The two major epidemics of the twenty-first century: obesity and cancer

Systematic preoperative approach for bariatric surgery, perioperative results, and economic impact

Introduction

Obesity is a complex systemic condition, involving numerous anatomical and metabolic changes. Therefore, a comprehensive preoperative assessment is essential for each patient contemplating bariatric surgery.

Objetive

This study presents the findings of a proposed protocol designed to streamline the pre-anesthesia consultation process. Our aim was to compare the efficiency and costs of consultations guided by the protocol with those conducted without a specific strategy. The secondary outcomes assessed included postoperative (PO) length of hospital stay and surgical duration.

Matherial and methods

We conducted a retrospective cross-sectional analysis involving 206 clinical cases. Statistical analyses, including the chi-squared test, Student's t-test, and Mann-Whitney U test, were utilized based on the type of variables.

Results

The results showed a significant reduction in the costs, pre-anesthesia consultation duration, time spent in the recovery unit, and the need for referrals. However, no statistically significant differences were observed in the delay before surgery and length of hospital stays, measured in days.

Conclusion

This algorithm offers a promising approach for optimizing perioperative management in bariatric surgery, demonstrating its effectiveness in cutting costs and reducing the need for referrals.

Risk reduction of non-hormonal cancers following bariatric surgery

Metabolic and bariatric surgery (MBS) is the most effective intervention for weight loss leading to significant resolution of obesity-related medical conditions. Recent literature has demonstrated risk reduction of certain cancer types after MBS. Studies have shown an overall reduction in the risk of hormonal cancer, such as breast and endometrial cancer. However, the association between bariatric surgery and the incidence of various types of non-hormonal cancer such as esophageal, gastric, liver, gallbladder, colorectal, pancreatic and kidney cancer remains contested. The aim of this study was to highlight obesity and its relationship to cancer development as well as bariatric surgery and its role in cancer reduction with focus on non-hormonal cancers.

Evolution of human genes encoding cell surface receptors involved in the regulation of appetite: an analysis based on the phylostratigraphic age and divergence indexes

Genes encoding cell surface receptors make up a significant portion of the human genome (more than a thousand genes) and play an important role in gene networks. Cell surface receptors are transmembrane proteins that interact with molecules (ligands) located outside the cell. This interaction activates signal transduction pathways in the cell. A large number of exogenous ligands of various origins, including drugs, are known for cell surface receptors, which accounts for interest in them from biomedical researchers. Appetite (the desire of the animal organism to consume food) is one of the most primitive instincts that contribute to survival. However, when the supply of nutrients is stable, the mechanism of adaptation to adverse factors acquired in the course of evolution turned out to be excessive, and therefore obesity has become one of the most serious public health problems of the twenty-first century. Pathological human conditions characterized by appetite violations include both hyperphagia, which inevitably leads to obesity, and anorexia nervosa induced by psychosocial stimuli, as well as decreased appetite caused by neurodegeneration, inflammation or cancer. Understanding the evolutionary mechanisms of human diseases, especially those related to lifestyle changes that have occurred over the past 100-200 years, is of fundamental and applied importance. It is also very important to identify relationships between the evolutionary characteristics of genes in gene networks and the resistance of these networks to changes caused by mutations. The aim of the current study is to identify the distinctive features of human genes encoding cell surface receptors involved in appetite regulation using the phylostratigraphic age index (PAI) and divergence index (DI). The values of PAI and DI were analyzed for 64 human genes encoding cell surface receptors, the orthologs of which were involved in the regulation of appetite in model animal species. It turned out that the set of genes under consideration contains an increased number of genes with the same phylostratigraphic age (PAI = 5, the stage of vertebrate divergence), and almost all of these genes (28 out of 31) belong to the superfamily of G-protein coupled receptors. Apparently, the synchronized evolution of such a large group of genes (31 genes out of 64) is associated with the development of the brain as a separate organ in the first vertebrates. When studying the distribution of genes from the same set by DI values, a significant enrichment with genes having a low DIs was revealed: eight genes (GPR26, NPY1R, GHSR, ADIPOR1, DRD1, NPY2R, GPR171, NPBWR1) had extremely low DIs (less than 0.05). Such low DI values indicate that most likely these genes are subjected to stabilizing selection. It was also found that the group of genes with low DIs was enriched with genes that had brain-specific patterns of expression. In particular, GPR26, which had the lowest DI, is in the group of brain-specific genes. Because the endogenous ligand for the GPR26 receptor has not yet been identified, this gene seems to be an extremely interesting object for further theoretical and experimental research. We believe that the features of the genes encoding cell surface receptors we have identified using the evolutionary metrics PAI and DI can be a starting point for further evolutionary analysis of the gene network regulating appetite.

The Impact of Bariatric Surgery on the Incidence of Colorectal Cancer in Patients with Obesity-a Systematic Review and Meta-analysis of Registry Data

PURPOSE

Cancer and obesity represent two of the most significant global health concerns. The risk of malignancy, including colorectal cancer (CRC), increases with obesity. The aim of this study was to perform a systematic review and meta-analysis to determine the value of bariatric surgery in reducing CRC risk in patients with obesity using registry data.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed as per PRISMA guidelines. The risk of CRC was expressed as a dichotomous variable and reported as odds ratios (OR) with 95% confidence intervals (CIs) using the Mantel-Haenszel method. A multi-treatment comparison was performed, examining the risk reduction associated with existing bariatric surgery techniques. Analysis was performed using RevMan, R packages, and Shiny.

RESULTS

Data from 11 registries including 6,214,682 patients with obesity were analyzed. Of these, 14.0% underwent bariatric surgery (872,499/6,214,682), and 86.0% did not undergo surgery (5,432,183/6,214,682). The mean age was 49.8 years, and mean follow-up was 5.1 years. In total, 0.6% of patients who underwent bariatric surgery developed CRC (4,843/872,499), as did 1.0% of unoperated patients with obesity (54,721/5,432,183). Patients with obesity who underwent bariatric surgery were less likely to develop CRC (OR: 0.53, 95% CI: 0.36-0.77, P < 0.001, I2 = 99%). Patients with obesity undergoing gastric bypass surgery (GB) (OR: 0.513, 95% CI: 0.336-0.818) and sleeve gastrectomy (SG) (OR: 0.484, 95% CI: 0.307-0.763) were less likely to develop CRC than unoperated patients.

CONCLUSION

At a population level, bariatric surgery is associated with reduced CRC risk in patients with obesity. GB and SG are associated with the most significant reduction in CRC risk.

PROSPERO REGISTRATION

CRD42022313280.

The influence of male and female overweight/obesity on IVF outcomes: a cohort study based on registration in Western China

BACKGROUND

Overweight/obesity can affect fertility, increase the risk of pregnancy complications, and affect the outcome of assisted reproductive technology (ART). However, due to confounding factors, the accuracy and uniformity of published findings on IVF outcomes have been disputed. This study aimed to assess the effects of both male and female body mass index (BMI), individually and in combination, on IVF outcomes.

METHODS

This retrospective cohort study included 11,191 couples undergoing IVF. Per the Chinese BMI standard, the couples were divided into four groups: normal; female overweight/obesity; male overweight/obesity; and combined male and female overweight/obesity. The IVF outcomes of the four groups were compared and analysed.

RESULTS

Regarding the 6569 first fresh IVF-ET cycles, compared with the normal weight group, the female overweight/obesity and combined male/female overweight/obesity groups had much lower numbers of available embryos and high-quality embryos (p < 0.05); additionally, the fertilization (p < 0.001) and normal fertilization rates (p < 0.001) were significantly decreased in the female overweight/obesity group. The combined male/female overweight/obesity group had significant reductions in the available embryo (p = 0.002), high-quality embryo (p = 0.010), fertilization (p = 0.001) and normal fertilization rates (p < 0.001); however, neither male or female overweight/obesity nor their combination significantly affected the clinical pregnancy rate (CPR), live birth rate (LBR) or abortion rate (p > 0.05).

CONCLUSION

Our findings support the notion that overweight/obesity does not influence pregnancy success; however, we found that overweight/obesity affects the fertilization rate and embryo number and that there are sex differences.

Electrospun Membranes Designed for Burst Release of New Gold-Complexes Inducing Apoptosis of Melanoma Cells

Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free metallic complexes, directly in contact with the MeWo cell line culture, and embedded in fibers of Polycaprolactone (PCL) membranes produced by the electrospinning technique. Membranes functionalized with complexes were prepared to evaluate the efficiency of the membranes against the melanoma cells and therefore their feasibility in the application as an antitumoral patch for topical use. Both series of tests highlighted a very effective antitumoral activity, manifesting a very relevant cell viability inhibition after both 24 h and 48 h. In the case of the AuM1 complex at the concentration of 20 mM, melanoma cells completely died in this short period of time. A mortality of around 70% was detected from the tests performed using the membranes functionalized with AuM1 complex at a very low concentration (3 wt.%), even after 24 h of the contact period. The synthesized complexes also manifest high selectivity with respect to the MeWo cells. The peculiar structural and morphological organization of the nanofibers constituting the membranes allows for a very effective antitumoral activity in the first 3 h of treatment. Experimental points of the release profiles were perfectly fitted with theoretical curves, which easily allow interpretation of the kinetic phenomena occurring in the release of the synthesized complexes in the chosen medium.

Acute supplementation with grapes in obese subjects did not affect postprandial metabolism: a randomized, double-blind, crossover clinical trial

PURPOSE

The aim of this study was to determine whether grape polyphenols have a "second-meal effect", modulating glucose and lipid elevations in the postprandial period after two successive meals in subjects with obesity.

METHODS

A randomized, double-blind, placebo-controlled, acute clinical trial was conducted. Twenty-five obese subjects (BMI =  ≥ 30 and < 40 kg/m2) were randomly divided into two groups. At an initial visit, blood was collected in a fasting state and the subjects received breakfast and 46 g of either grape powder (equivalent to 252 g fresh grapes) or placebo, both solved in water. Lunch was provided 5 h later and then blood was collected after 0, 30, 60, 120, 180, 240, 300, 330, 360, and 420 min since arrival. Two weeks later, at a second visit, the subjects received the other powder. The following were determined: glucose, insulin, triglycerides, uric acid, blood count, hemoglobin, viscosity, antioxidant capacity, and satiety perception.

RESULTS

Postprandial increases were observed as expected in, for example, glucose and triglycerides after breakfast and lunch. The grape powder supplementation did not cause any significant modification compared to placebo, in these parameters; nor did it significantly modify plasma antioxidant capacity in the 6 h postprandial period.

DISCUSSION

Single grape powder supplementation did not modify postprandial responses in obese subjects, probably because the polyphenol dose was insufficient to induce such an effect. The result of a combination of grape with other polyphenol-rich products or chronic supplementation with grape powder on postprandial responses remains to be elucidated.

TRIAL REGISTRATION NUMBER

www.clinicaltrials.gov , NCT03741218.

Organoid-Transplant Model Systems to Study the Effects of Obesity on the Pancreatic Carcinogenesis in vivo

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related mortality among adults in developed countries. The discovery of the most common genetic alterations as well as the development of organoid models of pancreatic cancer have provided insight into the fundamental pathways driving tumor progression from a normal cell to non-invasive precursor lesion and finally to widely metastatic disease, offering new opportunities for identifying the key driver of cancer evolution. Obesity is one of the most serious public health challenges of the 21st century. Several epidemiological studies have shown the positive association between obesity and cancer-related morbidity/mortality, as well as poorer prognosis and treatment outcome. Despite strong evidence indicates a link between obesity and cancer incidence, the molecular basis of the initiating events remains largely elusive. This is mainly due to the lack of an accurate and reliable model of pancreatic carcinogenesis that mimics human obesity-associated PDAC, making data interpretation difficult and often confusing. Here we propose a feasible and manageable organoid-based preclinical tool to study the effects of obesity on pancreatic carcinogenesis. Therefore, we tracked the effects of obesity on the natural evolution of PDAC in a genetically defined transplantable model of the syngeneic murine pancreatic preneoplastic lesion (mP) and tumor (mT) derived-organoids that recapitulates the progression of human disease from early preinvasive lesions to metastatic disease. Our results suggest that organoid-derived transplant in obese mice represents a suitable system to study early steps of pancreatic carcinogenesis and supports the hypothesis that inflammation induced by obesity stimulates tumor progression and metastatization during pancreatic carcinogenesis.

Lipid and metabolic profiles in female dogs with mammary carcinoma receiving dietary fish oil supplementation

Background

Dyslipidemias induce angiogenesis and accelerate the development and in vitro growth of breast tumors. The aim of this study was to assess the lipid and metabolic profile of female dogs with mammary carcinomas and their correlations with body condition score and degree of tumor malignancy, as well as to study the effect of dietary fish oil supplementation on these animals.

Results

Overweight or obese dogs had more aggressive carcinomas and higher triglyceride (p = 0.0363), VLDL (p = 0.0181), albumin (p = 0.0188), globulin (p = 0.0145) and lactate (p = 0.0255) concentrations. There was no change in the lipid profile after supplementation with fish oil at any concentration. However, in relation to the metabolic profile, glucose (p = 0.0067), total protein (p = 0.0002) and globulin (p = 0.0002) concentrations were increased when 90% omega-3 fish oil was used as a dietary supplement.

Conclusion

Obese dogs showed altered lipid and metabolic profiles and more aggressive tumors, suggesting an important relationship between dyslipidemia and tumor aggressiveness. Supplementation with fish oil, rich in omega-3 fatty acids, may alter metabolic parameters in cancer patients.

Overexpression of cancer stem cell marker Lgr5 in colorectal cancer patients and association with clinicopathological findings

BACKGROUND

To determine the expression of cancer stem cell marker Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) in colorectal carcinoma samples compared to normal adjacent tissue and any possible association with clinicopathological findings.

METHODS

This study was performed on forty samples of cancerous colorectal tissues (case group) and their adjacent normal mucosa (control group) in Imam Khomeini Hospital (Sari, Mazandaran, Iran). Expression of Lgr5 in tissue sections was done by immunohistochemistry. Statistical analysis was carried out using SPSS software.

RESULTS

Forty colorectal cancer patients including 21 males (57.8±11.6 years) and 19 females (58.4±12.77 years) were enrolled. Lgr5 was overexpressed in tumoral samples than normal adjacent tissues (77.5% vs 27.5%, p<0.001). Also, no association was found between primary tumor, regional lymph nodes, invasion, histological type, grade, distant metastasis and IHC results. Patients with low Lgr5 expression had a better survival rate than patients with high expression but this was not statistically significant (p=0.121).

CONCLUSION

The higher immunoreactivity of Lgr5 in colorectal cancer tissues may indicate its role as a cancer stem cell marker in tumor carcinogenesis and patient's survival however; Lgr5 is not associated with pathological prognostic variables.

Metformin Reduces Prostate Tumor Growth, in a Diet-Dependent Manner, by Modulating Multiple Signaling Pathways

Prostate-cancer is strongly influenced by obesity, wherein metformin could represent a promising treatment; however, the endocrine metabolic/cellular/molecular mechanisms underlying these associations and effects are still unclear. To determine the beneficial antitumoral effects of metformin on prostate cancer progression/aggressiveness and the relative contribution of high-fat diet (HFD; independently of obesity), we used HFD-fed immunosuppressed mice inoculated with PC3 cells (which exhibited partial resistance to diet-induced obesity) compared with low-fat diet (LFD)-fed control mice. Moreover, gene expression analysis was performed on cancer-associated genes in the xenografted tumors, and the antitumorigenic role of metformin on tumoral (PC3/22Rv1/LNCaP) and normal (RWPE1) prostate cells was evaluated. The results demonstrate that HFD is associated with enhanced prostate cancer growth irrespective of body weight gain and endocrine metabolic dysregulations and that metformin can reduce prostate cancer growth under LFD but more prominently under HFD, acting through the modulation of several tumoral-associated processes (e.g., cell cycle, apoptosis, and/or necrosis). Moreover, the actions observed in vivo could be mediated by the modulation of the local expression of GH/IGF1 axis components. Finally, it was demonstrated that metformin had disparate effects on proliferation, migration, and prostate-specific antigen secretion from different cell lines. Altogether, these data reveal that metformin inhibits prostate cancer growth under LFD and, specially, under HFD conditions through multiple metabolic/tumoral signaling pathways.Implications: The current study linking dietary influence on metformin-regulated signaling pathways and antitumoral response provides new and critical insight on environment-host interactions in cancer and therapy. Mol Cancer Res; 15(7); 862-74. ©2017 AACR.

Kernel Density Estimation as a Measure of Environmental Exposure Related to Insulin Resistance in Breast Cancer Survivors

Background: Environmental factors may influence breast cancer; however, most studies have measured environmental exposure in neighborhoods around home residences (static exposure). We hypothesize that tracking environmental exposures over time and space (dynamic exposure) is key to assessing total exposure. This study compares breast cancer survivors' exposure to walkable and recreation-promoting environments using dynamic Global Positioning System (GPS) and static home-based measures of exposure in relation to insulin resistance.Methods: GPS data from 249 breast cancer survivors living in San Diego County were collected for one week along with fasting blood draw. Exposure to recreation spaces and walkability was measured for each woman's home address within an 800 m buffer (static), and using a kernel density weight of GPS tracks (dynamic). Participants' exposure estimates were related to insulin resistance (using the homeostatic model assessment of insulin resistance, HOMA-IR) controlled by age and body mass index (BMI) in linear regression models.Results: The dynamic measurement method resulted in greater variability in built environment exposure values than did the static method. Regression results showed no association between HOMA-IR and home-based, static measures of walkability and recreation area exposure. GPS-based dynamic measures of both walkability and recreation area were significantly associated with lower HOMA-IR (P < 0.05).Conclusions: Dynamic exposure measurements may provide important evidence for community- and individual-level interventions that can address cancer risk inequities arising from environments wherein breast cancer survivors live and engage.Impact: This is the first study to compare associations of dynamic versus static built environment exposure measures with insulin outcomes in breast cancer survivors. Cancer Epidemiol Biomarkers Prev; 26(7); 1078-84. ©2017 AACR.

Very low-density lipoprotein (VLDL)-induced signals mediating aldosterone production

Aldosterone, secreted by the adrenal zona glomerulosa, enhances sodium retention, thus increasing blood volume and pressure. Excessive production of aldosterone results in high blood pressure and contributes to cardiovascular and renal disease, stroke and visual loss. Hypertension is also associated with obesity, which is correlated with other serious health risks as well. Although weight gain is associated with increased blood pressure, the mechanism by which excess fat deposits increase blood pressure remains unclear. Several studies have suggested that aldosterone levels are elevated with obesity and may represent a link between obesity and hypertension. In addition to hypertension, obese patients typically have dyslipidemia, including elevated serum levels of very low-density lipoprotein (VLDL). VLDL, which functions to transport triglycerides from the liver to peripheral tissues, has been demonstrated to stimulate aldosterone production. Recent studies suggest that the signaling pathways activated by VLDL are similar to those utilized by AngII. Thus, VLDL increases cytosolic calcium levels and stimulates phospholipase D (PLD) activity to result in the induction of steroidogenic acute regulatory (StAR) protein and aldosterone synthase (CYP11B2) expression. These effects seem to be mediated by the ability of VLDL to increase the phosphorylation (activation) of their regulatory transcription factors, such as the cAMP response element-binding (CREB) protein family of transcription factors. Thus, research into the pathways by which VLDL stimulates aldosterone production may identify novel targets for the development of therapies for the treatment of hypertension, particularly those associated with obesity, and other aldosterone-modulated pathologies.

Laparoscopic transperitoneal adrenalectomy in morbidly obese patients is not associated with worse short-term outcomes

OBJECTIVES

To evaluate the impact of obesity and morbid obesity on short-term outcomes after laparoscopic adrenalectomy.

METHODS

The study included 520 consecutive patients undergoing laparoscopic adrenalectomy for adrenal tumor. The entire study group was divided depending on the body mass index: group 1 (normal weight), <25 kg/m² ; group 2 (overweight), 25-30 kg/m² ; and group 3 (obese) 30-40 kg/m² . Additionally, group 4 (morbidly obese) was distinguished. Study end-points were: operative time, intraoperative blood loss, total length of hospital stay, morbidity rate and 30-day readmission rate.

RESULTS

The mean operative times were 88.8, 94.7, 93.5, and 99.9 min in groups 1, 2, 3 and 4, respectively (P = 0.1444). Complications were comparable between groups (12.8% vs 8.8% vs 8.2% vs 11.5%, P = 0.5295). The mean intraoperative blood loss was 66.8 versus 78.3 versus 60.7 versus 92.4, P = 0.1399. There were no differences in conversion rate between groups.

CONCLUSIONS

Obesity has no influence on short-term outcomes of laparoscopic transperitoneal adrenalectomy. This procedure is feasible regardless of the body mass index. Therefore, it can be offered to all patient groups including those morbidly obese individuals in whose case preoperative weight loss seems unnecessary.

Relationship between metabolic syndrome and metabolic syndrome score and beta cell function by gender in Korean populations with obesity

The present study was conducted to assess the relationships between metabolic syndrome and metabolic syndrome score (MSS) and beta cell function by gender in Korean populations with obesity. This study included 1,686 adults aged 20 or older using the 2010 Korea National Health and Nutrition Examination Survey (KNHANES) data, which represent national data in Korea. The key study results were as follows: First, in men, after adjusting for related variables (including body mass index), metabolic syndrome (p=0.005) and MSS (p=0.018) were inversely associated with the homeostatic model assessment of beta cell function (HOMA-B) values. Second, in women, after adjusting for related variables, metabolic syndrome (p=0.616) and MSS (p=0.929) were not associated with HOMA-B levels. In conclusion, metabolic syndrome and MSS were inversely associated with beta cell function in Korean men with obesity, but not in Korean women with obesity.

VLDL-activated cell signaling pathways that stimulate adrenal cell aldosterone production

Aldosterone plays an important role in regulating ion and fluid homeostasis and thus blood pressure, and hyperaldosteronism results in hypertension. Hypertension is also observed with obesity, which is associated with additional health risks, including cardiovascular disease. Obese individuals have high serum levels of very low-density lipoprotein (VLDL), which has been shown to stimulate aldosterone production; however, the mechanisms underlying VLDL-induced aldosterone production are still unclear. Here we demonstrate in human adrenocortical carcinoma (HAC15) cells that submaximal concentrations of angiotensin II and VLDL stimulate aldosterone production in an additive fashion, suggesting the possibility of common mechanisms of action. We show using inhibitors that VLDL-induced aldosterone production is mediated by the PLC/IP3/PKC signaling pathway. Our results suggest that PKC is upstream of the extracellular signal-regulated kinase (ERK) activation previously observed with VLDL. An understanding of the mechanisms mediating VLDL-induced aldosterone production may provide insights into therapies to treat obesity-associated hypertension.

The causal relevance of body mass index in different histological types of lung cancer: A Mendelian randomization study

Body mass index (BMI) is inversely associated with lung cancer risk in observational studies, even though it increases the risk of several other cancers, which could indicate confounding by tobacco smoking or reverse causality. We used the two-sample Mendelian randomization (MR) approach to circumvent these limitations of observational epidemiology by constructing a genetic instrument for BMI, based on results from the GIANT consortium, which was evaluated in relation to lung cancer risk using GWAS results on 16,572 lung cancer cases and 21,480 controls. Results were stratified by histological subtype, smoking status and sex. An increase of one standard deviation (SD) in BMI (4.65 Kg/m(2)) raised the risk for lung cancer overall (OR = 1.13; P = 0.10). This was driven by associations with squamous cell (SQ) carcinoma (OR = 1.45; P = 1.2 × 10(-3)) and small cell (SC) carcinoma (OR = 1.81; P = 0.01). An inverse trend was seen for adenocarcinoma (AD) (OR = 0.82; P = 0.06). In stratified analyses, a 1 SD increase in BMI was inversely associated with overall lung cancer in never smokers (OR = 0.50; P = 0.02). These results indicate that higher BMI may increase the risk of certain types of lung cancer, in particular SQ and SC carcinoma.

Influence of obesity and bariatric surgery on gastric cancer

Esophageal and gastric cancer (GC) are related to obesity and bariatric surgery. Risk factors, such as gastroesophageal reflux and Helicobacter pylori, must be investigated and treated in obese population. After surgery, GC reports are anecdotal and treatment is not standardized. This review aims to discuss GC related to obesity before and after bariatric surgery.

Obesity promotes PhIP-induced small intestinal carcinogenesis in hCYP1A-db/db mice: involvement of mutations and DNA hypermethylation of Apc

Obesity is associated with an increased risk of cancer. To study the promotion of dietary carcinogen-induced gastrointestinal cancer by obesity, we employed 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) to induce intestinal tumorigenesis in CYP1A-humanized (hCYP1A) mice, in which mouse Cyp1a1/1a2 was replaced with human CYP1A1/1A2 Obesity was introduced in hCYP1A mice by breeding with Lepr(db/+) mice to establish the genetically induced obese hCYP1A-Lepr(db/db) mice or by feeding hCYP1A mice a high-fat diet. PhIP induced the formation of small intestinal tumors at the ages of weeks 28-40 in obese hCYP1A mice, but not in lean hCYP1A mice. No tumors were found in colon and other gastrointestinal organs in the lean or obese mice. Using immunohistochemistry (IHC), we found strong positive staining of NF-κB p65, pSTAT3 and COX2 as well as elevated levels of nuclear β-catenin (Ctnnb1) in small intestinal tumors, but not in normal tissues. By sequencing Apc and Ctnnb1 genes, we found that most PhIP-induced small intestinal tumors in obese mice carried only a single heterozygous mutation in Apc By bisulfite-sequencing of CpG islands of Apc, we found DNA hypermethylation in a CpG cluster located in its transcription initiation site, which most likely caused the inactivation of the wild-type Apc allele. Our findings demonstrate that PhIP-induced small intestinal carcinogenesis in hCYP1A-db/db mice is promoted by obesity and involves Apc mutation and inactivation by DNA hypermethylation. This experimental result is consistent with the association of obesity and the increased incidence of small intestinal cancer in humans in recent decades.

Prevalence of Malignancies in Patients With Primary Aldosteronism

CONTEXT

Primary aldosteronism (PA) is the most common cause of secondary hypertension. Aldosterone excess can cause DNA damage in vitro and in vivo. Single case reports have indicated a coincidence of PA with renal cell carcinoma and other tumors. However, the prevalence of benign and malignant neoplasms in patients with PA has not yet been studied.

PATIENTS AND DESIGN

In the multicenter MEPHISTO study, the prevalence of benign and malignant tumors was investigated in 335 patients with confirmed PA. Matched hypertensive subjects from the population-based Study of Health in Pomerania cohort served as controls.

RESULTS

Of the 335 PA patients, 119 (35.5%) had been diagnosed with a tumor at any time, and 30 had two or more neoplasms. Lifetime malignancy occurrence was reported in 9.6% of PA patients compared to 6.0% of hypertensive controls (P = .08). PA patients with a history of malignancy had higher baseline aldosterone levels at diagnosis of PA (P = .009), and a strong association between aldosterone levels and the prevalence of malignancies was observed (P = .03). In total, 157 neoplasms were identified in the PA patients; they were benign in 61% and malignant in 25% of the cases (14% of unknown dignity). Renal cell carcinoma was diagnosed in five patients (13% of all malignancies) and was not reported in controls

CONCLUSION

Compared to hypertensive controls, the prevalence of malignancies was positively correlated with aldosterone levels, tended to be higher in PA patients, but did not differ significantly.

Adipose tissue dysfunction and its effects on tumor metabolism

Growing by an alarming rate in the Western world, obesity has become a condition associated with a multitude of diseases such as diabetes, metabolic syndrome and various cancers. Generally viewed as an abnormal accumulation of hypertrophied adipocytes, obesity is also a poor prognostic factor for recurrence and chemoresistance in cancer patients. With more than two-thirds of the adult population in the United States considered clinically overweight or obese, it is critical that the relationship between obesity and cancer is further emphasized and elucidated. Adipocytes are highly metabolically active cells, which, through release of adipokines and cytokines and activation of endocrine and paracrine pathways, affect processes in neighboring and distant cells, altering their normal homeostasis. This work will examine specifically how adipocyte-derived factors regulate the cellular metabolism of malignant cells within the tumor niche. Briefly, tumor cells undergo metabolic pressure towards a more glycolytic and hypoxic state through a variety of metabolic regulators and signaling pathways, i.e., phosphoinositol-3 kinase (PI3K), hypoxia-inducible factor-1 alpha (HIF-1α), and c-MYC signaling. Enhanced glycolysis and high lactate production are hallmarks of tumor progression largely because of a process known as the Warburg effect. Herein, we review the latest literature pertaining to the body of work on the interactions between adipose and tumor cells, and underlining the changes in cancer cell metabolism that have been targeted by the currently available treatments.

Incidence of cancer following bariatric surgery: systematic review and meta-analysis

Obesity is linked to the development of cancer. Previous studies have suggested that there is a relationship between bariatric surgery and reduced cancer risk. Data sources were from Medline, Embase, and Cochrane Library. From 951 references, 13 studies met the inclusion criteria (54,257 participants). In controlled studies, bariatric surgery was associated with a reduction in the risk of cancer. The cancer incidence density rate was 1.06 cases per 1000 person-years within the surgery groups. In the meta-regression, we found an inverse relationship between the presurgical body mass index and cancer incidence after surgery (beta coefficient -0.2, P < 0.05). Bariatric surgery is associated with reduced cancer risk in morbidly obese people. However, considering the heterogeneity among the studies, conclusions should be drawn with care.

PLA2G16 Expression in Human Osteosarcoma Is Associated with Pulmonary Metastasis and Poor Prognosis

Background

Osteosarcoma is the most frequent type of malignant bone tumor in children and adolescents and is associated with a high propensity for lung metastasis. Recent experiments have indicated that PLA2G16 contributes to osteosarcoma progression and metastasis in both mouse and human osteosarcoma cell lines. The aim of this study was to compare the expression of PLA2G16 in non-metastatic and metastatic osteosarcomas to determine whether PLA2G16 expression can serve as a biomarker of osteosarcoma prognosis and metastasis.

Methods

Quantitative real-time PCR was used to examine PLA2G16 mRNA in primary osteosarcoma patients (18 patients without metastases and 17 patients with metastases), and immunohistochemistry (IHC) staining of PLA2G16 was performed on tissue microarrays from 119 osteosarcoma patients. Tumor metastatic behavior and survival of the patients were followed up for a minimum of 36 months and a maximum of 171 months. The prognostic value of PLA2G16 expression was evaluated by the Kaplan–Meier method and a log-rank test. Multivariate Cox regression analysis was used to identify significant independent prognostic factors.

Results

Osteosarcoma patients with metastasis showed a higher expression of PLA2G16 at both the mRNA and protein levels (both at P values< 0.05) than did patients without metastasis. Osteosarcoma patients with positive IHC staining of PLA2G16 expression at primary sites had shorter overall survival and metastasis-free survival (both at P values <0.02). Moreover, multivariate Cox analysis identified PLA2G16 expression as an independent prognostic factor to predict poor overall survival and metastasis-free survival (both P values < 0.03).

Conclusions

This study indicated that PLA2G16 expression is a significant prognostic factor in primary osteosarcoma patients for predicting the development of metastases and poor survival.

Adipocyte secreted factors enhance aggressiveness of prostate carcinoma cells

Obesity has been associated with increased incidence and risk of mortality of prostate cancer. One of the proposed mechanisms underlying this risk association is the change in adipokines expression that could promote the development and progression of the prostate tumor cells. The main goal of this study was to evaluate the effect of preadipocyte and adipocyte secretome in the proliferation, migration and invasion of androgen independent prostate carcinoma cells (RM1) and to assess cell proliferation in the presence of the adiposity signals leptin and insulin. RM1 cells were co-cultured in with preadipocytes, adipocytes or cultured in their respective conditioned medium. Cell proliferation was assessed by flow cytometry and XTT viability test. Cell migration was evaluated using a wound healing injury assay of RM1 cells cultured with conditioned media. Cellular invasion of RM1 cells co-cultured with adipocytes and preadipocytes was assessed using matrigel membranes. Preadipocyte conditioned medium was associated with a small increase in RM1 proliferation, while adipocytes conditioned media significantly increased RM1 cell proliferation (p<0.01). Adipocytes also significantly increased the RM1 cells proliferation in co-culture (p <0.01). Cell migration was higher in RM1 cells cultured with preadipocyte and adipocyte conditioned medium. RM1 cell invasion was significantly increased after co-culture with preadipocytes and adipocytes (p <0.05). Insulin also increased significantly the cell proliferation in contrast to leptin, which showed no effect. In conclusion, prostate carcinoma cells seem to be influenced by factors secreted by adipocytes that are able to increase their ability to proliferate, migrate and invade.

BMI and lifetime changes in BMI and cancer mortality risk

Body Mass Index (BMI) is known to be associated with cancer mortality, but little is known about the link between lifetime changes in BMI and cancer mortality in both males and females. We studied the association of BMI measurements (at baseline, highest and lowest BMI during the study-period) and lifetime changes in BMI (calculated over different time periods (i.e. short time period: annual change in BMI between successive surveys, long time period: annual change in BMI over the entire study period) with mortality from any cancer, and lung, colorectal, prostate and breast cancer in a large cohort study (n=8,645. Vlagtwedde-Vlaardingen, 1965-1990) with a follow-up on mortality status on December 31^st 2008. We used multivariate Cox regression models with adjustments for age, smoking, sex, and place of residence. Being overweight at baseline was associated with a higher risk of prostate cancer mortality (hazard ratio (HR) =2.22; 95% CI 1.19-4.17). Obesity at baseline was associated with a higher risk of any cancer mortality [all subjects (1.23 (1.01-1.50)), and females (1.40 (1.07-1.84))]. Chronically obese females (females who were obese during the entire study-period) had a higher risk of mortality from any cancer (2.16 (1.47-3.18), lung (3.22 (1.06-9.76)), colorectal (4.32 (1.53-12.20)), and breast cancer (2.52 (1.15-5.54)). We found no significant association between long-term annual change in BMI and cancer mortality risk. Both short-term annual increase and decrease in BMI were associated with a lower mortality risk from any cancer [all subjects: (0.67 (0.47-0.94)) and (0.73 (0.55-0.97)), respectively]. In conclusion, a higher BMI is associated with a higher cancer mortality risk. This study is the first to show that short-term annual changes in BMI were associated with lower mortality from any type of cancer.

Obesity research: Status quo and future outlooks

Obesity is a multifactorial disease showing a pandemic increase within the last decades in developing, and developed countries. It is associated with several severe comorbidities such as type II diabetes, hypertension, sleep apnea, non-alcoholic steatosis hepatis and cancer. Due to the increasing number of overweight individuals worldwide, research in the field of obesity has become more vital than ever. Currently, great efforts are spend to understand this complex disease from a biological, psychological and sociological angle. Further insights of obesity research come from bariatric surgery that provides new information regarding hormonal changes during weight loss. The initiation of programs for obesity treatment, both interventional and pharmaceutical, are being pursued with the fullest intensity. Currently, bariatric surgery is the most effective therapy for weight loss and resolution of comorbidities in morbid obese patients. Reasons for weight loss and remission of comorbidities following Roux-en-Y-Gastric Bypass, Sleeve Gastrectomy, and other bariatric procedures are therefore under intense investigation. In this review, however, we will focus on obesity treatment, highlighting new insights and future trends of gut hormone research, the relation of obesity and cancer development via the obesity induced chronic state of inflammation, and new potential concepts of interventional and conservative obesity treatment.

Could signal transducer and activator of transcription 3 be a therapeutic target in obesity-related gastrointestinal malignancy?

INTRODUCTION

A large body of evidence has implicated the signal transducer and activator of transcription (STAT) family and particularly the ubiquitously expressed STAT3 protein in the pathogenesis of colorectal, hepatocellular, gastric and pancreatic carcinoma.

DISCUSSION

Concomitantly, an increasing body of epidemiological evidence has linked obesity and its associated pro-inflammatory state with the development of gastrointestinal cancers. Visceral adipose tissue is no longer considered inert and is known to secrete a number of adipocytokines such as leptin, interleukin (IL)-6, IL-8, IL-1β and tumour necrosis factor-alpha (TNF-α) into the surrounding environment. Interestingly, these adipocytokines are strongly linked with the Janus kinase (JAK)/STAT pathway of signal transduction and there is experimental evidence linking IL-1β, IL-8 and TNF-α to JAK/STAT signaling in other tissues. The result is an up-regulation of a wide range of anti-apoptotic, pro-metastatic and pro-angiogenic genes and processes. This is particularly relevant for gastrointestinal malignancy as these factors have the potential to signal adjacent endothelial cells in a paracrine manner.

CONCLUSION

This review examines the potential role of the STAT3 signaling pathway in the pathogenesis of obesity-related gastrointestinal malignancy and the potential therapeutic role of STAT3 blockade given its status as a signaling hub for a number of inflammatory adipocytokines.

Ethnic differences in prevalence of general obesity and abdominal obesity among low-income rural Kazakh and Uyghur adults in far western China and implications in preventive public health

BACKGROUND

The global pandemic of obesity has become a disastrous public health issue that needs urgent attention. Previous studies have concentrated in high-income urban settings and few cover low-income rural settings especially nomadic residents in mountain areas. This study focused on low-income rural and nomadic minority people residing in China's far west and investigated their prevalence and ethnic differences of obesity.

METHODS

A questionnaire-based survey and physical examination of 8,036 individuals were conducted during 2009-2010, using stratified cluster random sampling method in nomadic Kazakhs and rural Uyghur residents (≥ 18 years old) in 18 villages, Xinjiang, China, about 4,407 km away from capital Beijing. Obesity was defined by BMI and WC.

RESULTS

The overall prevalence of general and abdominal obesity in Kazakh adults were 18.3% and 60.0%, respectively and in Uyghur, 7.6% and 54.5%, respectively. Female's prevalence of obesity was higher than male's for general obesity (45-54 age group in Uyghur, P = 0.041) and abdominal obesity (≥ 55 years in Kazakhs, P(55 ∼) = 0.010, P(65 ∼) = 0.001; and ≥ 18 years in Uyghurs, P<0.001). Kazakh's prevalence of obesity was higher than Uyghur's (general obesity: ≥ 35 years, P<0.001; abdominal obesity: ≥ 25 years in males and ≥ 65 years in females, P<0.01). The prevalence of obesity increased after 18 years old and subsequently decreased after 55 years old. Meat consumption, older age, and female gender had a higher risk of obesity in these two minorities.

CONCLUSIONS

Both general and abdominal obesity were common in rural ethnic Kazakhs and Uyghurs. The prevalence rates were different in these two minorities depending on ethnicity, gender, and age. Kazakhs, females and elderly people may be prioritized in prevention of obesity in western China. Because of cost-effectiveness in measuring BMI and WC, we recommend that BMI and WC be integrated into local preventive policies in public health toward screening obesity and related diseases in low-income rural minorities.

Large litter rearing improves leptin sensitivity and hypothalamic appetite markers in offspring of rat dams fed high-fat diet during pregnancy and lactation

Maternal high-fat (HF) diet has long-term consequences on the offspring's metabolic phenotype. Here, we determined the effects of large litter (LL) rearing in offspring of rat dams fed HF diet during gestation and lactation. Pregnant Sprague-Dawley rats were maintained on standard chow (CHOW) or HF diet throughout gestation and lactation. Pups were raised in normal litters (NLs) (10 pups/dam) or LLs (16 pups/dam) during lactation, resulting in 4 groups: CHOW-NL, CHOW-LL, HF-NL, and HF-LL. The offspring were weaned onto to either CHOW or HF diet on postnatal day 21. Male and female pups with maternal HF diet (HF-NL) had greater body weight and adiposity, higher plasma leptin levels, impaired glucose tolerance, abnormal hypothalamic leptin signaling pathways (lower leptin receptor-b [OB-Rb] and signal transducer and activator of transcription 3, higher suppressor of cytokine signaling 3 mRNA expression) and appetite markers (lower neuropeptide Y and Agouti-related peptide mRNA expression), and reduced phospho-signal transducer and activator of transcription 3 level in response to leptin in the arcuate nucleus at weaning, whereas LL rearing normalized these differences. When weaned onto CHOW diet, adult male offspring from HF diet-fed dams continued to have greater adiposity, higher leptin levels, and lower hypothalamic OB-Rb, and LL rearing improved them. When weaned onto HF diet, both adult male and female offspring with maternal HF diet had greater body weight and adiposity, higher leptin levels, impaired glucose tolerance, lower OB-Rb, and higher suppressor of cytokine signaling 3 in hypothalamus compared with those of CHOW dams, whereas LL rearing improved most of them except male OB-Rb expression. Our data suggest that LL rearing improves hypothalamic leptin signaling pathways and appetite markers in an age- and sex-specific manner in this model.

Inhibition of SREBP transcriptional activity by a boron-containing compound improves lipid homeostasis in diet-induced obesity

Dysregulation of lipid homeostasis is intimately associated with obesity, type 2 diabetes, and cardiovascular diseases. Sterol regulatory-element binding proteins (SREBPs) are the master regulators of lipid biosynthesis. Previous studies have shown that the conserved transcriptional cofactor Mediator complex is critically required for the SREBP transcriptional activity, and recruitment of the Mediator complex to the SREBP transactivation domains (TADs) is through the MED15-KIX domain. Recently, we have synthesized several boron-containing small molecules. Among these novel compounds, BF175 can specifically block the binding of MED15-KIX to SREBP1a-TAD in vitro, resulting in an inhibition of the SREBP transcriptional activity and a decrease of SREBP target gene expression in cultured hepatocytes. Furthermore, BF175 can improve lipid homeostasis in the mouse model of diet-induced obesity. Compared with the control, BF175 treatment decreased the expression of SREBP target genes in mouse livers and decreased hepatic and blood levels of lipids. These results suggest that blocking the interaction between SREBP-TADs and the Mediator complex by small molecules may represent a novel approach for treating diseases with aberrant lipid homeostasis.

Phosphorylation of sterol regulatory element binding protein-1a by protein kinase A (PKA) regulates transcriptional activity

The counter-regulatory hormone glucagon inhibits lipogenesis via downregulation of sterol regulatory element binding protein 1 (SREBP-1). The effect of glucagon is mediated via protein kinase A (PKA). To determine if SREBP-1 is a direct phosphorylation target of PKA, we conducted mass spectrometry analysis of recombinant n-terminal SREBP-1a following PKA treatment in vitro. This analysis identified serines 331/332 as bona-fide phosphorylation targets of PKA. To determine the functional consequences of phosphorylation at these sites, we constructed mammalian expression vector for both nSREBP-1a and 1c isoforms in which the candidate PKA phosphorylation sites were mutated to active phosphomimetic or non-phosphorylatable amino acids. The transcriptional activity of SREBP was reduced by the phosphomimetic mutation of S332 of nSREBP-1a and the corresponding serine (S308) of nSREBP-1c. This site is a strong candidate for mediating the negative regulatory effect of glucagon on SREBP-1 and lipogenesis.

Prevalence of overweight and obesity and their associations with socioeconomic status in a rural Han Chinese adult population

Background

The purpose of this study is to describe the prevalence of overweight, general obesity, and abdominal obesity and examine their associations with socioeconomic status in a rural Chinese adult population.

Methods

This cross-sectional study was performed on 15,236 participants ≥ 35 years of age (6,313 men [41.4%] and 8,923 women [58.6%]). Each participant’s weight, height, waist circumference (WC), and hipline circumference (HC) were measured, and demographic and socioeconomic data were collected using questionnaires.

Results

The mean body mass index (BMI) values were 23.31 ± 2.96 and 23.89 ± 3.23 kg m^-2 and the mean WC values were 79.13 ± 8.43 and 79.54 ± 8.27 cm for men and women, respectively. The age-standardized prevalence rates of overweight (BMI ≥ 24.0 kg m^-2), general obesity (BMI ≥ 28.0 kg m^-2), and abdominal obesity (WC ≥ 85 cm for men and ≥ 80 cm for women) were 32.0%, 6.7%, and 27.0% for men and 35.1%, 9.7%, and 48.3% for women, respectively. All gender differences were statistically significant (p < 0.001). In addition, the age-specific prevalence rates of general and abdominal obesity slowly decreased among men but sharply increased among women as age increased (p < 0.001). In subsequent logistic regression analysis, educational level was negatively associated with both general obesity and abdominal obesity among women but positively associated with abdominal obesity among men. No significant correlation was found between obesity and income.

Conclusions

These results suggest a high prevalence of obesity which might differ by gender and age, and an inverse association among women and a mixed association among men noted between education and obesity in our locality. Preventive and therapeutic programs are warranted to control this serious public health problem. The gender-specific characteristics of populations at high-risk of developing obesity should be taken into consideration when designing interventional programs.

Social disparities, health risk behaviors, and cancer

BACKGROUND

Overall cancer incidence rates decreased in the most recent time period in both men and women, largely due to improvements in surgical therapeutic approaches (tertiary prevention) and screening programs (secondary prevention), but differences in cancer incidence and survival according to socioeconomic status are documented worldwide. Health risk behaviors, defined as habits or practices that increase an individual's likelihood of harmful health outcomes, are thought to mediate such inequalities.

DISCUSSION

Obesity has been related with increased cancer incidence and mortality due to imbalance of leptin and adiponectin which are connected to activation of PI3K, MAPK, and STAT3 pathways and decreasing insulin/insulin-like growth factor (IGF)-1 and mTOR signaling via activation of 5 AMP-activated protein kinase (AMPK), respectively. Physical activity has been associated to prevent cancer by the aforementioned obesity-related mechanisms, but also increasing level of circulating vitamin D, which has been related to lower risk of several cancers, and increasing prostaglandin F2a and reducing prostaglandin E2, which are both related with cancer prevention and promotion, respectively. A large number of different substances may induce themselves a direct cytotoxicity and mutagenic action on cells by smoking, whereas alcohol promote immune suppression, the delay of DNA repair, inhibition of the detoxification of carcinogens, the production of acetaldehyde, and the contribution to abnormal DNA methylation. The combined smoking and alcohol drinking habits have been shown to increase cancer risk by smoke action of increasing the acetaldehyde burden following alcohol consumption and alcohol action of enhancing the activation of various procarcinogens contained in tobacco smoke.

CONCLUSIONS

Interventions at the social level may be done to increase awareness about cancer risks and promote changing in unhealthy behaviors.

Possible role of intestinal fatty acid oxidation in the eating-inhibitory effect of the PPAR-α agonist Wy-14643 in high-fat diet fed rats

PPAR-α plays a key role in lipid metabolism; it enhances fatty acid oxidation (FAO) and ketogenesis. Pharmacological PPAR-α activation improves insulin sensitivity and reduces food intake, but its mechanisms of action remain unknown. We here report that intraperitoneal (IP) administration of the PPAR-α agonist Wy-14643 (40 mg/kg BW) reduced food intake in adult male rats fed a high-fat diet (HFD, 49% of the energy) mainly through an increase in the latency to eat after injection, and without inducing a conditioned taste avoidance. Also, IP administered Wy-14643 caused an acute (the first 60 min) decrease in the respiratory quotient (RQ) and an increase in hepatic portal vein β-hydroxybutyrate level (at 35 min) without affecting plasma non-esterified fatty acids. Given the known stimulatory effect of PPAR-α on FAO and ketogenesis, we measured the protein expression level of carnitine palmitoyltransferase-1 (CPT 1A) and mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMG-CoAS2), two key enzymes for FAO and ketogenesis, respectively, in liver, duodenum and jejunum. Wy-14643 induced a significant increase in the expression of CPT 1A in the jejunum and duodenum and of HMG-CoAS2 in the jejunum, but neither CPT 1A nor HMG-CoAS2 expression was increased in the liver. The induction of CPT 1A and HMG-CoAS2 expression was associated with a decrease in the lipid droplet content selectively in the jejunum. Our findings indicate that Wy-14643 stimulates FAO and ketogenesis in the intestine, in particular in the jejunum, rather than in the liver, thus supporting the hypothesis that PPAR-α activation inhibits eating by stimulating intestinal FAO.

The role of chronic inflammation in obesity-associated cancers

There is a strong relationship between metabolism and immunity, which can become deleterious under conditions of metabolic stress. Obesity, considered a chronic inflammatory disease, is one example of this link. Chronic inflammation is increasingly being recognized as an etiology in several cancers, particularly those of epithelial origin, and therefore a potential link between obesity and cancer. In this review, the connection between the different factors that can lead to the chronic inflammatory state in the obese individual, as well as their effect in tumorigenesis, is addressed. Furthermore, the association between obesity, inflammation, and esophageal, liver, colon, postmenopausal breast, and endometrial cancers is discussed.

Cancer and heterogeneity of obesity: a potential contribution of brown fat

Obesity has lately been drawing additional attention as a potential cancer risk and, with some exceptions as a prognostic factor. As obesity is a complex issue characterized by different variants, mechanisms and manifestations, its role in cancer development is also a complex problem exceeding the basic fact of the fat content rising above certain limits. Therefore, in the present paper obesity is viewed as a heterogeneous entity, which has distinct connections with cancer pathogenesis. Among other issues, emphasis is made on the state of white and brown adipose tissue, in particular the association of specific brown fat features and the so-called white fat browning with the functions of normal and mutated tumor suppressor genes, such as PTEN and BRCA1. These connections are considered from the viewpoint implying the existence of two types of hormonal carcinogenesis and of hormonal mediation of the genetic predisposition to tumor development, and should be accounted for in prevention and treatment of both obesity and cancer.

Dietary supplementation with Agaricus blazei murill extract prevents diet-induced obesity and insulin resistance in rats

OBJECTIVE

Dietary supplement may potentially help to fight obesity and other metabolic disorders such as insulin-resistance and low-grade inflammation. The present study aimed to test whether supplementation with Agaricus blazei murill (ABM) extract could have an effect on diet-induced obesity in rats.

DESIGN AND METHODS

Wistar rats were fed with control diet (CD) or high-fat diet (HF) and either with or without supplemented ABM for 20 weeks.

RESULTS

HF diet-induced body weight gain and increased fat mass compared to CD. In addition HF-fed rats developed hyperleptinemia and insulinemia as well as insulin resistance and glucose intolerance. In HF-fed rats, visceral adipose tissue also expressed biomarkers of inflammation. ABM supplementation in HF rats had a protective effect against body weight gain and all study related disorders. This was not due to decreased food intake which remained significantly higher in HF rats whether supplemented with ABM or not compared to control. There was also no change in gut microbiota composition in HF supplemented with ABM. Interestingly, ABM supplementation induced an increase in both energy expenditure and locomotor activity which could partially explain its protective effect against diet-induced obesity. In addition a decrease in pancreatic lipase activity is also observed in jejunum of ABM-treated rats suggesting a decrease in lipid absorption.

CONCLUSIONS

Taken together these data highlight a role for ABM to prevent body weight gain and related disorders in peripheral targets independently of effect in food intake in central nervous system.

The influence of glucocorticoid signaling on tumor progression

The diagnosis of cancer elicits a broad range of well-characterized stress-related biobehavioral responses. Recent studies also suggest that an individual's neuroendocrine stress response can influence tumor biology. One of the major physiological pathways altered by the response to unrelenting social stressors is the hypothalamic-pituitary-adrenal or HPA axis. Initially following acute stress exposure, an increased glucocorticoid response is observed; eventually, chronic stress exposure can lead to a blunting of the normal diurnal cortisol pattern. Interestingly, recent evidence also links high primary tumor glucocorticoid receptor expression (and associated increased glucocorticoid-mediated gene expression) to more rapid estrogen-independent breast cancer progression. Furthermore, animal models of human breast cancer suggest that glucocorticoids inhibit tumor cell apoptosis. These findings provide a conceptual basis for understanding the molecular mechanisms underlying the influence of the individual's stress response, and specifically glucocorticoid action, on breast cancer and other solid tumor biology. How this increased glucocorticoid signaling might contribute to cancer progression is the subject of this review.

Relationships between dietary macronutrients and adult neurogenesis in the regulation of energy metabolism

Of the environmental factors which have an impact on body weight, nutrients are most influential. Within normal limits, hypothalamic and related neuronal populations correct perturbations in energy metabolism, to return the body to its nutritional set-point, either through direct response to nutrients or indirectly via peripheral appetite signals. Excessive intake of certain macronutrients, such as simple carbohydrates and SFA, can lead to obesity and attendant metabolic dysfunction, also reflected in alterations in structural plasticity, and, intriguingly,neurogenesis, in some of these brain regions. Neurogenesis, previously thought to occur only in the embryo, is now known to take place in the adult brain, dependent on numerous stimulating and inhibiting factors, including dietary components. Because of classic associations between neurogenesis and the hippocampus, in learning and cognition, this brain region has also been the focus of attention in the study of links between diet and neurogenesis. Recently, however, a more complete picture of this relationship has been building: not only has the hypothalamus been shown to satisfy the criteria for a neurogenic niche, but appetite-related mediators, including circulating hormones, such as leptin and ghrelin, pro-inflammatory cytokines and the endocannabinoid intracellular messengers, are also being examined for their potential role in mediating neurogenic responses to macronutrients. The present review draws together these observations and investigates whether n-3 PUFA may exert their attenuating effects on body weight through the stimulation of adult neurogenesis. Exploration of the effects of nutraceuticals on neurogenic brain regions may encourage the development of new rational therapies in the fight against obesity.