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Liver Function Tests in the Differential Diagnosis of Hepatotoxicity
Published in Robert G. Meeks, Steadman D. Harrison, Richard J. Bull, Hepatotoxicology, 2020
It is not surprising that a variety of changes in the levels of various lipids and lipoproteins occur in hepatobiliary disorders since the liver is so intimately involved in lipid metabolism. Serum triglycerides, phospholipids, fatty acid acids, and total cholesterol and its ester are occasionally used to differentiate cholestatic from necrotic processes (Bass et al., 1976). Although changes in triglycerides and total cholesterol levels are not liver-specific, the percent of cholesterol ester (CE) or the occurrence of a unique “lipoprotein-X” (LP-X) can suggest hepatocellular deficiencies or cholestasis, respectively, may be present (Kaplowitz et al., 1982). In hepatocellular disorders, less CE is formed due to low lecithin cholesterol acyltransferase (LCAT) activity in the liver. Elevated levels of both total cholesterol and LP-X are observed in animals with biliary obstruction (Sabesin, 1982). Normal lipoproteins are spherical bodies, while the abnormal LP-X is spherical in structure (Monzato et al., 1976). After the elimination of extrahepatic obstruction in animals, LP-X quickly disappears from the plasma and hepatic LCAT activity returns (Ritland and Bergan, 1975). Although LP-X is not more sensitive than other tests to detect cholestasis, it is another useful test that could be used. The density classes of lipoproteins (VLDL; LDL; HDL; HDL2) are also occasionally measured and are altered significantly in hepatobiliary disorders (Cooper, 1982). There is a need for investigations on such lipids in laboratory animals.
Hypercholesterolemia due to lipoprotein-X manifesting as pseudohyponatremia in a patient with cholestasis
Published in Baylor University Medical Center Proceedings, 2023
Farhan Azad, Norah Abu Mughaedh, Abdurahman Alloghbi, Ibrahim Tawhari
Pseudohyponatremia is an artifactual reduction of serum sodium and is defined by a serum concentration of <135 mEq/L in the presence of a normal serum osmolality (280–300 mOsm/kg).1 It occurs when plasma water volume, which typically constitutes 93% of serum, deviates due to lipid or protein accumulation in the nonaqueous component. The most common cause is elevated plasma protein, followed by triglycerides >1500 mg/dL, with hypercholesterolemia being a rare cause. A literature review revealed a sparse number of recent cases, with four cases associated with graft-vs-host disease after bone marrow or stem cell transplantation, three cases related to primary biliary cirrhosis, and one case with obstructive liver disease.2 Pseudohyponatremia caused by lipoprotein-X (Lp-X) accumulation in severe hepatic cholestasis is atypical.3
A novel pathogenic variant in LCAT causing FLD. A case report
Published in Acta Clinica Belgica, 2022
Nuria Goñi Ros, Ricardo González-Tarancón, Paula Sienes Bailo, Elvira Salvador-Ruperez, Martín Puzo Bayod, José Puzo Foncillas
He also showed hypertension, hyperuricemia, chronic kidney disease (CKD) (stage 5) and an altered lipid profile (hypertriglyceridemia (330 mg/dL) and low HDL cholesterol (13 mg/dL)). Low HDL cholesterol is the most remarkable lipid trait both in mild-to-moderate CKD patients as well as in advanced renal disease stages, and it has been previously shown that LCAT concentration is a major determinant of the low HDL phenotype. Specifically, unesterified cholesterol level is the main biochemical accountant for renal disease progression [9]. LCAT deficiency carries the accumulation, in different organs, of phospholipids and unesterified cholesterol [10]. Kidney disease is the major cause of morbidity in patients with complete LCAT deficiency. Hypertension and progressive deterioration of renal function leading to end-stage of renal disease are frequent among patients suffering from FLD and need renal replacement therapy [11]. Developmental mechanisms of renal lesions are not clearly understood, but some authors like Lynn et al. [12] have suggested the role of an abnormal lipoprotein-X (LpX), usually absent in physiological conditions and mainly made of phospholipids and unesterified cholesterol; in the stimulation of monocytes infiltration. Monocytes could contribute to the glomerulosclerosis and renal insufficiency by the presence of foamy cells, producers of cytokines and growth factors. In addition, nephrotic syndrome can itself reduce LCAT activity due to the urinary loss. Appearance and progression of renal failure is variable among FLD cases, and it is likely related to the biochemical phenotype rather than to the inherited mutation [13]. All this highlights the interest of renal biopsy in the diagnosis of LCAT deficiency [14], being electron microscopy the key in this process as lipid deposits appear as irregular small grains, dense to electrons [15].
The clinical and laboratory investigation of dysbetalipoproteinemia
Published in Critical Reviews in Clinical Laboratory Sciences, 2020
Christopher S. Boot, Ahai Luvai, Robert D. G. Neely
Striate palmar xanthomata, which are caused by the deposition of yellow-orange colored carotene-incorporated remnant lipoproteins, are widely considered a pathognomonic sign of FDBL [9]. It should be noted that white palmar crease infiltration accompanying severe lipoprotein X accumulation has been reported [10]. In a well described South African FDBL cohort, palmar crease xanthomata were observed in only 20% of cases while they were present in 64% of a North American cohort [9,11].