Changes in gluconeogenesis and intracellular lipid accumulation characterize uremic human hepatocytes ex vivo

Abstract

It is well known that reduced glomerular filtration rate (GFR) leads to an increased risk of dyslipidemia, insulin resistance, and cardiovascular mortality. The liver is a central organ for metabolism, but its function in the uremic setting is still poorly characterized. We used human primary hepatocytes isolated from livers of nine donors with normal renal function to investigate perturbations in key metabolic pathways following exposure to uremic (n ϭ 8) or healthy (n ϭ 8) sera, and to serum-free control medium. Both uremic and healthy elicited consistent responses from hepatocytes from multiple donors and compared with serum-free control. However, at physiological insulin concentrations, uremic cells accumulated 56% more intracellular lipids. Also, when comparing uremic with healthy medium after culture, it contained more very-low-density lipoprotein-triglyceride and glucose. These changes were accompanied by decreased phosphorylation of AktS473. mRNA levels of key regulators of gluconeogenesis in uremic sera-treated hepatocytes such as phosphoenolpyruvate carboxykinase 1 and glucose 6-phosphate were elevated. We also found increased expression of 11␤-hydroxysteroid dehydrogenase mRNA in uremic cells, along with high phosphorylation of downstream p53 and phospholipase C-␥1Y783. Thus our ex vivo data suggest that the uremic hepatocytes rapidly develop a glycogenic and lipogenic condition accompanied by perturbations in a large number of signaling networks.human primary hepatocytes; kidney disease; dyslipidemia; insulin signaling REGARDLESS OF ETIOLOGY, the loss of renal function (uremia) is also a state of dyslipidemia (7) and insulin resistance (5, 11). Despite that nondiabetic uremic patients are commonly euglycemic, they exhibit increased circulating insulin levels and impaired glucose disposal rate (5, 11). Furthermore, circulating lipids in uremic subjects are prevalently characterized by an elevated presence of triglycerides (TGs), a reduced highdensity lipoprotein (HDL) concentration, and increased lowdensity lipoprotein (LDL) concentration (7, 11).Notwithstanding its central role in metabolism, relatively little is known about hepatic function under conditions of impaired renal functionality. Indirect measures appear to show a normal glucose uptake and glycogen synthesis rate in the uremic liver (5), whereas decreased levels of hepatic lecithincholesterol acyltransferase (LCAT) have been linked to low circulating HDL in the same patient group (10).Recently, Chapagain et al. (3) reported a central role for elevated hepatic 11␤-hydroxysteroid dehydrogenase (HSD) type 1, a determinant of intracellular cortisone signaling, in the development of insulin resistance and dyslipidemia in two nondiabetic rodent models of uremia. Notably, short-term administration of carbenoxolone, a specific 11␤-HSD1 inhibitor, resulted in normalization of glucose tolerance and circulating insulin levels, along with an altered hepatic expression of gluconeogenic and lipogenic genes.Despite these advances, our understanding of th...

Glucocorticoid activation by 11β‐hydroxysteroid dehydrogenase enzymes in relation to inflammation and glycaemic control in chronic kidney disease: A cross‐sectional study

“…9,11 Furthermore, studies in human hepatocytes and animal models of uraemia report marked increases in 11β-HSD1 activity. 7,8 Our results are therefore consistent with a growing body of evidence that increased inflammatory induction of 11β-HSD1 contributes considerably to abnormal GC metabolism in patients with CKD.…”

“…6 However, in vitro and animal models of uraemia propose concurrent 11β-HSD1 upregulation and associated cortisol generation. 7,8 Chronic kidney disease (CKD) entails a pro-inflammatory state. 9 Pro-inflammatory cytokines are potent inducers of 11β-HSD1 activity, promoting local GC activation both in vitro and in vivo.…”

Human Carboxylesterase 2 Reverses Obesity-Induced Diacylglycerol Accumulation and Glucose Intolerance

“…Liver tissue was attained from the Liver Center, Karolinska University Hospital (Huddinge, Sweden), with informed donor consent from individuals with metastatic cancer or from donor livers unsuitable for transplantation. Primary human hepatocytes were isolated from freshly resected liver tissue as previously described ( Li et al., 2016a ). Cells were plated on collagen-coated plates in William’s-E media containing 25 mM HEPES, 2 mM glutamine, 120 nM insulin, and 100 nM dexamethasone, and transfected with lipofectamine RNAiMAX and 100 nmol of silencer select siRNA (Life Technologies) in 1% DMSO.…”

Intestinal Lymphatic Dysfunction in Kidney Disease

“…The characteristics of these abnormalities vary depending on the degree of kidney impairment, the underlying etiology, and whether proteinuria, especially nephrotic syndrome, is present. [101][102][103][104][105][106][107] Aside from altering lipid levels, a low-grade chronic proinflammatory and high oxidative state prevails across the entire spectrum of kidney disease. This creates a milieu that promotes formation of oxidatively and enzymatically modified lipoproteins and lipid metabolites (eg prostaglandins, lysophosphatidic acid) that directly modulate LEC phenotype and lymphatic growth, barrier function, and contractility.…”