Journal o f Hepatology 1997; 27:639-644 Printed in Denmark • All rights reserved Munksgaard" Copenhagen Copyright © European Association for the Study of the Liver 1997 Journal of Hepatology ISSN 0168-8278 Lipoprotein alterations in liver cirrhosis: a possible contribution to changes in plasma oncotic pressure and viscosity Carme Matas 1,3, Jorge Joven 1, Elisabet Vilella l, Xavier Clivill6 l, Maria Cabr6 l, Eduard Prats 2 and Jordi Camps 1 1Centre de Recerca Biomddica, 2Servei de Medicina Interna, Hospital Universitari de Sant Joan, Reus, 3Departament d'Enginyeria Quimica, Universitat de Girona, Spain Background~Aims: To investigate whether physico- chemical alterations in plasma lipoproteins are associ- ated with changes in plasma oncotic pressure and vis- cosity in liver cirrhosis. Methods: The study included 66 patients with cir- rhosis (confirmed by liver biopsy) and 58 healthy vol- unteers. The constituents measured were: the concen- tration, density and composition of plasma lipopro- teins; plasma oncotic pressure and viscosity; and the concentrations of albumin, total protein, haptoglobin, transferrin, immunoglobulin M and a2-macroglobulin. Results: Step-wise multiple regression analysis indi- cated that, in the patients with cirrhosis, plasma on- cotic pressure was significantly correlated with plasma albumin+viscosity (r=+0.85; p<0.001) and with plasma total protein+the density of low density lipo- protein (r= +0.74; p<0.001). The inclusion of viscos- ity and the density of low density lipoprotein in the regression equations significantly improved the ob- served correlation between albumin and plasma oncot- ic pressure (r=+0.70; p<0.001). Similarly, plasma viscosity was significantly correlated with the sum of plasma total protein and cholesterol (r=+0.68; p<0.001). The inclusion of cholesterol in the re- gression equation significantly increased the observed correlation between total protein and plasma viscosity (r= + 0.59; p<0.001). Conclusions: These results suggest that lipoprotein alterations associated with liver cirrhosis may play a role in determining plasma oncotic pressure and vis- cosity, and thus could influence the progression of the disease. Key words: Lipoproteins; Liver cirrhosis; Oneotic pressure; Rheology; Viscosity. B IOPHYSICALalterations in plasma, such as changes in viscosity and colloidal osmotic pressure (oncot- ic pressure), are involved in the pathophysiology of sev- eral diseases. Oncotic pressure is an important deter- minant of intravascular volume. The imbalance be- tween oncotic pressure and capillary hydrostatic press- ure is of primary importance in the onset of edema while, in liver cirrhosis, reduced oncotic pressure con- tributes to ascites production in patients with renal so- dium and water retention (1). Plasma viscosity is a major determinant of capillary blood flow through the microcirculation (2,3) which, if impaired, could result in potentially-important clinical sequelae. Received 9 December 1996," revised 6 May; accepted 13 May 1997 Correspondence: Jordi Camps, Ph.D., Centre de Recerca Biom6dica, Hospital Universitari de Sant Joan, C/. Sant Joan s/n, 43201 Reus (Catalunya), Spain. Tel: 34 77 310300. Fax: 34 77 312569. Several studies have suggested that plasma lipopro- tein concentration may be associated with plasma on- cotic pressure and viscosity in the normal population (4,5), pathological states (6) and in cell cultures (7-10). Chronic liver disease is known to profoundly alter the metabolism of lipoproteins, since the liver is the critical organ in their synthesis and degradation (11,12). Lipo- proteins, in liver disease, are altered not only in relation to concentration but also with regard to shape (12-14), composition and the lipid distribution within the vari- ous lipoprotein classes (15). It may be hypothesized that these physico-chemical changes influence, at least to some degree, plasma oncotic pressure and viscosity in patients with cirrhosis. The aim of the present study was to investigate whether alterations in lipoprotein density, concen- tration or composition are associated with changes in plasma oncotic pressure and viscosity in a group of pa- tients with liver cirrhosis. For comparison, associations 639