10 Autoimmunity was an emerging and exciting frontier. The concept of Burnet that autoreactive cells could escape into the peripheral circulation as “forbidden clones”11-13 heralded an era of disease discovery and understanding, and autoimmune hepatitis was a product of this surge. Autoimmunity, however, was still a vague pathogenic mechanism; it was not an etiologic agent like a virus or a drug; and it

could not be measured in the clinic. The evolving requisites for autoimmunity, especially the requirement for the transfer of disease by antibodies or lymphocytes, were restrictive,14,15 and “autoimmune” vied with “idiopathic” as an apt descriptor for the see more fledgling condition. The wobbly legs of autoimmune hepatitis would persist for at least 2 decades. Systemic lupus erythematosus almost swallowed it16 and drug-induced17 and virus-related18,19 conditions repeatedly threatened its Rapamycin supplier legitimacy. The goals of this review are to illustrate the dynamics of successful clinical investigation in liver disease and to underscore the vital role of the clinician nonscientist in starting and completing the circle of care from bedside-to-bench-to-bedside. Autoimmune hepatitis will be the “illustrative model” by which to accomplish these goals, and I will be the typical “clinician nonscientist.” The script can be applied broadly and accommodate any

substitute model or actor. The principal components of this tutorial are indicated below, and they rely heavily of good fortune, good mentoring, appropriate goal identification, adherence to protocol, compulsive record keeping, personal resilience, and strong collaborations. CALD, chronic active liver disease; HBsAg, hepatitis B surface antigen; HLA, human leukocyte antigen; IAIHG, International Autoimmune Hepatitis find more Group; MELD, Model for End-Stage Liver Disease. From 1969 to 1972, I had the good fortune to interact with academic clinicians who had a keen interest in

the study of liver disease (Table 1). At the Philadelphia General Hospital, Geobel Marin advocated the principles of controlled clinical trial and “double-blinded” investigation as the bases for new knowledge in clinical medicine, and my first article comparing peritoneoscopy with unguided needle biopsy of the liver illustrated some of these principles.20 At the University of Pennsylvania, Roger Soloway had just returned from a fellowship at the Mayo Clinic, and he presented wonderful data derived from a now classic controlled clinical trial that described the natural history and treatment of “chronic active liver disease”.21 My commitment to the study of liver disease was established through these contacts in Philadelphia as was my desire to train at the Mayo Clinic. Fortunately, Bill Summerskill agreed to accommodate this desire. The military draft interrupted my transition to Mayo, but my assignment to the U.S.

Five minutes later, dose-response curves to cumulative doses of acetylcholine (ACh, 10−7, 10–6, and 10−5M) were evaluated. The concentration of ACh was increased by one log unit every 1.5 minutes. Response to cumulative doses of ACh was calculated as a percent change in PP. In a different group of rats, a portal perfusion pressure-response curve to Mtx was obtained by adding increasing doses of Mtx (10−6, 10−5, 10−4, 5 − 10−4 mol/L) to the reservoir every 5 minutes. Protein nitrotyrosination (3-NT), Selleckchem Roxadustat a marker of peroxynitrite production and oxidative stress due to NO reaction with ROS, was determined by western blotting (see Supporting Information for details). Blots were

probed with a mouse anti–3-NT (1:1,000) monoclonal antibody (Sigma,

Madrid, Spain) and mouse anti–glyceraldehyde-3-phosphate dehydrogenase (GAPDH) antibody (1:1,000 dilution; Santa Cruz Biotechnology, Santa Cruz, CA). X-ray films were exposed, developed, fixed, and scanned. Densitometry of digital images was performed with Melanie version 6 software. GAPDH was used as control of sample loading. Endothelial NO synthase (eNOS) and phosphorylated eNOS (p-eNOS) protein detection was performed with mouse Cell Cycle inhibitor anti-eNOS (1 μg/mL dilution; BD Biosciences, San Jose, CA) and rabbit anti–p-eNOS (1:500 dilution; Cell Signaling Technology) as described for 3-NT. Quantitative densitometric values were compared between eNOS and p-eNOS blots. GAPDH was used as control of sample loading. Measurements of guanosine 3′,5′-cyclic monophosphate, a marker of NO bioavailability, were performed in control and cirrhotic rat liver homogenates from

HC and CIH rats (see Supporting Information for details). The results are expressed as picomoles per milliliter. Mtx and ACh were purchased from Sigma (Madrid, Spain). Statistical analysis was performed using SPSS version 15.0 for Windows (SPSS Inc., Chicago, IL). All data are reported as the mean ± SEM. Comparisons between groups were performed using analysis of variance followed by Student’s t test or the nonparametric test for unpaired data (Mann-Whitney) when appropriate. Differences were considered significant at P < 0.05. selleck compound 3-NT, nitrotyrosine; ACh, acetylcholine; CBDL, common bile duct ligation; CCl4, carbon tetrachloride; CIH, chronic intermittent hypoxia; eNOS, endothelial nitric oxide synthase; HC, handled controls; MAP, mean arterial pressure; Mtx, methoxamine; NO, nitric oxide; OSAS, obstructive sleep apnea syndrome; p-eNOS, phosphorylated eNOS; PP, portal pressure; ROS, reactive oxygen species. Rats after 12 weeks of CCl4 inhalation and CBDL rats had macroscopic cirrhosis and signs of portal hypertension as shown by the presence of ascites, collateral circulation, or splenomegaly (Table 1). Rats with 8 weeks of CCl4 inhalation showed macroscopic micronodular cirrhosis without ascites. Body weight was recorded to determine whether the exposure protocol altered weight gain.

LPA levels above 30mg/dL are considered an important risk factor for CVD. Conversely, LPA levels inversely correlate with the incidence of diabetes and HOMA-IR (Cardiovasc Diabetol, 2012). We therefore aimed to assess the impact of an oral 4 week 150g/day FC on hepatic lipid metabolism reflected by total hepatic lipid content (HLC), fatty acid saturation and phosphorous metabolites (PM; indicating hepatic energy metabolism), and

glucose homeostasis. Moreover, we aimed to explore the role of LPA as potential biomarker predicting hepatic sensibility to fructose induced (lipo)toxicity. Methods: Ten healthy volunteers were enrolled in a pilot study (m: f=5: 5; median age 24.5 (21-37)). HLC (CH2 fraction of total signal), unsaturation- (UI), saturation- (SI=1-UI) and polyunsaturation indices (PUI) were determined http://www.selleckchem.com/products/i-bet-762.html by single voxel 3.0-T 1H-, PM by 31P-MRS. BMI was assessed GSK2118436 research buy clinically. Blood was collected at days 1, 14 and 28 for routine laboratory analysis, LPA at baseline and fasted glucose. Results: Mean BMI was 21.11 ± 2.68 (SD) kg/m^2 and increased after FC (21.51 ± 2.77; p<0.001). UIs increased from mean 0.175 ± 0.087 to 0.226 ± 0.066 (p=0.034 one-tailed; large effect size r=0.568). Similarly, fasting glucose levels increased (mean 83.2mg/dL ± 8.37 to 88.4 ± 5.48, p=0.035). Notably, total HLC, PUIs, PM, ALT, AST and yGt remained unchanged (p>0.05). Analysis

of responders to FC (FCR; n=6) as reflected by increased total click here HLC (as potential indicator for lipid partitioning of potentially toxic lipid intermediates as neutral TG) versus non-responders (FCNR; n=4) revealed αATP depletion in FCNR (mean 3.003 ± 2.07 to 1.67 ± 0.413; p=0.034 onetailed). In FCR reflected by increased UI (n=7) γATP depletion was

observed (mean 2.18 ± 0.71 to 1.51 ± 0.4; p=0.036). Notably, baseline LPA levels inversely correlated with total HLC following FC (r=-0.801; p=0.004; r^2=0.652; non-linear fit: r^2=0.594) and delta-αATP (r=-0.652; p=0.039). Conclusions: MRS is feasible to detect slight changes in intrahepatic lipid composition after FC in healthy young volunteers. Changes in fatty acid saturation indices may occur earlier compared to other well established markers of liver damage. Moreover, serum LPA may also serve as a novel biomarker to differentiate between individuals at increased risk for NAFLD, particularly under fructose challenge. Approaches aimed at lowering LPA to counteract CVD risk should also consider potential interactions with hepatic lipid content and partitioning. Disclosures: Michael Trauner – Advisory Committees or Review Panels: MSD, Janssen; Consulting: Falk Pharma, Phenex, Amgen; Grant/Research Support: Intercept; Patent Held/Filed: Med Uni Graz (norUDCA); Speaking and Teaching: Falk Foundation, Roche, Gilead The following people have nothing to disclose: Christian Kienbacher, Martin Gajdosik, Michael Krebs, Stefan Traussnigg, Werner Dolak, Petra E.

LPA levels above 30mg/dL are considered an important risk factor for CVD. Conversely, LPA levels inversely correlate with the incidence of diabetes and HOMA-IR (Cardiovasc Diabetol, 2012). We therefore aimed to assess the impact of an oral 4 week 150g/day FC on hepatic lipid metabolism reflected by total hepatic lipid content (HLC), fatty acid saturation and phosphorous metabolites (PM; indicating hepatic energy metabolism), and

glucose homeostasis. Moreover, we aimed to explore the role of LPA as potential biomarker predicting hepatic sensibility to fructose induced (lipo)toxicity. Methods: Ten healthy volunteers were enrolled in a pilot study (m: f=5: 5; median age 24.5 (21-37)). HLC (CH2 fraction of total signal), unsaturation- (UI), saturation- (SI=1-UI) and polyunsaturation indices (PUI) were determined ABT-737 in vivo by single voxel 3.0-T 1H-, PM by 31P-MRS. BMI was assessed buy CX-5461 clinically. Blood was collected at days 1, 14 and 28 for routine laboratory analysis, LPA at baseline and fasted glucose. Results: Mean BMI was 21.11 ± 2.68 (SD) kg/m^2 and increased after FC (21.51 ± 2.77; p<0.001). UIs increased from mean 0.175 ± 0.087 to 0.226 ± 0.066 (p=0.034 one-tailed; large effect size r=0.568). Similarly, fasting glucose levels increased (mean 83.2mg/dL ± 8.37 to 88.4 ± 5.48, p=0.035). Notably, total HLC, PUIs, PM, ALT, AST and yGt remained unchanged (p>0.05). Analysis

of responders to FC (FCR; n=6) as reflected by increased total learn more HLC (as potential indicator for lipid partitioning of potentially toxic lipid intermediates as neutral TG) versus non-responders (FCNR; n=4) revealed αATP depletion in FCNR (mean 3.003 ± 2.07 to 1.67 ± 0.413; p=0.034 onetailed). In FCR reflected by increased UI (n=7) γATP depletion was

observed (mean 2.18 ± 0.71 to 1.51 ± 0.4; p=0.036). Notably, baseline LPA levels inversely correlated with total HLC following FC (r=-0.801; p=0.004; r^2=0.652; non-linear fit: r^2=0.594) and delta-αATP (r=-0.652; p=0.039). Conclusions: MRS is feasible to detect slight changes in intrahepatic lipid composition after FC in healthy young volunteers. Changes in fatty acid saturation indices may occur earlier compared to other well established markers of liver damage. Moreover, serum LPA may also serve as a novel biomarker to differentiate between individuals at increased risk for NAFLD, particularly under fructose challenge. Approaches aimed at lowering LPA to counteract CVD risk should also consider potential interactions with hepatic lipid content and partitioning. Disclosures: Michael Trauner – Advisory Committees or Review Panels: MSD, Janssen; Consulting: Falk Pharma, Phenex, Amgen; Grant/Research Support: Intercept; Patent Held/Filed: Med Uni Graz (norUDCA); Speaking and Teaching: Falk Foundation, Roche, Gilead The following people have nothing to disclose: Christian Kienbacher, Martin Gajdosik, Michael Krebs, Stefan Traussnigg, Werner Dolak, Petra E.

All reactions were performed in triplicate using the ABI 7300 real-time PCR system (Life Technologies). The ITGB6, B4 and A3 expression levels were normalized using the average expression levels of the endogenous control genes B2M and TBP. The correlations among the clinicopathological findings and among 3-MA molecular weight integrins β6, β4 and α3, fibronectin and laminin expression in CoCC, CCC, HCC and classical CHC were assessed by Fisher’s exact test or the

χ2-test and Mann–Whitney U-test. anova was used in the comparison among the ITGB6, B4 and A3 mRNA levels in the hepatic tumors. P < 0.05 was considered significant. IMMUNOHISTOCHEMISTRY DEMONSTRATED THE absence of β6 integrin in normal liver cells and bile duct epithelia but frequent expression on the bile duct epithelium of interlobular and septal ducts with weak positivity on bile ductular epithelium in injured liver tissues, including chronic hepatitis. No positivity for β6 integrin immunostaining was observed in 21 (91%) of 23 CoCC (Table 2, Fig. 1a,b,h) and all HCC (Fig. 1g),

whereas low or highly positive staining for these integrins was demonstrated in 23 (82%) of 28 CCC (Table 2, Fig. 1d–f). The cytoplasmic, cell membrane and basal lamina U0126 patterns of positive immunostaining were found in CCC (Fig. 1i) and CoCC. The predominant pattern observed in CCC was the cell membrane pattern (61%), whereas the cytoplasmic pattern or basal lamina pattern was predominant in each of two CoCC with focal positivity (Fig. 1c). Positive immunostaining for biliary type integrins learn more β4 and α3 in normal liver was evident on the biliary epithelium of the interlobular and septal

bile ducts, with faint or no positive staining on the bile ductular epithelium. Positive immunostaining for β4 and α3 on the bile duct epithelium was enhanced in the injured or diseased liver tissues. With regard to hepatic tumors, no or low positive staining for β4 was observed in most (91%) CoCC and all HCC, except one, whereas highly positive staining was evident in most (96%) CCC (Table 2, Fig. 2a–d,j). The predominant pattern of positive staining in CCC was the basal lamina type (Fig. 2d,k). Highly positive immunostaining for α3 was found in 11 (48%) of 23 CoCC and eight (19%) of 42 HCC, but it was more frequently observed in 21 (75%) of 28 CCC (Table 2, Fig. 2f–i,l). The immunoreactivity for α3 was localized to the cytoplasm of the tumor cells, and it was not detected in the cell membrane or basal lamina (Fig. 2f,h,i).

All reactions were performed in triplicate using the ABI 7300 real-time PCR system (Life Technologies). The ITGB6, B4 and A3 expression levels were normalized using the average expression levels of the endogenous control genes B2M and TBP. The correlations among the clinicopathological findings and among YAP-TEAD Inhibitor 1 research buy integrins β6, β4 and α3, fibronectin and laminin expression in CoCC, CCC, HCC and classical CHC were assessed by Fisher’s exact test or the

χ2-test and Mann–Whitney U-test. anova was used in the comparison among the ITGB6, B4 and A3 mRNA levels in the hepatic tumors. P < 0.05 was considered significant. IMMUNOHISTOCHEMISTRY DEMONSTRATED THE absence of β6 integrin in normal liver cells and bile duct epithelia but frequent expression on the bile duct epithelium of interlobular and septal ducts with weak positivity on bile ductular epithelium in injured liver tissues, including chronic hepatitis. No positivity for β6 integrin immunostaining was observed in 21 (91%) of 23 CoCC (Table 2, Fig. 1a,b,h) and all HCC (Fig. 1g),

whereas low or highly positive staining for these integrins was demonstrated in 23 (82%) of 28 CCC (Table 2, Fig. 1d–f). The cytoplasmic, cell membrane and basal lamina GSK3235025 nmr patterns of positive immunostaining were found in CCC (Fig. 1i) and CoCC. The predominant pattern observed in CCC was the cell membrane pattern (61%), whereas the cytoplasmic pattern or basal lamina pattern was predominant in each of two CoCC with focal positivity (Fig. 1c). Positive immunostaining for biliary type integrins selleck β4 and α3 in normal liver was evident on the biliary epithelium of the interlobular and septal

bile ducts, with faint or no positive staining on the bile ductular epithelium. Positive immunostaining for β4 and α3 on the bile duct epithelium was enhanced in the injured or diseased liver tissues. With regard to hepatic tumors, no or low positive staining for β4 was observed in most (91%) CoCC and all HCC, except one, whereas highly positive staining was evident in most (96%) CCC (Table 2, Fig. 2a–d,j). The predominant pattern of positive staining in CCC was the basal lamina type (Fig. 2d,k). Highly positive immunostaining for α3 was found in 11 (48%) of 23 CoCC and eight (19%) of 42 HCC, but it was more frequently observed in 21 (75%) of 28 CCC (Table 2, Fig. 2f–i,l). The immunoreactivity for α3 was localized to the cytoplasm of the tumor cells, and it was not detected in the cell membrane or basal lamina (Fig. 2f,h,i).

The potential of further studies of brown algae in these important areas has been increasingly hindered by the absence of tools for manipulation of gene expression that would facilitate further mechanistic analysis and gene function studies at a molecular level.

The aim of this study was to establish a method that would allow the analysis of gene function through RNAi-mediated gene knockdown. We show that injection of double-stranded RNA (dsRNA) check details corresponding to an α-tubulin gene into Fucus serratus Linnaeus zygotes induces the loss of a large proportion of the microtubule cytoskeleton, leading to growth arrest and disruption of cell division. Injection of dsRNA targeting β-actin led to reduced rhizoid growth, enlarged cells and the failure to develop apical hair cells. The silencing effect on actin expression was maintained for 3 months. These results

indicate that the Fucus embryo possesses a functional RNA interference system that can be exploited to investigate gene function during embryogenesis. “
“Understanding responses of marine algae to changing ocean temperatures requires knowledge of the impacts of elevated temperatures and the likelihood of adaptation to thermal stress. The potential for rapid evolution of thermal tolerance is dependent selleck kinase inhibitor on the levels of heritable genetic variation in response to thermal stress within a population. Here, we use a quantitative genetic breeding design to establish whether there is a heritable variation in thermal sensitivity in two populations of a habitat-forming intertidal macroalga, Hormosira banksii (Turner) Descaisne. Gametes from multiple find more parents were mixed and growth and photosynthetic performance were measured in the resulting embryos, which were incubated under control and elevated temperature (20°C and 28°C). Embryo growth was reduced at 28°C, but significant interactions between male genotype and temperature in one population indicated the presence of genetic variation

in thermal sensitivity. Selection for more tolerant genotypes thus has the ability to result in the evolution of increased thermal tolerance. Furthermore, genetic correlations between embryos grown in the two temperatures were positive, indicating that those genotypes that performed well in elevated temperature also performed well in control temperature. Chlorophyll a fluorescence measurements showed a marked decrease in maximum quantum yield of photosystem II (PSII) under elevated temperature. There was an increase in the proportion of energy directed to photoinhibition (nonregulated nonphotochemical quenching) and a concomitant decrease in energy used to drive photochemistry and xanthophyll cycling (regulated nonphotochemical quenching). However, PSII performance between genotypes was similar, suggesting that thermal sensitivity is related to processes other than photosynthesis.

The image data were evaluated

by two readers in consensus for the visualization of cerebral arterial segments on a 5-point scale (0 = vessel cannot be distinguished; 4 = excellent image quality). The Wilcoxon signed-rank test was used for statistical analysis. Note that P < .05 was considered to indicate a significant difference. The depiction of cerebral arterial segments with FD-CTA was significantly superior compared to CTA in most vessel segments (P < .05 in 20 of 23 anatomic regions) and was without significant difference compared Dinaciclib cost with DSA in large and medium intracranial vessels. The results suggest that the cerebral arteries can be visualized by FD-CTA in high resolution, in many vessel segments comparable to DSA. “
“The diagnostic performance of 64-detector computed tomographic angiography (CTA) for detection of small intracranial aneurysms

(SIAs) was evaluated. In this prospective study, 112 consecutive Torin 1 chemical structure patients underwent 64-detector CTA before volume-rendering rotation digital subtraction angiography (VR-RDSA) or surgery. VR-RDSA or intraoperative findings or both were used as the gold standards. The accuracy, sensitivity, specificity, and positive predictive values (PPV) and negative predictive values (NPV), as measures to detect or rule out SIAs, were determined by patient-based and aneurysm size-based evaluations. The reference standard methods revealed 84 small aneurysms in 71 patients. The results of patient-based 64-detector CTA evaluation for SIAs were: accuracy, 98.2%; sensitivity, 98.6%; specificity, 97.6%; PPV, 98.6%; and NPV, 97.6%. The aneurysm-based evaluation results were: accuracy, 96.8%; sensitivity, 97.6%; specificity, 95.1%; PPV, 97.6%; and NPV, 95.1%. Two false-positive and two false-negative findings for aneurysms <3 mm in size occurred in the 64-detector CTA analysis. The diagnostic performance of 64-detector CTA did not improve much compared with 16-detector CTA for detecting SIAs, especially for very small aneurysms. VR-RDSA is still necessary for patients with a history of subarachnoid hemorrhage if the CTA findings are negative. "
“Acute

basilar artery occlusion is associated click here with a high risk of stroke, mortality, and poor outcome in survivors. Timely vessel revascularization is critical to improve the clinical outcome in this condition. A subset of patients survives acute occlusion with mild or no disability and some of these individuals develop recurrent ischemic events despite optimal medical therapy. The strategy for management of these patients is unknown. We described 3 patients with chronic intracranial vertebrobasilar occlusions who presented with recurrent ischemic symptoms and progressive disability. All 3 patients were treated successfully with angioplasty and stenting. One patient experienced headache postprocedure and was found to have subarachnoid hemorrhage, which was self-limiting without need for intervention or result in permanent neurological sequela.

The majority of patients with chronic pancreatitis will eventually develop pancreatic exocrine insufficiency depending on the etiology of the disease. Half of the patients with chronic alcoholic pancreatitis will suffer from pancreatic exocrine insufficiency after 12 years from the onset of the disease.1 Apart from abdominal cramps and the typical characteristics of fatty stools associated learn more with steatorrhea (loose, greasy, foul-smelling voluminous stools that are difficult to flush), which are not always evident because patients tend to limit fat ingestion, the main clinical manifestation of pancreatic exocrine insufficiency is

malnutrition. In fact, maldigestion is the main cause of weight loss in patients with pancreatic exocrine insufficiency. These patients present with low circulating levels of micronutrients,

fat soluble vitamins and lipoproteins, which have been related to a high morbidity and mortality secondary to an increased risk of malnutrition-related complications and cardiovascular events.2 In fact, chronic pancreatitis is associated with a 4- to 5-fold increased risk of death compared to the general population matched by age and gender.3,4 Functional evaluation of the exocrine pancreas may be important to support the diagnosis of chronic pancreatitis in cases of inconclusive morphological findings on imaging methods. However, the most relevant role of the functional evaluation of the pancreas is the detection of primary

or secondary pancreatic insufficiency in patients with known pancreatic disease CB-839 cost find more or after gastrointestinal surgery, to aid in the indication of enzyme substitution therapy and to monitor the efficacy of this therapy. Quantification of the coefficient of fat absorption (CFA) after fecal fat determination by the classical Van de Kamer test is the gold standard for the diagnosis of fat maldigestion. Despite that, this test has several important disadvantages limiting its clinical applicability. Patients must keep on a standard diet containing around 100 g of fat daily for 5 consecutive days and collect the whole amount of feces produced over the last 3 days. This is not easy to comply for many patients. A three-day collection is needed to allow a sufficiently long period to reduce errors and variability. Not only patient compliance is a limitation for the fecal fat quantification but mainly difficulty in handling of stool samples in the lab. Stool samples collected over 3 days must be first homogenized and then processed according to a manual method that renders this test unpleasant and cumbersome. A methodology based on near infrared reflectance analysis (NIRA) has greatly simplified the quantification of fat in stool and thus helps enable the wide application of this test in clinical routine.5 Nevertheless, difficulties associated with patient compliance remain to be addressed.

We have identified TSP-1 as a novel immediate early gene derived from ECs, showing that the expression level of TSP-1 was immediately PARP cancer up-regulated and returned to basal levels by 24 hours in response to PH hepatectomy. Our findings and the previous report28 suggest that ECs may play two distinct roles in hepatocyte proliferation after PH hepatectomy: One is an antiproliferative role by activating the TSP-1/TGF-β1 axis within 24 hours, and the other is a proproliferative role by activating VEGFR-2 after 24 hours. This finding is consistent with the evidence that TSP-1 inhibits the activation of VEGFR-2

through its receptor, CD47, in ECs,23 and suggests that the reduction of TSP-1 expression may be required for the functional shift in ECs from an anti- to a proproliferative role in hepatocytes. Microvascular rearrangement is important for tissue remodeling, and the antiangiogenic action is one of the well-recognized functions of TSP-1.29 Selleck Olaparib However, the expression of CD31 mRNA for monitoring angiogenesis did not show any significant difference between WT and TSP-1-null mice at 24, 48, and 72 hours after PH hepatectomy (Hayashi H, and Sakai T;

unpublished data), suggesting that TSP-1 does not affect vascularization during liver regeneration after PH hepatectomy. TGF-β1 is known to be a potent inhibitor of mitogen-stimulated DNA synthesis in cultured hepatocytes.3 p21 is important for inhibiting hepatocyte proliferation in vivo, especially at the G1/S transition of the cell cycle,20 and the expression of p21 is up-regulated by TGF-β1.30 There is evidence that TGF-β1 mRNA induction occurs within 4 hours and remains elevated until 72 hours after PH hepatectomy.5, 6 In contrast, we found the only limited activation of TGF-β signaling in an earlier phase (within 24 hours), with a peak at ∼12 hours. It is known that TGF-β is secreted as latent forms and

selleck chemicals llc they are converted into active TGF-β in response to injury. There are several mechanisms for activation, such as by proteases, integrins (e.g., αvβ6 and αvβ8), and TSP-1, all of which are likely to be tissue specific.31 Whereas the complete lack of TGF-β-mediated signal in hepatocyte-specific TGF-β type II receptor knockout mice accelerates hepatocyte proliferation in the later phase (∼36-48 hours) after hepatectomy,7 the role of TGF-β signaling in the earlier phase (within 24 hours) remains to be elucidated. Our present findings provide compelling evidence that locally activated TGF-β1 mediated by TSP-1 as an immediate early gene is critical in the early phase (within 24 hours) post PH posthepatectomy to initiate the inhibitory effect on hepatocyte proliferation, and this TGF-β signaling has a functional link to the G1/S-phase transition by modulating p21 protein expression. A major downstream target of TGF-β1, PAI-1,21 is a negative regulator of liver regeneration, and PAI-1-null mice show acceleration of liver regeneration after Fas-mediated massive hepatocyte death.