Hyperresistinemia is associated with postmenopausal breast cancer

Serum and urinary levels of MIF, CD74, DDT and CXCR4 among patients with type 1 diabetes mellitus, type 2 diabetes and healthy individuals: Implications for further research

Background

Macrophage migration inhibitory factor (MIF) is a highly conserved cytokine with pleiotropic properties, mainly pro-inflammatory. MIF seems to exert its pro-inflammatory features by binding to its transmembrane cellular receptor CD74. MIF also has CXCR4, which acts as a co-receptor in this inflammatory process. Apart from MIF, D-dopachrome tautomerase (DDT) or MIF2, which belongs to the MIF superfamily, also binds to receptor CD74. Therefore, these molecules, MIF, CD74, DDT and CXCR4 are suggested to work together orchestrating an inflammatory process. Diabetes mellitus is characterised by chronic low-grade inflammation. Therefore, the aim of the present study was to evaluate serum and urinary levels of the aforementioned molecules among patients with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM) and among healthy controls.

Methods

We enrolled 13 patients with T1DM, 74 patients with T2DM and 25 healthy individuals as controls. Levels of CD74, CXCR4, DDT, and MIF were measured using ELISA Kits according to the manufacturer's instructions.

Results

We documented increased serum MIF levels together with higher urinary CD74 levels among patients with T1DM, when compared to patients with T2DM and healthy adults. In particular, patients with T1DM showed significantly increased levels of MIF compared to T2DM (p = 0.011) and healthy controls (p = 0.0093). CD74 in urine were significantly higher in patients with T1DM compared to those affected with T2DM (p = 0.0302) and healthy group (p = 0.0099). On the contrary, serum CD74 were similar among the three groups. No statistical differences were identified in CXCR4 levels both in serum and in urine of all groups. Patients with T2DM and overweight/obesity had increased urinary levels of CD74, when compared to lean patients with T2DM.

Conclusion

The increased serum MIF levels and urinary CD74 levels among patients with T1DM may be attributed to the autoimmune milieu, which characterises patients with T1DM, when compared to patients with T2DM. These two findings merit further attention as they could pave the way for further research regarding the potential beneficial effects of inhibitors of MIF among patients with T1DM, especially in the early stages of T1DM. Finally, the role of inhibitors of MIF could be further explored in the context of obesity among patients with T2DM.

25-hydroxyvitamin D and parathyroid hormone in new onset sepsis: A prospective study in critically ill patients

Hypovitaminosis D is highly prevalent in critically ill patients, and it has been suggested to be a risk factor for infections, sepsis and higher mortality. We sought to investigate whether serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) in critically ill patients with new onset sepsis are associated with severity and outcome. We prospectively included 50 consecutive critically ill adult cases with new onset sepsis and 50 healthy controls matched for age and sex. PTH and 25(OH)D were determined in serum via electrochemiluminescence immunoassays at inclusion in the study in all cases and controls, and one week after sepsis onset in cases. Patients had reduced 25(OH)D compared to controls at sepsis onset (7.9 ± 3 vs 24.6 ± 6.7 ng/mL, p < 0.001), whilst PTH was similar (median (range): 34.5 (5.7-218.5) vs 44.2 (14.2-98.1) pg/mL, p = 0.35). In patients, 25(OH)D upon enrollment and one week after did not differ significantly (7.9 ± 3 vs 7 ± 4.3 ng/mL, p = 0.19). All patients presented with hypovitaminosis D (25(OH)D < 20 ng/mL), while 40 patients (80 %) had vitamin D deficiency (25(OH)D < 12 ng/mL) at sepsis onset, including all ten (20 %) nonsurvivors, who died within 28 days from sepsis onset. Patients with sepsis (N = 28) and septic shock (N = 22) as well as survivors (N = 40) and nonsurvivors (N = 10) had similar 25(OH)D at enrollment (p > 0.05). 25(OH)D was positively correlated with ionized calcium (r = 0.46, p < 0.001) and negatively with PTH (p < 0.05), while inflammatory biomarkers or the severity scores exhibited no correlation with 25(OH)D. Patients with septic shock and nonsurvivors had lower PTH than patients with sepsis and survivors respectively (42.2 ± 42.9 vs 73.4 ± 61.9 pg/mL, p = 0.04, and 18.3 ± 10.7 vs 69.9 ± 58.8 pg/mL, p = 0.001, respectively). C-reactive protein was negatively associated with PTH (r = -0.44, p = 0.001). In conclusion, vitamin D deficiency was present in 80 % of critically ill patients at sepsis onset, while nonsurvivors exhibited lower PTH than survivors. Additional, larger and multicenter studies are warranted to elucidate the contribution of vitamin D and PTH to the pathogenesis of sepsis and its outcomes.

Diet patterns, gut microbiota and metabolic disorders: Perspectives and challenges

The worldwide surge in obesity and associated metabolic disorders is emerging as a significant public health issue for societies and healthcare systems. Available evidence has shown that alterations in the gut microbiota could be implicated in the pathogenesis of obesity and associated disorders. A healthy gut microbiome is characterized by richness and high microbial diversity. Gut microbiota affect how the host responds to diet, and conversely, the host may modify the gut microbiota through changes in dietary habits. Diet can impact and alter the composition, diversity, and species richness of the gut microbiota over time. An unhealthy diet, high in fat and sugar, may lead to decreased microbial diversity, reduced synthesis of metabolites that maintain gut permeability, damage to the mucus layer, increased bacterial translocation and lipopolyssacharide which can trigger endotoxemia, chronic subclinical inflammation and metabolic disorders. Currently, the impact of diet on gut microbial composition and its involvement in the pathogenic mechanisms underlying metabolic disorders is one of the most promising areas of research in nutrition. This special issue has gathered original research articles in topics related to diet patterns, gut microbiota, obesity and associated metabolic disorders as well as brief reports, reviews and perspectives in the wider field of translational and clinical metabolic research. In particular, the aim of this Special Issue was to present evidence connecting gut microbiota with metabolic disorders, explore the underlying mechanisms of this association, and examine how diet patterns may influence this relationship.

Resistin and omentin in breast cancer: A systematic review and meta-analysis

Breast cancer (BC) is the most frequently diagnosed cancer and a leading cause of cancer-related mortality among women globally. Resistin, omentin and ghrelin, adipokines involved in inflammation and metabolic regulation, have been implicated in cancer development, yet their associations with BC remain unclear. This systematic review and meta-analysis aimed to elucidate the relationships between resistin, omentin, and ghrelin concentrations and BC, while exploring potential moderators such as body mass index (BMI) and menopausal status. A comprehensive search of electronic databases up to 13 May 2024 identified studies comparing resistin and omentin, but not ghrelin, concentrations in BC patients and healthy controls. Standardized mean differences (SMDs) were calculated using random-effects models, and meta-regression and subgroup analyses were performed to investigate sources of heterogeneity. Analysis of 11 studies showed that BC patients exhibited significantly higher resistin concentrations compared to controls, with a pooled SMD of 2.05 (95 % CI 1.24 to 2.86, p < 0.001). Meta-regression indicated that BMI significantly moderated the resistin-BC association (p = 0.003). In contrast, omentin concentrations presented a complex picture, with a pooled SMD of -0.27 (95 % CI -1.39 to 0.84, I^2 = 96.2 %, p < 0.001), indicating substantial heterogeneity and inconclusive results, whereas only one study investigated ghrelin. Our findings support a significant association between elevated resistin concentrations and BC, suggesting a potential role of resistin in BC pathophysiology. The data on omentin and ghrelin remain inconclusive, warranting further investigation. Future research should focus on large, longitudinal studies with standardized methodologies to validate these findings and clarify the role of adipokines in BC.

Clinical metabolomics: Useful insights, perspectives and challenges

Metabolomics, a cutting-edge omics technique, is a rapidly advancing field in biomedical research, concentrating on the elucidation of pathogenetic mechanisms and the discovery of novel metabolite signatures predictive of disease risk, aiding in earlier disease detection, prognosis and prediction of treatment response. The capacity of this omics approach to simultaneously quantify thousands of metabolites, i.e. small molecules less than 1500 Da in samples, positions it as a promising tool for research and clinical applications in personalized medicine. Clinical metabolomics studies have proven valuable in understanding cardiometabolic disorders, potentially uncovering diagnostic biomarkers predictive of disease risk. Liquid chromatography-mass spectrometry is the predominant analytical method used in metabolomics, particularly untargeted. Metabolomics combined with extensive genomic data, proteomics, clinical chemistry data, imaging, health records, and other pertinent health-related data may yield significant advances beneficial for both public health initiatives, clinical applications and precision medicine, particularly in rare disorders and multimorbidity. This special issue has gathered original research articles in topics related to clinical metabolomics as well as research articles, reviews, perspectives and highlights in the broader field of translational and clinical metabolic research. Additional research is necessary to identify which metabolites consistently enhance clinical risk prediction across various populations and are causally linked to disease progression.

The Molecular and Genetic Interactions between Obesity and Breast Cancer Risk

Breast cancer (BC) is considered the leading cause of death among females worldwide. Various risk factors contribute to BC development, such as age, genetics, reproductive factors, obesity, alcohol intake, and lifestyle. Obesity is considered to be a pandemic health problem globally, affecting millions of people worldwide. Obesity has been associated with a high risk of BC development. Determining the impact of obesity on BC development risk in women by demonstrating the molecular and genetic association in pre- and post-menopause females and risk to BC initiation is crucial in order to improve the diagnosis and prognosis of BC disease. In epidemiological studies, BC in premenopausal women was shown to be protective in a certain pattern. These altered effects between the two phases could be due to various physiological changes, such as estrogen/progesterone fluctuating levels. In addition, the relationship between BC risk and obesity is indicated by different molecular alterations as metabolic pathways and genetic mutation or epigenetic DNA changes supporting a strong connection between obesity and BC risk. However, these molecular and genetic alteration remain incompletely understood. The aim of this review is to highlight and elucidate the different molecular mechanisms and genetic changes occurring in obese women and their association with BC risk and development.

The first combined meta‐analytic approach for elucidating the relationship of circulating resistin levels and RETN gene polymorphisms with colorectal and breast cancer

Background

Evidence suggests that circulating resistin levels are altered in colorectal cancer (CRC) and breast cancer (BC). Again, polymorphisms in resistin-encoding gene RETN have been evaluated in CRC and BC. However, there is a scarcity of data establishing the relationship of resistin and RETN polymorphisms (rs1862513 and rs3745367) with these cancers. This study aimed to analyze the relationship of resistin levels and RETN polymorphisms with CRC and BC in a combined meta-analytic approach.

Main body of the abstract

After a comprehensive online literature search, screening and eligibility check, 41 articles (31 with resistin level and 10 with RETN polymorphisms) were retrieved for meta-analyses. The mean difference (MD) of resistin was calculated and pooled to investigate the effect sizes with a 95% confidence interval (CI), and the connection of genetic polymorphisms was analyzed with an odds ratio (OR) and 95% CI. The analysis showed that resistin level is significantly higher in CRC (MD = 3.39) and BC (MD = 3.91) patients. Subgroup analysis in CRC showed significantly higher resistin in serum (MD = 4.61) and plasma (MD = 0.34), and in BC, a significantly elevated resistin level was reported in premenopausal (MD = 7.82) and postmenopausal (MD = 0.37) patients. Again, RETN rs1862513 showed a significantly strong association with CRC (codominant 1—OR 1.24, codominant 2—OR 1.31, dominant model—OR 1.25, and allele model—OR 1.16) and with BC (codominant 2—OR 1.51, codominant 3—OR 1.51, recessive model—OR 1.51, and allele model—OR 1.21). RETN rs3745367 did not show any association with these cancers.

Short conclusion

Overall, our analysis indicates that higher circulating resistin levels are associated with an elevated risk of CRC and premenopausal and postmenopausal BC. Besides, rs1862513 in RETN gene is significantly connected with both CRC and BC.

Circulating Omentin-1 as a Biomarker at the Intersection of Postmenopausal Breast Cancer Occurrence and Cardiometabolic Risk: An Observational Cross-Sectional Study

Aberrant circulating omentin-1, which is an anti-inflammatory and pro-apoptotic adipokine, has been reported in various solid tumors. Therefore, we investigated whether or not circulating omentin-1 could be associated with postmenopausal BC (PBC) and could be used as a potential diagnostic and clinical tool taking into consideration clinicopathologic features, tumor markers, as well as anthropometric, metabolic, and inflammatory parameters. Serum omentin-1, tumor markers (CA15-3 and CEA); metabolic (insulin, glucose, HOMA index, and serum lipids), anthropometric (BMI, waist circumference, and fat mass), and inflammatory (TNF-α, IL-6, hsCRP) parameters; classic adipokines (leptin and adiponectin); the Mediterranean diet (MedDiet) score; and cardiovascular (CVD) risk were determined in 103 postmenopausal women with pathologically confirmed incident invasive BC, 103 controls matched on age, 51 patients with benign breast lesions (BBL), and 50 obese postmenopausal women of similar age. The mean serum omentin-1 was significantly lower in cases than in controls and patients with BBL (p < 0.001). In the patients, omentin-1 was inversely associated with tumor, metabolic and inflammatory biomarkers, cancer stage, and the number of infiltrated lymph nodes (p < 0.05). In all study participants, omentin-1 was negatively correlated with CVD risk and positively correlated with MedDiet score. Lower circulating omentin-1 was independently associated with PBC occurrence above and beyond known risk factors. According to the ROC curve analysis, the overall diagnostic performance of omentin-1 (0.84, 95% CI 0.79-0.89) is similar to CA15-3. Circulating omentin-1 may be a biomarker at the intersection of PBC and cardiometabolic risk in postmenopausal women, and could be modulated by the adoption of a MedDiet. Further mechanistic and large multicentric prospective and longitudinal studies are required to elucidate the ontological role of omentin-1 in BC and CVD risks, as well as its diagnostic and prognostic ability and its therapeutic potential.

LEP as a potential biomarker in prognosis of breast cancer: Systemic review and meta analyses (PRISMA)

PURPOSE

Obesity strongly affects the prognosis of various malignancies, including breast cancer. Leptin (LEP) may be associated with obesity and breast cancer prognosis. The purpose of our study was to determine the prognostic value of LEP in breast cancer.

METHOD

We conducted a multi-omic analysis to determine the prognostic role of LEP. Different public bioinformatics platforms (Oncomine, Gene Expression Profiling Interactive Analysis, University of California Santa Cruz Xena, bc-GenExMiner, PrognoScan database, R2-Kaplan-Meier Scanner, UALCAN, Search Tool for the Retrieval of Interacting Genes/Proteins database , and The Database for Annotation, Visualization and Integrated Discovery) were used to evaluate the roles of LEP. Clinicopathological variables were evaluated.

RESULTS

LEP was downregulated in breast cancer tissues compared to levels in normal tissues. By co-expressed gene analysis, a positive correlation between LEP and SLC19A3 was observed. Based on the clinicopathological analysis, low LEP expression was associated with older age, higher stage, lymph node status, human epidermal growth factor receptor 2 (HER2) status, estrogen receptor (ER+) positivity, and progesterone receptor (PR+) positivity. Kaplan-Meier survival analysis showed that low LEP expression indicated a poorer prognosis. LEP is hypermethylated in breast cancer tissues in PrognoScan and R2-Kaplan Meier Scanner, and low LEP expression was correlated with poor prognosis. LEP protein-protein interactions were analyzed using Search Tool for the Retrieval of Interacting Genes/Proteins database. Gene ontology analysis results showed that cellular component is mainly associated with the endosome lumen, cytosol, and secretory granules and is upregulated. For the biological process energy reserve, metabolic processes exhibited the greatest regulation compared to the others. In molecular function, it was mainly enriched in a variety of combinations, but hormone activity showed the highest regulation.

CONCLUSION

Our study provides evidence for the prognostic role of LEP in breast cancer and as a novel potential therapeutic target in such malignancies. Nevertheless, further validation is required.

Association Between Serum Insulin and C-Peptide Levels and Breast Cancer: An Updated Systematic Review and Meta-Analysis

Background

Several studies have reported that hyperinsulinemia plays a part in the etiology of breast cancer. However, no consensus has been reached. Therefore, we conducted a meta-analysis to explore the role of insulin and C-peptide in breast cancer.

Methods

A systematic search in PubMed, Embase, and The Cochrane Library was conducted up to September, 2020. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to measure effect sizes. Publication bias was assessed using the Egger test. Stability of these results was evaluated using sensitivity analyses.

Results

Fourteen articles including 27,084 cases and five articles including 2,513 cases were extracted for serum insulin levels and C-peptide levels. We found that C-peptide levels were positively associated with breast cancer with overall SMD = 0.37 (95% CI = 0.09–0.65, I² = 89.1%). Subgroup analysis by control source illustrated a positive relationship between breast cancer and C-peptide levels in population-based control. Subgroup analysis by C-peptide level indicated a positive correlation between breast cancer and C-peptide levels no matter C-peptide levels in case group is ≤3 ng/ml or >3 ng/ml. Subgroup analysis by age showed that C-peptide level positively correlated to breast cancer in women between the ages of 50 and 60. However, we did not identify any relationship between breast cancer and insulin levels (SMD = 0.22, 95% CI = −0.06–0.50, I² = 97.3%).

Conclusion

This meta-analysis demonstrated that C-peptide levels were positively related to breast cancer in women, and no relationship between insulin levels and breast cancer was found.

Adipocytokines visfatin and resistin in breast cancer: Clinical relevance, biological mechanisms, and therapeutic potential

Obesity is one of the major modifiable risk factors in breast cancer, with obese adipose tissue showing a pathological role in breast cancer development and malignancy via the release of secretory factors, such as proinflammatory cytokines and adipocytokines. The current article focuses on visfatin and resistin, two such adipocytokines that have emerged over the last two decades as leading breast cancer promoting factors in obesity. The clinical association of circulating visfatin and resistin with breast cancer and their biological mechanisms are reviewed, in addition to their role in the context of tumor-stromal interactions in the breast cancer microenvironment. Recent findings have unraveled several mediators of visfatin and resistin that are involved in the crosstalk between breast cancer cells and adipose tissue in the breast tumor microenvironment, including growth differentiation factor 15 (GDF15), interleukin 6 (IL-6), and toll-like receptor 4 (TLR4). Finally, current therapeutics targeting visfatin and resistin and their respective pathways are discussed, including future therapeutic strategies such as new drug design or neutralizing peptides that target extracellular visfatin or resistin. These hold promise in the development of novel breast cancer therapies and are of increasing relevance as the prevalence of obesity-related breast cancer increases worldwide.

Resistin in metabolism, inflammation, and disease

Resistin is a small secretory protein that has a pleiotropic role in rodents and humans. Both rodent resistin and human resistin have an extremely stable and high-order multimeric structure. Moreover, there is significant variation in the source of secretion and the diversity of functions of resistin. Mouse resistin resists insulin action and contributes to type 2 diabetes mellitus, while human resistin plays a role in inflammation and also functions as a small accessory chaperone. Currently, active research in the area identified a significant role for resistin in stress biology and as a biomarker in diagnostics to evaluate disease status and treatment outcome. This review summarizes recent developments within resistin biology including their association with obesity, inflammation, stress response mechanisms, and its role in clinical diagnostics.

The Role of Adipokines in Breast Cancer: Current Evidence and Perspectives

PURPOSE

The current review shows evidence for the role of adipokines in breast cancer (BC) pathogenesis summarizing the mechanisms underlying the association between adipokines and breast malignancy. Special emphasis is given also on intriguing insights into the relationship between obesity and BC as well as on the role of novel adipokines in BC development.

RECENT FINDINGS

Recent evidence has underscored the role of the triad of obesity, insulin resistance, and adipokines in postmenopausal BC. Adipokines exert independent and joint effects on activation of major intracellular signal networks implicated in BC cell proliferation, growth, survival, invasion, and metastasis, particularly in the context of obesity, considered a systemic endocrine dysfunction characterized by chronic inflammation. To date, more than 10 adipokines have been linked to BC, and this catalog is continuously increasing. The majority of circulating adipokines, such as leptin, resistin, visfatin, apelin, lipocalin 2, osteopontin, and oncostatin M, is elevated in BC, while some adipokines such as adiponectin and irisin (adipo-myokine) are generally decreased in BC and considered protective against breast carcinogenesis. Further evidence from basic and translational research is necessary to delineate the ontological role of adipokines and their interplay in BC pathogenesis. More large-scale clinical and longitudinal studies are awaited to assess their clinical utility in BC prognosis and follow-up. Finally, novel more effective and safer adipokine-centered therapeutic strategies could pave the way for targeted oncotherapy.

The Role of Adipose Tissue and Adipokines in Sepsis: Inflammatory and Metabolic Considerations, and the Obesity Paradox

PURPOSE

Sepsis has become a global health problem with rising incidence and high mortality, creating a substantial social and economic burden. Early diagnosis and treatment can improve outcome, but reliable sepsis biomarkers are lacking. This review summarizes current evidence of the pathophysiological mechanisms linking adipose tissue to sepsis and presents experimental and clinical data on adipokines and sepsis along with important insights into the obesity paradox in sepsis survival.

RECENT FINDINGS

Sepsis is characterized by significant alterations in circulating cytokines and adipokines, biologically active molecules produced by the adipose tissue, being implicated in metabolic and inflammatory processes. Although data are inconclusive regarding classic adipokines such as leptin and adiponectin, recent evidence have highlighted the striking elevation of resistin and visfatin in critical illness and sepsis as well as their association with sepsis severity and outcomes. Given that inflammatory and metabolic pathways are involved in sepsis, studying adipokines presents an attractive, innovative, and promising research field that may provide more powerful diagnostic and prognostic biomarkers as well as novel therapeutic targets, empowering the therapeutic armamentarium for sepsis management in order to improve survival.

Circulating eNampt and resistin as a proinflammatory duet predicting independently mortality in critically ill patients with sepsis: A prospective observational study

BACKGROUND

The adipocytokines eNampt and resistin are involved in the regulation of inflammation exerting pro-inflammatory actions. Our aim was to jointly investigate whether circulating eNampt and resistin, and their kinetics predict 28-day mortality of sepsis.

METHODS

In a prospective study, serum eNampt and resistin were determined in 102 critically ill patients fulfilling the diagnostic criteria of SEPSIS-3, at enrollment and one week after, and in 102 healthy controls matched on age, gender and month of diagnosis.

RESULTS

Serum eNampt and resistin were significantly higher in septic patients than controls (p < 0.001), and higher in septic shock compared to sepsis (p < 0.001). Both eNampt and resistin decreased significantly during the first week of sepsis (p < 0.001). However, patients with septic shock presented a sustained elevation of eNampt and resistin compared to patients with sepsis. Both adipocytokines were positively correlated with sepsis severity scores and lactate. Baseline eNampt was a better discriminator of sepsis and septic shock compared to C-reactive protein and procalcitonin. Serum eNampt and resistin were higher in nonsurvivors than in survivors during the first week of sepsis. Prolonged and sustained elevation of both eNampt and resistin, as reflected by a lower percentage change from their baseline values, was independently associated with 28-day mortality (HR: 0.05, 95% C.I. 0.01-0.28, p = 0.001; HR: 0.19, 95% C.I. 0.07-0.50, p = 0.001, respectively), after adjustment for significant clinical and laboratory biomarkers.

CONCLUSION

Circulating eNampt and resistin, and their kinetics may represent useful diagnostic and prognostic biomarkers in critically ill septic patients. More prospective studies are needed to elucidate their ontological and pathophysiological role in sepsis.

Impact of obesity on breast cancer recurrence and minimal residual disease

BACKGROUND

Obesity is associated with an increased risk of breast cancer recurrence and cancer death. Recurrent cancers arise from the pool of residual tumor cells, or minimal residual disease (MRD), that survives primary treatment and persists in the host. Whether the association of obesity with recurrence risk is causal is unknown, and the impact of obesity on MRD and breast cancer recurrence has not been reported in humans or in animal models.

METHODS

Doxycycline-inducible primary mammary tumors were generated in intact MMTV-rtTA;TetO-HER2/neu (MTB/TAN) mice or orthotopic recipients fed a high-fat diet (HFD; 60% kcal from fat) or a control low-fat diet (LFD; 10% kcal from fat). Following oncogene downregulation and tumor regression, mice were followed for clinical recurrence. Body weight was measured twice weekly and used to segregate HFD mice into obese (i.e., responders) and lean (i.e., nonresponders) study arms, and obesity was correlated with body fat percentage, glucose tolerance (measured using intraperitoneal glucose tolerance tests), serum biomarkers (measured by enzyme-linked immunosorbent assay), and tissue transcriptomics (assessed by RNA sequencing). MRD was quantified by droplet digital PCR.

RESULTS

HFD-Obese mice weighed significantly more than HFD-Lean and LFD control mice (p < 0.001) and had increased body fat percentage (p < 0.001). Obese mice exhibited fasting hyperglycemia, hyperinsulinemia, and impaired glucose tolerance, as well as decreased serum levels of adiponectin and increased levels of leptin, resistin, and insulin-like growth factor 1. Tumor recurrence was accelerated in HFD-Obese mice compared with HFD-Lean and LFD control mice (median relapse-free survival 53.0 days vs. 87.0 days vs. 80.0 days, log-rank p < 0.001; HFD-Obese compared with HFD-Lean HR 2.52, 95% CI 1.52-4.16; HFD-Obese compared with LFD HR 2.27, 95% CI 1.42-3.63). HFD-Obese mice harbored a significantly greater number of residual tumor cells than HFD-Lean and LFD mice (12,550 ± 991 vs. 7339 ± 2182 vs. 4793 ± 1618 cells, p < 0.001).

CONCLUSION

These studies provide a genetically engineered mouse model for study of the association of diet-induced obesity with breast cancer recurrence. They demonstrate that this model recapitulates physiological changes characteristic of obese patients, establish that the association between obesity and recurrence risk is causal in nature, and suggest that obesity is associated with the increased survival and persistence of residual tumor cells.

Early menarche is independently associated with subclinical hypothyroidism: a cross-sectional study

Background Subclinical hypothyroidism (SH) is more frequent in females than males, with a female to male ratio ranging from 1.5 to 5 in the general population. The aim of this study was to evaluate for the first time the association of reproductive factors, particularly age at menarche, with SH risk. Materials and methods In a cross-sectional study, reproductive factors such as age at menarche, at menopause and at first birth, lactation, parity, full-term pregnancies, reproductive years, use of oral contraceptives and hormonal replacement therapy, somatometric data and insulin resistance parameters were recorded in 72 consecutive female patients with SH and 72 healthy female controls matched on age (±5 years) and date of diagnosis (±1 month). Results SH cases exhibited significantly younger age at menarche than controls (12.6 ± 1.2 vs. 13.3 ± 0.8 years, respectively, p < 0.001). Cases presented later age at first pregnancy with a lower number of full-term pregnancies (p = 0.04). Early age at menarche was independently associated with SH risk, above and beyond thyroid autoimmunity, body mass index (BMI), hip circumference (HC), homeostatic model assessment of insulin resistance and alcohol consumption [odds ratio (OR): 0.22, 95% confidence interval (CI): 0.11-0.44; p < 0.001]. Conclusions It is possible that an interplay of early exposure to estrogens, as expressed by early menarche, and induction of thyroid autoimmunity may be associated with SH risk. More prospective studies shedding light on the role of estrogens in SH are required to confirm these findings.

Association between circulating leptin concentration and G-2548A gene polymorphism in patients with breast cancer: a meta-analysis

INTRODUCTION

The aim of this meta-analysis was to summarize the evidence on the serum/plasma leptin concentrations in breast cancer (BC) patients, as well as the associations between leptin G-2548A gene polymorphisms and susceptibility to BC.

MATERIAL AND METHODS

Potentially relevant studies about serum/plasma leptin levels and leptin G-2548A gene polymorphism were selected using the electronic databases PubMed, EMBASE and The Cochrane Library (from January 1 1995 to Jun 30 2017, no language restrictions). The potential sources of heterogeneity were assessed by the Q statistic and quantified using I² ; publication bias was qualitatively assessed by funnel plot and quantitatively assessed by Egger's linear regression test.

RESULTS

A total of 1141 articles were retrieved after database searches, and 27 studies with 9516 subjects (4542 BC patients/4974 controls) were finally included. The results indicated that BC patients had significantly higher leptin levels compared with healthy controls (SMD = 1.65, 95% CI: 1.21-2.09, p < 0.001), but there was no association between leptin G-2548A polymorphism and BC (OR = 1.05, 95% CI: 0.80-1.39, p = 0.722). Subgroup analyses demonstrated increased leptin levels in BC patients of different region, race, body mass index and waist circumference.

CONCLUSIONS

Our results revealed a significantly higher leptin level in BC patients than in healthy controls, but no association between leptin G-2548A polymorphism and BC susceptibility was found.

Association of serum leptin with breast cancer: A meta-analysis

BACKGROUND

Accumulating evidence has demonstrated that leptin is associated to the tumorigenesis and progression of breast cancer (BC). However, these studies remain inconsistent. Thus, a meta-analysis was conducted to investigate the role of leptin in the patients with BC.

METHOD

A systematic search in PubMed, Embase, ISI Web of Science, and Chinese National Knowledge Infrastructure (CNKI) databases was conducted up to September 1, 2017. The standardized mean difference (SMD) with 95% confidence interval (CI) was applied to pool the effect size. A funnel plot and Egger test were used to evaluate publication bias.

RESULTS

Finally, 43 eligible studies were included in the current meta-analysis. Overall, serum leptin levels in BC cases were significantly higher compared with the controls (SMD = 0.61, P <.0001). When subgroup analyses were restricted to ethnicity and menstrual status, higher serum leptin concentration was also detected in patients with BC. Moreover, BC cases with body mass index (BMI) >25 indicated significantly higher serum leptin levels (SMD = 1.48, P = .034). Furthermore, the BC cases with lymph node metastases showed significantly higher serum leptin concentration (SMD = 0.53, P = .015).

CONCLUSION

The present meta-analysis suggests that the serum leptin may profiles as a pivotal role in the pathogenesis and metastasis of BC. In addition, leptin will provide useful information for a therapeutic target to treat BC.

Chemerin as a biomarker at the intersection of inflammation, chemotaxis, coagulation, fibrinolysis and metabolism in resectable non-small cell lung cancer

OBJECTIVES

Chemerin is an emerging adipocytokine at the intersection of inflammation, chemotaxis, thrombosis, fibrinolysis and metabolism. Our aims were 1) to explore circulating chemerin in resectable non-small cell lung cancer (NSCLC) taking into account its several interfaces; 2) to study its diagnostic potential; and 3) to assess its associations with clinicopathological features of NSCLC.

MATERIALS AND METHODS

In a large case-control study, serum chemerin, insulin resistance and lipid parameters, classic adipocytokines, inflammatory, coagulation, fibrinolysis and tumor biomarkers were determined in 110 consecutive patients with resectable NSCLC and 110 healthy controls matched on age (± 5 years), gender and date of blood draw (± 1 month).

RESULTS

NSCLC cases exhibited significantly elevated circulating chemerin compared to controls (p < 0.001). In NSCLC cases, chemerin was positively associated with Homeostasis model assessment score of insulin resistance (HOMA-IR), fibrinogen, plasminogen activity, tumor and inflammatory biomarkers, adiponectin, number of infiltrated lymph nodes and NSCLC stage. In control participants, circulating chemerin was positively correlated with somatometric, metabolic, lipid, hemostatic and inflammatory biomarkers, and leptin. Serum chemerin was independently associated with NSCLC, above and beyond NSCLC risk factors (OR: 2.20, 95% CI: 1.09-4.40, p = 0.03). In cases, hemostatic parameters (platelet count and plasminogen activity), HOMA-IR, CYFRA 21-1, creatinine and plant food consumption emerged as independent predictors of circulating chemerin (p < 0.05). Serum chemerin greater than 220 μg/L (cut-off point) yielded a sensitivity and a specificity of 63% and 91.8% respectively with a modest discriminative ability (AUC = 0.72, 95% C.I. 0.64-0.79) for the diagnosis of NSCLC.

CONCLUSION

Chemerin may represent a potentially useful biomarker in NSCLC integrating tumor-promoting networks, inflammatory and hemostatic mechanisms, and cancer-related metabolic pathways. More preclinical, prospective and longitudinal studies highlighting the pathogenetic role of chemerin in NSCLC are needed to corroborate and extend these data.

Serum adiponectin in breast cancer: A meta-analysis

BACKGROUND

Accumulating data have found that adiponectin is involved in development of breast cancer (BC). However, these results were inconsistent.

METHOD

A systematic search in PubMed, Embase, ISI Web of Science, and Chinese National Knowledge Infrastructure databases were conducted up to October 1, 2017. The standardized mean difference (SMD) with 95% confidence interval was applied to pool the effect size.

RESULTS

Finally, 31 eligible studies were included in this meta-analysis. The overall results indicated that serum adiponectin levels in BC cases were significantly lower than the controls (SMD = -0.33, P < 0.0001). As for the subgroup analysis of menstrual status, serum adiponectin levels were significantly lower in pre- and postmenopausal BC cases. Moreover, the subgroup analysis by ethnicity in pre- and postmenopausal group indicated an inverse association between adiponectin levels and BC risk in Asian population, but not in Caucasian population.

CONCLUSION

The present meta-analysis suggests that low serum adiponectin concentration may be associated with an increased BC risk in premenopausal and postmenopausal women, especially among Asians. Adiponectin may serve as a biomarker of BC risk and help to identify subjects at high risk for BC development.

Association between serum leptin levels and breast cancer risk: An updated systematic review and meta-analysis

BACKGROUND

Many studies have indicated that leptin is correlated with breast cancer occurrence and tumor behavior. However, this issue remains controversial. Therefore, we conducted an updated meta-analysis to investigate the role of leptin in breast cancer.

METHODS

We performed a systematic literature search and identified relevant papers up to 1 September 2017. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to evaluate effect sizes.

RESULTS

Thirty-five eligible studies were included in the current meta-analysis. Serum leptin levels were related to breast cancer risk as demonstrated by calculations of the overall SMD = 0.46 (95% CI = 0.31-0.60, I = 93.5%). A subgroup analysis of BMI identified an association between breast cancer and serum leptin levels in patients who are overweight and obese (overweight: SMD = 0.35, 95% CI = 0.13-0.57, I = 88.1%; obesity: SMD = 1.38, 95% CI = 0.64-2.12, I = 89.6%). Additionally, menopausal status subgroup analysis revealed a significant association in postmenopausal women (SMD = 0.26, 95% CI = 0.12-0.40, I = 77.9%). Furthermore, we identified a significant association between breast cancer and serum leptin levels in Chinese women (SMD = 0.61, 95% CI = 0.44-0.79, I = 40.6%).

CONCLUSION

The results of this meta-analysis suggested that leptin could be a potential biomarker for breast cancer risk in women, especially overweight/obese or postmenopausal women. Therefore, it may be useful for identifying subjects with a high risk for breast cancer who may benefit from preventive treatments.

The role of extracellular and intracellular Nicotinamide phosphoribosyl-transferase in cancer: Diagnostic and therapeutic perspectives and challenges

Nicotinamide phosphoribosyl-transferase (Nampt) or pre-B cell colony-enhancing factor or visfatin represents a pleiotropic molecule acting as an enzyme, a cytokine and a growth factor. Intracellular Nampt plays an important role in cellular bioenergetics and metabolism, particularly NAD biosynthesis. NAD biosynthesis is critical in DNA repair, oncogenic signal transduction, transcription, genomic integrity and apoptosis. Although its insulin-mimetic function remains a controversial issue, extracellular Nampt presents proliferative, anti-apoptotic, pro-inflammatory, pro-angiogenic and metastatic properties. Nampt is upregulated in many malignancies, including obesity-associated cancers, and is associated with worse prognosis. Serum Nampt may be a potential diagnostic and prognostic biomarker in cancer. Pharmacologic agents that neutralize Nampt or medications that decrease Nampt levels or downregulate signaling pathways downstream of Nampt may prove to be useful anti-cancer treatments. In particular, Nampt inhibitors as monotherapy or in combination therapy have displayed anti-cancer activity in vivo and in vitro. The aim of this review is to explore the role of Nampt in cancer pathophysiology as well as to synopsize the mechanisms underlying the association between extracellular and intracellular Nampt, and malignancy. Exploring the interplay of cellular bioenergetics, inflammation and adiposopathy is expected to be of importance in the development of preventive and therapeutic strategies against cancer.

The association between obesity related adipokines and risk of breast cancer: a meta-analysis

The risk of breast cancer is significantly increased among obese women as the deleterious adipokines can be over secreted and beneficial adipokines can be hyposecreted. We aim to evaluate the association between obesity-associated adipokines and breast cancer. We searched PubMed, EMBASE, Web of Science, and Chinese Biomedical Literature (CBM) databases for studies reporting association of obesity related adipokines with breast cancer published before Sept. 15, 2015. Initially, 26783 publications were identified, and later, 119 articles were selected for further meta-analysis. Out of these 119 studies, twenty-six studies had reported adipokine levels among obese and non-obese healthy subjects and ninety-three studies had reported adipokine levels among patients with breast cancer. The subjects with BMI >25 kg/m2 had significantly lower adiponectin levels and higher leptin and tumor necrosis factor-α (TNF-α) levels than those with BMI <25 kg/m2. Decreased concentrations of adiponectin, and increased concentrations of leptin, IL-6, IL-8, TNF-α, resistin and visfatin were significantly associated with risk of breast cancer. Adipokine levels were strongly associated with breast cancer among Asian women as compared to non-Asian women. Our results might explain the relationship of obesity, adipokine levels and risk of breast cancer, especially in Asian women.

Biological Mechanisms for the Effect of Obesity on Cancer Risk: Experimental Evidence

Multiple epidemiological studies demonstrated that overweight and obesity significantly increase the risk of several types of cancer. As the prevalence of obesity is dramatically rising, it is expected that it will represent one of the major lifestyle-associated risk factors for cancer development in the near future. Numerous recent studies expanded knowledge about key players and pathways, which are deregulated in the obese state and potentially promote cancer initiation, progression and aggressiveness via remote and local effects. These players include (but are not limited to) insulin/IGF, adipokines and inflammatory signaling molecules as well as metabolites. Nevertheless, the detailed mechanisms linking obesity and malignant transformation at the systemic, cellular and molecular level still demand further investigation. Additionally, dysfunctional molecular metabolic pathways appear to be specific for distinct cancer entities, thereby yet precluding definition of a common principle. This chapter will present an overview of the current knowledge of molecular nodes linking obesity and cancer and will briefly touch upon potential therapy options addressing metabolic cancer etiologies.

Circulating resistin levels and obesity-related cancer risk: A meta-analysis

Resistin levels have been reported to be abnormal in obesity-related cancer patients with epidemiological studies yielding inconsistent results. Therefore, a meta-analysis was performed to assess the association between blood resistin levels and obesity-related cancer risk. A total of 13 studies were included for pooling ORs analysis. High resistin levels were found in cancer patients (OR= 1.20, 95% CI= 1.10-1.30). After excluding one study primarily contributing to between-study heterogeneity, the association between resistin levels and cancer risk was still significant (OR=1.18, 95% CI = 1.09-1.28). Stratification analysis found resistin levels were not associated with cancer risk in prospective studies. Meta-regression analysis identified factors such as geographic area, detection assay, or study design as confounders to between-study variance. The result of 18 studies of pooling measures on SMD analysis was that high resistin levels were associated with increased cancer risk (SMD = 0.94, 95% CI = 0.63-1.25), but not in the pooling SMD analysis of prospective studies. Except for the studies identified as major contributors to heterogeneity by Galbraith plot, resistin levels were still higher in cancer patients (SMD = 0.75, 95% CI = 0.63-0.87) in retrospective studies. Meta-regression analysis found factors, such as geographic area, BMI-match, size, and quality score, could account for 66.7% between-study variance in pooling SMD analysis of retrospective studies. Publication bias was not found in pooling ORs analysis. Our findings indicated high resistin levels were associated with increased obesity-related cancer risk. However, it may not be a predictor.

Hyperresistinemia and metabolic dysregulation: a risky crosstalk in obese breast cancer

Breast cancer is the most common malignancy among women worldwide. There is extensive literature on the relationship between body weight and breast cancer risk but some doubts still remain about the role of adipokines per se, the role of insulin and glucose regardless of obesity, as well as the crosstalk between these players. Thus, in this study, we intend to determine the relation between body mass index (BMI), glycaemia, insulinemia, insulin-resistance, blood adipokine levels and tumour characteristics in a Portuguese group of pre- and postmenopausal overweight/obese women with breast cancer. We evaluated clinical and biochemical data in 154 participants, divided in 4 groups: (1) control with BMI <25 kg/m(2), n = 29 (CT); (2) control with BMI >25 kg/m(2), n = 48 (CTOb); (3) breast cancer with BMI <25 kg/m(2), n = 30 (BC); and (4) breast cancer with BMI >25 kg/m(2), n = 47 (BCOb). In women with breast cancer, we also performed tumour characterization. We found that BCOb present increased fasting blood glucose, insulin, resistin and monocyte chemoattractant protein 1, insulin resistance and more aggressive tumours. Notably, this profile is not correlated with BMI, proposing the involvement of other processes than adiposity. Altogether, our results suggest that glucose dysmetabolism, insulin resistance and changes in adipokine secretion, in particular resistin, may be involved in the development and progression of breast cancer in overweight/obese pre- and postmenopausal women.

Elevated Resistin Gene Expression in African American Estrogen and Progesterone Receptor Negative Breast Cancer

INTRODUCTION

African American (AA) women diagnosed with breast cancer are more likely to have aggressive subtypes. Investigating differentially expressed genes between patient populations may help explain racial health disparities. Resistin, one such gene, is linked to inflammation, obesity, and breast cancer risk. Previous studies indicated that resistin expression is higher in serum and tissue of AA breast cancer patients compared to Caucasian American (CA) patients. However, resistin expression levels have not been compared between AA and CA patients in a stage- and subtype-specific context. Breast cancer prognosis and treatments vary by subtype. This work investigates differential resistin gene expression in human breast cancer tissues of specific stages, receptor subtypes, and menopause statuses in AA and CA women.

METHODS

Differential gene expression analysis was performed using human breast cancer gene expression data from The Cancer Genome Atlas. We performed inter-race resistin gene expression level comparisons looking at receptor status and stage-specific data between AA and CA samples. DESeq was run to test for differentially expressed resistin values.

RESULTS

Resistin RNA was higher in AA women overall, with highest values in receptor negative subtypes. Estrogen-, progesterone-, and human epidermal growth factor receptor 2- negative groups showed statistically significant elevated resistin levels in Stage I and II AA women compared to CA women. In inter-racial comparisons, AA women had significantly higher levels of resistin regardless of menopause status. In whole population comparisons, resistin expression was higher among Stage I and III estrogen receptor negative cases. In comparisons of molecular subtypes, resistin levels were significant higher in triple negative than in luminal A breast cancer.

CONCLUSION

Resistin gene expression levels were significantly higher in receptor negative subtypes, especially estrogen receptor negative cases in AA women. Resistin may serve as an early breast cancer biomarker and possible therapeutic target for AA breast cancer.

Resistin, a fat-derived secretory factor, promotes metastasis of MDA-MB-231 human breast cancer cells through ERM activation

Resistin, an adipocyte-secreted factor, is known to be elevated in breast cancer patients. However, the molecular mechanism by which resistin acts is not fully understood. The aim of this study was to investigate whether resistin could stimulate invasion and migration of breast cancer cells. Here, we report that resistin stimulated invasion and migration of breast cancer cells as well as phosphorylation of c-Src. Inhibition of c-Src blocked resistin-induced breast cancer cell invasion. Resistin increased intracellular calcium concentration, and chelation of intracellular calcium blocked resistin-mediated activation of Src. Resistin also induced phosphorylation of protein phosphatase 2A (PP2A). Inhibition of c-Src blocked resistin-mediated PP2A phosphorylation. In addition, resistin increased phosphorylation of PKCα. Inhibition of PP2A enhanced resistin-induced PKCα phosphorylation, demonstrating that PP2A activity is critical for PKCα phosphorylation. Resistin also increased phosphorylation of ezrin, radixin, and moesin (ERM). Additionally, ezrin interacted with PKCα, and resistin promoted co-localization of ezrin and PKCα. Either inhibition of c-Src and PKCα or knock-down of ezrin blocked resistin-induced breast cancer cells invasion. Moreover, resistin increased expression of vimentin, a key molecule for cancer cell invasion. Knock-down of ezrin abrogated resistin-induced vimentin expression. These results suggest that resistin play as a critical regulator of breast cancer metastasis.

Evaluation of diagnostic and predictive value of serum adipokines: Leptin, resistin and visfatin in postmenopausal breast cancer

Obesity is a well-known risk factor for cancer. The associations of obesity with postmenopausal breast cancer (PBC) have been previously proven in clinical studies. The mechanisms underlying these associations remain unexplained completely, however, adipose tissue as an endocrine organ producing adipokines may interfere with cancer development. The aim of this study is to investigate the diagnostic and predictive value of serum levels of leptin, resistin and visfatin with inflammatory and tumour markers in relation to anthropometrics, clinicopathological features of PBC. This study included 298 postmenopausal Saudi females categorised into three groups. One hundred and ten BC patients with age matched, 89 healthy control (HC) and 99 females with benign breast lesion (BBL). For all subjects CA15-3, hsCRP, resistin, visfatin and leptin were measured by ELISA. Serum levels of leptin, resistin and visfatin were significantly higher in BC compared to BBL and HC groups (p<0.05). Their levels were also significantly higher in advanced TNM stage, tumour size, LN invasion, histological grade and negative ER or PR cases. The most significant predictor of leptin level was ER (p<0.05). While for resistin and visfatin level the most significant independent predictor was LN invasion. ROC analysis for serum leptin revealed AUC=0.795; 95% CI, 0.724-0.866. Resistin showed AUC=0.875; 95% CI, 0.821-0.928. Meanwhile, visfatin greater than 12.2ng/mL demonstrated a sensitivity and specificity of 97.6% and 92.6%, respectively and AUC=0.724; 95% CI, 0.643-0.804. In conclusion serum leptin, resistin, and visfatin levels could be considered of potential diagnostic value for PBC and they would be independent predictors of LN invasion and ER negative PBC cases.

Leptin, adipocytes and breast cancer: Focus on inflammation and anti-tumor immunity

More than one million new cases of breast cancer are diagnosed worldwide each year and more than 400,000 deaths are caused by the disease. The origin of this pathology is multifactorial and involved genetic, hormonal, environmental and nutritional factors including obesity in postmenopausal women. The role played by the adipose tissue and their secretions, ie adipokines, is beginning to be recognized. Plasma adipokine levels, which are modulated during obesity, could have “remote” effects on mammary carcinogenesis. Breast cancer cells are surrounded and locally influenced by an adipocyte microenvironment, which is probably more extensive in obese people. Hence, leptin appears to be strongly involved in mammary carcinogenesis and may contribute to the local pro-inflammatory mechanisms, especially in obese patients, who have increased metastatic potential and greater risk of mortality. This review presents the multifaceted role of leptin in breast cancer development and the different molecular pathways involved such as inflammation, oxidative stress and antitumor immunity.

Human resistin and the RELM of Inflammation in diabesity

The initial discovery of resistin and resistin-like molecules (RELMs) in rodents suggested a role for these adipocytokines in molecular linkage of obesity, Type 2 Diabetes mellitus and metabolic syndrome. Since then, it became apparent that the story of resistin and RELMs was very much of mice and men. The putative role of this adipokine family evolved from that of a conveyor of insulin resistance in rodents to instigator of inflammatory processes in humans. Structural dissimilarity, variance in distribution profiles and a lack of corroborating evidence for functional similarities separate the biological functions of resistin in humans from that of rodents. Although present in gross visceral fat deposits in humans, resistin is a component of inflammation, being released from infiltrating white blood cells of the sub-clinical chronic low grade inflammatory response accompanying obesity, rather than from the adipocyte itself. This led researchers to further explore the functions of the resistin family of proteins in inflammatory-related conditions such as atherosclerosis, as well as in cancers such as endometrial and gastric cancers. Although elevated levels of resistin have been found in these conditions, whether it is causative or as a result of these conditions still remains to be determined.

Resistin: insulin resistance to malignancy

Adipose tissue is recognized as an endocrine organ that secretes bioactive substances known as adipokines. Excess adipose tissue and adipose tissue dysfunction lead to dysregulated adipokine production that can contribute to the development of obesity-related co-morbidities. Among the various adipokines, resistin, which was initially considered as a determinant of the emergence of insulin resistance in obesity, has appeared as an important link between obesity and inflammatory processes. Several experimental and clinical studies have suggested an association between increased resistin levels and severe conditions associated with obesity such as cardiovascular disease and malignancies. In this review, we present the growing body of evidence that human resistin is an inflammatory biomarker and potential mediator of obesity-associated diseases. A common pathway seems to involve the combined alteration of immune and inflammatory processes that favor metabolic disturbances, atherosclerosis and carcinogenesis. The mode of action and the signaling pathways utilized by resistin in its interactions with target cells could involve oxidative and nitrosative stress. Therefore, resistin could function as a key molecule in the complications of obesity development and could potentially be used as a diagnostic and prognostic marker.

Resistin as a biomarker linking obesity and inflammation to cancer: potential clinical perspectives

Excess body weight is associated with various types of malignancies. Resistin, originally described as an adipocyte-specific hormone modulating insulin resistance in rodents, may exhibit proliferative, antiapoptotic, proinflammatory, proangiogenic and metastatic properties. Accumulating evidence supports a role of resistin as a risk factor and potential diagnostic and prognostic biomarker in cancer. In this report, the current knowledge about resistin's properties and pathophysiological implications in cancer in the context of dysregulated adipose tissue in obesity is summarized; clinical translations, preventive and therapeutic considerations, and future perspectives in the field of resistin research are discussed. At the same time, several enigmatic issues involving resistin receptor and signaling pathways remain to be clarified in order to unmask its ontological role in cancer pathophysiology.

Circulating adiponectin and breast cancer risk: a systematic review and meta-analysis

BACKGROUND

We conducted a meta-analysis in order to investigate whether circulating adiponectin, an insulin-sensitizing hormone produced by adipocytes, is associated with breast cancer risk.

METHODS

A systematic literature search was performed in PubMed, Medline, EMBASE, ISI Web of Knowledge and the Cochrane Library. The summary relative risk (SRR) was calculated by pooling the different study-specific estimates using the random effect models. Meta-regression, subgroup and sensitivity analyses were carried out to investigate between-study heterogeneity and to test publication bias.

RESULTS

Data from 15 observational studies, published between 2003 and April 2013 for a total of 4249 breast cancer cases, were analysed. The SRR for the 'highest' vs 'lowest' adiponectin levels indicated a 34% reduction in breast cancer risk [95% confidence interval (CI): 13%-50%]. Between-study heterogeneity was not substantial (I(2)=53%). Ten studies were included in the dose-response analysis: the SRR for an increase of 3 µg/ml of adiponectin corresponded to a 5% risk reduction (95% CI: 1%-9%). The comparison between 'highest' and 'lowest' levels of adiponectin showed an inverse association in postmenopausal women (SRR=0.80; 95% CI: 0.63-1.01) and an indication of an inverse relationship in premenopausal women (SRR=0.72, 95% CI: 0.30-1.72). No evidence of publication bias was found.

CONCLUSIONS

Low circulating adiponectin levels are associated with an increased breast cancer risk. However, properly designed studies are needed to confirm the role of adiponectin as breast cancer biomarker, and clinical trials should be performed to identify those interventions that may be effective in modulating adiponectin levels and reducing breast cancer risk.

The relationship between gut and adipose hormones, and reproduction

BACKGROUND

Reproductive function is tightly regulated by nutritional status. Indeed, it has been well described that undernutrition or obesity can lead to subfertility or infertility in humans. The common regulatory pathways which control energy homeostasis and reproductive function have, to date, been poorly understood due to limited studies or inconclusive data. However, gut hormones and adipose tissue hormones have recently emerged as potential regulators of both energy homeostasis and reproductive function.

METHODS

A PubMed search was performed using keywords related to gut and adipose hormones and associated with keywords related to reproduction.

RESULTS

Currently available evidence that gut (ghrelin, obestatin, insulin, peptide YY, glucagon-like peptide-1, glucose-dependent insulinotropic peptide, oxyntomodulin, cholecystokinin) and adipose hormones (leptin, adiponectin, resistin, omentin, chemerin) interact with the reproductive axis is presented. The extent, site and direction of their effects on the reproductive axis are variable and also vary depending on species, sex and pubertal stage.

CONCLUSIONS

Gut and adipose hormones interact with the reproductive axis as well as with each other. While leptin and insulin have stimulatory effects and ghrelin has inhibitory effects on hypothalamic GnRH secretion, there is increasing evidence for their roles in other sites of the reproductive axis as well as evidence for the roles of other gut and adipose hormones in the complex interplay between nutrition and reproduction. As our understanding improves, so will our ability to identify and design novel therapeutic options for reproductive disorders and accompanying metabolic disorders.