[The treatment of hyperglycaemia in critically ill patients: comparison of standard protocol and computer algorithm]

INTRODUCTION

Hyperglycemia is commonly observed in patients hospitalized on intensive care units. It is has been demonstrated that normalization of blood glucose level using intensive insulin therapy significantly improves prognosis of these patients. The aim of our study was comparison of standard protocol of intensive insulin therapy used on cardiac surgery ICU in General University Hospital in Prague and computer algorithm MPC (Model Predictive Control).

PATIENTS AND METHODS

20 patients with glycaemia higher than 6.7 mmol/l at the time of admission to ICU were included into the study, 10 subjects were randomized for standard treatment, 10 for treatment with MPC algorithm. Glycaemia was measured hourly during 48 hours, insulin infusion was rate was adjusted hourly in MPC algorithm or in 1-2 hours in standard protocol group.

RESULTS

Blood glucose levels were in the target range significantly longer in MPC relative to standard protocol group (26.3 +/- 2.1 hrs vs 20.3 +/- 2.5 hrs). Mean blood glucose was also lower using MPC algorithm (6.47 +/- 0.11 vs 6.72 +/- 0.23 mmol/l). On the contrary the target range was established faster using standard protocol (8.9 +/- 1.2 vs 10.3 +/- 0.9 hrs), duration of hyperglycaemia was the same in both groups (7.3 +/- 1.9 in standard protocol vs 7.3 +/- 1.3 hrs in MPC algorithm). Average 48-hours insulin dose was higher in MPC than standard protocol group (230.2 +/- 38.8 vs 199.1 +/- 27.8 IU/48 hrs). 2 hypoglycaemic episodes occured in 2 patients in standard protocol group.

CONCLUSIONS

Our results show that the use of MPC algorithm result in more effective blood glucose control in critically ill patients than standard protocol.

Increased angiotensinogen production in epicardial adipose tissue during cardiac surgery: possible role in a postoperative insulin resistance

Critical illness induces among other events production of proinflammatory cytokines that in turn interfere with insulin signaling cascade and induce insulin resistance on a postreceptor level. Recently, local renin-angiotensin system of adipose tissue has been suggested as a possible contributor to the development of insulin resistance in patients with obesity. The aim of our study was to determine local changes of the renin-angiotensin system of subcutaneous and epicardial adipose tissue during a major cardiac surgery, which may serve as a model of an acute stress potentially affecting endocrine function of adipose tissue. Ten patients undergoing elective cardiac surgery were included into the study. Blood samples and samples of subcutaneous and epicardial adipose tissue were collected at the beginning and at the end of the surgery. Blood glucose, serum insulin and adiponectin levels were measured and mRNA for angiotensinogen, angiotensin-converting enzyme and angiotensin II type 1 receptor were determined in adipose tissue samples using RT PCR. Cardiac surgery significantly increased both insulin and blood glucose levels suggesting the development of insulin resistance, while serum adiponectin levels did not change. Expression of angiotensinogen mRNA significantly increased in epicardial adipose tissue at the end of surgery relative to baseline but remained unchanged in subcutaneous adipose tissue. Fat expression of angiotensin-converting enzyme and type 1 receptor for angiotensin II were not affected by surgery. Our study suggests that increased angiotensinogen production in epicardial adipose tissue may contribute to the development of postoperative insulin resistance.

[Laparoscopic gastric tubulization--sleeve gastrectomy--another option for bariatric food intake restriction in morbidly obese subjects]

INTRODUCTION

Nowadays, obesity is the commonest multifactorial metabolic disorder. The role of bariatric surgery, i.e. surgery specializing in the treatment of obesity, in the management of obese patients, where conservative therapy failed and who have high incidence of obesity relapses, or in morbidly obese subjects (BMI > 40, resp. BMI > 35), as well as in superobese subjects (BMI > 60), is irreplacable. Most of the surgical procedures for the morbid obesity treatement use miinvasive laparocopic techniques. Recent options include the method of gastric tubulization- Sleeve Gastrectomy (SG), which , as a "single procedure" has been performed in some clinics since 2003.

MATERIAL AND METHODOLOGY

In the 1st Surgical Clinic of the 1st Medical faculty of the Charles University and General Faculty Hospital, the authors have intensively studied the problematics of bariatric surgery since 1983. Since Janury 2006, a total of 39 morbidly obese patients (MO), where adjustable gastric bandage had not been indicated for various reasons, have been indicated for laparoscopic sleeve gastrectomy. Gastric bandage was not indicated, for instance, in cases where poor cooperation ("sweet-eaters, binge-eaters") could be expected or when good cooperation and adherence to diet restrictions in patients with SAGB could not be guaranteed.

RESULTS

Our study group of 39 morbidly obese patients included 30 females and 9 males. The mean age was 37.6 y.o.a., the mean weight was 127 kg, the mean height 164 cm and the mean BMI was 41.3. A nine- month follow up phase could be assessed only in 27 heavily obese subjects following SGs. The mean weight loss was 17.3 kg, the mean percentile excess weight loss (EWL) was 28.1% and the final mean reduction in BMI was 12.1. No serious late complications were recorded in the study group.

CONCLUSION

Sleeve gastrectomy presents with a rather higher risk rates compared to gastric bandage, however, the risk remains considerably lower compared to that in malabsorption procedures. Unfortunately, there is no long- term experience regarding maintanance of the weight loss or possible development of serious late complications. Current excellent long- term weight reduction clinical results are very promissing.

[The influence of obesity on the gene expression of adiponectin and its receptor in subcutaneous adipose tissue]

The objective of the study was to measure the concentration of adiponectin in plasma, its mRNA expression and the expression of the adiponectin receptors AdipoR1 and AdipoR2 in subcutaneous adpipose tissue (ST) of women with various levels of fat in their organism. A further objective of the study was to determine to what extent the stated parameters correlate with obesity as defined by BMI (body mass index) and how it can be affected by a very low calorie diet (VLCD).

PATIENT SAMPLE

The sample of 70 women was divided into groups by BMI: patients with class 3 obesity (BMI > 40 kg.m(-2), n = 25), patients with class 1 and 2 obesity (BMI 30-40 kg.m(-2), n = 15), overweight patients (BMI 25-30 kg.m(-2), n = 10) and a normal healthy control group (BMI 20-25 kg.m(-2), n = 20). In the case of 14 women with class 3 obesity, the parameters were measured before and after a three-week diet with an energy content of 2200 kJ (550 kcal)/day (VLCD).

METHOD

Plasma concentrations of adiponectin were measured using an ELISA kit (LINCO Research, USA). Subcutaneous adipose tissue was taken using biopsy. RNA was isolated using a MagNA Pure Compact RNA Isolation Kit (Tissue) (Roche, SRN). The gene expression of adiponectin, AdipoR1 and AdipoR2 was determined using the real-time PCR (RT-PCR) method on a ABI Real-Time PCR 7500 instrument (Applied Biosystems, USA) with TaqMan Gene Expression Assays hydrolisation probes. beta-2-mikroglobulin (beta2M) was used as an endogenous control, to which the data was normalised.

RESULTS

The circulatory concentration of adiponectin, its mRNA expression and the mRNA expression of AdipoR1 in ST correlate negatively with BMI (r = -0.524, p < 0.001; r = -0.460, p < 0 001; p = -0.354, p = 0.004). The expression of AdipoR2 in ST did not correlate with BMI. The VLCD reduced weight by 9% but did not affect the plasma concentration of adiponectin or the rate of its expression, or the expression of AdipoR1 and AdipoR2.

CONCLUSION

Our results show that not only the circulatory concentration of adiponectin but also its mRNA expression and the expression of AdipoR1 in ST are significantly lower in obese women compared to a control group and may contribute to the development of metabolic complications in obesity.

Adiponectin and resistin gene polymorphisms in patients with anorexia nervosa and obesity and its influence on metabolic phenotype

Genes for adiponectin and resistin are candidate genes of insulin resistance and type 2 diabetes mellitus. The aim of our study was to determine the frequency of single nucleotide polymorphisms (SNP) 45T>G and 276G>T of the adiponectin gene and 62G>A and -180C>G of the resistin gene in patients with obesity (OB), anorexia nervosa (AN) and in control healthy normal-weight women (NW) and to study the influence of particular genotypes on serum concentrations of these hormones and on insulin sensitivity. Serum adiponectin, resistin, tumor necrosis factor alpha (TNF-alpha), insulin, cholesterol, glycated hemoglobin (HbA1c) and blood glucose levels were measured in 77 patients with OB, 28 with AN and 38 NW. DNA analysis was carried out by polymerase chain reaction with restriction analysis of PCR product. The presence of SNP ADP+276 G>T allele was accompanied by higher cholesterol levels in AN patients, higher adiponectin concentrations in OB patients and lower HbA1c levels in NW. SNP of the resistin gene 62G>A was associated with lower HbA1c in NW and higher cholesterol concentrations in OB group. The carriers of the minor G allele in the position -180 of the resistin gene within AN group had significantly higher BMI relative to non-carriers. We conclude that polymorphisms in adiponectin and resistin genes can contribute to metabolic phenotype of patients with obesity and anorexia nervosa.

Adiponectin as a potential marker of prostate cancer progression: studies in organ-confined and locally advanced prostate cancer

Serum levels of adiponectin were measured in patients with benign prostatic hyperplasia and prostate cancer of pT2 and pT3 stage. Adiponectin ELISA assay, immunohistochemistry, and selected metabolic and biochemical parameters measurement was performed in 25 patients with benign prostatic hyperplasia and 43 with prostate cancer (17 patients with organ-confined and 26 patients with locally advanced disease). Serum adiponectin levels did not differ between prostate benign hyperplasia and cancer clinical stage T2, but was significantly higher in pT3 relative to pT2 group (14.51+/-4.92 vs. 21.41+/-8.12, P = 0.003). Tissue immunohistochemistry showed enhanced staining in neoplastic prostate glands and intraepithelial neoplasia relative to benign prostatic hyperplasia without distinction between disease grade and stage. Serum adiponectin levels are higher in locally advanced relative to organ-confined prostate cancer and may thus serve as an auxiliary marker providing further improvement for discrimination between pT2 and pT3 stages.

[Adiponectin and atherosclerosis]

Obesity combined with other components of the insulin resistance syndrome is an important risk factor for atherosclerosis and its complications. The exact mechanisms through which the above diseases are linked have not yet been fully elucidated. One of the possible links may be a disturbance of the endocrine function of the adipose tissue of obese persons which produces an increased amount of proinflammatory and proatherogenic hormones and a lower amount of factors protecting against such pathologies. Adiponectin is the only hormone produced by the adipose tissue with a proven antiinflammatory and antiatherosclerotic effect. This hormone is predominantly produced by adipocytes and its concentrations are decreased in patients with obesity, insulin resistance and atherosclerosis. The objective of the article is to summarize current experimental and clinical knowledge of the links between adiponectin and atherosclerosis and to discuss possible utilization of adiponectin as a marker for atherosclerosis, and the potential for its exploitation in the prevention and/or treatment of atherosclerosis.

[Pilot study to evaluate blood glucose control by a model predictive control algorithm with variable sampling rate vs. routine glucose management protocol in peri- and postoperative period in cardiac surgery patients]

BACKGROUND

Increased blood glucose levels are frequently observed in critically ill patients. Recent studies have shown that the normalization of glycemia by intensive insulin therapy decreases mortality, length of the hospitalization and number of complications.

METHODS AND RESULTS

The aim of this pilot study was to compare blood glucose control by an automated model predictive control algorithm with variable sampling rate (eMPC) with routine glucose management protocol (RP) in peri- and postoperative period in cardiac surgery patients. 20 patients were included into this study (14 men and 6 women, mean age 68 +/- 10 let, BMI 28.3 +/- 5.0 kg/m2). 10 patients were randomized for treatment using eMPC algorithm and 10 patients for routine protocol. All patients underwent elective cardiac surgery and were treated with continuous insulin infusion to maintain glycemia in target range 4.4-6.1 mmol/l. The study duration was 24 hours. Mean blood glucose was significantly lower in eMPC vs. RP group (5.80 +/- 0.45 vs. 7.23 +/- 0.84 mmol/l, p < 0.05). Percentage of time in target range was significantly higher in eMPC vs. RP group (67.6 +/- 8.7% vs. 27.6 +/- 15.8%, p < 0.05). Percentage of time above the target range was higher in RP vs. eMPC group. Average insulin infusion rate was higher in eMPC vs. RP group (4.18 +/- 1.19 vs. 3.24 +/- 1.43 IU/hour, p < 0.05). Average sampling interval was significantly shorter in eMPC vs. RP group (1.51 +/- 0.24 vs. 2.03 +/- 0.16 hour, p < 0.05). No severe hypoglycaemia in either group occurred during the study.

CONCLUSIONS

The results of our pilot study suggest that eMPC algorithm is more effective in maintaining euglycemia in peri- and post-operative period in patients after cardiac surgery and comparably safe as compared to RP.

Influence of PPAR-alpha agonist fenofibrate on insulin sensitivity and selected adipose tissue-derived hormones in obese women with type 2 diabetes

PPAR-alpha agonists improve insulin sensitivity in rodent models of obesity/insulin resistance, but their effects on insulin sensitivity in humans are less clear. We measured insulin sensitivity by hyperinsulinemic-isoglycemic clamp in 10 obese females with type 2 diabetes before and after three months of treatment with PPAR-alpha agonist fenofibrate and studied the possible role of the changes in endocrine function of adipose tissue in the metabolic effects of fenofibrate. At baseline, body mass index, serum glucose, triglycerides, glycated hemoglobin and atherogenic index were significantly elevated in obese women with type 2 diabetes, while serum HDL cholesterol and adiponectin concentrations were significantly lower than in the control group (n=10). No differences were found in serum resistin levels between obese and control group. Fenofibrate treatment decreased serum triglyceride concentrations, while both blood glucose and glycated hemoglobin increased after three months of fenofibrate administration. Serum adiponectin or resistin concentrations were not significantly affected by fenofibrate treatment. All parameters of insulin sensitivity as measured by hyperinsulinemic-isoglycemic clamp were significantly lower in an obese diabetic group compared to the control group before treatment and were not affected by fenofibrate administration. We conclude that administration of PPAR-alpha agonist fenofibrate for three months did not significantly affect insulin sensitivity or resistin and adiponectin concentrations in obese subjects with type 2 diabetes mellitus. The lack of insulin-sensitizing effects of fenofibrate in humans relative to rodents could be due to a generally lower PPAR-alpha expression in human liver and muscle.

Effect of PPAR-gamma agonist treatment on markers of endothelial dysfunction in patients with type 2 diabetes mellitus

Thiazolidinediones are insulin-sensitizing drugs acting through peroxisome proliferator-activated receptor (PPAR)-gamma. The aim of our study was to evaluate the effect of 5-month treatment with PPAR-gamma agonist--rosiglitazone (4 mg/day), on the circulating markers of endothelial dysfunction and to evaluate the role of changes in endocrine function of adipose tissue in this process. Biochemical and metabolic parameters, circulating adiponectin, resistin, ICAM-1, VCAM-1, E-selectin, P-selectin, PAI-1, myeloperoxidase (MPO), and matrix metalloproteinase-9 (MMP-9) concentrations were assessed in 10 women with type 2 DM before and after rosiglitazone treatment and in a control group of healthy women. At baseline, diabetic group had significantly higher serum concentrations of glucose, glycated hemoglobin, V-CAM and PAI-1 compared to control group. Adiponectin levels tended to be lower in diabetic group, while resistin concentrations did not differ from control group. Rosiglitazone treatment improved diabetes compensation, significantly reduced VCAM-1, PAI-1 and E-selectin concentrations and increased adiponectin levels, while it did not affect serum resistin concentrations. Adiponectin concentrations at baseline were inversely related to E-selectin and MPO levels, this correlation disappeared after rosiglitazone treatment. We conclude that 5-month rosiglitazone treatment significantly reduced several markers of endothelial dysfunction. This effect could be at least in part attributable to marked increase of circulating adiponectin levels.

Increased lipolysis of subcutaneous abdominal adipose tissue and altered noradrenergic activity in patients with Cushing's syndrome: an in-vivo microdialysis study

Cushing's syndrome is associated with typical central redistribution of adipose tissue. The aim of the study was to assess lipolysis and catecholamines and their metabolites in subcutaneous abdominal adipose tissue using an in-vivo microdialysis technique. Nine patients with Cushing's syndrome and nine age-, gender- and body mass index (BMI)-matched control subjects were included in the study. Local glycerol concentrations were significantly increased in subcutaneous adipose tissue of patients with Cushing's syndrome (p<0.001). Plasma noradrenaline, dihydroxyphenylglycol and dihydroxyphenylalanine were decreased in patients with Cushing's syndrome (p<0.02, p<0.05, and p<0.02, respectively). Adrenaline, noradrenaline, dihydroxyphenylglycol and dihydroxyphenylalanine concentrations in subcutaneous abdominal adipose were non-significantly higher in patients with Cushing's syndrome. In conclusion, we showed that lipolysis in subcutaneous adipose tissue of patients with Cushing's syndrome is significantly increased as compared to healthy subjects. This finding together with non-significantly increased local catecholamine concentrations in these patients suggests a possible link between increased lipolysis and catecholaminergic activity in subcutaneous adipose tissue.

Increased adiponectin is negatively linked to the local inflammatory process in patients with rheumatoid arthritis

Adiponectin has been shown to exert insulin-sensitizing, anti-atherogenic, and anti-inflammatory properties in metabolic diseases. It has been suggested that adiponectin may play a role in rheumatoid arthritis (RA). To assess adiponectin in serum and synovial fluid from patients with RA and osteoarthritis (OA), and in serum from healthy controls. Adiponectin and CRP levels were analyzed by ELISA. The clinical activity of RA patients was assessed according to the 28 joint count Disease Activity Score. Synovial fluid adiponectin was significantly higher in RA than in OA patients (p<0.001). Adiponectin was negatively associated with the leukocyte count in RA synovial fluid (r=-0.45, p<0.05). Serum adiponectin was higher in RA compared to healthy controls (p<0.02), however comparable to OA patients. Serum adiponectin was higher than in synovial fluid in both diseases (p<0.001). In general, women had higher adiponectin levels than men. Adiponectin was not related to age, disease duration, body mass index, or disease activity of RA patients. Adiponectin is decreased in synovial fluid compared to serum indicating that peripheral fat stores are major producers of adiponectin into the blood stream. However, increased synovial fluid adiponectin in RA patients may counterpart the local inflammatory process.

Resistin in rheumatoid arthritis synovial tissue, synovial fluid and serum

BACKGROUND

Resistin is a newly identified adipocytokine which has demonstrated links between obesity and insulin resistance in rodents. In humans, proinflammatory properties of resistin are superior to its insulin resistance-inducing effects.

OBJECTIVES

To assess resistin expression in synovial tissues, serum and synovial fluid from patients with rheumatoid arthritis, osteoarthritis and spondylarthropathies (SpA), and to study its relationship with inflammatory status and rheumatoid arthritis disease activity.

METHODS

Resistin expression and localisation in synovial tissue was determined by immunohistochemistry and confocal microscopy. Serum and synovial fluid resistin, leptin, interleukin (IL)1beta, IL6, IL8, tumour necrosis factor alpha, and monocyte chemoattractant protein-1 levels were measured. The clinical activity of patients with rheumatoid arthritis was assessed according to the 28 joint count Disease Activity Score (DAS28).

RESULTS

Resistin was detected in the synovium in both rheumatoid arthritis and osteoarthritis. Staining in the sublining layer was more intensive in patients with rheumatoid arthritis compared with those with osteoarthritis. In rheumatoid arthritis, macrophages (CD68), B lymphocytes (CD20) and plasma cells (CD138) but not T lymphocytes (CD3) showed colocalisation with resistin. Synovial fluid resistin was higher in patients with rheumatoid arthritis than in those with SpA or osteoarthritis (both p<0.001). In patients with rheumatoid arthritis and SpA, serum resistin levels were higher than those with osteoarthritis (p<0.01). Increased serum resistin in patients with rheumatoid arthritis correlated with both CRP (r=0.53, p<0.02), and DAS28 (r=0.44, p<0.05), but not with selected (adipo) cytokines.

CONCLUSION

The upregulated resistin at local sites of inflammation and the link between serum resistin, inflammation and disease activity suggest a role for resistin in the pathogenesis of rheumatoid arthritis.

[Monitoring of glucose concentration in critical patients, comparing arterial blood glucose concentrations and interstitial glucose concentration measured by microdialysis technique]

INTRODUCTION

Recent studies have shown that normalization of blood glucose in critically ill patients by intensive insulin therapy significantly decreases their mortality and morbidity. The aim of our study was to compare interstitial glucose concentrations in subcutaneous adipose tissue (measured by microdialysis technique) and arterial blood glucose concentrations to test the suitability of subcutaneous adipose tissue for long-term placement of biosensors for glucose measurement in critically ill patients.

PATIENTS AND METHODS

20 patients (16 men and 4 women) after cardiac surgery hospitalized at postoperative intensive care unit were included into the study. Mean age was 68 +/- 10 years, BMI was 28.3 +/- 3.9 year. Only patients with glycemia higher than 6.7 mmol/l at a time of admission to the ICU were included. Samples for measurement of interstitial glucose concentrations were collected in 60 minutes intervals during 48 hours using microdialysis of the subcutaneous adipose tissue. Perfusion fluid was 5% mannitol, perfusion rate was 1 microl/min. Arterial blood glucose concentration was measured in 60 minutes intervals, absolute concentrations of interstitial glucose were calculated using ionic reference technique.

RESULTS

Mean arterial glucose concentration during the study was 6.7 +/- 0.56 mmol/l, absolute concentration of glucose in interstitial fluid was 3.55 +/- 0.58 mmol/l. Mean correlation coefficient between arterial and interstitial concentrations was 0.77 +/- 0.15.

CONCLUSION

Our study demonstrated good correlation between interstitial glucose concentrations in subcutaneous adipose tissue and arterial blood glucose concentrations in post-cardiac surgery patients. Further studies are needed to evaluate this relationship in patients with more severely disturbed perfusion of subcutaneous adipose tissue.

PPAR-alpha and insulin sensitivity

Peroxisome proliferator-activated receptors (PPAR) belong to the nuclear receptor superfamily of ligand-activated transcription factors. PPAR-alpha, first of its three subtypes (alpha, beta, gamma) has traditionally been considered an important regulator of lipid metabolism while its role in the regulation of insulin sensitivity has not been recognized until recently. Here we summarize the experimental and clinical studies focusing on the role of PPAR- alpha in the regulation of insulin sensitivity. In most of the experimental studies the activation of PPAR-alpha in rodents leads to improvement of insulin sensitivity by multiple mechanisms including improvement of insulin signaling due to a decrease of ectopic lipids in non-adipose tissues and decrease of circulating fatty acids and triglycerides. In contrast, the effect of PPAR-alpha agonist in humans is much less pronounced probably due to a lower expression of PPAR-alpha relative to rodents and possibly other mechanisms. Further clinical studies using more potent PPAR-alpha agonists on a larger population need to be performed to evaluate the possible role of PPAR- alpha in the regulation of insulin sensitivity in humans.

The influence of very-low-calorie diet on serum leptin, soluble leptin receptor, adiponectin and resistin levels in obese women

The aim of our study was to determine whether adipocyte-derived hormones leptin, adiponectin and resistin contribute to the improvement of insulin sensitivity after very-low calorie diet (VLCD). Therefore, serum levels of these hormones were measured in fourteen obese females before and after three weeks VLCD and in seventeen age- and sex-matched healthy controls. Body mass index, HOMA index, serum insulin and leptin levels in obese women before VLCD were significantly higher than in control group (BMI 48.01+/-2.02 vs. 21.38+/-0.42 kg/m(2), HOMA 10.72+/-2.03 vs. 4.69+/-0.42, insulin 38.63+/-5.10 vs. 18.76+/-1.90 microIU/ml, leptin 77.87+/-8.98 vs. 8.82+/-1.52 ng/ml). In contrast, serum adiponectin and soluble leptin receptors levels were significantly lower in obese women before VLCD than in the control group. No differences were found in serum glucose and resistin levels between the obese group before VLCD and the control group. VLCD significantly decreased BMI, HOMA index, serum glucose, insulin and leptin levels and increased soluble leptin receptor levels. The changes in serum adiponectin and resistin levels in obese women after VLCD did not reach statistical significance. We conclude that leptin and soluble leptin receptor levels were affected by VLCD while adiponectin and resistin concentrations were not. Therefore, other mechanisms rather than changes in the endocrine function of the adipose tissue are probably involved in the VLCD-induced improvement of insulin sensitivity.

The influence of hormonal changes during menstrual cycle on serum adiponectin concentrations in healthy women

Adiponectin is an adipocyte-derived hormone involved in the regulation of carbohydrate and lipid metabolism. Its concentrations are decreased in patients with obesity, type 2 diabetes and atherosclerosis and are higher in females than in males. Gender differences of adiponectin levels raise the possibility that sex hormones directly regulate its serum concentrations, which may in turn influence insulin sensitivity in different phases of the menstrual cycle. To test this hypothesis we measured serum adiponectin, estradiol, progesterone, luteinizing hormone and follicle-stimulating hormone concentrations daily throughout the menstrual cycle in six healthy women. Mean adiponectin levels strongly positively correlated with serum cortisol concentrations [R=0.94286; p=0.0048 (Spearman correlation test)], but were not significantly related to other anthropometric, biochemical and hormonal characteristics of the subjects (BMI, blood glucose, insulin, testosterone, prolactin, cholesterol, HDL cholesterol, LDL cholesterol, triglycerides concentrations, or atherogenic index). Furthermore, no significant changes of serum adiponectin levels were found throughout the menstrual cycle. We conclude that changes in sex hormones during the menstrual cycle do not affect total circulating adiponectin levels in healthy women. Therefore, the differences in insulin sensitivity in various phases of the menstrual cycle are not due to changes of circulating adiponectin levels.

Plasma levels of total and active ghrelin in acromegaly and growth hormone deficiency

Ghrelin is an endogenous growth hormone (GH) secretagogue recently isolated from the stomach. Although it possesses a strong GH releasing activity in vitro and in vivo, its physiological significance in endogenous GH secretion remains unclear. The aim of this study was to characterize plasma ghrelin levels in acromegaly and growth hormone deficiency (GHD). We investigated plasma total and active ghrelin in 21 patients with acromegaly, 9 patients with GHD and 24 age-, sex- and BMI-matched controls. In all subjects, we further assessed the concentrations of leptin, soluble leptin receptor, insulin, IGF-I, free IGF-I and IGFBP-1, 2, 3 and 6. Patients with acromegaly and GHD as well as control subjects showed similar levels of total ghrelin (controls 2.004+/-0.18 ng/ml, acromegalics 1.755+/-0.16 ng/ml, p=0.31, GHD patients 1.704+/-0.17 ng/ml, p=0.35) and active ghrelin (controls 0.057+/-0.01 ng/ml, acromegalics 0.047+/-0.01 ng/ml, p=0.29, GHD patients 0.062+/-0.01 ng/ml, p=0.73). In acromegalic patients plasma total ghrelin values correlated negatively with IGF-I (p<0.05), in GHD patients active ghrelin correlated with IGF-I positively (p<0.05). In the control group, total ghrelin correlated positively with IGFBP-2 (p<0.05) and negatively with active ghrelin (p=0.05), BMI (p<0.05), WHR (p<0.05), insulin (p=0.01) and IGF-I (p=0.05). Plasma active ghrelin correlated positively with IGFBP-3 (p=0.005) but negatively with total ghrelin and free IGF-I (p=0.01). In conclusion, all groups of the tested subjects showed similar plasma levels of total and active ghrelin. In acromegaly and growth hormone deficiency plasma ghrelin does not seem to be significantly affected by changes in GH secretion.

[Peroxisome proliferator activated receptors (PPAR) and insulin sensitivity: experimental studies]

Peroxisome proliferator activated receptors (PPARs) belong to the nuclear receptor superfamily, which act as transcription factors. PPARs affect expression of many genes, which products are involved in lipid and carbohydrates metabolism, cell proliferation and differentiation and numerous other processes. Three different subtypes (isoforms) of PPARs have been identified: PPAR-alpha, PPAR-gamma, PPAR-delta. PPAR-alpha receptors play an important role in the regulation of lipid metabolism: they decrease circulating fatty acids and triglyceride levels. Recently, the ability of PPAR-alpha receptors to improve insulin sensitivity in rodent model of insulin resistance have been documented and numerous studies have focused on this topic. One of the possible mechanisms of its action on the insulin sensitivity is lowering of ectopic lipids in liver and muscle tissues with subsequent heightening of insulin signalling cascade. Here we summarize the experimental studies focusing on the role of PPAR-alpha in the regulation of insulin sensitivity and discuss possible mechanisms involved.

[Polymorphisms of adiponectin and resistin genes in patients with obesity and anorexia nervosa]

BACKGROUND

Adiponectin and resistin are hormones that may represent a link between obesity and insulin resistance. Genes for these hormones are new candidate genes of insulin resistance and type 2 diabetes mellitus. The aim of our study was to determine the frequency of single nucleotide polymorphisms 45T > G and 276T > G of adiponectin gene and 62G > A and -180C > G of resistin gene in patients with obesity, anorexia nervosa and in lean women and to study the influence of particular genotypes on serum concentrations of these hormones.

METHODS AND RESULTS

Serum adiponectin, resistin, TNF-alfa and insulin levels were measured in 51 patients with obesity, 17 with anorexia nervosa and 17 lean women. DNA analysis was carried out by means of polymerase chain reaction (PCR) with restriction analysis of PCR product (RFLP). Adiponectin levels were lowest in obese women and highest in anorexia nervosa patients. Resistin concentrations were lowest in anorexia nervosa and highest in obese patients. Genotype analysis within respective groups showed no differences in assessed parameters when comparing different adiponectin and resistin polymorphisms. The only difference detected was significantly higher BMI in G/G genotype relative to T allele carries in 276 position of ADP gene in control group (23.48 +/- 0.85 vs. 19,7 +/- 0.95, p < 0.05). In anorexia nervosa patients, frequency of G allele in RETN -180 polymorphism was significantly higher relative to control group (p < 0.05).

CONCLUSIONS

Polymorphisms 45T > G a 276T > G of ADP gene and 62G>A and -180C > G RETN gene did not influence serum ADP and RETN concentrations. BMI was influenced by T allele presence in 276 position of ADP gene in control group only. Anorexia nervosa patients had higher frequency of G allele of RETN -180 polymorphism compared to healthy women.

Plasma levels of active and total ghrelin in renal failure: a relationship with GH/IGF-I axis

Ghrelin was originally isolated from the rat stomach and significant amounts were found also in the kidney. Present study was designed to examine changes in ghrelin levels in renal failure and their relationship to the GH/IGF-I axis. Fourty patients with mild-to-severe CRF (19 men, 21 women, aged 62.5 +/- 2.2 years, BMI 27.57 +/- 0.73 kg/m(2)) and 34 healthy control subjects (17 men, 17 women, aged 60 +/- 2.6 years, BMI 27.55 +/- 0.79 kg/m(2)) were included in the study. Total ghrelin levels were significantly increased in patients with chronic renal failure (CRF) (p < 0.0001). Total ghrelin in CRF correlated positively with active ghrelin (p < 0.001), GH (p < 0.05), IGF-I (p < 0.05), free IGF-I (p = 0.0001), IGFBP-3 (p < 0.01), IGFBP-2 and -6 (p < 0.05). Active ghrelin in CRF correlated positively with IGF-I (p < 0.001), free-IGF-I (p < 0.005), IGFBP-2 (p < 0.05) and IGFBP-3 (p < 0.05). However, most of the correlation were markedly reduced and the significance disappeared after adjustment for different creatinine levels. Hemodialysis in patients with end stage renal disease (ESRD) resulted in a significant reduction of plasma total and active ghrelin (p < 0.01 and p < 0.001 respectively). In conclusion we demonstrated elevated plasma levels of total ghrelin in CRF, and a reduction of total and active ghrelin after a single course of hemodialysis in ESRD. The elevation of ghrelin levels could be caused by impaired clearance and/or metabolism of ghrelin in the kidney. We did not prove clearly significant relationship between ghrelin serum levels and parameters of GH/IGF-I axis in study subjects.

Adipocytokines and cancer

Adipose tissue-produced hormones significantly affect the metabolism of lipids and carbohydrates as well as numerous other processes in human body. It is generally accepted that endocrine dysfunction of adipose tissue may represent one of the causal links between obesity and insulin resistance/diabetes. Epidemiological studies underlined that obesity represents a significant risk factor for the development of cancer, although the exact mechanism of this relationship remains to be determined. Multiple recent studies have indicated that some of adipose tissue-derived hormones may significantly influence the growth and proliferation of tumorous stroma and malignant cells within. Here we review current knowledge about possible relationship of leptin and adiponectin to the etiopathogenesis of different malignant tumors. Most of the studies indicated that while leptin may potentiate the growth of cancer cells in vitro, adiponectin appears to have an opposite effect. Further studies are necessary to decide whether obesity-induced endocrine dysfunction of adipose tissue can directly influence carcinogenesis in different tissues and organs.

Adipocyte-derived hormones in heroin addicts: the influence of methadone maintenance treatment

Heroin addiction markedly affects the nutritional and metabolic status and frequently leads to malnutrition. The aim of our study was to compare circulating concentration of adipose tissue-derived hormones leptin, adiponectin and resistin in 12 patients with heroin addiction before and after one-year methadone maintenance treatment with the group of 20 age- and body mass index-matched healthy subjects. Basal serum leptin and adiponectin levels in heroin addicts were significantly decreased (3.4+/-0.4 vs. 4.5+/-0.6 ng/ml and 18.9+/-3.3 vs. 33.9+/-3.1 ng/microl, respectively; p 0.05) while serum resistin concentrations were increased compared to healthy subjects (10.1+/-1.2 vs. 4.6+/-0.3 ng/ml; p 0.05). Moreover, positive correlation of serum leptin levels with body mass index was lost in the addicts in contrast to control group. One year of methadone maintenance treatment normalized serum leptin, but not serum adiponectin and resistin concentrations. In conclusion, circulating concentrations of leptin, adiponectin and resistin are markedly altered in patients with chronic heroin addiction. These alterations appear to be relatively independent of nutritional status and insulin sensitivity.