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Abstract Introduction Mitochondrial dysfunction plays a central role in the general pathogenesis of non-alcoholic fatty liver disease (NAFLD), increasing the risk of developing steatosis and subsequent hepatocellular inflammation. We aimed to assess hepatic mitochondrial function by a non-invasive 13C-methionine breath test (MeBT) in patients with histologically proven NAFLD. Methods 118 NAFLD-patients and 18 healthy controls were examined by MeBT. Liver biopsy specimens were evaluated according to the NASH scoring system. Results Higher grades of NASH activity and fibrosis were independently associated with a significant decrease in cumulative 13C-exhalation (expressed as cPDR(%)). cPDR1.5h was markedly declined in patients with NASH and NASH cirrhosis compared to patients with simple steatosis or borderline diagnosis (cPDR1.5h: 3.24 ± 1.12% and 1.32 ± 0.94% vs. 6.36 ± 0.56% and 4.80 ± 0.88% respectively; p < 0.001). 13C-exhalation further declined in the presence of advanced fibrosis which was correlated with NASH activity (r = 0.36). The area under the ROC curve (AUROC) for NASH diagnosis was estimated to be 0.87 in the total cohort and 0.83 in patients with no or mild fibrosis (F0-1). Conclusion The 13C-methionine breath test indicates mitochondrial dysfunction in non-alcoholic fatty liver disease and predicts higher stages of disease activity. It may, therefore, be a valuable diagnostic addition for longitudinal monitoring of hepatic (mitochondrial) function in non-alcoholic fatty liver disease.

Objective: beta-Cell mass declines progressively during the course of diabetes, and various antidiabetic treatment regimens have been suggested to modulate beta-cell mass. However, imaging methods allowing the monitoring of changes in beta-cell mass in vivo have not yet become available. We address whether pancreatic beta-cell area can be assessed by functional test of insulin secretion in humans.Research Design and Methods: A total of 33 patients with chronic pancreatitis (n = 17), benign pancreatic adenomas (n = 13), and tumors of the ampulla of Vater (n = 3) at various stages of glucose tolerance were examined with an oral glucose load before undergoing pancreatic surgery. Indexes of insulin secretion were calculated and compared with the fractional beta-cell area of the pancreas.Results: beta-Cell area was related to fasting glucose concentrations in an inverse linear fashion (r = -0.53, P = 0.0014) and to 120-min postchallenge glycemia in an inverse exponential fashion (r = -0.89). beta-Cell area was best predicted by a C-peptide-to-glucose ratio determined 15 min after the glucose drink (r = 0.72, P < 0.0001). However, a fasting C-peptide-to-glucose ratio already yielded a reasonably close correlation (r = 0.63, P < 0.0001). Homeostasis model assessment (HOMA) beta-cell function was unrelated to beta-cell area.Conclusions: Glucose control is closely related to pancreatic beta-cell area in humans. A C-peptide-to-glucose ratio after oral glucose ingestion appears to better predict beta-cell area than fasting measures, such as the HOMA index. [ABSTRACT FROM AUTHOR]

Objective: beta-Cell regeneration has been proposed as a possible treatment for diabetes, but the capacity for new beta-cell formation in humans is yet unclear. In young rats, partial pancreatectomy prompts new beta-cell formation to restore beta-cell mass. We addressed the following questions: In adult humans: 1) Does partial pancreatectomy provoke new beta-cell formation and increased beta-cell mass? 2) Is beta-cell turnover increased after partial pancreatectomy? Research Design and Methods: Protocol 1: human pancreatic tissue was collected from 13 patients who underwent two consecutive partial pancreas resections, and markers of cell turnover were determined in both tissue samples, respectively. Protocol 2: pancreas volumes were determined from abdominal computer tomography scans, performed in 17 patients on two separate occasions after partial pancreatectomy. Results: Protocol 1: fasting glucose concentrations increased significantly after the 50% pancreatectomy (P = 0.01), but the fractional beta-cell area of the pancreas remained unchanged (P = 0.11). beta-Cell proliferation, the overall replication index (Ki67 staining), and the percentage of duct cells expressing insulin were similar before and after the partial pancreatectomy. The overall frequency of apoptosis (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling) was slightly increased following the partial pancreatectomy (P = 0.02). Protocol 2: pancreatic volume was approximately 50% reduced to 35.6 +/- 2.6 ccm(3) by the partial pancreatectomy. The total pancreatic volume was unchanged after an interval of 247 +/- 160 days (35.4 +/- 2.7 ccm(3); P = 0.51). Conclusions: Unlike in rodents, a 50% pancreatectomy does not prompt beta-cell regeneration in adult humans. This explains the high incidence of diabetes after pancreatic resections. Such differences in beta-cell turnover between rodents and humans should be born in mind when evaluating new treatment options aiming to restore beta-cell mass in patients with diabetes. [ABSTRACT FROM AUTHOR]

Abstract Background To determine the general appearance of normal axillary lymph nodes (LNs) in real-time tissue sonoelastography and to explore the method′s potential value in the prediction of LN metastases. Methods Axillary LNs in healthy probands (n=165) and metastatic LNs in breast cancer patients (n=15) were examined with palpation, B-mode ultrasound, Doppler and sonoelastography (assessment of the elasticity of the cortex and the medulla). The elasticity distributions were compared and sensitivity (SE) and specificity (SP) were calculated. In an exploratory analysis, positive and negative predictive values (PPV, NPV) were calculated based upon the estimated prevalence of LN metastases in different risk groups. Results In the elastogram, the LN cortex was significantly harder than the medulla in both healthy (p=0.004) and metastatic LNs (p=0.005). Comparing healthy and metastatic LNs, there was no difference in the elasticity distribution of the medulla (p=0.281), but we found a significantly harder cortex in metastatic LNs (p=0.006). The SE of clinical examination, B-mode ultrasound, Doppler ultrasound and sonoelastography was revealed to be 13.3%, 40.0%, 14.3% and 60.0%, respectively, and SP was 88.4%, 96.8%, 95.6% and 79.6%, respectively. The highest SE was achieved by the disjunctive combination of B-mode and elastographic features (cortex >3mm in B-mode or blue cortex in the elastogram, SE=73.3%). The highest SP was achieved by the conjunctive combination of B-mode ultrasound and elastography (cortex >3mm in B-mode and blue cortex in the elastogram, SP=99.3%). Conclusions Sonoelastography is a feasible method to visualize the elasticity distribution of LNs. Moreover, sonoelastography is capable of detecting elasticity differences between the cortex and medulla, and between metastatic and healthy LNs. Therefore, sonoelastography yields additional information about axillary LN status and can improve the PPV, although this method is still experimental.

Abstract Background Cerebral inflammation is a hallmark of neuronal degeneration. Dipeptidyl peptidase IV, aminopeptidase N as well as the dipeptidyl peptidases II, 8 and 9 and cytosolic alanyl-aminopeptidase are involved in the regulation of autoimmunity and inflammation. We studied the expression, localisation and activity patterns of these proteases after endothelin-induced occlusion of the middle cerebral artery in rats, a model of transient and unilateral cerebral ischemia. Methods Male Sprague-Dawley rats were used. RT-PCR, immunohistochemistry and protease activity assays were performed at different time points, lasting from 2 h to 7 days after cerebral ischemia. The effect of protease inhibitors on ischemia-dependent infarct volumes was quantified 7 days post middle cerebral artery occlusion. Statistical analysis was conducted using the t-test. Results Qualitative RT-PCR revealed these proteases in ipsilateral and contralateral cortices. Dipeptidyl peptidase II and aminopeptidase N were up-regulated ipsilaterally from 6 h to 7 days post ischemia, whereas dipeptidyl peptidase 9 and cytosolic alanyl-aminopeptidase were transiently down-regulated at day 3. Dipeptidyl peptidase 8 and aminopeptidase N immunoreactivities were detected in cortical neurons of the contralateral hemisphere. At the same time point, dipeptidyl peptidase IV, 8 and aminopeptidase N were identified in activated microglia and macrophages in the ipsilateral cortex. Seven days post artery occlusion, dipeptidyl peptidase IV immunoreactivity was found in the perikarya of surviving cortical neurons of the ipsilateral hemisphere, whereas their nuclei were dipeptidyl peptidase 8- and amino peptidase N-positive. At the same time point, dipeptidyl peptidase IV, 8 and aminopeptidase N were targeted in astroglial cells. Total dipeptidyl peptidase IV, 8 and 9 activities remained constant in both hemispheres until day 3 post experimental ischemia, but were increased (+165%) in the ipsilateral cortex at day 7. In parallel, aminopeptidase N and cytosolic alanyl-aminopeptidase activities remained unchanged. Conclusions Distinct expression, localization and activity patterns of proline- and alanine-specific proteases indicate their involvement in ischemia-triggered inflammation and neurodegeneration. Consistently, IPC1755, a non-selective protease inhibitor, revealed a significant reduction of cortical lesions after transient cerebral ischemia and may suggest dipeptidyl peptidase IV, aminopeptidase N and proteases with similar substrate specificity as potentially therapy-relevant targets.