Study Protocol: insulin and its role in cancer

IGF-1 alters the human parietal pleural electrochemical profile by inhibiting ion trans-cellular transportation after interaction with its receptor

OBJECTIVE

The effect of IGF-1 in the human pleural permeability and the underlying mechanisms involved were investigated.

DESIGN

Specimens from thoracic surgical patients were mounted in Ussing chambers. Solutions containing IGF-1 (1 nM-100 nM) and IGF-1 Receptor Inhibitor (1 μΜ), amiloride 10 μM (Na(+) channel blocker) and ouabain 1 mM (Na(+)-K(+) pump inhibitor) were used in order to investigate receptor and ion transporter involvement respectively. Trans-mesothelial Resistance (R(TM)) across the pleural membrane was determined as a permeability indicator. Immunohistochemistry for IGF-1 receptors was performed.

RESULTS

IGF-1 increased R(TM) when added on the interstitial surface for all concentrations (p=.008, 1 nM-100 nM) and decreased it on the mesothelial surface for higher concentrations (p=.046, 100 nM). Amiloride and ouabain inhibited this effect. The IGF-1 Receptor Inhibitor also totally inhibited this effect. Immonuhistochemistry demonstrated the presence of IGF-1 receptors in the pleura.

CONCLUSIONS

It is concluded that IGF-1 changes the electrophysiology of the human parietal pleura by hindering the normal ion transportation and therefore the pleural fluid recycling process. This event is achieved after IGF-1 interaction with its receptor which is present in the human pleura.

Elevated insulin and insulin resistance are associated with the advanced pathological stage of prostate cancer in Korean population

The study was designed to investigate the effect of serum glucose, insulin and insulin resistance on the risk of prostate cancer (CaP) and on the clinicopathological characteristics in Korean men. Subjects were retrospectively recruited from 166 CaP patients underwent radical prostatectomy and 166 age-matched benign prostatic hyperplasia (BPH) patients. The serum was taken on the morning of the day of operation and insulin resistance was assessed by homeostasis model assessment insulin resistance index (HOMA-IR). Men in highest tertile of insulin was associated with 55% reduced odds of CaP than those with the lowest tertile (OR = 0.45, 95% CI = 0.23-0.89, P = 0.022). The patients in highest tertile of insulin had a more than 5.6 fold risk of locally advanced stage than those in the lowest tertile (OR = 5.62, 95% CI = 1.88-16.83, P = 0.002). Moreover, the patients in the highest tertile HOMA-IR group was associated with an increased risk of locally advanced stage than the lowest tertile group (OR = 3.10, 95% CI = 1.07-8.99, P = 0.037). These results suggest that elevated insulin and insulin resistance are associated with the advanced pathological stage of prostate cancer in Korean patients.

Increasing insulin resistance is associated with increased severity and prevalence of gastro-oesophageal reflux disease

BACKGROUND

The diagnosis of gastro-oesophageal reflux disease (GERD) is based on reflux symptoms. Although metabolic syndrome has been linked to erosive oesophagitis (EO), the impact of insulin resistance, the core of the metabolic syndrome, on reflux symptoms remains to be elucidated.

AIM

To assess the effects of insulin resistance on GERD, including both endoscopic findings and symptoms.

METHODS

A total of 743 sonographic noncirrhotic adult subjects, who underwent an upper gastrointestinal endoscopic examination, completed a gastro-oesophageal reflux questionnaire and had available fasting insulin data were included. Endoscopic findings were classified according to the Los Angeles classification. Homeostatic model assessment-insulin resistance (HOMA-IR) index was used to evaluate the status of insulin resistance. Univariate and multivariate approaches were used to evaluate the associations between insulin resistance and GERD.

RESULTS

Older age, male gender, smoking and alcohol consumption increased the prevalence of EO, but not GERD symptoms. A large waist circumference, high fasting blood glucose levels and high number of metabolic syndrome components were associated with increased prevalence of both EO and GERD symptoms, while high blood pressure was associated with increased prevalence of EO only. Moreover, higher scores in the gastro-oesophageal reflux questionnaire were associated with higher HOMA-IR index, and higher HOMA-IR index was associated with increased prevalence of EO (adjusted odds ratio 1.14, 95% CI 1.03-1.26, P = 0.012).

CONCLUSIONS

Our findings demonstrate clear associations between insulin resistance, metabolic syndrome and GERD. Whether reducing insulin resistance may improve GERD symptoms or EO deserves prospective study.

Promoting Effects of Streptozotocin-induced Diabetes on Induction of Hepatic Preneoplastic Lesions by Diethylnitrosamine in Rats

The effects of streptozotocin (STZ)-induced diabetes on induction of hepatic preneoplastic lesions by diethylnitrosamine (DEN) were investigated in male Fischer rats. A single dose of STZ was injected intravenously either 2 weeks before or after initiation with DEN. The blood glucose levels were significantly elevated from 1 week after STZ-injection until autopsy. The numbers of GST-P positive foci at 1 week after DEN administration in the STZ-injected rats were similar to those in the non-diabetic rats. In contrast, both the numbers and areas of GST-P positive foci > 2 mm in diameter 8 weeks after DEN administration were increased significantly in the rats treated with STZ after DEN exposure compared with the non-diabetic control rats. The results suggest that hepatic preneoplastic lesions initiated with DEN are promoted by STZ treatment-inducing diabetes.

Adiposity in childhood cancer survivors: insights into obesity physiopathology

As childhood cancer treatment has become more effective, survival rates have improved, and a number of complications have been described while many of these patients reach adulthood. Obesity is a well-recognized late effect, and its metabolic effects may lead to cardiovascular disease. Currently, studies concerning overweight have focused on acute lymphocytic leukemia and brain tumors, since they are at risk for hypothalamic-pituitary axis damage secondary to cancer therapies (cranial irradiation, chemotherapy, and brain surgery) or to primary tumor location. Obesity and cancer have metabolic syndrome features in common. Thus, it remains controversial if overweight is a cause or consequence of cancer, and to date additional mechanisms involving adipose tissue and hypothalamic derangements have been considered, comprising premature adiposity rebound, hyperinsulinemia, leptin regulation, and the role of peroxisome proliferator-activated receptor γ. Overall, further research is still necessary to better understand the relationship between adipogenesis and hypothalamic control deregulation following cancer therapy.

Type 2 diabetes and metabolic syndrome as conditions leading to malignant tumors

Az utóbbi években egyre több bizonyíték szólt a metabolikus szindróma és a 2-es típusú diabetes mellitus karcinogén hatásáról. A bizonyítékok között első helyen az epidemiológiai észlelések állnak. A különböző tumorfajták és a metabolikus szindróma, illetve a 2-es típusú diabetes mellitus között nemek, rasszok és földrajzi elterjedtség szerint eltérő mértékben mutatható ki kauzális összefüggés. A lehetséges közös patomechanizmusok az elhízáskor a zsírszövetben excesszíven termelődő adipokinek, a tartós és postprandialis hyperglykaemia, a hyperinsulinismus és az inzulinrezisztencia, egyéb növekedési faktorok, mint a proinzulin, inzulinszerű növekedési faktor-1, reaktív oxigén-szabadgyökök, angiogenezis, inflammáció és gyulladásos citokinek sejtproliferatív hatásai. Kiderült, hogy a peroxiszómaproliferátor aktiválta receptoroknak és az őket szabályozó ubiquitin proteaszómarendszernek is meghatározó szerepe van a sejtproliferáció befolyásolásában. Ezek a mechanizmusok metabolikus szindrómában mind atherosclerosis, mind karcinogenezis irányában kockázati tényezőként szerepelnek. Ez a felismerés új utat nyithat mindkét kórkép megelőzése és kezelése szempontjából.

Detection of metabolic syndrome features among childhood cancer survivors: a target to prevent disease

Along with the growing epidemic of obesity, the risk of atherosclerosis, cardiovascular disease morbidity, and mortality are increasing markedly. Several risk factors for cardiovascular disease, such as visceral obesity, glucose intolerance, arterial hypertension, and dyslipidemia commonly cluster together as a condition currently known as metabolic syndrome. Thus far, insulin resistance, and endothelial dysfunction are the primary events of the metabolic syndrome. Several groups have recommended clinical criteria for the diagnosis of metabolic syndrome in adults. Nonetheless, in what concerns children and adolescents, there are no unified definitions, and modified adult criteria have been suggested by many authors, despite major problems. Some pediatric disease states are at risk for premature cardiovascular disease, with clinical coronary events occurring very early in adult life. Survivors of specific pediatric cancer groups, particularly acute lymphocytic leukemia, central nervous system tumors, sarcomas, lymphomas, testicular cancer, and following bone marrow transplantation, may develop metabolic syndrome traits due to: hormonal deficiencies (growth hormone deficiency, thyroid dysfunction, and gonadal failure), drug or radiotherapy damage, endothelial impairment, physical inactivity, adipose tissue dysfunction, and/or drug-induced magnesium deficiency. In conclusion, some primary and secondary prevention remarks are proposed in order to reduce premature cardiovascular disease risk in this particular group of patients.