Darko Cerne

Comparison of laboratory parameters as risk factors for the presence and the extent of coronary or carotid atherosclerosis : the significance of apolipoprotein B to apolipoprotein all ratio

Abstract We compared several “new” risk factors (autoantibodies to oxidatively modified low density lipoprotein (LDL), sialic acid content of LDL, bilirubin and C-reactive protein) with “conventional” risk factors (apolipoprotein (apo) AI, AII and B, lipoprotein(a), triglycerides, and total, LDL and high density lipoprotein (HDL) cholesterol) for the presence and the extent of coronary or carotid atherosclerosis. Forty male patients with angiographically proven coronary atherosclerosis and 31 male patients with ultrasound-proven extracranial carotid atherosclerosis were compared to 40 age matched (53 ± 5 years) healthy males as control subjects, with negative parental history of atherosclerosis, no clinical signs of systemic or organ-related ischemic disease and normal extracranial carotid arteries. The apo B/apo AII ratio most powerfully indicated the presence and the extent of coronary or carotid atherosclerosis. Elevated lipoprotein(a) contributed significant additional information in the assessment of the atherosclerotic risk. Increase in Creactive protein indicated the presence (but not the extent) of coronary or carotid atherosclerosis with a similar power as lipoprotein(a). Decreased values of total bilirubin indicated the presence of atherosclerosis only in smokers. Autoantibodies to oxidatively modified LDL additionally described the atherosclerotic process, but were less important than apolipoproteins, lipoprotein(a), C-reactive protein or bilirubin. Sialic acid content of LDL added no information to the parameters discussed above. We demonstrated that in male patients apolipoproteins, especially the apo B/apo AII ratio, were better indicators of the presence and the extent of coronary or carotid atherosclerosis than C-reactive protein, bilirubin, autoantibodies to oxidatively modified LDL or sialic acid content of LDL.

Increased Fatty Acid Synthase Activity in Non-small Cell Lung Cancer Tissue Is a Weaker Predictor of Shorter Patient Survival than Increased Lipoprotein Lipase Activity

BACKGROUND AND AIMS Cumulative evidence suggests the involvement of fatty acid synthase (FAS) in tumor growth. We tested the hypothesis that increased FAS activity and gene expression in non-small cell lung cancer (NSCLC) tissue have a prognostic significance that is independent of that of increased lipoprotein lipase (LPL) activity in the same tissue. METHODS Forty two consecutive patients with resected NSCLC were enrolled in the study. Paired samples of lung cancer tissue and adjacent non-cancer lung tissue were collected from resected specimens for estimation of FAS activity and expression of its gene. LPL activity had previously been measured in the same tissues. During a 4-year follow-up, 21 patients died due to tumor progression. One patient died due to a non-cancer reason and was not included in the analysis. RESULTS High FAS activity in cancerous tissue relative to that in the adjacent non-cancer lung tissue was associated with weight loss in the 3 months immediately before tumor excision and patient death during the follow-up. Higher FAS activity in the cancer tissue was associated with higher LPL activity in the same tissue, which also predicted shorter patient survival, but LPL was the stronger predictor. FAS gene expression was higher in the adjacent non-cancer tissue than in the cancer tissue but had no predictive value. CONCLUSION Our study further underlines the involvement of cancer tissue FAS activity in tumor growth but also indicates its weaker importance compared to LPL activity.

MILDLY ELEVATED SERUM CREATININE CONCENTRATION CORRELATES WITH THE EXTENT OF CORONARY ATHEROSCLEROSIS

Mildly elevated serum creatinine concentration was proposed to be a marker for increased risk of cardiovascular disease mortality. The aim of our prospective study was to evaluate a possible association between serum creatinine concentration and extent of coronary atherosclerosis together with conventional risk factors for atherosclerosis. Serum creatinine concentration was measured in 40 male patients without overt renal or ischemic renal disease (mean age 53 ± 7 years) with stable or unstable angina undergoing routine coronary arteriography. The extent of coronary atherosclerosis was assessed by Gensini score. In univariate linear regression analysis Gensini score significantly correlated with serum concentrations of apolipoprotein AII (r = −0.3242, P < 0.05) and creatinine (r = +0.3194, P < 0.05), but not with serum concentrations of lipids (total, low- and high-density lipoprotein cholesterol, triglycerides), other apolipoproteins (apo B, apo AI), lipoprotein(a), autoantibodies to oxidatively modified low-density lipoprotein or age, weight and status of smoking, diabetes or hypertension. Multivariate linear regression analysis revealed that elevated serum creatinine was associated with the extent of coronary atherosclerosis independently of conventional risk factors for atherosclerosis. Mildly elevated serum creatinine was probably the marker of generalised vascular disease denoting early nephrovasculopathy in correlation with established atherosclerotic risk factors.

Cell-free DNA in the peritoneal effluent of peritoneal dialysis solutions.

The beneficial effects of novel peritoneal dialysis solutions low in glucose degradation products regarding peritoneal cell apoptosis and necrosis are well established in vitro, however in vivo data is lacking. Cell‐free DNA quantification is a possible method to determine cell damage through apoptosis and necrosis in vivo. We performed a prospective, cross‐over study on 26 stable continuous ambulatory peritoneal dialysis (CAPD) patients, treating each patient for 3 months in a randomized order with a conventional, lactate‐buffered, acidic solution (solution D) and a novel, bicarbonate/lactate‐buffered neutral solution (solution P). The timed overnight peritoneal effluent was sampled for cell‐free DNA quantification using a fluorometric assay. The effluent samples of eighteen patients were finally available for DNA quantification. The concentration range of cell‐free DNA in the peritoneal effluents was 1.8–9.5 µg/L. The coefficient of intrapatient variation in overnight effluent cell‐free DNA appearance was 15.6 ± 12.4%. Cell‐free DNA peritoneal appearance using solutions D and P was 14.9 ± 6.8 µg and 11.8 ± 3.4 µg, respectively (P = 0.02), with the average difference of 3.1 µg (95% CI, 0.7–5.6 µg). Our results show that cell‐free DNA is present in the overnight peritoneal effluent of stable CAPD patients. A significant decrease in the cell‐free DNA appearance with solution P was found; however, before accepting this as an indicator of a more biocompatible profile causing less peritoneal membrane cell necrosis and apoptosis, confirmatory data on larger patient samples are needed. Our results indicate the potential future role of cell‐free DNA in the diagnosis and prognosis of therapy‐related peritoneal membrane degeneration.

Increased Lipoprotein Lipase Activity in Non-small Cell Lung Cancer Tissue Predicts Shorter Patient Survival

BACKGROUND AND AIMS Cumulative evidence suggests the involvement of lipoprotein lipase (LPL) in tumor progression. We tested the hypothesis that increased LPL activity in resectable non-small cell lung cancer (NSCLC) tissue and the increased LPL gene expression in the surrounding non-cancer lung tissue found in our previous study are predictors of patient survival. METHODS Forty two consecutive patients with resected NSCLC were enrolled in the study. Paired samples of lung cancer tissue and adjacent non-cancer lung tissue were collected from resected specimens for baseline LPL activity and gene expression estimation. During a 4-year follow-up, 21 patients died due to tumor progression. One patient died due to a non-cancer reason and was not included in Cox regression analysis. RESULTS High LPL activity in cancer tissue (relative to the adjacent non-cancer lung tissue) predicted shorter survival, independently of standard prognostic factors (p=0.003). High gene expression in the non-cancer lung tissue surrounding the tumor had no predictive value. CONCLUSIONS Our study further underlines the involvement of cancer tissue LPL activity in tumor progression.

Standard citrate versus sequential citrate/anticoagulant-free anticoagulation during hemodialysis: a randomized trial.

In a randomized study, sequential anticoagulation for hemodialysis (citrate for the first 3.5 h, switching to 30-min anticoagulation-free hemodialysis) was compared to standard citrate anticoagulation. Fifty-two hemodialysis procedures were randomized either to sequential (n = 27) or standard citrate group (n = 25). The antithrombotic effect in the circuit was visually assessed after hemodialysis using a score from 1 (total clotting) to 5 (no clotting). The antithrombotic score for sequential versus standard group was as follows: dialyzer, 4.0 +/- 1.1 versus 4.8 +/- 0.4 (P < 0.01); arterial bubble trap, 4.0 +/- 1.2 versus 4.7 +/- 0.6 (P = 0.013); venous bubble trap, 4.0 +/- 1.3 versus 4.8 +/- 0.6 (P < 0.01). Serum citrate levels during sequential versus standard citrate anticoagulation (micromol/L) were as follows: at the beginning, 143 +/- 65 versus 148 +/- 77 (not significant [NS]); after 2 h, 317 +/- 157 versus 354 +/- 111 (NS); at the end, 125 +/- 81 versus 405 +/- 133 (P < 0.01). Sequential anticoagulation reduces the final serum citrate concentration to predialysis level. It can be a good anticoagulation strategy for patients in whom the reduction of citrate load is desired.

Treatment With Low-dose Atorvastatin, Losartan and Their Combination Increases Expression of Vasoactive-Related Genes in Rat Aortas

Recently it has been shown that statins and angiotensin receptor blockers (ARBs) at low doses express beneficial pleiotropic vascular effects. We aimed to explore whether these drugs at low doses induce the expression of vasoactive-related genes. Sixty adult Wistar rats were treated with low-dose atorvastatin (2 mg/kg), low-dose losartan (5 mg/kg), their combination or saline daily for 4, 6, or 8 weeks. Expression of the vasoactive-related genes endothelin receptor type A (EDNRA), endothelial nitric oxide synthase 3 (NOS3), inducible nitric oxide synthase 2 (NOS2), and angiotensin II receptor type 1 (AGTRL1a) was measured in isolated thoracic aortas. Expression of EDNRA gradually decreased, the lowest values being obtained after 8 weeks (low-dose atorvastatin, losartan [1.6- and 1-7-fold vs controls, respectively; both P < .05], and the combination [2.3-fold vs control, P < .001]). The highest values of NOS3 were obtained after 6 weeks (low-dose atorvastatin, losartan, and their combination, 3.1-fold, P < .01; 3.4-fold, P < .001; and 3.6-fold, P < .001 vs controls, respectively) and then declined after 8 weeks. The combination was more effective in inducing total NOS3 expression when compared to the separate drugs (1.4-fold; P < .05). Importantly, expression of NOS3 was associated with increased plasma NO levels and positively correlated with thoracic aorta relaxation. No changes in expression of NOS2 and AGTRL1a were observed. We showed that low-dose atorvastatin or losartan and especially their combination increases the expression of NOS3 and decreases the expression of EDNRA. These findings are valuable in explaining the effectiveness of the “low-dose pharmacological approach” for improvement in arterial function.

Relationship between the sialic acid content of low-density lipoprotein (LDL) and autoantibodies to oxidized LDL in the plasma of healthy subjects and patients with atherosclerosis.

Abstract To determine whether the sialic acid (SA) content of the low-density lipoprotein (LDL) is related to the plasma concentration of autoantibodies to oxidized LDL (oxLDL), we measured the SA content of LDL and the concentrations of oxLDL and autoantibodies to oxLDL in plasma of 20 apparently healthy subjects and 20 patients with advanced coronary atherosclerosis. In the healthy subjects the SA content of LDL correlated positively with plasma concentration of autoantibodies to oxLDL. In agreement with the literature the decreased SA content of LDL was associated with an increased fraction of oxLDL; a decreased fraction of oxLDL was associated with an increased plasma concentration of autoantibodies to oxLDL. In the patients the SA content of LDL and plasma concentrations of oxLDL and autoantibodies to oxLDL were not related. We conclude that the SA content of LDL correlates positively with plasma concentration of autoantibodies to oxLDL in healthy subjects. However, this association may vary depending on the stage of atherogenesis. Although our results suggest dependence of LDL SA content on the clearance of oxidatively modified (desialylated and oxidized) LDL from blood by autoantibodies to oxLDL, the mechanisms regulating the SA content of LDL await further studies.

Increased phosphatidylethanolamine N-methyltransferase gene expression in non-small-cell lung cancer tissue predicts shorter patient survival.

Lipid mobilization is of great importance for tumor growth and studies have suggested that cancer cells exhibit abnormal choline phospholipid metabolism. In the present study, we hypothesized that phosphatidylethanolamine N-methyltransferase (PEMT) gene expression is increased in non-small-cell lung cancer (NSCLC) tissues and that increased gene expression acts as a predictor of shorter patient survival. Forty-two consecutive patients with resected NSCLC were enrolled in this study. Paired samples of lung cancer tissues and adjacent non-cancer lung tissues were collected from resected specimens for the estimation of PEMT expression. SYBR Green-based real-time polymerase chain reaction was used for quantification of PEMT mRNA in lung cancer tissues. Lipoprotein lipase (LPL) and fatty acid synthase (FASN) activities had already been measured in the same tissues. During a four-year follow-up, 21 patients succumbed to tumor progression. One patient did not survive due to non-cancer reasons and was not included in the analysis. Cox regression analysis was used to assess the prognostic value of PEMT expression. Our findings show that elevated PEMT expression in the cancer tissue, relative to that in the adjacent non-cancer lung tissue, predicts shorter patient survival independently of standard prognostic factors and also independently of increased LPL or FASN activity, the two other lipid-related predictors of shorter patient survival. These findings suggest that active phosphatidylcholine and/or choline metabolism are essential for tumor growth and progression.

Lipoprotein lipase in non-small cell lung cancer tissue is highly expressed in a subpopulation of tumor-associated macrophages.

High lipoprotein lipase (LPL) activity in non-small cell lung cancer (NSCLC) tissue strongly predicts shorter patient survival. We tested the hypothesis that in NSCLC tissue, macrophages are the major site of LPL expression. LPL expression in the entire NSCLC tissue and in the adjacent non-cancer lung tissue was compared to the expression of genes preferentially expressed in macrophages. LPL expression at the cellular level was analyzed by mRNA fluorescence in situ hybridization. In the whole cancer tissue (but not in the adjacent non-cancer tissue), expression of LPL correlated with expression of genes preferentially expressed in macrophages (MSR1, CD163, FOLR2), but not with expression of genes preferentially expressed in tumor cells. All cells in the cancer and adjacent non-cancer tissue exhibit low LPL expression. However, in cancer tissue only, there were individual highly LPL-expressing cells which were macrophages. These LPL-overexpressing cells were approximately 10 times less abundant than anti-CD163-stained, tumor-associated macrophages. To conclude, in NSCLC tissue, a subpopulation of tumor-associated macrophages highly expresses LPL. Because tumor-associated macrophages are pro-tumorigenic, these cells should be further characterized to better understand the underlying nature of the close relationship between high LPL activity in NSCLC tissue and shorter patient survival.