Uta Merle

Regulation of hepcidin in HepG2 and RINm5F cells

Despite the high impact of the antimicrobial peptide hepcidin in iron homeostasis, the regulation of this hormone is still not completely understood. Studies concerning hepcidin regulation are performed at the mRNA level. For the first time we analyzed the regulation of hepcidin not only at mRNA, but also at protein level in a hepatoma and a pancreatic beta cell line using quantitative RT-PCR and immunoblot analysis. Our data show, that hepcidin is present in HepG2 and RINm5F cells. A significant up-regulation of hepcidin was observed in both cell lines by the inflammatory cytokine interleukin-6, lipopolysaccharide, and a slight upregulation by deferoxamine. A down-regulation was detected after stimulation with erythropoietin. Hepcidin was regulated by iron in a dose dependent manner: low doses up to 3 microM increased hepcidin expression, high doses of iron (65 microM) revealed a switch-over to down-regulation of hepcidin expression. Regulation of hepcidin in HepG2 and RINm5F cells at mRNA and protein level by these substances indicates its involvement in inflammation and iron metabolism.

Critical Role of Macrophages in Glucocorticoid Driven Vascular Calcification in a Mouse-Model of Atherosclerosis

Objective—Macrophage-derived products are known to play a crucial role during atherogenesis and vascular calcification. Glucocorticoids (GC) are important modulators of immune cell functions, but their specific effects on macrophages behavior during plaque formation are not defined. The present study was therefore designed to investigate the effects of macrophage-specific deletion of the glucocorticoid receptor (GRLysMCre) on atherogenesis and vascular calcification in a hyperlipidemic mouse-model. Methods and Results—Bone marrow was isolated from GRLysMCre mice and wild-type controls (GRflox) and subsequently transplanted into lethally irradiated LDL-receptor–deficient mice. Animals were fed a Western-type diet for 15 or 24 weeks, and atherosclerotic lesions within the aortic sinus were evaluated. At both time points, no significant difference in serum lipid and corticosterone concentrations, atherosclerotic lesion size and macrophage-content within the lesions could be observed. However, GRLysMCre mice showed less calcification as well as a significant reduction of RANKL, BMP2, and Msx2 expression within the vasculature. In vitro studies using conditioned media from macrophages which had been stimulated with dexamethasone demonstrated a dose-dependent increase in calcium deposition by vascular smooth muscle cells. Conclusion—This study demonstrates that macrophage-specific glucocorticoid receptor inactivation reduces vascular calcification without affecting atherosclerotic lesion size in LDL receptor–deficient mice.

An Early Increase in Gamma Glutamyltranspeptidase And Low Aspartate Aminotransferase Peak Values Are Associated With Superior Outcomes After Orthotopic Liver Transplantation

BACKGROUNDnPrediction of prognosis after liver transplantation (OLT) remains difficult. The present study determines if standard laboratory parameters measured within the first week after OLT correlate with outcome.nnnPATIENTS AND METHODSnLaboratory parameters measured within the first weak after OLT of 328 patients were grouped either graft loss or death within 90 days after (group 1: graft loss; group 2: death; group 3: neither graft loss nor death within 90 days).nnnRESULTSnPeak AST and ALT were significantly lower in group 3 (1867 and 1252 U/L) than in group 1 (4474 and 2077 U/L) or 2 (3121 and 1865 U/L). Bilirubin was significantly lower and gamma-GT significantly higher in group 3 compared to groups 1 and 2. In multivariate analysis, high AST peaks were independently associated with death or graft loss within 90 days. An increase in gamma-GT and low bilirubin early after transplantation were found to be independently associated with superior outcome.nnnDISCUSSIONnUnexpectedly, a disproportionate rise in gamma-GT was associated with graft and patient survival of more than 90 days. This might be explained by regeneration phenomena in the liver indicative of a well functioning graft.

Localization of the Wilson disease protein in murine intestine

Wilson disease is an inherited disorder of human copper metabolism, characterized by gradual accumulation of copper in tissues, predominantly liver and brain. The gene defect lies in the Wilson disease protein ATP7B, a copper transporting ATPase highly active in hepatocytes. In the liver, ATP7B is essential for excretion of excess copper into the bile and for copper loading of ceruloplasmin in the Golgi apparatus. The extrahepatic role of ATP7B is not yet completely understood. We analysed the intestinal expression of ATP7B in mice using RT‐PCR, Western blot and indirect immunofluorescence. We found abundant expression of ATP7B in stomach and small intestine, but not in colon. Using confocal microscopy we demonstrate a Golgi localization of ATP7B in enterocytes. In response to elevated copper, the Wilson disease protein shows an intracellular trafficking pattern in the intestinal polarized cell line CaCo‐2, moving away from the Golgi apparatus to dispersed vesicles. This suggests a role for intestinal ATP7B in sequestration of copper in intracellular vesicles for maintenance of copper homeostasis in the enterocyte. In conclusion, the expression of ATP7B in the small intestine might represent an additional regulatory mechanism to fine‐tune intestinal copper absorption.

Liver transplantation in HIV-positive patients

Abstract:u2002 Death from end‐stage liver disease (ESLD) because of chronic hepatitis B and C has become an increasing problem in human immunodeficiency virus (HIV)‐infected patients in the last years. This is mainly because of the dramatic decrease of HIV‐related morbidity and mortality since the introduction of highly active antiretroviral therapy (HAART). Although the data on the outcome of liver transplantation in HIV‐infected recipients with ESLD is limited, overall results seem comparable to non‐HIV‐infected recipients. Therefore, liver transplant centres around the world are increasingly accepting HIV‐infected individuals as organ recipients. Post‐transplantation control of HIV replication is achieved by continuing HAART. As in non‐HIV‐infected patients, hepatitis B virus recurrence is efficiently prevented by hepatitis B immunoglobulin and antiviral therapy. Re‐infection of the allograft with hepatitis C virus, however, remains an important problem, and progress to allograft cirrhosis may even be more rapid than in HIV‐negative patients. Interactions in drug metabolism between the HAART components and the immunosuppressive drugs are difficult to predict and require close monitoring of drug levels and dose adjustments. The complexity in this setting makes close cooperation between transplant surgeons, hepatologists, HIV‐clinicians and pharmacologists mandatory. As experience on liver transplantation in HIV‐infected individuals is still limited, to date results from large prospective trials addressing key issues are needed.

Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls

BackgroundIn Wilson disease, copper is not sufficiently excreted into bile due to the absence or malfunction of the Wilson protein copper ATPase in the excretory pathway of hepatocytes. Copper is found in sweat. It is unknown if the Wilson protein plays a role in copper excretion into sweat. It is the aim of this study to investigate Wilson protein expression in sweat glands and analysing its effects on copper excretion into sweat in controls and patients with Wilson disease.MethodsImmunofluorescent analysis of the Wilson protein in skin samples from normal rat, LEC rat and human skin biopsies were performed. Pilocarpin-induced sweat gland stimulation by iontophoretic transfer adapted from the methods used for cystic fibrosis sweat test was used for sweat induction. Sweat volume, sweat copper concentration, serum ceruloplasmin and serum copper were analysed in 28 Wilson patients and 21 controls.ResultsThe Wilson protein is expressed in human and rat sweat gland epithelia. Copper concentration in sweat is not significantly different between controls and Wilson patients. Wilson patients produce significantly smaller volumes of sweat compared to controls. Sweat production is partially reversible in Wilson patients under medical treatment for Wilson disease or after liver transplantationConclusionWilson patients show a reduced sweat production with unaltered sweat copper concentration. The Wilson protein might play an important role in physiological sweat production.

Hemophagocytic lymphohistiocytosis in an adult kidney transplant recipient successfully treated by plasmapheresis: A case report and review of the literature

Rationale: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease entity primarily described in children, but not less relevant in adults. It is characterized by a misdirected activation of the immune system, resulting in an uncontrolled cytokine release from macrophages and cytotoxic T-cells (CTLs). Primary HLH relies on a genetic predisposition, whereas secondary HLH develops in the context of infections, malignancies or autoimmune diseases. However, the awareness and therapeutic knowledge for HLH in adulthood is limited. Most therapy protocols are almost exclusively validated in pediatric cohorts and for primary HLH. Their transferability to adult individuals with mostly secondary HLH is doubtful. Especially the high liver and bone marrow toxicity of applied etoposide-based protocols is discussed controversially and connected to overwhelming infections and death. Patient concern: A 51-year old, male, kidney transplant recipient was admitted to our center suffering from diarrhea, fever, nausea, hyponatremia, kidney graft failure, disorientation, progressive hemodynamic instability, and multiorgan failure. Diagnoses: Clinical and laboratory findings resembled those of a septic shock. Ferritin and soluble interleukin-2 receptor (sCD25) levels were disproportionally elevated. Only a mild hepatosplenomegaly was diagnosed in a CT scan. A T2-weighted, fluid-attenuated inversion recovery MRI showed marked, bilateral and periventricular white matter hyperintensities. The cerebrospinal fluid (CSF) analysis showed a moderately elevated protein content and cell count. There was no evidence of any bacterial, viral, or parasitic infection. The diagnosis of HLH was made. Interventions & Outcomes: The patient was successfully treated by a combined approach consisting of plasma exchange (PE), corticosteroids, anakinra, and cyclosporine (CsA). Lessons: HLH is an important differential diagnosis in critically ill patients. Its unspecific clinical picture complicates an early diagnosis and may be misclassified as sepsis. A combination of plasma exchange (PE), corticosteroids, anakinra, and cyclosporine (CsA) may be a promising and less toxic approach for HLH therapy in adults.