Adipocytokines in relation to Hodgkin lymphoma in children

Circulating adiponectin levels in various malignancies: an updated meta-analysis of 107 studies

Early detection of cancers is challenging for lack of specific biomarkers. Adiponectin is an adipokine predominantly derived from adipocytes and hypoadiponectinemia has been reported to associate with risk of many types of cancers. However, available evidence is controversial. Some studies show that increased adiponectin levels correlate with cancer risk. Therefore, we performed a meta-analysis of the association between circulating adiponectin levels and cancer development. A systematic search of PubMed, EMBASE, Wiley Online Library and Cochrane Library was conducted for eligible studies involving circulating adiponectin and malignancies from inception to August 8, 2015. Standard mean differences (SMDs) with 95% confidence intervals (95% CIs) were calculated by use of a random-effect model. Funnel plot and Egger's linear regression test were conducted to examine the risk of publication bias. 107 studies were included with 19,319 cases and 25,675 controls. The pooled analysis indicated that circulating adiponectin levels were lower in patients with various cancers than in controls, with a pooled SMD of −0.334 μg/ml (95% CI, −0.465 to −0.203, P = 0.000). No evidence of publication bias was observed. Circulating high molecular weight adiponectin levels were also lower in cancer patients than in controls, with a pooled SMD of −0.502 μg/ml (95% CI, −0.957 to −0.047, P = 0.000). This meta-analysis provides further evidence that decreased adiponectin levels is associated with risk of various cancers. Hypoadiponectinemia may represent a useful biomarker for early detection of cancers.

Adipokines and Insulin Resistance in Young Adult Survivors of Childhood Cancer

We examined the association between adipokines (leptin, adiponectin, and resistin), radiotherapy, measurement of body fat, and insulin resistance among young adult survivors of childhood cancer (CCS). Materials and Methods. Seventy-six survivors were included (mean age 24.1 ± 3.5 years). Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA-IR). The serum levels of adipokines were assayed by immunoassays. Fat mass was evaluated by DXA. Results. Mean adiponectin level and mean body FAT were higher in the examined females than in males (10009 ± 6367 ng/mL versus 6433 ± 4136 ng/mL, p < 0.01; 35.98 ± 9.61% versus 22.7 ± 7.46%, p < 0.001). Among CCS, one of 75 patients met the criteria of insulin resistance, and in 14 patients there was impaired fasting glucose. The multiple regression model for females showed that leptin/adiponectin ratio (LA ratio) significantly affected HOMA-IR (increase of 0.024 per each unit of LA ratio; p < 0.05). Radiotherapy had no effect on serum adipokines and IR. Conclusion. The observed results support the hypothesis that adiponectin might be associated with insulin resistance and it can not be ruled out that changes in the mean level of adiponectin per FAT mass or leptin/adiponectin ratio may precede the occurrence of insulin resistance in the future.

The role of adiponectin in cancer: a review of current evidence

Excess body weight is associated not only with an increased risk of type 2 diabetes and cardiovascular disease (CVD) but also with various types of malignancies. Adiponectin, the most abundant protein secreted by adipose tissue, exhibits insulin-sensitizing, antiinflammatory, antiatherogenic, proapoptotic, and antiproliferative properties. Circulating adiponectin levels, which are determined predominantly by genetic factors, diet, physical activity, and abdominal adiposity, are decreased in patients with diabetes, CVD, and several obesity-associated cancers. Also, adiponectin levels are inversely associated with the risk of developing diabetes, CVD, and several malignancies later in life. Many cancer cell lines express adiponectin receptors, and adiponectin in vitro limits cell proliferation and induces apoptosis. Recent in vitro studies demonstrate the antiangiogenic and tumor growth-limiting properties of adiponectin. Studies in both animals and humans have investigated adiponectin and adiponectin receptor regulation and expression in several cancers. Current evidence supports a role of adiponectin as a novel risk factor and potential diagnostic and prognostic biomarker in cancer. In addition, either adiponectin per se or medications that increase adiponectin levels or up-regulate signaling pathways downstream of adiponectin may prove to be useful anticancer agents. This review presents the role of adiponectin in carcinogenesis and cancer progression and examines the pathophysiological mechanisms that underlie the association between adiponectin and malignancy in the context of a dysfunctional adipose tissue in obesity. Understanding of these mechanisms may be important for the development of preventive and therapeutic strategies against obesity-associated malignancies.

Adipokines, body fatness, and insulin resistance among survivors of childhood leukemia

BACKGROUND

Following our previous reports of an increased prevalence of insulin resistance and adiposity among acute lymphoblastic leukemia (ALL) survivors, particularly women treated with cranial radiotherapy (CRT), we aimed to (1) assess the relationships between adipokines (leptin and adiponectin), CRT, and measures of body fatness and (2) determine correlates of insulin resistance, by gender.

METHODS

We conducted cross-sectional evaluation of 116 ALL survivors (median age: 23.0 years; range: 18-37; average time from treatment: 17.5 years), including fasting laboratory testing (adiponectin, leptin, insulin, and glucose), anthropometric measurements (weight, height, and waist circumference), DXA (total body fat and truncal-to-lower-body-fat ratio), and abdominal CT (visceral fat). We estimated insulin resistance using the homeostasis model for assessment of insulin resistance (HOMA-IR). Analytic approaches included regression models and Wilcoxon rank sum testing.

RESULTS

Mean leptin per kilogram fat mass was higher for females (0.7 ng/ml/kg) than males (0.4 ng/ml/kg, P < 0.01), and among subjects who had received CRT compared to those who had not received CRT (females CRT =0.9 ng/ml/kg, no CRT = 0.7 ng/ml/kg; P = 0.1; males CRT = 0.5 ng/ml/kg, no CRT = 0.3 ng/ml/kg; P < 0.01). Elevated HOMA-IR was nearly uniformly present, even among subjects with BMI < 25 kg/m(2), and was associated with higher leptin:adiponectin ratio (LA ratio; P < 0.01).

CONCLUSIONS

Among survivors of childhood leukemia, higher leptin levels were associated with measures of body fat and insulin resistance. Anthropomorphic and metabolic changes many years after ALL treatment remain a major health problem facing survivors and may be related to central leptin resistance.