Glucocorticoids Regulate the Expression of the Human Osteoblastic Endothelin A Receptor Gene

The endothelial cell–derived peptide endothelin 1 (ET1) stimulates cell proliferation and differentiated functions of human osteoblastic cells (HOC), and HOC constitutively express the endothelin A receptor (ETR_A). Therefore, ET1 may play an important role in the regulation of bone cell metabolism. As glucocorticoids (GC) exert a profound influence on bone metabolism and increase the effects of ET1 on bone cell metabolism in vitro, the effects of GC on ETR_A expression in HOC were investigated. Dexamethasone (DEX) increased ETR_A mRNA levels in a dose- and time-dependent fashion. The effects of dexamethasone, prednisolone, and deflazacort on the increase of ETR_A mRNA levels correlate positively with their binding affinity to the GC receptor. Scatchard analysis of ET1 binding data to HOC revealed that DEX increased the binding capacity for ET1 from 25,300 to 62,800 binding sites per osteoblastic cell, leading to an enhanced mitogenic effect of ET1 on HOC after preincubation with DEX. Transiently transfected primary HOC with a reporter gene construct, containing the 5′-flanking region of the ETR_A gene fused to luciferase gene, showed a promoter-dependent expression of the reporter gene and the induction of reporter gene expression by DEX treatment. Total RNA extracts of femoral head biopsies with osteonecrotic lesions from GC-treated patients showed threefold higher ETR_A mRNA levels compared with extracts of bone biopsies from patients with traumatically induced osteonecrosis and coxarthrosis. Furthermore, GC treatment increased plasma ET1 levels by 50% compared with pretreatment values. These findings suggest that GC induced upregulation of ETR_A, and ET1 plasma levels enhance ET1''s anabolic action on bone cell metabolism. Increased ET1 concentrations may also impair bone perfusion by vasoconstriction in a metabolically activated skeletal region.     

Mesenteric inflammatory veno-occlusive disease – A rare cause of intestinal ischemia

Mesenteric inflammatory veno-occlusive disease (MIVOD) is a relatively recently known and not very often diagnosed form of ischemic bowel disease of low incidence und unknown etiology. We present the case of a patient who after presentation of inconclusive signs of epigastric pain and rectal bleeding suddenly developed right abdominal pain with local peritonism. Suspecting intestinal ischemia or perforated appendicitis we first performed laparoscopy, which showed an inflammable tumor of cecum, ascending colon and appendix with massive adhesions to the abdominal wall. We performed an open right hemicolectomy with primary anastomosis. The patient developed a deep vein thrombosis of the vena tibialis post. and vena saphena parva. After 12 months our patient is free of complaints and recurrence. Investigations carried out showed no evidence of hypercoagulopathy. The presentation of MIVOD can range from chronic inflammatory bowel disease with recurrent abdominal pain in combination with nausea, emesis and bloody diarrhea to acute abdomen. Therefore diagnostic misinterpretation and mistherapy as well as underdiagnosis is common. Histologic investigation shows a variable inflammatory infiltration of multiple veins of the intestinal wall and the mesentery as well as thrombotic vessel occlusion in different stages without involvement of the arteries. All forms of hypercoagulopathy, parasitic disease, sepsis and malignancy have to be excluded. Therapeutic success can only be achieved with surgical resection of the affected bowel, whereon in general no recurrence will occur.     

Preliminary report on the effect of xenoperfusion with human blood on cyclosporin A metabolism and cytochrome-P-4503A4-mRNA expression in a pig liver perfusion model

OBJECTIVES: Little is known about the effect of ischemia/reperfusion with xenogenic blood on function and gene expression of CYP3A4, the enzyme largely responsible for the metabolism of the immunosuppressants Cyclosporin A (CsA) and Tacrolimus. DESIGN AND METHODS: In a pig liver perfusion model, we have compared the effect of perfusion (3 h) after 20 h cold storage, with either pig or human blood on CsA metabolism and CYP3A4-mRNA expression. mCYP3A4-mRNA was quantified by RT-PCR, CsA and its major metabolites AM1, AM9, AM4N by RP-HPLC. IL-6 served as inflammation marker, GLDH and ALT to estimate tissue damage. RESULTS: Inflammatory response and tissue damage were more extensive during xenoperfusion. CYP3A4 expression decreased similarly during xenogenic and allogenic perfusion. CsA conversion to its metabolites was also comparable during xeno- and alloperfusion. CONCLUSION: There is no evidence that during the early reperfusion period pig liver CYP3A4 is severely affected if the organ is xenoperfused with human blood in comparison with alloperfusion.     

Plasma natriuretic peptide levels reflect changes in heart failure symptoms,left ventricular size and function after surgical mitral valve repair

BACKGROUND AND AIM: N-terminal pro-B-type natriuretic peptide (NT-proBNP) has diagnostic and prognostic value in patients with heart failure. The present prospective study was designed to assess whether changes in NT-proBNP levels after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial size, left ventricular size and left ventricular function. METHODS: The study population consisted of 22 patients (mean age: 62.8 +/- 14.2 years, 68% male) undergoing surgical mitral valve repair. Serial NT-proBNP measurements, transthoracic echocardiography and New York Heart Association (NYHA) class assessment were performed before and 6 months after surgery. RESULTS: All patients underwent successful mitral valve repair and no patients died during follow-up. The decrease in NT-proBNP level was associated with the reduction in left atrial dimension (r = 0.72, P < 0.001), left ventricular end-systolic dimension (r = 0.63, P = 0.002), left ventricular end-diastolic dimension (r = 0.46, P = 0.031), and the increase in fractional shortening (r = - 0.63, P = 0.002). Finally, patients with decreasing NT-proBNP levels revealed a significant improvement in heart failure symptoms (NYHA class). CONCLUSION: Changes in NT-proBNP after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial and ventricular dimensions and function.     

Quantitation of cell number by a positron emission tomography reporter gene strategy.

PURPOSE: An important potential of positron emission tomography (PET) is the capacity for quantitation of cell signals in an anatomic regions of interest. However, little is known about the constraints and parameters for using PET signal detection to establish cell numbers in regions of interest. In this study, we determined the correlation of PET signal to cell number, and characterized the cellular limit of detection for PET imaging. PROCEDURES: Cells expressing the herpes simplex virus type I thymidine kinase PET reporter gene (HSV1-sr39TK) were detected following accumulation of [(18)F]FHBG (9-[4-[(18)F]-fluoro-3-(hydroxymethyl) butyl]guanine) by microPET scanning and quantitation. RESULTS: When cells were cultured with [(18)F]FHBG in vitro, and then transferred to a model vascularized site, 73% retention was observed one hour post-transfer. Using this information, and the measured attenuation of PET signal in whole mouse scans, we assessed the per-cell uptake of [(18)F]FHBG in the vascularized site following standard parenteral administration of the substrate. We observed a cell number-dependent signal, with a limit of detection calculated as 10(6) cells in a region of interest of 0.1 mL volume. Quantitatively similar parameters were observed with stably tranfected N2a glioma cells and retrovirally transduced primary T lymphocytes. CONCLUSION: These methods and findings provide a strategy for quantitation of cellularity using PET imaging that has implications for both experimental models and clinical diagnosis.     

Metabolic inefficacy of a short-term low-dose insulin regimen in critically ill patients: a randomized, placebo-controlled trial

OBJECTIVE: Hyperglycemia and protein catabolism frequently occur in critically ill patients and both are associated with increased complication rates. These metabolic alterations can be improved by insulin administered exogenously. Since a wide range of insulin dosages have been used, this randomized, placebo-controlled, investigator-blinded, clinical study tests the hypothesis that a low-dose insulin regimen improves hyperglycemia and protein catabolism in critically ill medical patients. PATIENTS AND METHODS: The day after their admission to a medical intensive care unit, forty consecutive, critically ill medical patients were randomized for receiving either a low-dose insulin regimen (i.e. 1 IU/h) (treatment group, n = 20) or placebo (control group, n = 20) continuously over 24 hours. The primary endpoint was the efficacy of the low-dose insulin regimen to decrease serum glucose concentrations; the secondary endpoint was its influence on protein catabolism. Serum glucose concentrations and protein catabolism, which was assessed by the urea nitrogen appearance rate, were determined at baseline and at 8 and 24 hours thereafter. Serum insulin concentrations were measured at baseline and after 24 hours. RESULTS: After 24 hours the low-dose insulin regimen increased serum insulin concentrations compared with baseline (16.8+/-13.3 microU/ml and 11.5+/-16.9 microU/ml, respectively; p<0.05). Hyperglycemia and the urea nitrogen appearance rate did not change within the two groups of patients and there was no difference between the groups at the different time points. CONCLUSIONS: Administration of the low-dose insulin regimen was safe. However, the short-term low-dose insulin regimen was inefficient in influencing mild hyperglycemia and protein catabolism in critically ill medical patients.     

The reliability of fMRI activations in the medial temporal lobes in a verbal episodic memory task

The test-retest reliability of activation patterns elicited by encoding and recognition of word-pair associates within the whole brain and a predefined medial temporal region of interest (ROI) was investigated. Twenty healthy right-handed subjects were studied within two sessions, either on the same day or 210-308 days later. Three quantitative measures of reliability were calculated for the contrasts encoding and recognition versus a control condition within the ROI and also for the whole brain: A group correlational analysis between the lateralization indices of the first and second session, correlations of the individual SPM(t) maps of the first and the second run, and overlap ratios between both sessions. For the ROI, correlational analysis of lateralization indices during both encoding trials was significant. Eighty percent of the individual positive correlation coefficients of SPM(t) maps during encoding, and 75% during recognition reached significance. The mean percentage of overlapping voxels was 18% during encoding and 19% during recognition. The reproducibility measures evaluated for the whole brain demonstrated significantly higher values compared to the ROI. For the group that stayed inside the scanner, better whole brain test-retest reliability was observed, and no influence of the memory process (encoding or recognition) on reproducibility was found.     

Signal transducer of inflammation gp130 modulates atherosclerosis in mice and man

Liver-derived acute phase proteins (APPs) emerged as powerful predictors of cardiovascular disease and cardiovascular events, but their functional role in atherosclerosis remains enigmatic. We report that the gp130 receptor, which is a key component of the inflammatory signaling pathway within hepatocytes, influences the risk of atherosclerosis in a hepatocyte-specific gp130 knockout. Mice on an atherosclerosis-prone genetic background exhibit less aortic atherosclerosis (P < 0.05) with decreased plaque macrophages (P < 0.01). Translating these findings into humans, we show that genetic variation within the human gp130 homologue, interleukin 6 signal transducer (IL6ST), is significantly associated with coronary artery disease (CAD; P < 0.05). We further show a significant association of atherosclerotic disease at the ostium of the coronary arteries (P < 0.005) as a clinically important and heritable subphenotype in a large sample of families with myocardial infarction (MI) and a second independent population-based cohort. Our results reveal a central role of a hepatocyte-specific, gp130-dependent acute phase reaction for plaque development in a murine model of atherosclerosis, and further implicate IL6ST as a genetic susceptibility factor for CAD and MI in humans. Thus, the acute phase reaction should be considered an important target for future drug development in the management of CAD.