Plasma level and genetic variation of apolipoprotein E in patients with lipoprotein glomerulopathy

Background Lipoprotein glomerulopathy (LPG) is a renal disease characterized by thrombus-like lipoproteins in the glomerular capillaries and its abnormal lipoprotein profiles with marked elevation of apolipoprotein E (apoE). In this study, 15 Chinese patients with LPG were involed in exploring the association of the genetic variation and its plasma level in the pathogenesis of LPG.Methods A retrospective analysis of the clinical and pathological features was made in 15 patients with LPG. Plasma concentrations of apoE were measured with radial immunodiffusion assay. Genetic variations of apoE gene were detected using polymerase chain reaction and restriction fragment length polymorphism. Glomerular deposition of apoA, apoB and apoE in these patients were detected by immunofluorescence staining using monoclonal antibodies. Results Biochemical profiles of lipids and lipoproteins revealed markedly elevated levels of triglyceride, apoB and apoE, but approximately normal levels of total cholesterol, apoA1 and lipoprotein(a) [Lp(a)], which resembled familial hypertriglyceridemia. Genetic analysis demonstrated that the genotype distribution of apoE were 7 cases with (ε3/ε 4,)4 cases with ε3/ε 3 and 2 cases with ε2/ε 3. The other 2 cases (a mother and her son) showed a same distinct band. The band pattern of later 2 cases was quite similar to the apoE variant of Tokyo type. The calculated allele frequency of ε 4 was relatively high in cases with LPG in comparison with that in the normal controls. We further divided the 13 patients into three groups according to their genotypes of apoE. Patients with the genotype of apoE ε2/ε3 showed a lower level of plasma apoE as compared to those with apoE ε3/ε4 (P<0.05). The serum level of high-density lipoprotein (HDL) was the lowest in patients with the genotype of apoE ε3/ε4. No difference was found among the patients with different apoE genotype in the other clinical and pathological characteristics. Conclusions The genotype of apoE ε3/ε4 is the predominant one in Chinese patients with LPG. Patients with this genotype tend to have a higher plasma level of apoE and more severe lipid dysmetabolism. No correlation was found between the genotype of apoE and the clinical features in patients with LPG.

Lipoprotein glomerulopathy: clinical features and pathological characteristics in Chinese

Background Lipoprotein glomerulopathy (LPG), once recognized as a rare glomerular disease, has been reported around the world in recent years. In this study, we reported 8 patients of LPG and aimed to explore the clinical features and pathological characteristics of LPG under light microscope, immunofluorescence staining, and electron microscope.Methods Clinical manifestations were recorded on the day of renal biopsy. Biochemical patterns of lipids and lipoproteins were detected by routine examination. Plasma concentrations of apo B and apo E were determined by radial immunodiffusion assays. Biopsy specimens were then processed for light microscopy, immunohistochemical staining for immunoglobulins and complement components, and electron microscopy. Glomerular deposition of apo A, B, and E were detected using monoclonal antibodies on cryostatic sections.Results All of the eight patients presented with edema, microscopic hematuria, severe proteinuria, anemia, and enlarged kidney size. Biochemical profiles revealed high levels of triglycerides, apo B, and apo E. We noted increments of glomerular size and lipoprotein thrombi occupying capillary lumina in the glomeruli of all patients. Immunofluorescence staining showed that the thrombi were strongly positive for apo A, B, and E. Granules and various sizes of vacuoles were observed in the thrombi under electron microscope.Conclusion Compared with previous reports on LPG in other countries, unique clinical and pathological features were found in this group of Chinese LPG patients.