Breakfast Frequency and Smoking Initiation in University Students: A Retrospective Cohort Study.

Smoking causes various health problems. Limited studies have reported a clinical effect of skipping breakfast on smoking initiation among adolescents. This retrospective cohort study aimed to assess the dose-dependent association between skipping breakfast and smoking initiation in university students. This study included 17,493 male and 8880 female students aged 18-22 years at a national university in Japan. The association between breakfast frequency (eating every day and skipping occasionally, often, and usually) and smoking initiation was evaluated using Cox proportional hazards models adjusted for clinically relevant factors. Smoking initiation was observed in 2027 (11.6%) male and 197 (2.2%) female students over the median observational period of 3.0 and 3.1 years. Skipping breakfast was significantly associated with smoking initiation in a dose-dependent fashion in male students (the adjusted hazard ratios [95% confidence interval] of eating breakfast every day and skipping occasionally, often, and usually: 1.00 [reference], 1.30 [1.15, 1.46], 1.47 [1.21, 1.79], and 1.77 [1.40, 2.25], respectively). Female students skipping breakfast occasionally and often were more vulnerable to smoking initiation than those who ate breakfast every day (1.00 [reference], 1.86 [1.24, 2.78], 2.97 [1.66, 5.32], and 1.76 [0.55, 5.64], respectively). Breakfast frequency may be useful to identify university students at risk of smoking initiation who need improvement in their health literacy.

Short sleep duration and smoking initiation in university students: a retrospective cohort study.

PURPOSE: The aim of this study was to clarify an association between short sleep duration and smoking initiation. METHODS: Participants eligible for this retrospective cohort study were university students who were admitted to a single national university in Japan between 2007 and 2015. Baseline sleep duration and smoking status were measured using general questionnaires at health checkups at admission. During a 6-year observation period, smoking initiation was assessed using general questionnaires at annual health checkups. Cox proportional hazards models adjusted for clinically relevant factors were used to assess the association between sleep duration and smoking initiation. RESULTS: Of 17,493 men, including 540, 5,568, 8,458, 2,507, and 420 men with sleep duration of < 5, 5-6, 6-7, 7-8, and ≥ 8 h, respectively, smoking initiation was observed in 16.1%, 12.5%, 11.2%, 10.0%, and 11.7%, respectively, during a median observation period of 3.0 years. Men with shorter sleep duration were at a higher risk of smoking initiation (adjusted hazard ratio 1.49 [95% confidence interval 1.19-1.85], 1.11 [1.01-1.22], 1.00 [reference], 0.92 [0.80-1.06], and 1.00 [0.75-1.34], respectively). Of 8,880 women, including 267, 3,163, 4,220, and 1,230 women with sleep duration of < 5, 5-6, 6-7, and ≥ 7 h, respectively, smoking initiation was observed in 4.9%, 2.3%, 2.0%, and 2.2%, respectively, during a median observation period of 3.0 years. A similar dose dependent association was ascertained in women (2.50 [1.39-4.49], 1.18 [0.86-1.62], 1.00 [reference], and 1.22 [0.79-1.89], respectively). CONCLUSION: This study clarified that university students with short sleep duration were vulnerable to smoking initiation.

A Dose-Dependent Association between Alcohol Consumption and Incidence of Proteinuria and Low Glomerular Filtration Rate: A Systematic Review and Meta-Analysis of Cohort Studies.

Previous cohort studies have reported conflicting associations between alcohol consumption and chronic kidney disease, characterized by proteinuria and low glomerular filtration rate (GFR). This systematic review, which included 14,634,940 participants from 11 cohort studies, assessed a dose-dependent association of alcohol consumption and incidence of proteinuria and low estimated GFR (eGFR) of <60 mL/min/1.73 m2. Compared with non-drinkers, the incidence of proteinuria was lower in drinkers with alcohol consumption of ≤12.0 g/day (relative risk 0.87 [95% confidence interval 0.83, 0.92]), but higher in drinkers with alcohol consumption of 36.1-60.0 g/day (1.09 [1.03, 1.15]), suggesting a J-shaped association between alcohol consumption and the incidence of proteinuria. Incidence of low eGFR was lower in drinkers with alcohol consumption of ≤12.0 and 12.1-36.0 than in non-drinkers (≤12.0, 12.1-36.0, and 36.1-60.0 g/day: 0.93 [0.90, 0.95], 0.82 [0.78, 0.86], and 0.89 [0.77, 1.03], respectively), suggesting that drinkers were at lower risk of low eGFR. In conclusion, compared with non-drinkers, mild drinkers were at lower risk of proteinuria and low eGFR, whereas heavy drinkers had a higher risk of proteinuria but a lower risk of low eGFR. The clinical impact of high alcohol consumption should be assessed in well-designed studies.

Plasmodium infection inhibits tumor angiogenesis through effects on tumor-associated macrophages in a murine implanted hepatoma model.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death in China. The lack of an effective treatment for this disease results in a high recurrence rate in patients who undergo radical tumor resection, and the 5-year survival rate of these patients remains low. Our previous studies demonstrated that Plasmodium infection provides a potent antitumor effect by inducing innate and adaptive immunity in a murine Lewis lung carcinoma (LLC) model. METHODS: This study aimed to investigate the inhibitory effect of Plasmodium infection on hepatocellular carcinoma in mice, and various techniques for gene expression analysis were used to identify possible signal regulation mechanisms. RESULTS: We found that Plasmodium infection efficiently inhibited tumor progression and prolonged survival in tumor-bearing mice, which served as a murine implanted hepatoma model. The inhibition of tumor progression by Plasmodium infection was related to suppression of tumor angiogenesis within the tumor tissue and decreased infiltration of tumor-associated macrophages (TAMs). Further study demonstrated that matrix metalloprotease 9 (MMP-9) produced by TAMs contributed to tumor angiogenesis in the tumor tissue and that the parasite-induced reduction in MMP-9 expression in TAMs resulted in the suppression of tumor angiogenesis. A mechanistic study revealed that the Plasmodium-derived hemozoin (HZ) that accumulated in TAMs inhibited IGF-1 signaling through the PI3-K and MAPK signaling pathways and thereby decreased the expression of MMP-9 in TAMs. CONCLUSIONS: Our study suggests that this novel approach of inhibiting tumor angiogenesis by Plasmodium infection is of high importance for the development of new therapies for cancer patients. Video abstract.

Engineering an Artificial Membrane Vesicle Trafficking System (AMVTS) for the Excretion of ß-Carotene in Escherichia coli.

Large hydrophobic molecules, such as carotenoids, cannot be effectively excreted from cells by natural transportation systems. These products accumulate inside the cells and affect normal cellular physiological functions, which hinders further improvement of carotenoid production by microbial cell factories. In this study, we proposed to construct a novel artificial transport system utilizing membrane lipids to carry and transport hydrophobic molecules. Membrane lipids allow the physiological mechanism of membrane dispersion to be reconstructed and amplified to establish a novel artificial membrane vesicle transport system (AMVTS). Specifically, a few proteins in E. coli were reported or proposed to be related to the formation mechanism of outer membrane vesicles, and were individually knocked out or overexpressed to test their physiological functions. The effects on tolR and nlpI were the most significant. Knocking out both tolR and nlpI resulted in a 13.7% increase of secreted ß-carotene with a 35.6% increase of specific production. To supplement the loss of membrane components of the cells due to the increased membrane vesicle dispersion, the synthesis pathway of phosphatidylethanolamine was engineered. While overexpression of AccABCD and PlsBC in TW-013 led to 15% and 17% increases of secreted ß-carotene, respectively, the overexpression of both had a synergistic effect and caused a 53-fold increase of secreted ß-carotene, from 0.2 to 10.7 mg/g dry cell weight (DCW). At the same time, the specific production of ß-carotene increased from 6.9 to 21.9 mg/g DCW, a 3.2-fold increase. The AMVTS was also applied to a ß-carotene hyperproducing strain, CAR025, which led to a 24-fold increase of secreted ß-carotene, from 0.5 to 12.7 mg/g DCW, and a 61% increase of the specific production, from 27.7 to 44.8 mg/g DCW in shake flask fermentation. The AMVTS built in this study establishes a novel artificial transport mechanism different from natural protein-based cellular transport systems, which has great potential to be applied to various cell factories for the excretion of a wide range of hydrophobic compounds.

Characterization of peripheral blood T lymphocyte subsets in Chinese rhesus macaques with repeated or long-term infection with Plasmodium cynomolgi.

T lymphocytes play a vital role in antimalaria immunity, but there is little information about the role of T cells in malaria infection. In order to explore the profile of T cells in malaria immunity, we infected Chinese rhesus macaques with the malaria parasite (Plasmodium cynomolgi) and examined the dynamics of T cell subsets. Both repeated and long-term infections were involved. Our results showed that the monkeys in the repeated infection group acquired protective immunity through primary infection, which was evidenced by a much lower parasitemia, milder anemia, and milder fever during reinfection; the monkeys in the long-term infection group also developed protective immunity, but this was not sufficient to eliminate the parasite. The total counts of leukocytes, neutrophils, CD3+ T cells, CD4+ or CD8+ T cells, and naïve and memory CD4+ and CD8+ T cells declined during the acute phase of malaria but increased after the parasite was controlled. The total number of activated CD4+ T cells significantly increased during malaria in animals with a long-term infection, which remained at least 3 months after the termination of malaria. However, the activated CD4+ T cells decreased during the acute phase of infection in the repeated infection group and converted to preinfection levels after malaria was cured. Regulatory CD4+ T cells continued to increase during the malaria infections and quickly reverted to preinfection levels after the parasite was controlled. Our study provides a systematic analysis of the kinetic profiles of T lymphocyte subsets during malaria infections and provides some experimental insight into malaria immunology.

Antitumor effect of malaria parasite infection in a murine Lewis lung cancer model through induction of innate and adaptive immunity.

BACKGROUND: Lung cancer is the most common malignancy in humans and its high fatality means that no effective treatment is available. Developing new therapeutic strategies for lung cancer is urgently needed. Malaria has been reported to stimulate host immune responses, which are believed to be efficacious for combating some clinical cancers. This study is aimed to provide evidence that malaria parasite infection is therapeutic for lung cancer. METHODOLOGY/PRINCIPAL FINDINGS: Antitumor effect of malaria infection was examined in both subcutaneously and intravenously implanted murine Lewis lung cancer (LLC) model. The results showed that malaria infection inhibited LLC growth and metastasis and prolonged the survival of tumor-bearing mice. Histological analysis of tumors from mice infected with malaria revealed that angiogenesis was inhibited, which correlated with increased terminal deoxynucleotidyl transferase-mediated (TUNEL) staining and decreased Ki-67 expression in tumors. Through natural killer (NK) cell cytotoxicity activity, cytokine assays, enzyme-linked immunospot assay, lymphocyte proliferation, and flow cytometry, we demonstrated that malaria infection provided anti-tumor effects by inducing both a potent anti-tumor innate immune response, including the secretion of IFN-γ and TNF-α and the activation of NK cells as well as adaptive anti-tumor immunity with increasing tumor-specific T-cell proliferation and cytolytic activity of CD8(+) T cells. Notably, tumor-bearing mice infected with the parasite developed long-lasting and effective tumor-specific immunity. Consequently, we found that malaria parasite infection could enhance the immune response of lung cancer DNA vaccine pcDNA3.1-hMUC1 and the combination produced a synergistic antitumor effect. CONCLUSIONS/SIGNIFICANCE: Malaria infection significantly suppresses LLC growth via induction of innate and adaptive antitumor responses in a mouse model. These data suggest that the malaria parasite may provide a novel strategy or therapeutic vaccine vector for anti-lung cancer immune-based therapy.

Transition of tumor-associated macrophages from MHC class II(hi) to MHC class II(low) mediates tumor progression in mice.

BACKGROUND: Tumor-associated macrophages (TAMs) are the most abundant immune cells within the tumor stroma and play a crucial role in tumor development. Although clinical investigations indicate that high levels of macrophage (MΦ) infiltration into tumors are associated with a poor prognosis, the exact role played by TAMs during tumor development remains unclear. The present study aimed to investigate dynamic changes in TAM major histocompatibility complex (MHC) class II expression levels and to assess the effects of these changes on tumor progression. RESULTS: Significant inhibition of tumor growth in the murine hepatocellular carcinoma Hepa1-6 model was closely associated with partial TAM depletion. Strikingly, two distinct TAM subsets were found to coexist within the tumor microenvironment during Hepa1-6 tumor development. An MHC class II(hi) TAM population appeared during the early phase of tumor development and was associated with tumor suppression; however, an MHC class II(low) TAM population became increasingly predominant as the tumor progressed. CONCLUSIONS: Tumor progression was positively correlated with increasing infiltration of the tumor tissues by MHC class II(low) TAMs. Thus, targeting the transition of MΦ may be a novel strategy for drug development and immunotherapy.

Synergy of the antiretroviral protease inhibitor indinavir and chloroquine against malaria parasites in vitro and in vivo.

Many malaria-endemic areas are also associated with high rates of human immunodeficiency virus (HIV) infection. An understanding of the chemotherapeutic interactions that occur during malaria and HIV co-infections is important. Our previous studies have demonstrated that some antiretroviral protease inhibitors are effective in inhibiting Plasmodium falciparum growth in vitro. Currently, studies examining the interactions between antiretroviral protease inhibitors and antimalarial drugs are being conducted, but the data are limited. In this study, we examined the synergistic interactions between the antiretroviral protease inhibitor indinavir and chloroquine (CQ) in chloroquine-resistant and chloroquine-sensitive malaria parasites in vitro and in vivo. In vitro, by using modified fixed-ratio isobologram method, fractional inhibitory concentrations index (FICI) was calculated to indicate the interaction between the two drugs. The results demonstrated that indinavir interacted synergistically with chloroquine against both chloroquine-sensitive P. falciparum clone 3D7 (mean FICI 0.784) and multidrug-resistant P. falciparum clone Dd2 (mean FICI 0.599). In vivo drug interactions were measured using a 4-day suppressive test in a rodent malaria model infected with Plasmodium chabaudi. We observed that indinavir enhanced the antimalarial activity of chloroquine against both the chloroquine-sensitive line P. chabaudi ASS and the chloroquine-resistant line P. chabaudi ASCQ. More importantly, chloroquine had a 100% clearance of asexual parasites when used in combination with indinavir at an appropriate dose ratio (10 mg/kg CQ + 1.8 g/kg indinavir) where there was no obvious toxicity. We conclude from this study that the combination of indinavir and chloroquine may become a novel antimalarial drug regimen.