The multiple faces of nicotine and its implications in tissue and wound repair

Why Female Smokers Have Poorer Long-Term Health Outcomes than Male Smokers: The Role of Cigarette Smoking During Pregnancy

Objectives: Women's health status is better than men but the opposite is true for female smokers who usually have poorer long-health outcomes than male smokers. The objectives of this study were to thoroughly reviewed and analyzed relevant literature and to propose a hypothesis that may explain this paradox phenomenon. Methods: We conducted a search of literature from three English databases (EMBASE, MEDLINE, and Google Scholar) from inception to 13 November 2023. A combination of key words and/or subject headings in English was applied, including relevant terms for cigarette smoking, sex/gender, pregnancy, and health indicators. We then performed analysis of the searched literature. Results: Based on this review/analysis of literature, we proposed a hypothesis that may explain this paradox phenomenon: female smokers have worse long-term health outcomes than male smokers because some of them smoke during pregnancy, and the adverse effects of cigarette smoking during pregnancy is much stronger than cigarette smoking during non-pregnancy periods. Conclusion: Approval of our pregnancy-amplification theory could provide additional evidence on the adverse effect on women's long-term health outcomes for cigarette smoking during pregnancy.

Comparative study of the effects of cigarette smoke versus next generation tobacco and nicotine product extracts on endothelial function

Tobacco smoking and hemodynamic forces are key stimuli for the development of endothelial dysfunction. As an alternative to smoking, next generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their potential pro-inflammatory and atherogenic effects on the endothelium. In this study, we analyzed key parameters of endothelial function after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine. All experiments were performed under atheroprotective high laminar or atherogenic low flow with primary human endothelial cells. Treatment with 3R4F, but not alternative smoking products, reduced endothelial cell viability and wound healing capability via the PI3K/AKT/eNOS(NOS3) pathway. Laminar flow delayed detrimental effects on cell viability by 3R4F treatment. 3R4F stimulation led to activation of NRF2 antioxidant defense system at nicotine concentrations ≥0.56 μg/ml and increased expression of its target genes HMOX1 and NQO1. Treatment with HTP revealed an induction of HMOX1 and NQO1 at dosages with ≥1.68 μg/ml nicotine, whereas e-cig and nicotine exposure had no impact. Analyses of pro-inflammatory genes revealed an increased ICAM1 expression under 3R4F treatment. 3R4F reduced VCAM1 expression in a dose-dependent manner; HTP treatment had similar but milder effects; e-cig and nicotine treatment had no impact. SELE expression was induced by 3R4F under static conditions. High laminar flow prevented this upregulation. Stimulation with laminar flow led to downregulation of CCL2 (MCP-1). From this downregulated level, only 3R4F increased CCL2 expression at higher concentrations. Finally, under static conditions, all components increased adhesion of monocytes to endothelial cells. Interestingly, only stimulation with 3R4F revealed increased monocyte adhesion under atherosclerosis-prone low flow. In conclusion, all product categories activated anti-oxidative or pro-inflammatory patterns. NGP responses were typically lower than in 3R4F exposed cells. Also, 3R4F stimulation led to an impaired endothelial wound healing and induced a pro-inflammatory phenotype compared to NGP treatment.

Acute exposure of Nicotine during Drosophila puncture injury activates an epidermal wound response reaction

Epidermal wound reaction after injury can be visualized in Drosophila melanogaster embryos by transgenic fluorescent wound reporters. A “local” reaction is limited to the epidermal cells surrounding a wound site occurs in wildtype embryos. A “global” reaction extends beyond the wound site to all epidermal cells occurs in immune response mutants (e.g. Flotillin-2 and Toll). The aim of this investigation is to explore the effect of nicotine on the localization of Drosophila wound reaction. Nicotine may have the potential to negatively affect wound repair by inhibiting a local reaction, and ultimately impeding epidermal wound recovery in Drosophila. We find nicotine exposure activates a global reaction after puncture injury of Drosophila embryos. Determining the effect of nicotine exposure on wound reaction in Drosophila may lead to improved understanding of how nicotine use in humans may influence wound healing after tissue damage.

High Glucose Restraint of Acetylcholine-Induced Keratinocyte Epithelial-Mesenchymal Transition Is Mitigated by p38 Inhibition

Non-neuronal acetylcholine (Ach) plays important roles in various aspects of cell biology and homeostasis outside the neural system. Keratinocytes (KCs) have a functional cholinergic mechanism, suggesting that they respond to Ach. However, the physiological role and mechanism by which Ach modulates wound KC behavior in both nondiabetic and diabetic conditions are unexplored. We found an enrichment in neurotransmitter-related pathways in microdissected-migrating nondiabetic and diabetic KCs. We showed that Ach upregulated TGFβRII through Src-extracellular signal‒regulated kinase 1/2 pathway to potentiate TGFβ1-mediated epithelial‒mesenchymal transition in normoglycemic condition. Unexpectedly, KCs were nonresponsive to the elevated endogenous Ach in a hyperglycemic environment. We further showed that the activation of p38 MAPK in high glucose condition interferes with Src-extracellular signal‒regulated kinase 1/2 signaling, resulting in Ach resistance that could be rescued by inhibiting p38 MAPK. A better understanding of the cholinergic physiology in diabetic KCs could improve wound management and care. The finding suggests that mitigating the inhibitory effect of diabetic wound microenvironment has a direct clinical implication on the efficacy and safety of various wound healing agents to improve chronic diabetic wounds.

A Novel In Vivo Model to Study Impaired Tissue Regeneration Mediated by Cigarette Smoke

Cigarette smoke is associated with several pathologies including chronic respiratory diseases and cancer. In addition, exposure to cigarette smoke is correlated with impaired wound healing, where a significant decrease in the regenerative capacity of smokers is well documented and broadly considered a negative risk factor after trauma or surgery. So far, some in vitro and in vivo models have been described to study how exposure to cigarette smoke diminishes the regenerative potential in different organisms. However, although useful, many of these models are difficult and expensive to implement and do not allow high-throughput screening approaches. In order to establish a reliable and accessible model, we have evaluated the effects of cigarette smoke extract (CSE) on zebrafish development and regeneration. In this work, zebrafish embryos and larvae were exposed to low doses of aqueous CSE showing severe developmental abnormalities in a dose-dependent manner. Furthermore, when adult zebrafish were subjected to caudal fin amputation, we observed a significant decrease in the regenerative capacity of animals exposed to CSE. The effect was exacerbated in male and aged fish compared to female or young organisms. The establishment of a zebrafish model to assess the consequences of cigarette smoke and its effects on animal physiology could provide a new tool to study the underlying mechanisms involved in impaired tissue regeneration, and aid the development of novel approaches to treat complications associated with cigarette smoke toxicity.

Nicotine-enhanced stemness and epithelial-mesenchymal transition of human umbilical cord mesenchymal stem cells promote tumor formation and growth in nude mice

Cigarette smoking is a well-known risk factor in the development and progression of malignant diseases. Nicotine, the major constituent in cigarette smoke, has also shown negative effects on stem cells. Mesenchymal stem cells (MSCs) have been widely demonstrated to migrate into tumors and play key roles in cancer progression. However, the mechanisms by which nicotine impacts MSCs and tumorigenesis of lung cancer are still undetermined. In this study we investigated the effects of nicotine on human umbilical cord mesenchymal stem cells (hUC-MSCs) and the impacts of nicotine-treated hUC-MSCs on tumor formation and progression. We found that nicotine has a toxic effect on hUC-MSCs and changes the morphology, inhibits proliferation and promotes apoptosis of hUC-MSCs in a dose-dependent manner. Nicotine-treated hUC-MSCs produce higher level of IL-6. Moreover, nicotine promotes migration, stemness and epithelial-mesenchymal transition (EMT) of hUC-MSCs by inhibiting E-cadherin expression and upregulating mesenchymal markers such as N-cadherin and Vimentin, leading to the induction of stem cell markers Sox2, Nanog, Sall4, Oct4 and CD44. Migration and proliferation of non-small cell lung cancer A549 cells and breast cancer MCF-7 cells are promoted after their coculture with nicotine-treated hUC-MSCs in a cell-cell contact-independent manner. Furthermore, nicotine-treated hUC-MSCs promote tumor formation and growth of A549 cells in nude mice. These studies demonstrated that the enhanced stemness and EMT of hUC-MSCs induced by nicotine are critical for the development of tobacco-related cancers.

Trends in non-lactation breast abscesses in a tertiary hospital setting

BACKGROUND

The aim of this paper was to retrospectively review non-lactation breast abscesses treated in Princess Alexandra Hospital over a 10-year period and to illustrate the trends in size, risk factors, microbiological profile and management.

METHODS

A computerized search of the medical records was undertaken to identify all adult patients with a diagnosis of breast abscesses during June 2005-June 2015. Patients concurrently breastfeeding were excluded. A retrospectively review of the clinical records was performed.

RESULTS

Eighty-five abscesses were identified in 77 patients. The median patient age was 45 years and 93.7% were females. Smoking and diabetes mellitus were associated with a longer inpatient hospital stay. There was a significant difference in microbiology of abscesses in relation to size. Smaller abscesses (≤3.0 cm) predominantly had mixed anaerobes (54%), whereas larger abscesses had a dominance of Staphylococcus aureus (29%) and other aerobic microbes (33%) (P < 0.05). Seven percent of all abscesses had methicillin-resistant S. aureus. Flucloxacillin was prescribed solely in majority of the cases (45%) with addition of suitable mixed anaerobic cover in 12% cases. Of the 85 abscesses, 58.8% were managed non-operatively with antibiotics ± percutaneous drainage. Percutaneous aspiration had a shorter inpatient stay compared with patients who underwent operative management.

CONCLUSION

This represents the first Australian study solely analysing non-lactation breast abscess. Size was correlated significantly to characteristic bacteriology and empiric therapy should include both aerobic and anaerobic cover. The majority of non-lactation breast abscesses can be managed non-operatively with a combination of antibiotics and percutaneous aspiration.

Red Maca (Lepidium meyenii), a Plant from the Peruvian Highlands, Promotes Skin Wound Healing at Sea Level and at High Altitude in Adult Male Mice

Nuñez, Denisse, Paola Olavegoya, Gustavo F. Gonzales, and Cynthia Gonzales-Castañeda. Red maca (Lepidium meyenii), a plant from the Peruvian highlands, promotes skin wound healing at sea level and at high altitude in adult male mice. High Alt Med Biol 18:373-383, 2017.-Wound healing consists of three simultaneous phases: inflammation, proliferation, and remodeling. Previous studies suggest that there is a delay in the healing process in high altitude, mainly due to alterations in the inflammatory phase. Maca (Lepidium meyenii) is a Peruvian plant with diverse biological properties, such as the ability to protect the skin from inflammatory lesions caused by ultraviolet radiation, as well as its antioxidant and immunomodulatory properties. The aim of this study was to determine the effect of high altitude on tissue repair and the effect of the topical administration of the spray-dried extract of red maca (RM) in tissue repair. Studies were conducted in male Balb/c mice at sea level and high altitude. Lesions were inflicted through a 10 mm-diameter excisional wound in the skin dorsal surface. Treatments consisted of either (1) spray-dried RM extract or (2) vehicle (VH). Animals wounded at high altitude had a delayed healing rate and an increased wound width compared with those at sea level. Moreover, wounding at high altitude was associated with an increase in inflammatory cells. Treatment with RM accelerated wound closure, decreased the level of epidermal hyperplasia, and decreased the number of inflammatory cells at the wound site. In conclusion, RM at high altitude generate a positive effect on wound healing, decreasing the number of neutrophils and increasing the number of macrophages in the wound healing at day 7 postwounding. This phenomenon is not observed at sea level.

Cigarette smoke extract counteracts atheroprotective effects of high laminar flow on endothelial function

Tobacco smoking and hemodynamic forces are key stimuli in the development of endothelial dysfunction and atherosclerosis. High laminar flow has an atheroprotective effect on the endothelium and leads to a reduced response of endothelial cells to cardiovascular risk factors compared to regions with disturbed or low laminar flow. We hypothesize that the atheroprotective effect of high laminar flow could delay the development of endothelial dysfunction caused by cigarette smoking. Primary human endothelial cells were stimulated with increasing dosages of aqueous cigarette smoke extract (CSEaq). CSEaq reduced cell viability in a dose-dependent manner. The main mediator of cellular adaption to oxidative stress, nuclear factor erythroid 2-related factor 2 (NRF2) and its target genes heme oxygenase (decycling) 1 (HMOX1) or NAD(P)H quinone dehydrogenase 1 (NQO1) were strongly increased by CSEaq in a dose-dependent manner. High laminar flow induced elongation of endothelial cells in the direction of flow, activated the AKT/eNOS pathway, increased eNOS expression, phosphorylation and NO release. These increases were inhibited by CSEaq. Pro-inflammatory adhesion molecules intercellular adhesion molecule-1 (ICAM1), vascular cell adhesion molecule-1 (VCAM1), selectin E (SELE) and chemokine (C-C motif) ligand 2 (CCL2/MCP-1) were increased by CSEaq. Low laminar flow induced VCAM1 and SELE compared to high laminar flow. High laminar flow improved endothelial wound healing. This protective effect was inhibited by CSEaq in a dose-dependent manner through the AKT/eNOS pathway. Low as well as high laminar flow decreased adhesion of monocytes to endothelial cells. Whereas, monocyte adhesion was increased by CSEaq under low laminar flow, this was not evident under high laminar flow. This study shows the activation of major atherosclerotic key parameters by CSEaq. Within this process, high laminar flow is likely to reduce the harmful effects of CSEaq to a certain degree. The identified molecular mechanisms might be useful for development of alternative therapy concepts.

Current relevance of hypoxia in head and neck cancer

Head and Neck cancer (HNC) is a complex mix of cancers and one of the more common cancers with a relatively poor prognosis. One of the factors that may assist us in predicting survival and allow us to adjust our treatment strategies is the presence of tumor hypoxia. In this overview we aim to evaluate the current evidence and potential clinical relevance of tumor hypoxia in head and neck cancer according to an extensive search of current literature.An abundance of evidence and often contradictory evidence is found in the literature. Even the contradictory evidence and comparisons are difficult to judge as criteria and methodologies differ greatly, furthermore few prospective observational studies exist for verification of the pre-clinical studies. Despite these discrepancies there is clear evidence of associations between prognosis and poor tumor oxygenation biomarkers such as HIF-1α, GLUT-1 and lactate, though these associations are not exclusive. The use of genetic markers is expanding and will probably lead to significantly more and complex evidence. The lack of oxygenation in head and neck tumors is of paramount importance for the prediction of treatment outcomes and prognosis. Despite the wide array of conflicting evidence, the drive towards non-invasive prediction of tumor hypoxia should continue.

The repetitive use of non-thermal dielectric barrier discharge plasma boosts cutaneous microcirculatory effects

BACKGROUND

Non-thermal atmospheric plasma has proven its benefits in sterilization, cauterization and even in cancer reduction. Furthermore, physical plasma generated by dielectric barrier discharge (DBD) promotes wound healing in vivo and angiogenesis in vitro. Moreover, cutaneous blood flow and oxygen saturation can be improved in human skin. These effects are mostly explained by reactive oxygen species (ROS), but electric fields, currents and ultraviolet radiation may also have an impact on cells in the treated area. Usually, single session application is used. The aim of this study was to evaluate the effects of the repetitive use of cold atmospheric plasma (rCAP) on cutaneous microcirculation.

HYPOTHESIS

The repetitive use of non-thermal atmospheric plasma boosts cutaneous microcirculation effects.

METHODS

Microcirculatory data was assessed at a defined skin area of the radial forearm of 20 healthy volunteers (17 males, 3 females; mean age 39.1±14.8years; BMI 26.4±4.6kg/m(2)). Microcirculatory measurements were performed under standardized conditions using a combined laser Doppler and photospectrometry system. After baseline measurement, CAP was applied by a DBD plasma device for 90s and cutaneous microcirculation was assessed for 10min. Afterwards, a second session of CAP application was performed and microcirculation was measured for another 10min. Then, the third application was made and another 20min of microcirculatory parameters were assessed.

RESULTS

Tissue oxygen saturation and postcapillary venous filling pressure significantly increased after the first application and returned to baseline values within 10min after treatment. After the second and third applications, both parameters increased significantly vs. baseline until the end of the 40-minute measuring period. Cutaneous blood flow was significantly enhanced for 1min after the first application, with no significant differences found during the remainder of the observation period. The second application improved and prolonged the effect significantly until 7min and the third application until 13min.

CONCLUSION

These data indicate that the repetitive use of non-thermal atmospheric plasma boosts and prolongs cutaneous microcirculation and might therefore be a potential tool to promote wound healing.

Do you mind if I vape? Immediate effects of electronic cigarettes on perfusion in buccal mucosal tissue--a pilot study

The association between smoking and postoperative complications is compounded in patients who have oral and maxillofacial operations by an additional local effect, and patients often continue to smoke after operation despite advice to stop. Recent studies have suggested that nicotine may reduce inflammation and improve angiogenesis, so topical application may be beneficial for smokers. The electronic cigarette is increasing in popularity and more patients ask whether they can vape after operation. We investigated the effect of electronic cigarettes (of which half contained nicotine and half did not) on blood flow in the buccal mucosa in 10 volunteers immediately after vaping. Smokers were excluded as this was considered an additional variable in a small pilot study and our Trust has a no-smoking policy. After vaping for 5 minutes, capillary blood flow was measured in the buccal mucosa at 5-minute intervals using a laser Doppler probe, and the results were expressed as arbitrary perfusion units. There was a wide variation in results and a small but significant rise (p=0.008) as a result of nicotine vaping, but these fell to the same levels as before within 30 minutes. Electronic cigarettes may have an effect on blood flow to the oral mucosa, although further studies are needed to show whether they improve healing time after operation. Additional work is also needed to compare them with cigarettes.

Safety and Efficacy of Nicotine Replacement Therapy in the Perioperative Period: A Narrative Review

Patients who smoke cigarettes are at increased risk for development of complications both during and after surgical procedures, including respiratory, cardiac, and healing-related complications. Abstinence from smoking can considerably reduce these risks. Pharmacotherapy, including nicotine replacement therapy (NRT), is an important component of efficacious tobacco use interventions. However, the use of NRT in the perioperative period is controversial. In this narrative review, we discuss the current evidence for the efficacy and safety of NRT in patients scheduled for surgical procedures, with emphasis on evidence from human studies. We performed a literature search for articles published from January 1, 1990, through May 1, 2015, in the PubMed online database using various permutations of the Medical Subject Headings terms surgery; surgical procedures, operative; nicotine; and smoking cessation. Studies were selected for inclusion according to their relevance to the preclinical and clinical evidence pertaining to how NRT affects surgical outcome and long-term rates of abstinence from tobacco. There is strong evidence that NRT enhances the efficacy of tobacco use interventions. Some preclinical studies suggest that nicotine in high doses that exceed those produced by NRT decreases the viability of skin flaps. Although the available data are limited, there is no evidence from human studies that NRT increases the risk of healing-related or cardiovascular complications. Individual clinical trials of tobacco use interventions that include NRT have revealed either no effect or a reduction in complication rates. Therefore, given the benefits of smoking abstinence to both perioperative outcomes and long-term health and the efficacy of NRT in achieving and maintaining abstinence, any policies that prohibit the use of NRT in surgical patients should be reexamined.

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis

One of the important 'hallmarks' of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.

Characterization of ex vivo cultured neuronal- and glial- like cells from human idiopathic epiretinal membranes

Background

Characterization of the neuro-glial profile of cells growing out of human idiopathic epiretinal membranes (iERMs) and testing their proliferative and pluripotent properties ex vivo is needed to better understand the pathogenesis of their formation.

Methods

iERMs obtained during uneventful vitrectomies were cultivated ex vivo under adherent conditions and assessed by standard morphological and immunocytochemical methods. The intracellular calcium dynamics of the outgrowing cells was assessed by fluorescent dye Fura-2 in response to acetylcholine (ACh)- or mechano- stimulation.

Results

The cells from the iERMs formed sphere-like structures when cultured ex vivo. The diameter of the spheres increased by 5% at day 6 and kept an increasing tendency over a month time. The outgrowing cells from the iERM spheres had mainly glial- and some neuronal- like morphology. ACh- or mechano- stimulation of these cells induced intracellular calcium propagation in both cell types; in the neuronal-like cells resembling action potential from the soma to the dendrites. Immunocytochemistry confirmed presence of glial- and neuronal cell phenotype (GFAP and Nestin-1 positivity, respectively) in the iERMs, as well as presence of pluripotency marker (Sox2).

Conclusion

iERMs contain cells of neuronal- and glial- like origin which have proliferative and pluripotent potential, show functionality reflected through calcium dynamics upon ACh and mechano- stimulation, and a corresponding molecular phenotype.

The convergence of fracture repair and stem cells: interplay of genes, aging, environmental factors and disease

The complexity of fracture repair makes it an ideal process for studying the interplay between the molecular, cellular, tissue, and organ level events involved in tissue regeneration. Additionally, as fracture repair recapitulates many of the processes that occur during embryonic development, investigations of fracture repair provide insights regarding skeletal embryogenesis. Specifically, inflammation, signaling, gene expression, cellular proliferation and differentiation, osteogenesis, chondrogenesis, angiogenesis, and remodeling represent the complex array of interdependent biological events that occur during fracture repair. Here we review studies of bone regeneration in genetically modified mouse models, during aging, following environmental exposure, and in the setting of disease that provide insights regarding the role of multipotent cells and their regulation during fracture repair. Complementary animal models and ongoing scientific discoveries define an increasing number of molecular and cellular targets to reduce the morbidity and complications associated with fracture repair. Last, some new and exciting areas of stem cell research such as the contribution of mitochondria function, limb regeneration signaling, and microRNA (miRNA) posttranscriptional regulation are all likely to further contribute to our understanding of fracture repair as an active branch of regenerative medicine.

Cigarette smoking and gastrointestinal diseases: the causal relationship and underlying molecular mechanisms (review)

Cigarette smoking is an important risk factor for gastrointestinal (GI) disorders, including peptic ulcers, inflammatory bowel diseases, such as Crohn's disease and cancer. In this review, the relationship between smoking and GI disorders and the underlying mechanisms are discussed. It has been demonstrated that cigarette smoking is positively associated with the pathogenesis of peptic ulcers and the delay of ulcer healing. Mechanistic studies have shown that cigarette smoke and its active ingredients can cause mucosal cell death, inhibit cell renewal, decrease blood flow in the GI mucosa and interfere with the mucosal immune system. Cigarette smoking is also an independent risk factor for various types of cancer of the GI tract. In this review, we also summarize the mechanisms through which cigarette smoking induces tumorigenesis and promotes the development of cancer in various sections of the GI tract. These mechanisms include the activation of nicotinic acetylcholine receptors, the formation of DNA adducts, the stimulation of tumor angiogenesis and the modulation of immune responses in the GI mucosa. A full understanding of these pathogenic mechanisms may help us to develop more effective therapies for GI disorders in the future.

Angiopoietins in inflammation and their implication in the development of inflammatory bowel disease. A review

BACKGROUND

Angiopoietins are essential angiogenic mediators. Since inflammatory bowel disease (IBD) involves inflammation, ulceration and regeneration of the intestinal mucosa, the angiopoietin system has been proposed as a factor to maintain pathological angiogenesis during the development of the IBD.

AIM

To review the potential role of angiopoietins in the inflammation driven by angiogenesis during the course of the IBD.

METHODS

Publications were identified by PubMed searches using the following key words: angiopoietin; Tie-2 receptor; angiogenesis; inflammatory bowel disease and inflammation, in various combinations.

RESULTS

Angiopoietin-1 acts as a regulator of blood vessel maturation and has anti-inflammatory properties, whereas angiopoietin-2 marks the onset of angiogenesis and is required for normal formation of lymph vessels. Both angiopoietins make use of their angiogenic regulatory effects via the angiopoietin tyrosine-kinase receptor (Tie-2). While angiogenesis has been shown to promote and sustain many events of inflammation, the involvement of the angiopoietin system in IBD has been reported in few studies. It is not clear whether the angiopoietins' role in the development of intestinal inflammation is due to an imbalance in the levels of these proteins or this system exerts its pro-angiogenic properties through a different mechanism during the close-loop relationship between angiogenesis and inflammation.

CONCLUSIONS

Angiopoietins have key functions in the angiogenic process, and their abnormal activation might depend on their surrounding inflamed environment. The determination of these angiogenic factors in serum and tissue could be useful for monitoring IBD progression.

Is nicotine still the bad guy? Summary of the effects of smoking on patients with head and neck cancer in the postoperative period and the uses of nicotine replacement therapy in these patients

Smoking has long been implicated in the development and progression of numerous postoperative complications. The cause is largely thought to be the presence of reactive oxygen species (ROS) in cigarette smoke, which attenuates inflammation and affects neutrophil function. Wound healing is further compromised by deficiencies in vitamins C and E, which result from a higher vitamin turnover secondary to the oxidative stress produced by smoking. However, studies recently have found that the effects of nicotine may benefit healing if used in isolation. We summarise the effects that smoking and abstaining from smoking can have on inflammation and wound healing, and describe the possible benefits that nicotine replacement and antioxidant supplements can give.

Nicotine affects cutaneous wound healing in stressed mice

Stress is an important condition of modern life. Nicotine addiction can modulate the physiological response to stress. Cutaneous healing is a complex process resulting in scar formation, which can be delayed by stress. Therefore, the aim of this study was to investigate the effects of nicotine administration on cutaneous wound healing in chronically stressed mice. Male mice were submitted to rotational stress, whereas control animals were not subjected to stress. These stressed and control animals were treated with a transdermal nicotine patch that was changed every day. A full-thickness excisional lesion was also generated, and 14 days later, lesions had recovered. However, the Stress + Nicotine group presented a delay in wound contraction. These wounds showed a decrease in inflammatory cell infiltration and lower expression of transforming growth factor-β (TGF-β), whereas there was an increase in angiogenesis and tumor necrosis factor-α (TNF-α) expression. In vitro fibroblast migration was also impaired by the nicotine treatment of stressed-stimulated cells. In conclusion, nicotine administration potentiates the delay in wound closure observed in mice submitted to stress.

Nicotine promotes acquisition of stem cell and epithelial-to-mesenchymal properties in head and neck squamous cell carcinoma

The ability of nicotine to enhance the malignancy of cancer cells is known; however, the possibility that nicotine could regulate a cancer stem cell phenotype remains to be well-established. In this study we sought to determine whether long-term exposure to nicotine could promote cancer stem cell-like properties in two head and neck squamous cell carcinoma cell lines, UMSCC-10B and HN-1. Nicotine treatment induced epithelial-to-mesenchymal transition (EMT) in both cell lines by repressing E-cadherin expression, and led to the induction of stem cell markers Oct-4, Nanog, CD44 and BMI-1, which was reversed upon ectopic re-expression of E-cadherin. Nicotine-treated cells formed spheres at a higher efficiency than non-treated cells, formed larger tumors when injected into mice, and formed tumors with 4-fold greater efficiency compared to control cells when injected at limiting doses. Consistent with previous literature, nicotine-treated cells demonstrated a greater capacity for survival and also a higher tendency to invade. Comparison of microRNA profiles between nicotine and control cells revealed the upregulation of miR-9, a repressor of E-cadherin, and the downregulation of miR-101, a repressor of EZH2. Taken together, these results suggest that nicotine may play a critical role in the development of tobacco-induced cancers by regulating cancer stem cell characteristics, and that these effects are likely mediated through EMT-promoting, microRNA-mediated pathways. Further characterization of such pathways remains a promising avenue for the understanding and treatment of tobacco-related cancers.

Treating a collagen scaffold with a low concentration of nicotine promoted angiogenesis and wound healing

BACKGROUND

Nicotine, one of the major pharmacologically active agents of cigarette smoke, has various effects on cell proliferation, and it has recently been reported to have angiogenic effects. In our previous study, we showed that the topical administration of nicotine at a low concentration accelerated wound healing. This study aimed to evaluate the efficacy of nicotine and synergistic effects of combination treatment with nicotine and basic fibroblast growth factor (bFGF) in a murine excisional wound model treated with artificial dermis.

METHODS

Full-thickness defects (8 mm in diameter) were created on the backs of mice, and artificial dermis was sutured to the defects. Phosphate-buffered saline (10 μL), nicotine (10(-3), 10(-4), or 10(-5) M), bFGF (0.5 μg), and both bFGF and 10(-4) M nicotine were topically administered to the artificial dermal tissue for 7 d. The mice were killed on day 14, and the wound area, neoepithelium length, and area of newly formed capillaries in the artificial dermis were evaluated.

RESULTS

The wound areas treated with 10(-4) M nicotine, bFGF, or bFGF plus 10(-4) M nicotine were significantly smaller than those in the control group. In these three groups, the neoepithelium in the bFGF plus 10(-4) M nicotine group was significantly longer than that in the other groups. There was no significant difference between the neoepithelium lengths of the control and 10(-5) M nicotine groups. The 10(-3) M nicotine group displayed the least re-epithelization among the groups.

CONCLUSIONS

In this study, 10(-4) M nicotine induced angiogenesis in, and accelerated the healing of, wounds treated with artificial dermis. bFGF and nicotine had synergistic effects, and the combined use of nicotine and bFGF is an effective wound healing method.

Vagus nerve stimulation blocks vascular permeability following burn in both local and distal sites

Recent studies have shown that vagus nerve stimulation (VNS) can block the burn-induced systemic inflammatory response (SIRS). In this study we examined the potential for VNS to modulate vascular permeability (VP) in local sites (i.e. skin) and in secondary sites (i.e. lung) following burn. In a 30% total body surface area burn model, VP was measured using intravascular fluorescent dextran for quantification of the VP response in skin and lung. A peak in VP of the skin was observed 24h post-burn injury, that was blocked by VNS. Moreover, in the lung, VNS led to a reduction in burn-induced VP compared to sham-treated animals subjected to burn alone. The protective effects of VNS in this model were independent of the spleen, suggesting that the spleen was not a direct mediator of VNS. These studies identify a role for VNS in the regulation of VP in burns, with the translational potential of attenuating lung complications following burn.

Prenatal ablation of nicotinic receptor alpha7 cell lineages produces lumbosacral spina bifida the severity of which is modified by choline and nicotine exposure

Lumbosacral spina bifida is a common debilitating birth defect whose multiple causes are poorly understood. Here, we provide the first genetic delineation of cholinergic nicotinic receptor alpha7 (Chrna7) expression and link the ablation of the Chrna7 cell lineage to this condition in the mouse. Using homologous recombination, an IRES-Cre bi-cistronic cassette was introduced into the 3′ noncoding region of Chrna7 (Chrna7:Cre) for identifying cell lineages expressing this gene. This lineage first appears at embryonic day E9.0 in rhombomeres 3 and 5 of the neural tube and extends to cell subsets in most tissues by E14.5. Ablation of the Chrna7:Cre cell lineage in embryos from crosses with conditionally expressed attenuated diphtheria toxin results in precise developmental defects including omphalocele (89%) and open spina bifida (SB; 80%). We hypothesized that like humans, this defect would be modified by environmental compounds not only folic acid or choline but also nicotine. Prenatal chronic oral nicotine administration substantially worsened the defect to often include the rostral neural tube. In contrast, supplementation of the maternal diet with 2% choline decreased SB prevalence to 38% and dramatically reduced the defect severity. Folic acid supplementation only trended towards a reduced SB frequency. The omphalocele was unaffected by these interventions. These studies identify the Chrna7 cell lineage as participating in posterior neuropore closure and present a novel model of lower SB that can be substantially modified by the prenatal environment. © 2012 Wiley Periodicals, Inc.

Cigarette smoke-induced early growth response-1 regulates the expression of the cysteine-rich 61 in human skin dermal fibroblasts

Tobacco smoke is known to be an element contributing to accelerate premature skin ageing. Cysteine-rich 61 (Cyr61) is a member of the connective tissue factor CCN (Cyr61, CTGF and Nov) family, and early growth response-1 (Egr-1) is a generally expressed member of the zinc-finger family of transcription factors. To investigate the regulatory potential of Egr-1 on expression of Cyr61 by smoking, this study examined the hypothesis that cigarette smoke-induced Egr-1 induces expression of Cyr61 in human skin dermal fibroblasts (HSDF). HSDF were exposed to different concentrations of cigarette smoke extract (CSE) for 24 h; a cytotoxicity assay was then performed for the detection of cell proliferation. Results of Western blot and reverse transcription-polymerase chain reaction (RT-PCR) showed that CSE induces a transient synthesis of Egr-1 in HSDF. Cyr61 mRNA and protein levels showed a marked increase in a time-dependent manner after CSE exposure. Following transfection with an Egr-1 overexpression vector, HSDF showed increased activity of the Cyr61 promoter in a dose-dependent manner. Using Egr-1 interfering RNA, we confirmed that CSE-induced Cyr61 expression was dependent on Egr-1 expression. Findings of this study indicate that Egr-1-dependent induction of Cyr61 may contribute to premature skin ageing by smoking.

Angiogenin, angiopoietin-1, angiopoietin-2, and endostatin serum levels in inflammatory bowel disease

BACKGROUND

Angiogenesis is a complex process, involving a great number of mediators. It is implicated in the pathogenesis of numerous diseases, holding a critical role in inflammatory bowel disease (IBD). The objective of this study was to assess serum levels of angiogenin, angiopoietin-1, angiopoietin-2, and endostatin in IBD patients.

METHODS

Measurement of all angiogenesis mediators was performed with a commercially available enzyme-linked immunosorbent assay. Fifty-two patients with ulcerative colitis (UC), 59 with Crohn's disease (CD), and 55 healthy controls (HC) were included in the study. The values were analyzed with regard to disease and patients characteristics.

RESULTS

Angiogenin levels were significantly higher in IBD patients compared to HC (P < 0.001) and in UC and CD smoker patients compared to nonsmokers (P = 0.0121 and P = 0.005, respectively). Angiogenin levels were lower in UC patients receiving 5-aminosalicylate (5-ASA) alone, compared to those receiving combined therapy (P = 0.0478). Angiopoietin-1 levels were significantly lower in IBD patients compared to HC (P < 0.0001) and increased in smokers compared to nonsmoker UC patients (P = 0.0085). IBD patients demonstrated increased angiopoietin-2 levels compared to HC (P = 0.0131), while CD patients with disease restricted to the colon had significantly lower levels compared to other disease locations (P < 0.0001). Higher endostatin levels were recorded in UC patients with extensive colitis.

CONCLUSIONS

Elevated serum angiogenin and angiopoietin-2 levels and lower serum angiopoietin-1 levels were shown in IBD patients, as well as a different pattern of angiogenic factor alterations related to location, treatment, smoking habits and gender.

Interaction between smoking and polymorphism in the promoter region of the VEGFA gene is associated with ischemic heart disease and myocardial infarction in rheumatoid arthritis

OBJECTIVE

To determine whether variants in the vascular endothelial growth factor A (VEGFA) gene are associated with ischemic heart disease (IHD) and/or myocardial infarction (MI) in patients with rheumatoid arthritis (RA), and whether there is evidence of a gene-smoking interaction.

METHODS

PCR-RFLP assays were used to determine the genotypes of VEGFA single-nucleotide polymorphisms (SNP) including VEGFA-2578A/C (rs699947), -460C/T (rs833061), +405C/G (rs2010963), and +936C/T (rs3025039) in 418 subjects with RA. Smoking history was obtained on each patient, and IHD and MI status was recorded. Associations with IHD/MI were assessed using contingency tables and logistic regression analyses.

RESULTS

Strong linkage disequilibrium was detected among VEGFA-2578, -460, and +405. SNP located in the VEGFA promoter region (-2578, -460) were found to be associated with IHD and MI, whereas +405 and +936, in the 5'-untranslated region (UTR) and 3'-UTR, respectively, were not. Haplotype analysis suggested that the A/C/G haplotype was associated with increased risk of IHD (OR 2.37, 95% CI 1.22-4.62) and MI (OR 4.10, 95% CI 1.45-11.49). Smoking was also independently associated with IHD and MI, and evidence of interaction between smoking and the VEGFA promoter SNP was found. Multivariate analyses indicated that the strongest associations with IHD and MI were due to the combined effect of the VEGFA-2578 A allele and smoking (OR 3.52 and 7.11, respectively), independent of risk factors such as age, sex, diabetes, C-reactive protein, hypercholesterolemia, and hypertension.

CONCLUSION

Interaction between smoking and polymorphism in the VEGFA gene is associated with IHD and MI in patients with RA.

Up-regulation of TNF-alpha secretion by cigarette smoke is mediated by Egr-1 in HaCaT human keratinocytes

Many epidemiologic studies have pointed to a significant association between cigarette smoking and inflammatory skin disease such as psoriasis. Cigarette smoke induces expression of regulators of inflammation such as interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor (TNF)-alpha. It was recently demonstrated that early growth response-1 (Egr-1) transcription factor is significantly up-regulated in the skin lesions of patients with psoriasis. The mechanism by which cigarette smoke extract (CSE) regulates inflammatory cytokine expression in keratinocyte was still unknown. The aim of this study was to investigate the signalling of CSE-induced Egr-1 expression and the role for Egr-1 in CSE-induced TNF-alpha expression. Cytotoxicity of CSE in HaCaT cells was measured by thiazolyl blue tetrazolium bromide (MTT) assay. CSE-induced Egr-1 expression was investigated by western blot, luciferase reporter assay and confocal microscopy. TNF-alpha expression was measured by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Involvement of Egr-1 in CSE-induced TNF-alpha secretion was determined by using Egr-1 specific siRNA. CSE increases the Egr-1 expression, promoter activity and its nuclear translocation in human HaCaT keratinocytes. CSE activates mitogen-activated protein kinase (MAPK) pathways including extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). Up-regulation of Egr-1 expression by CSE stimulation was found to be inhibited by an ERK and JNK but not p38 inhibitor. CSE increases TNF-alpha expression and secretion. This increase is mediated by CSE-induced Egr-1 expression. Our results showed that CSE induces Egr-1 expression via MAPK pathway in human keratinocytes and TNF-alpha expression by Egr-1. This pathway may contribute to the development of inflammatory disease such as psoriasis.

Long-term consequences of fetal and neonatal nicotine exposure: a critical review

Cigarette smoking during pregnancy is associated with numerous obstetrical, fetal, and developmental complications, as well as an increased risk of adverse health consequences in the adult offspring. Nicotine replacement therapy (NRT) has been developed as a pharmacotherapy for smoking cessation and is considered to be a safer alternative for women to smoking during pregnancy. The safety of NRT use during pregnancy has been evaluated in a limited number of short-term human trials, but there is currently no information on the long-term effects of developmental nicotine exposure in humans. However, animal studies suggest that nicotine alone may be a key chemical responsible for many of the long-term effects associated with maternal cigarette smoking on the offspring, such as impaired fertility, type 2 diabetes, obesity, hypertension, neurobehavioral defects, and respiratory dysfunction. This review will examine the long-term effects of fetal and neonatal nicotine exposure on postnatal health.

Apoptotic cells activate the "phoenix rising" pathway to promote wound healing and tissue regeneration

The ability to regenerate damaged tissues is a common characteristic of multicellular organisms. We report a role for apoptotic cell death in promoting wound healing and tissue regeneration in mice. Apoptotic cells released growth signals that stimulated the proliferation of progenitor or stem cells. Key players in this process were caspases 3 and 7, proteases activated during the execution phase of apoptosis that contribute to cell death. Mice lacking either of these caspases were deficient in skin wound healing and in liver regeneration. Prostaglandin E(2), a promoter of stem or progenitor cell proliferation and tissue regeneration, acted downstream of the caspases. We propose to call the pathway by which executioner caspases in apoptotic cells promote wound healing and tissue regeneration in multicellular organisms the "phoenix rising" pathway.