The implication of adipocyte ATP-binding cassette A1 and G1 transporters in metabolic complications of obesity.

Obesity is characterised by imbalance in lipid metabolism manifested by high concentrations of circulating triacylglycerols and total cholesterol as well as low high-density lipoprotein (HDL) levels. Abnormalities related to these lipids lead to metabolic complications such as type 2 diabetes, arterial hypertension and cardiovascular disease. Despite extensive research, it is still unclear why a subset of obese subjects develop metabolic syndrome, while others do not. The aim of our work was to assess total and plasma membrane expressions of cholesterol transport proteins: adipocyte ATP-binding cassette A1 (ABCA1), adipocyte ATP-binding cassette G1 (ABCG1), class B scavenger receptor (SR-BI) in visceral and subcutaneous adipose tissue of obese subjects with and without metabolic syndrome. To keep our preliminary study group uniform, we focused on women, who constitute the majority of bariatric patients. The study was performed on 34 patients: 24 morbidly obese women subjected to bariatric surgery, half of whom had metabolic syndrome; and 10 lean subjects undergoing elective laparoscopic cholecystectomy. Total and plasma membrane expressions of cholesterol transport proteins (SR-BI, ABCA1 and ABCG1) were assessed in samples of both visceral and subcutaneous adipose and analysed in relation to other clinical and laboratory parameters. We demonstrated lower plasma membrane expressions of ABCG1 in visceral adipose tissue of obese patients with metabolic syndrome as compared to lean ones. In addition, total ABCG1 expressions in both types of adipose tissue were lower in morbidly obese patients with metabolic syndrome compared to those without metabolic syndrome. Plasma membrane ABCA1 expressions in visceral adipose tissue were lower in the group of morbidly obese patients without metabolic syndrome, compared to lean patients. We did not find any significant differences in SR-BI expressions. Because of ABCG1 is responsible for cholesterol efflux to HDL, reduced plasma membrane expression of ABCG1 in VAT of morbidly obese women with metabolic syndrome may leads to a significantly decreased concentration of HDL in serum. This may be also confirmed by high positive correlation between both parameters.

Interleukin-6 deficiency modifies the effect of high fat diet on myocardial expression of fatty acid transporters and myocardial lipids.

Chronic inflammation is a critical feature of obesity in the development of myocardial dysfunction. The observations that interleukin-6 (IL-6) is implicated in lipid and glucose homeostasis as well as its connection with the pathogenesis of insulin resistance might suggest the involvement of this cytokine in metabolic disorders of the failing heart. In the present study we aimed to assess the effects of IL-6 ablation in mice fed with normal and high fat diet on the myocardial expression of glucose and fatty acid transporting proteins, and to evaluate the paralleled alterations in lipid content. We demonstrated that mice devoid of IL-6 exert reduced glucose transporter type 4 (GLUT-4) expression (-26%) and plasma membrane abundance (-43%), with no effect on glucose transporter type 1 (GLUT-1) content. Although there were no significant alterations in fatty acid translocase (FAT/CD36) and plasma membrane-associated fatty acid-binding protein (FABPpm) levels, we revealed a substantial decline in intramyocardial triacylglycerol level (-49%). Challenging of IL-6 knockout (KO) mice with high fat diet evoked an increase in FAT/CD36 expression (+19%) concomitantly with a trend for its reduced amount in plasma and mitochondrial membranes. Additionally, an increase in triacylglycerol level (+56%) was noticed, simultaneously with elevated content of saturated (+62%), monounsaturated (+69%) and polyunsaturated (+38%) fatty acids in this lipid fraction. The presented data reflect different roles of IL-6 in cardiomyocytes under selected conditions (i.e., normal and excessive lipid supply).

Influence of narrowband ultraviolet B phototherapy on serum tumour necrosis factor-like weak inducer of apoptosis (TWEAK) in patients with psoriasis.

Psoriasis is characterized by keratinocyte resistance to apoptosis. We recently demonstrated an increase in serum tumour necrosis factor-like weak inducer of apoptosis (TWEAK) in patients after topical treatment for psoriasis. We decided to verify whether narrowband ultraviolet B (NB-UVB) has a similar effect. Serum concentration of TWEAK was estimated in patients with exacerbated plaque psoriasis treated with NB-UVB. Baseline TWEAK levels were similar in patients with psoriasis and healthy controls, and Psoriasis Area and Severity Index (PASI) correlated inversely with TWEAK levels. Treatment with NB-UVB caused a significant reduction in PASI and concurrent increase in serum TWEAK. This finding may be due to increased expression of TWEAK receptor in psoriatic skin, which has been reported previously, with consequent binding of excess soluble TWEAK during treatment and subsequent release after treatment. Severity of plaque psoriasis and its improvement after NB-UVB treatment may be associated with TWEAK concentrations. The importance of our findings remains to be established.

Creatinine or cystatin C - which is a better index of renal function in morbid obesity?

PURPOSE: The most important index of renal function is estimated glomerular filtration rate (eGFR) which can be calculated from creatinine or cystatin C concentration in serum. There is uncertainty, which formula is best suited to assess renal function in morbidly obese patients. The aim of this study was to evaluate eGFR in patients with morbid obesity using formulas: Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Grubb, Le Bricon, Hoek, Larsson, and to compare the obtained results. MATERIAL AND METHODS: In 40 morbidly obese patients, serum concentration of cystatin C and creatinine were assayed. Values of eGFR were calculated using the above-mentioned formulas. RESULTS: The mean value of eGFR ranged from 85.9 to 111.1 ml/min/1.73 m², depending on the formula. The biggest difference between the obtained values was 29% (Grubb vs. Hoek p<0.01). After calculation of eGFR from creatinine concentration (MDRD), 7 patients were qualified to the 2nd and 3rd stage of chronic renal disease, while application of Hoek's formula, based on cystatin C concentration, allotted 27 patients to 2nd and 3rd stage of chronic renal disease. Le Bricon formula gave eGFR values, that correlated best with albuminuria. CONCLUSION: eGFR calculated using Le Bricon formula based on the cystatin C concentration was significantly lower than eGFR calculated from creatinine concentration and was more closely associated with albuminuria. Relying only on creatinine concentration to estimate glomerular filtration rate can lead to underestimation of renal malfunction in obese patients.

Estrogens modulate RANKL-RANK/osteoprotegerin mediated interleukin-6 effect on thyrotoxicosis-related bone turnover in mice.

Interleukin-6 has been shown to cause imbalance between bone resorption and formation in thyrotoxicosis. The aim of the present study was an attempt to estimate the influence of estrogens on thyrotoxicosis-related disturbances in bone turnover in relation to RANKL-RANK/osteoprotegerin system in IL-6 deficient mice. The study was performed on 56, 12-13 weeks old, female mice: C57BL/6J (wild-type; WT) and C57BL/6J (IL6-/-Kopf) (IL-6 knock-out; IL6KO). The mice were randomly divided into 8 groups with 7 mice in each one: 1. WT controls, 2. IL6KO controls, 3. WT mice with thyrotoxicosis, 4. IL6KO mice with thyrotoxicosis, 5. WT ovariectomized, 6. IL6KO ovariectomized, 7. WT ovariectomized mice with thyrotoxicosis, and 8. IL6KO ovariectomized mice with thyrotoxicosis. Experimental model of menopause was evoked by bilateral ovariectomy carried out in 8-9 weeks old mice. Thyrotoxicosis was induced by intraperitoneal injection of levothyroxine at a dose of 1 µg/g daily over 21 days. The serum levels of TRACP5b, osteocalcin, OPG, and RANKL were determined by ELISA. RANKL serum concentrations were elevated significantly in all groups of ovariectomized mice as compared to respective controls, however, in a minor degree in IL6KO thyrotoxic mice as compared to wild-type animals. Osteoprotegerin serum levels were significantly increased in all thyrotoxic groups of mice except ovariectomized IL6KO animals. To sum up, the results of the present study suggest that IL-6 plays a key role in stimulation of RANKL-RANK/OPG system and this effect is strongly enhanced in conditions of accelerated bone turnover such as thyrotoxicosis and/or estrogen depletion.

Targeting Notch signaling in pancreatic cancer patients--rationale for new therapy.

Pancreatic cancer is one of the most aggressive and devastating human malignancies. Despite new knowledge in the molecular profile of pancreatic cancer and its precursor lesions, survival rates have changed very little over the last 40 years. Therefore, a better understanding of the detailed mechanisms underlying the pathogenesis of this disease is critical if we expect to develop new and effective strategies for prevention, early diagnosis and treatment of pancreatic cancer. The review herein focuses on a distinctive signaling pathway, the Notch pathway, which has recently been associated with carcinogenesis, including pancreatic cancer. It is aimed at summarizing key results which support a role for this pathway in the initiation, progression and maintenance of pancreatic cancer as a rationale for targeting and inhibiting this pathway in pancreatic cancer patients.

A crucial role of interleukin-6 in the pathogenesis of thyrotoxicosis-related disturbances of bone turnover in mice.

Interleukin-6 (IL-6) has been shown to be involved in the pathogenesis of several bone diseases characterized by a negative balance between bone resorption and formation. The aim of the study was to estimate serum markers of bone turnover: osteoclast-derived tartrate-resistant acid phosphatase form 5a (TRACP 5b) reflecting resorption, and osteocalcin as a marker of bone formation in IL-6 knock-out mice to assess the role of IL-6 in the pathogenesis of thyrotoxicosis-related disturbances of bone metabolism. The study was performed on forty, 14-15 weeks old, female mice: C57BL/6J (wild-type; WT) and C57BL/6J (IL6-/-Kopf) (IL-6 knock-out; IL6KO). The mice were randomly divided into 4 groups with 10 mice in each one: 1. WT mice in thyrotoxicosis (WT-thx), 2. WT controls (WT-ctrl), 3. IL6KO mice with thyrotoxicosis (IL6KO-thx), and 4. IL6KO controls. Experimental model of hyperthyroidism was induced by intraperitoneal injection of levothyroxine at a dose of 1 microg/g, daily over 21 days. The serum levels of TRACP 5b and osteocalcin were determined by ELISA. Serum concentration of TRACP 5b (median and interquartile ranges) were significantly increased in both groups of mice with thyrotoxicosis: WT [28.2(18.8-41.6) U/l] and IL6KO [26.4(23.0-31.2) U/l] as compared to the respective controls. Osteocalcin serum levels in IL6KO-thx mice [111.9(103.1-175.6) ng/ml] were significantly elevated in comparison to WT-thx animals [46.1(32.5-58.9) ng/ml]. In summary, the results of the present study suggest that IL-6 plays a crucial role in thyrotoxicosis-related disturbances of bone turnover in mice, determining the imbalance between bone resorption and bone formation caused by excess of thyroid hormones predominantly by inhibition of bone formation.

Glycoprotein CD44 variant 4 expression in tumour epithelial cells of patients with colorectal cancer.

The aim of this study was to check if the expression of CD44v4 in epithelial cells of the colorectal cancer correlates with the pTN stage and the histopathological grade of malignancy--G. Samples of tumour tissue (TT), as well as those of healthy tissue (HT) and of tumour adjacent tissue (TAT) were obtained from 25 patients. An evaluation of the expression of CD44v4 was performed in a flow cytometer. The mean value of the percentage of epithelial cells with co-expression of CD44v4 was lower in pT2 stage than that in pT3 only in HT. The expression of CD44v4 in epithelial cells was higher in cases without lymph node metastases only in TAT. The expression of CD44v4 in epithelial cells was higher in G2 than in G3 degree only in TAT as well. According to the obtained results, it is difficult to state if CD44v4 can influence the progress of colorectal cancer.

Clinical usefulness of K-RAS mutation detection in colorectal cancer and in surgical margins of the colon.

The incidence of K-RAS gene mutations in tumour and surgical margins was investigated in 63 patients with adenocarcinomas of varied clinical stage and histological grade. Point mutations of codon 12 K-RAS gene were detected, using the PCR-RFPL technique in cancer tissue in 23 patients (36.5%) and in colon margin mucosa in 1 patient (3.7%), out of 27 examined subjects. No significant correlations were found between the mutations and clinical features. Tumours, located in the left colon, and mucinous neoplasms displayed a higher incidence of mutations. No correlation was observed with either Dukes or TMN clinical advancement.

Plasma VEGF-A and its soluble receptor R1 correlate with the clinical stage of colorectal cancer.

UNLABELLED: Our aim was to assess plasma VEGF-A and its soluble receptor R1 (sVEGF-R1) in patients with colorectal cancer, in comparison with apparently healthy subjects. METHODS: Samples of plasma were collected from 26 patients with colorectal cancer before surgery and on post-operative day 3 and 10, frozen and eventually assessed, using ELISA kits. RESULTS: We found an increase in VEGF-A in colorectal cancer patients and a strong positive correlation between metastatic spread and postoperative VEGF-A, which also correlated with CA19.9. Soluble VEGF-R1 showed a positive correlation with lymph node involvement. CONCLUSIONS: Our findings may suggest that the patients with high postoperative VEGF-A should be scanned for metastases. In view of our finding that sVEGFR-1 correlates with lymph node involvement, precautions must be taken in studies of sVEGFR-1 as a potential therapeutic agent.

Chymotrypsin-like activity in rat tissues in experimental acute pancreatitis.

PURPOSE: Increase in intracellular chymotrypsin activity was reported during acute pancreatitis. Beside chymotrypsin, there are at least two enzymes with chymotrypsin-like activity: proteasome and lysosomal cathepsin A. Until now it is not known whether and to what extent they contribute to increases in chymotrypsin activity in acute pancreatitis. Our aim was to study organ chymotrypsin-like activities during experimental acute pancreatitis. MATERIAL AND METHODS: Rat cerulein model of acute pancreatitis was used. The chymotrypsin-like activities were assessed in pancreas, liver, lung, heart, spleen and kidney using highly selective synthetic substrates of the proteasome and the cathepsin A, at neutral and acidic pH. Determinations after addition of selective inhibitor were also performed. RESULTS: During acute pancreatitis we found in the pancreas an increase only in neutral chymotrypsin-like activity, as compared to the control animals. In other organs neutral chymotrypsin-like activity did not increase, and in kidney it even decreased. There were no changes in acidic chymotrypsin-like activity in any of organs studied. The studies using the inhibitor of the proteasome showed that the neutral chymotrypsin-like activity in the pancreas of the rats with acute pancreatitis should not be attributed to the proteasome activity, but rather to the chymotrypsin. CONCLUSIONS: Our results did not confirm any significant contribution of proteasome or cathepsin A to increased chymotrypsin-like activity in acute pancreatitis. We showed a decrease in neutral chymotrypsin-like activity of proteasome in the kidney, but the significance of this finding remains to be established.

Tryptophan metabolism via the kynurenine pathway in experimental chronic renal failure.

BACKGROUND: Kidneys are involved in tryptophan (TRP) metabolism in two ways. They eliminate TRP derivatives on the one hand, and they produce several enzymes taking part in TRP metabolism mainly via the kynurenine pathway on the other. The aim of the present study was to examine the time-course of changes in the peripheral kynurenine products degradation during experimental chronic renal failure in rats. METHODS: Tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid, xanthurenic acid, anthranilic acid and quinolinic acid were determined in plasma using high-performance liquid chromatography technique with UV, fluorescence and electrochemical detection. RESULTS: A decreased TRP level and significant increase in kynurenine pathway metabolite concentrations in plasma of uremic rats were found. CONCLUSIONS: Substantial disturbances in the peripheral kynurenic pathway were observed in experimental chronic renal failure. They may contribute to several symptoms of uremia.

[Kynurenic pathway in health and disease]. / Szlak kinureninowy w zdrowiu i w chorobie.

The paper gives a review about kynurenic pathway metabolism of tryptophan. The implications of its metabolites in pathomechanism of several dysfunctions of tissues and organs as well as possibilities of therapeutic interference are described.

[Levels of dimethyl-L-arginine in ultrafiltrate and blood pressure in patients during hemodialysis]. / Zawartosc dwu metylo L-argininy w ultrafiltracie a zachowanie sie cisnienia krwi u chorych w czasie hemodializy.

The contant of dimethyl-L-arginine in the ultrafiltrate obtained during dialysis session from 30 patients with end-stage renal failure maintaned on chronic hemodialyses was studies. 14 patients were normotensive and 16 were hypertensive. In patients with hypertension dimethyl-L-arginine level was significantly elevated (mean value 7.67 mumol/l), when compared to patients with normal blood pressure (mean value 2.37 mumol/l). Prolongation of the dialysis session is postulated in hypertensive patients.