Effects of transdermal nicotine delivery on cognitive outcomes: A meta-analysis

The impact of APOE and smoking history on cognitive function in older, long-term breast cancer survivors

PURPOSE

This study aims to determine whether older breast cancer survivors score lower on neuropsychological tests compared to matched non-cancer controls and to test the hypotheses that survivors who were APOE ε4 carriers would have the lowest cognitive performance but that smoking history would decrease the negative effect of ε4 on cognition.

METHODS

Female breast cancer survivors who had been diagnosed and treated at age 60 or older and were 5-15-year survivors (N = 328) and age and education matched non-cancer controls (N = 162) were assessed at enrollment and at 8-, 16-, and 24-month follow-ups with standard neuropsychological and psychological assessments. Blood for APOE genotyping was collected, and smoking history was assessed at enrollment. Participants were purposely recruited so that approximately 50% had a history of treatment with chemotherapy or no chemotherapy and approximately 50% had a smoking history.

RESULTS

After adjusting for age, cognitive reserve, depression, and fatigue, breast cancer survivors scored significantly lower on all domains of cognitive function. A significant two-way interaction demonstrated that the negative effect of ε4 on cognitive performance was stronger among survivors. A significant three-way interaction supported the hypothesis that smoking history had a protective effect on cognitive function in ε4 carriers that was more pronounced in the controls than the survivors.

CONCLUSIONS

The results support the long-term cognitive impact of breast cancer diagnosis and treatments on older, disease-free survivors, particularly for ε4 carriers. The results also emphasize the importance of assessing smoking history when examining APOE and cognition and are an example of the complex interactions of age, genetics, health behaviors, and disease history in determining cognitive function.

IMPLICATIONS FOR CANCER SURVIVORS

These results help explain why only a subset of breast cancer survivors appear to be vulnerable to cognitive problems.

Novel Therapeutic Hybrid Systems Using Hydrogels and Nanotechnology: A Focus on Nanoemulgels for the Treatment of Skin Diseases

Topical and transdermal drug delivery are advantageous administration routes, especially when treating diseases and conditions with a skin etiology. Nevertheless, conventional dosage forms often lead to low therapeutic efficacy, safety issues, and patient noncompliance. To tackle these issues, novel topical and transdermal platforms involving nanotechnology have been developed. This review focuses on the latest advances regarding the development of nanoemulgels for skin application, encapsulating a wide variety of molecules, including already marketed drugs (miconazole, ketoconazole, fusidic acid, imiquimod, meloxicam), repurposed marketed drugs (atorvastatin, omeprazole, leflunomide), natural-derived compounds (eucalyptol, naringenin, thymoquinone, curcumin, chrysin, brucine, capsaicin), and other synthetic molecules (ebselen, tocotrienols, retinyl palmitate), for wound healing, skin and skin appendage infections, skin inflammatory diseases, skin cancer, neuropathy, or anti-aging purposes. Developed formulations revealed adequate droplet size, PDI, viscosity, spreadability, pH, stability, drug release, and drug permeation and/or retention capacity, having more advantageous characteristics than current marketed formulations. In vitro and/or in vivo studies established the safety and efficacy of the developed formulations, confirming their therapeutic potential, and making them promising platforms for the replacement of current therapies, or as possible adjuvant treatments, which might someday effectively reach the market to help fight highly incident skin or systemic diseases and conditions.

Lynx1 and the family of endogenous mammalian neurotoxin-like proteins and their roles in modulating nAChR function

The promise of nicotinic receptors as a therapeutic target has yet to be fully realized, despite solid data supporting their involvement in neurological and neuropsychiatric diseases. The reasons for this are likely complex and manifold, having to do with the widespread action of the cholinergic system and the biophysical mechanism of action of nicotinic receptors leading to fast desensitization and down-regulation. Conventional drug development strategies tend to focus on receptor subtype-specific action of candidate therapeutics, although the broad agonist, nicotine, is being explored in the clinic. The potential negative effects of nicotine make the search for alternate strategies warranted. Prototoxins are a promising yet little-explored avenue of nicotinic receptor drug development. Nicotinic receptors in the brain belong to a complex of proteins, including those that bind to the extracellular face of the receptor, as well as chaperones that bind the intracellular domain, etc. Lynx prototoxins have allosteric modularity effects on receptor function and number and have been implicated in complex in vivo processes such as neuroplasticity, learning, and memory. Their mechanism of action and binding specificity on sets of nAChR subtypes present intriguing possibilities for more efficacious and nuanced therapeutic targeting than nicotinic receptor subtypes alone. An allosteric drug may restrict its actions to physiologically relevant time points, which tend to be correlated with salient events which would be encoded into long-term memory storage. Rather than blanketing the brain with a steady and prolonged elevation of agonist, an allosteric nAChR compound could avoid side effects and loss of efficacy over time. This review details the potential strengths and challenges of prototoxin proteins as therapeutic targets, and some of the utility of such therapeutics based on the emerging understanding of cholinergic signaling in a growing number of complex neural processes.

Biologically Active Compounds Present in Tobacco Smoke: Potential Interactions Between Smoking and Mental Health

Tobacco dependence remains one of the major preventable causes of premature morbidity and mortality worldwide. There are well over 8,000 compounds present in tobacco and tobacco smoke, but we do not know what effect, if any, many of them have on smokers. Major interest has been on nicotine, as well as on toxic and carcinogenic effects and several major and minor components of tobacco smoke responsible for the negative health effects of smoking have been elucidated. Smokers themselves report a variety of positive effects from smoking, including effects on depression, anxiety and mental acuity. Smoking has also been shown to have protective effects in Parkinson’s Disease. Are the subjective reports of a positive effect of smoking due to nicotine, of some other components of tobacco smoke, or are they a manifestation of the relief from nicotine withdrawal symptoms that smoking provides? This mini-review summarises what is currently known about the components of tobacco smoke with potential to have positive effects on smokers.

α7 nicotinic acetylcholine receptors in the hippocampal circuit: taming complexity

Cholinergic innervation of the hippocampus uses the neurotransmitter acetylcholine (ACh) to coordinate neuronal circuit activity while simultaneously influencing the function of non-neuronal cell types. The α7 nicotinic ACh receptor (nAChR) subtype is highly expressed throughout the hippocampus, has the highest calcium permeability compared with other subtypes of nAChRs, and is of high therapeutic interest due to its association with a variety of neurological disorders and neurodegenerative diseases. In this review, we synthesize research describing α7 nAChR properties, function, and relationship to cognitive dysfunction within the hippocampal circuit and highlight approaches to help improve therapeutic development.

Nicotine Ingestion Reduces Heart Rate Variability in Young Healthy Adults

Around the whole world, smoking is considered harmful to human health, such as increasing the risk of cardiovascular disease (CVD, such as coronary heart disease and stroke) and lung cancer. The purpose of this study was to explore whether nicotine, the main component of tobacco, has adverse effects on heart rate variability (HRV) in adolescents, so as to remind adolescents not to smoke and not to take pleasure in abusing nicotine. In this study, 40 male and 40 female young healthy nonsmoking subjects were selected to analyze the changes of HRV after taking 4 mg nicotine orally. We found that nicotine reduced HRV in young healthy male and female subjects, and there was no gender difference in this effect (P > 0.05). In conclusion, smoking is harmful to the cardiac system of young people, especially when nicotine content ≥4 mg dosage.