AB0124 EFFECTS OF INHIBITOR K-CARRAGEENAN ON HAECs INFLAMMATORY RESPONSE TO LDLs ISOLATED FROM SLE PATIENTS

Background

Systemic Lupus Erythematosus (SLE) is an autoimmune disease with a high risk of atherosclerosis and cardiovascular events. It was previously reported by our group that low-density lipoprotein (LDL) particles isolated from SLE patients, during an active state of the disease (‘flare’), promoted an exaggerated inflammatory response in human aortic endothelial cells (HAECs). However, the molecular mechanisms underlying this response still remain elusive.

Objectives

The hypothesis of this study is that these SLE-LDLs would be using receptor LOX-1, associated with inflammatory conditions and altered lipoproteins, to generate the proatherogenic response in HAECs.

Methods

LOX-1 pharmacological inhibitor k-carrageenan was used before the stimulation of HAECs with LDLs isolated from healthy controls (10), non-active (13), or active-SLE patients (13). Gene expression, protein, and cell migration assays were performed to evaluate HAECs inflammatory response.

Results

LOX-1 inhibition with k-carrageenan significantly reduced the expression of vascular cell adhesion molecule 1 (VCAM-1) and restored the gene expression of endothelial nitric oxide synthase (eNOS) in HAECs incubated with non-active SLE LDLs.

Conclusion

While VCAM-1 down-regulation was expected, the immediate next step derived from the observed results will be a deeper understanding of how LOX-1 inhibition may restore the endothelial ability to synthetize NO in the presence of altered LDL. This will allow gaining insight not only on the development of atherosclerosis but also on the clue mechanisms involved in the pathogenesis of SLE.

Disclosure of Interests

None declared

APOA5 gene expression in the human intestinal tissue and its response to in vitro exposure to fatty acid and fibrate

BACKGROUND AND AIMS

APOA5, a key gene regulating triglyceride (TG) levels, is reported to be expressed exclusively in the liver where it may regulate TG-rich particle synthesis and secretion. Since the same lipoprotein processing occurs in the intestine, we have postulated that this organ would also express APOA5.

METHODS AND RESULTS

We have detected the APOA5 gene expression in C57BL/6J mouse and in human small intestine samples. In humans, it is expressed mainly in the duodenum and colon, with messenger RNA (mRNA) levels four orders of magnitude lower than in the liver, and the protein product being one-sixth of the liver equivalent. Subsequently, we carried out in vitro experiments in TC-7/CaCo(2) human intestinal cells to analyse the expression of APOA5, APOC3, APOB and MTP genes after the incubation with long- and short-chain fatty acids, and a peroxisome proliferator-activated receptor alpha (PPARα) agonist (Wy 14643, a fibrate therapeutic agent). In the TC-7 cell line, APOA5 expression was significantly upregulated by saturated fatty acids. The short-chain fatty acid butyrate increased APOA5 expression almost fourfold while APOB was downregulated by increasing butyrate concentrations. When TC-7 cells were incubated with PPARα agonist, the APOA5 expression was increased by 60%, while the expression of APOB, MTP and APOC3 was decreased by 50%, 30% and 45%, respectively.

CONCLUSION

Our results demonstrate that APOA5 is expressed in the intestine, albeit at a much lower concentration than in the liver. While it remains to be determined whether intestinal apo A-V is functional, our in vitro experiments show that its expression is modifiable by dietary and pharmacological stimuli.

The APOA5-1131 T>C variant enhances the association between RBP4 and hypertriglyceridemia in diabetes

BACKGROUND AND AIM

Type 2 diabetic patients have an increased prevalence of hypertriglyceridemia. RBP4 has been associated with insulin resistance and hypertriglyceridemia in obesity, the metabolic syndrome and type 2 diabetes. APOA5 is proposed to be a genetic modulator of triglycerides. The aim of this study was to evaluate the relationship between RBP4 plasma levels and lipid disturbances and to determine the impact of the APOA5-1131 T>C variant on this relationship in type 2 diabetic patients.

METHODS AND RESULTS

A total of 165 type 2 diabetic patients were included in the study. RBP4 plasma levels and the APOA5-1131 T>C variant were determined and the complete lipid profile was assessed by sequential ultracentrifugation. RBP4 was positively correlated with triglyceride levels in plasma and with all the components of triglyceride-rich lipoproteins. Despite the fact that a statistically significant relationship between the APOA5 genetic variant and RBP4 plasma levels was not found, the hypertriglyceridemic effect of high RBP4 levels was enhanced by the presence of the APOA5-1131 T>C genetic variant. Correlation coefficients were 2-fold higher for TC carriers compared to TT carriers with regard to RBP4 plasma levels and all the components of triglyceride-rich lipoproteins. Those type 2 diabetic patients with high RBP4 plasma concentrations and who were TC carriers showed an increased incidence of hypertriglyceridemia (OR=7.46, P=0.010).

CONCLUSION

RBP4 is associated with hypertriglyceridemia in type 2 diabetic patients. The RBP4 effect is conditioned by the presence of the APOA5-1131 T>C genetic variant.

[Kidney transplantation and pregnancy: experience with 6 patients]

From 1983 to 1991, six pregnant women bearing a renal transplant were admitted at the P Universidad Católica de Chile Clinic Hospital. All of them were under immunosuppressive therapy with azathioprine and prednisone. One patient was also receiving cyclosporine. Four had chronic hypertension; 1 presented intrahepatic cholestasis of pregnancy; 2, premature rupture of membranes, and 3, preeclampsia (superimposed to chronic hypertension). There were no abortions. The median gestational age at delivery was 35.5 weeks. Only one of the six newborns was small for gestational age; the others were of appropriate size. There were no neonatal problems or congenital anomalies. Deterioration of the renal function was observed in two patients. One patient presented rejection to the transplanted kidney. Pregnancy following renal transplantation is not exempt of risks, but multidisciplinary management, close prenatal control and opportune interruption of gestation play a key role in the successful outcome of these pregnancies.