INCREASED VLDL LEVELS AND DIMINISHED RENAL EXCRETION OF URIC-ACID IN HYPERURICAEMIC-HYPERTRIGLYCERIDEMIC PATIENTS

The objective was to study the lipoprotein levels in primary hyperuricaemic patients and to analyse their renal management of urates in order to check for some potential influence of altered lipid levels on the renal excretion of urates by this type of patient. Overall 115 male individuals were studied in five groups, namely: 30 primary hyperuricaemic (group I); 27 primary hyperuricaemic-hypercholesterolaemic (group II); nine primary hyperuricaemic-hypertriglyceridaemic (group III); 33 primary hyperuricaemic-mixed hyperlipidaemic (group IV); and 16 normouricaemic-normolipidaemic subjects (group C). All patients were subjected to blood analyses for uric acid, total triglycerides, total protein, creatinine, high density lipoprotein (HDL) cholesterol, very low density lipoprotein (VLDL) cholesterol, low density lipoprotein (LDL) cholesterol, apoprotein (ape) AI, apoprotein B, apoprotein CII and apoproteins CIII1 and CIII2. For urine analysis creatinine, creatinine clearance, uric acid excretion, clearance and fractional excretion were measured in 24 h urine samples. Mixed and pure hyperuricaemic-hypertriglyceridaemic patients exhibited increased levels of VLDL components, decreased fractional excretion of uric acid and increased apo CIII/CII ratios. The increased levels of structural VLDL components were negatively (and statistically significantly) correlated with the fractional excretion of uric acid; this suggests a close biological relationship between the two parameters. Taking into account the role played by apo C in VLDL metabolism, the altered apo CIII/CII ratios found in hyperuricaemic- hypertriglyceridaemic patients (both pure and mixed) suggest that this apoprotein plays a central role in the physiopathology of the alterations observed.