chronically exposed to cigarette smoke condensate (CSC) showed a decreased wound-healing capacity with an increased expression of NRF2 and MMP9. Using quantitative proteomics, we identified 4728 proteins, of which 105 proteins were overexpressed (≥2-fold) and 41 proteins were downregulated (≤2-fold) in primary skin keratinocytes chronically exposed to CSC. We observed an alteration in the expression of several proteins involved in maintenance of epithelial barrier integrity, including keratin 80 (5.3 fold, p value 2.5 × 10-7), cystatin A (3.6-fold, p value 3.2 × 10-3), and periplakin (2.4-fold, p value 1.2 × 10-8). Increased expression of proteins associated with skin hydration, including caspase 14 (2.2-fold, p value 4.7 × 10-2) and filaggrin (3.6-fold, p value 5.4 × 10-7), was also observed. In addition, we report differential expression of several proteins, including adipogenesis regulatory factor (2.5-fold, p value 1.3 × 10-3) and histone H1.0 (2.5-fold, p value 6.3 × 10-3) that have not been reported earlier. Bioinformatics analyses demonstrated that proteins differentially expressed in response to CSC are largely related to oxidative stress, maintenance of skin integrity, and anti-inflammatory responses. Importantly, treatment with vitamin E, a widely used antioxidant, could partially rescue adverse effects of CSC exposure in primary skin keratinocytes. The utility of antioxidant-based new dermatological formulations in delaying or preventing skin aging and oxidative damages caused by chronic cigarette smoke exposure warrants further clinical investigations and multi-omics research.

The isolated perfused human skin flap model: A missing link in skin penetration studies?

Development of effective (trans)dermal drug delivery systems requires reliable skin models to evaluate skin drug penetration. The isolated perfused human skin flap remains metabolically active tissue for up to 6h during in vitro perfusion. We introduce the isolated perfused human skin flap as a close-to-in vivo skin penetration model. To validate the model's ability to evaluate skin drug penetration the solutions of a hydrophilic (calcein) and a lipophilic (rhodamine) fluorescence marker were applied. The skin flaps were perfused with modified Krebs-Henseleit buffer (pH7.4). Infrared technology was used to monitor perfusion and to select a well-perfused skin area for administration of the markers. Flap perfusion and physiological parameters were maintained constant during the 6h experiments and the amount of markers in the perfusate was determined. Calcein was detected in the perfusate, whereas rhodamine was not detectable. Confocal images of skin cross-sections shoved that calcein was uniformly distributed through the skin, whereas rhodamine accumulated in the stratum corneum. For comparison, the penetration of both markers was evaluated on ex vivo human skin, pig skin and cellophane membrane. The proposed perfused flap model enabled us to distinguish between the penetrations of the two markers and could be a promising close-to-in vivo tool in skin penetration studies and optimization of formulations destined for skin administration.

The skin aging exposome

The term "exposome" describes the totality of exposures to which an individual is subjected from conception to death. It includes both external and internal factors as well as the human body's response to these factors. Current exposome research aims to understand the effects all factors have on specific organs, yet today, the exposome of human skin has not received major attention and a corresponding definition is lacking. This review was compiled with the collaboration of European scientists, specialized in either environmental medicine or skin biology. A comprehensive review of the existing literature was performed using PubMed. The search was restricted to exposome factors and skin aging. Key review papers and all relevant, epidemiological, in vitro, ex vivo and clinical studies were analyzed to determine the key elements of the exposome influencing skin aging. Here we propose a definition of the skin aging exposome. It is based on a summary of the existing scientific evidence for the role of exposome factors in skin aging. We also identify future research needs which concern knowledge about the interaction of distinct exposomal factors with each other and the resulting net effects on skin aging and suggest some protective measures.

The association between metabolic syndrome and pressure ulcers among individuals living with spinal cord injury

OBJECTIVE

The objective of this study was to identify the relationship between metabolic syndrome (MetS) and pressure ulcers (PrU), after controlling for demographic and injury characteristics, socioeconomic factors, health behaviors and fatigue among participants with spinal cord injury (SCI).

METHODS

This cross-sectional study recruited 350 participants with SCI from a hospital in the western region of the USA. Blood tests and physical examination were performed. Waist circumference, high-density cholesterol, triglycerides, blood pressure and fasting glucose were used to diagnose MetS according to Criteria for Clinical Diagnosis of Metabolic Syndrome defined by the American Heart Association. All other variables were self-reported. Three-stage multivariate logistic regression models were conducted to evaluate the effects of three sequential sets of predictors, including demographic/injury, socio-environmental/behavioral and health factors, basing the order of analysis on the Theoretical Risk and Prevention Model.

RESULTS

The prevalence of PrU and MetS was 11.0% (n=36) and 35.3% (n=115), respectively. Ethnicity, smoking, alcohol consumption and MetS were statistically associated with PrU in the full model. Participants who were non-Hispanic (odds ratio (OR)=10.30, 95% confidence interval (CI): 3.46-30.65), smokers (OR=2.69, 95% CI: 1.00-7.27) and drank over 30 drinks per month (OR=5.26, 95% CI: 1.24-22.26) had greater odds of having a PrU compared with those who were Hispanic, non-smokers and non-drinkers, respectively. We also observed a positive association between MetS and PrU (OR_MetS=3.71, 95% CI: 1.45-9.52), even after controlling for all other factors.

CONCLUSION

Participants who had MetS had higher odds of PrU than those without MetS after adjusting for multiple covariates. Unhealthy behaviors such as smoking and excess drinking were positively associated with PrU.

Lower subcortical gray matter volume in both younger smokers and established smokers relative to non-smokers

Although established adult smokers with long histories of nicotine dependence have lower neural tissue volume than non-smokers, it is not clear if lower regional brain volume is also observed in younger, less established smokers. The primary goal of this study was to investigate neural tissue volume in a large group of smokers and non-smokers, with a secondary goal of measuring the impact of age on these effects. We used voxel-based morphometry to compare regional gray matter volume in 118 individuals (59 smokers, 59 age- and gender-matched non-smokers). Younger smokers had significantly lower gray matter volume in the left thalamus and the left amygdala than their non-smoking peers (family-wise error-corrected clusters, P < 0.05). There was no correlation between smoking use variables and tissue volume among younger smokers. Established smokers had significantly lower gray matter volume than age-matched non-smokers in the insula, parahippocampal gyrus and pallidum. Medial prefrontal cortex gray matter volume was negatively correlated with pack-years of smoking among the established smokers, but not the younger smokers. These data reveal that regional tissue volume differences are not limited exclusively to established smokers. Deficits in young adults indicate that cigarette smoking may either be deleterious to the thalamus and amygdala at an earlier age than previously reported, or that pre-existing differences in these areas may predispose individuals to the development of nicotine dependence.

The Risk Factors for Failure of an Upper Extremity Replantation: Is the Use of Cigarettes/Tobacco a Significant Factor?

Background

The purpose of this study was to explore the potential risk factors associated with the failure of an upper extremity replantation with a focus on cigarette or tobacco use.

Patients and Methods

A cohort of 102 patients with 149 replants (6 extremities, 143 digits) and a mean age of 41 years (range 5 to 72 years) was enrolled in this study. The data collected included age, gender, tobacco/cigarettes use, trauma mechanism, underlying disease (e.g., hypertension (HTN), diabetes mellitus (DM), etc.), and vein graft use. An analysis with a multivariable regression was conducted to identify the risk factors of replant failure and their respective odds ratios (ORs).

Results

Multilevel generalized linear mixed models (GLMMs) with a binomial distribution and logit link showed that smoking did not increase the risk of replant failure (p = 0.234). In addition, the survival of replants was not affected by DM or HTN (p = 0.285 and 0.938, respectively). However, the replantation results were significantly affected by the age of the patients and the mechanism of injury. Patients older than 50 years and those with avulsion or crush injuries tended to have a higher risk of replant failure (OR = 2.29, 6.45, and 5.42, respectively; p = 0.047, 0.028, and 0.032, respectively).

Conclusions

This study showed that the use of cigarettes/tobacco did not affect the replantation outcome. The main risks for replant failure included being older than 50 years and the trauma mechanism (avulsion or crush injuries).

Case Report: Nicotine Replacement Therapy (NRT) in Hospitalized Surgical Patient

Hospital surgical services are often reluctant to offer nicotine replacement therapy (NRT) to inpatients due to concerns that nicotine leads to vasoconstriction and impaired wound healing. However, multiple potential health benefits result from offering NRT to hospitalized surgical patients who use tobacco products. A 28-year-old female patient, hospitalized following a motor vehicle accident, experienced severe nicotine withdrawal symptoms and a strong desire to smoke. After a Tobacco Treatment Specialist (TTS) consultation, the Physical Medical and Rehabilitation service at the hospital began her on NRT with positive outcomes. The patient experienced decreased cravings and withdrawal symptoms, as well as an increased desire to remain tobacco free after discharge. More surgical patients may have an increased commitment to remain tobacco free after discharge, if their withdrawal symptoms are treated during hospitalization using NRT.

Optimizing perioperative management of total joint arthroplasty

Clinical pathways for total joint arthroplasty have been shown to reduce costs and significantly impact perioperative outcomes mainly through reducing provider variability. Effective clinical pathways link evidence to individual practice and balance costs with local experience, outcomes, and access to resources for responsible perioperative management. Common components of clinical pathways with major impact on perioperative outcomes are: 1) implementing pathways designed to include multimodal analgesia with regional anesthesia, 2) use of tranexamic acid to reduce blood loss, and 3) preconditioning followed by participation in early, accelerated rehabilitation programs to prevent postoperative complications related to immobility.

Tobacco use may be associated with increased revision and complication rates following total hip arthroplasty

The purpose of this study was to compare the clinical outcomes of total hip arthroplasty in patients who were smokers to patients who were non-smokers. All total hip arthroplasties performed between 2007 and 2009 were reviewed to identify patients who indicated tobacco use. There were 110 smokers who were matched in a 1:2 ratio to 220 non-smoking patients. At a mean follow-up of 51 months (range, 24 to 72 months), smokers had an overall significantly lower survivorship of 92% (n = 9 revisions), compared to 99% (n = 2 revisions) in non-smokers. In addition, there were five complications in smokers (one pneumonia, three superficial infections, and one deep peroneal nerve palsy) compared to none in non-smokers. These results indicate that patients who smoke had higher overall revisions and postoperative complications.

PDE-5 inhibition improves skin flap viability in rats that are exposed to nicotine

INTRODUCTION

Nicotine causes ischemia and necrosis of skin flaps. Phosphodiesterase-5 (PDE-5) inhibition enhances blood flow and vasculogenesis. This study examines skin flap survival in rats exposed to nicotine that are treated with and without PDE-5 inhibition.

MATERIALS AND METHODS

Eighty six rats were divided into five groups. Group 1 received saline subcutaneous (SC) once per day. Group 2 received nicotine SC 2 mg/kg day. Group 3 received sildenafil intraperitoneal (IP) 10 mg/kg day. Group 4 received nicotine SC 2 mg/kg and sildenafil IP 10 mg/kg day. Group 5 received nicotine SC 2 mg/kg day and sildenafil IP 10 mg/kg two times daily. After 28 days of treatment, modified McFarlane flaps were created, silicone sheets were interposed, and flaps were sutured. Photographs were taken on postoperative days 1, 3, and 7 and fluorescence angiography was used on day 7, both to evaluate for skin flap necrosis. Rats were euthanized and flaps were harvested for Vascular Endothelial Growth Factor (VEGF) Western blot analysis. Images were analyzed by three blinded observers using ImageJ, and necrotic indices were calculated.

RESULTS

The nicotine and PDE-5 inhibition twice-daily group showed a 46% reduction in flap necrosis when compared to saline only (P < 0.05) and a 54% reduction when compared to nicotine only (P < 0.01). Fluorescence angiographic image analysis revealed reductions in flap necrosis (P < 0.01). VEGF analysis trended toward increased VEGF for all sildenafil-treated groups (P > 0.05).

CONCLUSIONS

PDE-5 inhibition exhibits a dose-dependent reduction in skin flap necrosis in rats exposed to nicotine. This suggests that PDE-5 inhibition may mitigate the ill effects of smoking on skin flaps.

The effect of TENS on random pattern flap survival in nicotinized rats

The adverse effects of cigarettes, due to their nicotine content, may cause important ischemic complications in flaps. Electrical stimulation increases blood flow in ischemic tissues, the level of vascular endothelial growth factor, capillary density, and angiogenesis while decreasing oxygen tension in tissues. Electrical stimulation is also known to increase survival rate in flaps. In this study, which tests the hypothesis that TENS (a type of electrical stimulation) contributes to enhancement of flap viability by eliminating the adverse effects of nicotine, 40 rats were divided into 4 groups of 10 rats. Nicotinization was achieved by subcutaneous administration of 2 mg/kg per day to the rats, other than those in the Control group, for 4 weeks. The rats in one of the nicotinized groups received 20 mA, 80 Hz TENS (TENS1 group) for 1 hour daily throughout the last week before McFarlane flaps of random pattern were made in the backs of all the rats. Another nicotinized group was subjected to TENS in a similar dose after flap elevation (TENS2 group). Flap blood flow was measured before and 48 hours after their construction, and their fluorescein perfusion was measured immediately after the flap elevation. The comparison of the survival rates of the flaps revealed that, although the blood flow in the Nicotine group was significantly lower than in the Control group, it was significantly higher in the TENS1 group than in both the Control and Nicotine groups. The proportion of the area stained with fluorescein, immediately after the elevation of flaps, was significantly reduced in the Nicotine group compared to the Control group. In the TENS1 group, however, it was greater than in the nicotine and TENS2 groups. Flap viability rates decreased significantly in the Nicotine group compared with the Control group. In the TENS2 group, however, an increase was observed compared with the Nicotine group.These findings suggest that although TENS performed before flap elevation does not contribute to flap survival, despite causing a rise in blood flow, it enhances flap survival when applied postoperatively. Given the practicality and low cost of TENS, it can be concluded that it may be possible to use it in the management of ischemic complications in flap operations in smokers.

Oro-facial manifestations in patients with eating disorders

Studies have reported that the oral health status is jeopardized in patients with eating disorders. The aim was to review the oro-facial manifestations in patients with eating disorders. The address the focused question was "What is the oro-dental health status in patients with eating disorders?" MEDLINE/PubMed and Google Scholar databases were searched from 1948 to March 2012 using the following terms in various combinations: "Anorexia nervosa", "bulimia nervosa", "eating disorders", "dental", "oral health status". Letters to the editor, unpublished data and articles published in languages other than English were excluded. Dry lips, burning tongue and parotid gland swelling are common manifestations in patients with eating disorders as compared to medically healthy controls. The association of dental caries and periodontal disease in patients with eating disorders remains debatable. Temporomandibular disorders have also been reported to be more prevalent in patients with eating disorders as compared to healthy controls. A critical oral-dental examination during routine dental check-ups may reveal valuable information regarding the presence or absence of eating disorders in routine dental patients. This may be important information, updating the medical history, supporting the role of the physician.

Nicotine replacement therapy after subarachnoid hemorrhage is not associated with increased vasospasm

BACKGROUND AND PURPOSE

A significant number of patients with aneurysmal subarachnoid hemorrhage are active smokers and at risk for acute nicotine withdrawal. There is conflicting literature regarding the vascular effects of nicotine and theoretical concern that it may worsen vasospasm. The literature on the safety of nicotine replacement therapy and its effects on vasospasm is limited.

METHODS

A retrospective analysis was conducted of a prospectively collected database of aneurysmal subarachnoid hemorrhage patients admitted to the neurointensive care unit from 1994 to 2008. Paired control subjects matched for age, sex, Fisher score, aneurysm size and number, hypertension, and current medication were analyzed. The primary outcome was clinical and angiographic vasospasm and the secondary outcome was Glasgow Outcome Score on discharge. Conditional logistic models were used to investigate univariate and multivariate relationships between predictors and outcome.

RESULTS

Two hundred fifty-eight active smoking patients were included of which 87 were treated with transdermal nicotine replacement therapy. Patients were well matched for age, sex, gender, Fisher score, aneurysm size and number, hypertension, and current medications, but patients who received nicotine replacement therapy had less severe Hunt-Hess scores and Glasgow coma scores. There was no difference in angiographic vasospasm, but patients who received nicotine replacement therapy were less likely to have clinical vasospasm (19.5 versus 32.8%; P=0.026) and a Glasgow Outcome Score <4 on discharge (62.6% versus 81.6%; P=0.005) on multivariate analysis.

CONCLUSIONS

Nicotine replacement therapy was not associated with increased angiographic vasospasm and was associated with less clinical vasospasm and better Glasgow Outcome Score scores on discharge.

Estrogen dependence of the renal vasodilatory effect of nicotine in rats: role of α7 nicotinic cholinergic receptor/eNOS signaling

AIMS

We recently reported that acute exposure to nicotine vasodilates the renal vasculature of male rats via facilitation of endothelial nitric oxide synthase (eNOS). In this study, we investigated whether this effect of nicotine is sexually dimorphic and the role of estrogen in modulating the nicotine effect.

MAIN METHODS

Nicotine-evoked vasodilation was evaluated in phenylephrine-preconstricted perfused kidneys obtained from male, proestrus female, ovariectomized (OVX) and estrogen-replaced OVX (OVXE(2)) rats.

KEY FINDINGS

Nicotine infusion (5×10(-5), 1×10(-4), and 5×10(-4) M) produced greater concentration-dependent reductions in the renal perfusion pressure (RPP) in an isolated kidney from proestrus females than from males. Inhibition of NOS by N(G)-nitro-L-arginine abolished the nicotine-evoked reduction in RPP and abolished the gender difference in the nicotine effect. Nicotine vasodilation was also attenuated in kidneys isolated from OVX and diestrus rats, models characterized by reduced estrogen levels. Further, estrogen or L-arginine supplementation in OVX rats largely restored the renal vasodilatory response to nicotine. Estrogen receptor blockade by tamoxifen abrogated the enhanced nicotine-evoked vasodilation elicited by E(2) in OVX rats. The nitrite/nitrate levels and protein expressions of eNOS and α(7) nicotinic cholinergic receptor (α(7) nAChRs) were significantly higher in renal tissues of OVXE(2) compared with OVX rats, suggesting a facilitatory effect for E(2) on α(7) nAChRs/eNOS signaling.

SIGNIFICANCE

Estrogen-dependent facilitation of NOS signaling mediates the enhanced vasodilator capacity of nicotine in the renal vasculature of female rats. Preliminary evidence also suggests a potential role for α(7) nAChRs in this estrogen-dependent phenomenon.

Uncoupled angiogenesis and osteogenesis in nicotine-compromised bone healing

Nicotine is the main chemical component responsible for tobacco addiction. This study aimed to evaluate the influence of nicotine on angiogenesis and osteogenesis and the associated expression of angiogenic and osteogenic mediators during bone healing. Forty-eight adult New Zealand White rabbits were randomly assigned to a nicotine group and a control group. Nicotine pellets (1.5 g, 60-day time release) or placebo pellets were implanted in the neck subcutaneous tissue. The nicotine or placebo exposure time for all the animals was 7 weeks. Unilateral mandibular distraction osteogenesis was performed. Eight animals in each group were euthanized on day 5, day 11 of active distraction, and week 1 of consolidation, respectively. The mandibular samples were subjected to radiographic, histologic, immunohistochemical, and real-time reverse-transcriptase polymerase chain reaction examinations. Nicotine exposure upregulated the expression of hypoxia inducible factor 1alpha and vascular endothelial growth factor and enhanced angiogenesis but inhibited the expression of bone morphogenetic protein 2 and impaired bone healing. The results indicate that nicotine decouples angiogenesis and osteogenesis in this rabbit model of distraction osteogenesis, and the enhanced angiogenesis cannot compensate for the adverse effects of nicotine on bone healing.

Sex and hormonal influences on the nicotine-induced attenuation of isoprenaline vasodilations in the perfused rat kidney

We previously reported that nicotine impairs betta-adrenoceptor-mediated renovascular control in male rats. Here, we investigated the roles of sex and estrogen in nicotine-betta-adrenoceptor renal interaction. The effect of nicotine on renal vasodilations caused by isoprenaline was evaluated in phenylephrine-preconstricted perfused kidneys of male and proestrus female rats in absence and presence of NG-nitro-<span class="smallcap">l</span>-arginine (<span class="smallcap">l</span>-NNA, a NOS inhibitor). The interaction was also studied in diestrus and ovariectomized (OVX) rats treated with or without estradiol, tamoxifen, or <span class="smallcap">l</span>-arginine. Bolus isoprenaline (0.03-8.0 micromol) elicited dose-dependent renal vasodilations; female preparations were more sensitive (smaller ED50) to isoprenaline-induced vasodilation than were male preparations. Infusion of nicotine (500 micromol/L) reduced isoprenaline vasodilations in the 2 sexes and abolished male-female differences in isoprenaline responses. <span class="smallcap">l</span>-NNA reduced isoprenaline vasodilations in proestrus but not in male preparations. Also, in the presence of <span class="smallcap">l</span>-NNA, nicotine caused no attenuation of isoprenaline vasodilations in proestrus preparations. Renal responses to isoprenaline together with the attenuation of these responses by nicotine were reduced by OVX and restored to near-proestrus levels after supplementation with estradiol, the estrogen receptor modulator tamoxifen, or <span class="smallcap">l</span>-arginine. In diestrus rats, which exhibited reduced plasma estradiol, nicotine caused less attenuation of isoprenaline vasodilations. We conclude that impairment of estrogen-NOS signaling constitutes a possible cellular mechanism for the detrimental effect of nicotine on isoprenaline vasodilations in female rats. The mechanism of the nicotine-induced attenuation of isoprenaline vasodilation in male kidneys, which is NOS-independent, remains to be elucidated.