99mTc-GSA scintigraphy with SPECT for assessment of hepatic function and functional volume during liver regeneration in a rat model of partial hepatectomy.

UNLABELLED: Small-animal models are crucial to gain insights in the complex recovery mechanisms of liver function during liver regeneration. (99m)Tc-Mebrofenin hepatobiliary scintigraphy (HBS) has been introduced for noninvasive assessment of liver function in the clinical setting as well as in experimental research. However, HBS is restricted to planar modalities in small animals because hepatic kinetics are generally too fast for SPECT acquisition. (99m)Tc-DTPA-galactosyl serum albumin (where DTPA is diethylenetriaminepentaacetic acid) ((99m)Tc-GSA) scintigraphy is an alternative, receptor-mediated, noninvasive liver function test. After hepatic uptake, (99m)Tc-GSA remains trapped in the liver, which readily enables additional SPECT for the assessment of both liver function and liver functional volume within one test. In this study we evaluated the use of (99m)Tc-GSA scintigraphy combined with SPECT for the assessment of liver function and liver functional volume in normal and regenerating rat livers. METHODS: The reproducibility of (99m)Tc-GSA scintigraphy and SPECT was investigated by repeated measurements within the same rat. For the assessment in a regenerating liver, (99m)Tc-GSA scintigraphy with SPECT was performed on 1, 3, 5, and 7 d (n = 6 rats per time point) after 70% partial hepatectomy (PH). RESULTS: The correlation between repeated (99m)Tc-GSA measurements was strong (r = 0.75, P = 0.019). In normal rat livers, there was a strong, significant correlation between liver functional volume and conventional liver volume (r = 0.93; < 0.0001). The correlation between (99m)Tc-GSA uptake and liver volume was moderate (r = 0.62, P = 0.043). During the regeneration process, (99m)Tc-GSA uptake was significantly lower compared with both liver volume (P < 0.001) and liver functional volume (P < 0.001), when expressed as a percentage of baseline levels. There was a strong correlation between liver functional volume and conventional liver volume in the regenerating liver (r = 0.92, P < 0.0001). CONCLUSION: (99m)Tc-GSA scintigraphy combined with SPECT is a feasible, noninvasive method to assess hepatic functional volume in normal rat liver as well as in the regenerating rat liver. However, the hepatic (99m)Tc-GSA uptake as a liver function test seems to underestimate hepatic regeneration in comparison to liver volume.

C-reactive protein and natural IgM antibodies are activators of complement in a rat model of intestinal ischemia and reperfusion.

BACKGROUND: The role of C-reactive protein (CRP), natural immunoglobulin M (IgM), and natural IgM against phosphorylcholine (anti-Pc IgM) was investigated in relation with complement activation in a rat model of intestinal ischemia and reperfusion (II/R). The effect of C1-esterase inhibitor (C1-Inh) on this complement activation along with other inflammatory mediators was also studied. METHODS: Rats were subjected to 1 h of superior mesenteric artery occlusion and 3 h of reperfusion. Intravenous administration of vehicle (human albumin) or C1-Inh (200 U/kg) was performed before (n = 8) or after ischemia (n = 8). II/R increased levels of C4b/c, CRP, IgM, anti-Pc IgM, and myeloperoxidase activity in the intestinal homogenates and induced vascular leakage. RESULTS: A good correlation was observed in the intestinal homogenates between C4b/c and CRP levels. Clear depositions of C3, CRP, and IgM in intestinal tissue were demonstrated after II/R, and a strong correlation of both CRP and IgM with complement was observed. C1-Inh administered before ischemia reduced the complement activation response after II/R, as reflected by decreased levels of C4b/c in conjunction with reduced anti-Pc IgM in the intestinal homogenates. C1-Inh also decreased leakage of albumin when administered before ischemia. C1-Inh after ischemia reduced C4b/c levels and myeloperoxidase activity in the homogenates. CONCLUSIONS: CRP and IgM depositions correlated well with local complement activation, which suggests a role of these molecules in complement activation. Furthermore, C1-Inh inhibited potentially II/R injury either administered before or after ischemia, by attenuating complement activation induced by CRP and/or natural IgM antibodies.

IL-10 attenuates hepatic I/R injury and promotes hepatocyte proliferation.

BACKGROUND: One of the most important determinants of the outcome of hepatic ischemia and reperfusion (I/R) injury is the onset of the inflammatory response. Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine. It inhibits the production of interleukin-6 (IL-6), which however, also is involved in priming hepatocyte proliferation. The aim of this study was to examine the protective effects and the influence on the regenerative response of exogenous as well as endogenous IL-10 in a rat model of hepatic I/R injury. MATERIALS AND METHODS: Seventy percent Liver I/R was induced in male Wistar rats for 60 min followed by 24 h reperfusion. One group underwent a midline laparotomy with recombinant rat (rr)IL-10 administration (SHAM + IL-10). The other groups underwent 60 min ischemia with administration of saline (I/R + saline), rrIL-10 [at two different time-points, i.e., I/R + IL-10pre(ischemia) and I/R + IL-10end(ischemia)] or anti-rat IL-10 antibody (I/R + antiIL-10). RESULTS: Parenchymal damage, as assessed by plasma alanine aminotransferase and aspartate aminotransferase, was significantly reduced by rrIL-10 and by endogenous IL-10 (P < 0.05). Also, rrIL-10 significantly reduced IL-6 production and the accumulation of neutrophils in liver and lung tissue, as measured by myeloperoxidase activity. Necrosis and apoptosis were significantly reduced and hepatocyte proliferation was stimulated by rrIL-10. CONCLUSIONS: RrIL-10 and, to a lesser extent, endogenous IL-10, attenuate damage and inflammation, while rrIL-10 also promotes proliferation after hepatic I/R injury in rats. Therefore, rrIL-10 has potential use to prevent I/R injury and to promote liver regeneration after partial liver resection with temporary inflow occlusion.

Risk assessment of posthepatectomy liver failure using hepatobiliary scintigraphy and CT volumetry.

UNLABELLED: A major part of morbidity and mortality after liver resections is caused by inadequate remnant liver function leading to liver failure. It is therefore important to develop accurate diagnostic tools that can predict the risk of liver resection-related morbidity and mortality. In this study, preoperative hepatobiliary scintigraphy of the future remnant liver and CT volumetric measurement of the future remnant liver were performed on patients who were to undergo liver resection. The accuracy of risk assessment for postoperative morbidity, liver failure, and mortality was evaluated. METHODS: Forty-six patients who were scheduled for liver resection because of hepatobiliary tumors, including 17 patients with parenchymal disease (37%) and 13 patients with hilar cholangiocarcinoma (28%), were assessed preoperatively. Hepatobiliary scintigraphy was performed by drawing regions of interest around the future remnant to calculate (99m)Tc-mebrofenin uptake in it. CT volumetry was used to measure the volume of the total liver, the tumors, and the future remnant. Receiver-operating-characteristic analysis was performed to assess cutoff values for risk assessment of morbidity, liver failure, and mortality. Furthermore, univariate and multivariate analyses were performed to determine factors related to morbidity and mortality. RESULTS: Morbidity and mortality rates were 61% and 11%, respectively. Liver failure occurred in 6 patients (13%). Significantly decreased uptake in the future remnant was found in patients in whom liver failure and liver failure-related mortality developed (P=0.003 and 0.02, respectively). The volume of the future remnant was not significantly associated with any of the outcome parameters. In receiver-operating-characteristic analysis, uptake cutoff values for liver failure and liver failure-related mortality were 2.5%/min/body surface area and 2.2%/min/body surface area, respectively. In multivariate analysis, uptake was the only significant factor associated with liver failure. CONCLUSION: Preoperative measurement of (99m)Tc-mebrofenin uptake in the future remnant liver on hepatobiliary scintigraphy proved more valuable than measurement of the volume of the future remnant on CT in assessing the risk of liver failure and liver failure-related mortality after partial liver resection.

Preservation of steatotic livers: a comparison between cold storage and machine perfusion preservation.

Liver grafts are frequently discarded due to steatosis. Steatotic livers can be classified as suboptimal and deteriorate rapidly during hypothermic static preservation, often resulting in graft nonfunction. Hypothermic machine perfusion (MP) has been introduced for preservation of donor livers instead of cold storage (CS), resulting in superior preservation outcomes. The aim of this study was to compare CS and MP for preservation of the steatotic donor rat liver. Liver steatosis was induced in male Wistar rats by a choline-methionine-deficient diet. After 24 hours hypothermic CS using the University of Wisconsin solution (UW) or MP using UW-Gluconate (UW-G), liver damage (liver enzymes, perfusate flow, and hyaluronic acid clearance) and liver function (bile production, ammonia clearance, urea production, oxygen consumption, adenosine triphosphate [ATP] levels) were assessed in an isolated perfused rat liver model. Furthermore, liver biopsies were visualized by hematoxylin and eosin staining. Animals developed 30 to 60% steatosis. Livers preserved by CS sustained significantly more damage as compared to MP. Bile production, ammonia clearance, urea production, oxygen consumption, and ATP levels were significantly higher after MP as compared to CS. These results were confirmed by histology. In conclusion, MP improves preservation results of the steatotic rat liver, as compared to CS.

Severe steatosis increases hepatocellular injury and impairs liver regeneration in a rat model of partial hepatectomy.

OBJECTIVE: The aim of this study was to assess the influence of severe steatosis with inflammation on hepatocellular recovery after 70% hepatectomy in a rat model of diet-induced steatosis. BACKGROUND: Patients with steatosis have an increased risk of inflammatory complications after liver resection. This might be attributable to Kupffer cell-mediated inflammation in steatotic livers causing progressive injury. METHODS: Male Wistar rats were fed a standard methionine- and choline-deficient diet for 1 or 5 weeks. A 70% partial hepatectomy (PH) was performed, after which rats were killed at 24, 48, or 72 hours. The extent of steatosis and inflammation was determined by assessment of hepatic triglycerides, cytokine content, and histopathology. Outcome parameters were: liver regeneration (MIB-5 proliferation rate, mitotic index, and regenerating liver mass), hepatocellular injury (plasma aminotransferases, lipid peroxidation, histopathology, and apoptosis), Kupffer cell-mediated proinflammatory response (TNF-alpha, IL-1beta, IL-6, IL-10 in plasma and liver) and antioxidant content (total glutathione). RESULTS: Methionine- and choline-deficient diet induced uncomplicated steatosis after 1 week (<30% hepatocytes affected without inflammation) and severe steatosis after 5 weeks (>60% hepatocytes affected, including prominent inflammation) as confirmed by histopathology. After PH, liver regeneration was impaired at all time points in the severe steatosis group as compared with the mild and control groups (P < 0.05). Hepatocellular injury was significantly increased in the severe steatosis group at all time points (P < 0.05). Kupffer cell-mediated inflammatory responses were aggravated in the severe steatosis group along with decreased antioxidant content (P < 0.05). Necrosis was the main type of cell death in severe steatotic livers compared with mainly apoptotic cell death in mild steatotic and normal livers. CONCLUSION: Steatosis with prominent inflammation impaired liver regeneration probably because of increased hepatocellular lipid peroxidation and damage in concert with Kupffer cell-mediated proinflammatory responses. These results suggest an increased risk of performing extensive liver resection in the presence of severe steatosis.

Peritoneal lavage with activated protein C alters compartmentalized coagulation and fibrinolysis and improves survival in polymicrobial peritonitis.

OBJECTIVE: During peritonitis, intra-abdominal fibrin entraps bacteria and hampers their elimination. Systemic administration of anticoagulant activated protein C improves survival in patients with severe sepsis, but its precise mode of action is unclear. This study in polymicrobial peritonitis assessed the effects of local activated protein C administration in peritoneal lavage fluid on coagulation, fibrinolysis, and survival. DESIGN: Prospective, randomized study. SETTING: University-based research laboratory. SUBJECTS: C57BL/6 mice. INTERVENTIONS: Twenty-four hours after induction of peritonitis by cecal ligation and puncture, mice underwent peritoneal lavage with activated protein C (1.0 microg/mL) or saline. Peritoneal lavage fluid, blood, and lungs were sampled after 24, 48, or 72 hrs (n = 8/group/time point). For survival analysis, maximum observation was 96 hrs (n = 22/group). Clotting time, tissue factor expression, thrombin-antithrombin complexes, fibrin degradation products (D-dimers), plasminogen activator, and plasminogen activator inhibitor were used to assess coagulation and fibrinolysis responses. MEASUREMENTS AND MAIN RESULTS: Activated protein C lavage reduced abdominal bacterial load, abdominal and pulmonary clotting times, D-dimers (p < .05 vs. saline), pulmonary tissue factor expression, and fibrin depositions, without clear effects on systemic thrombin generation. Activated protein C lavage decreased plasma and abdominal tissue plasminogen activator levels with increased inhibitor plasminogen activator inhibitor-1 levels (p < .05) but had reverse effects on pulmonary fibrinolysis. Survival improved from 55% (saline) to 80% after intra-abdominal activated protein C administration (p = .03). CONCLUSIONS: Peritoneal lavage with activated protein C may rebalance coagulation and fibrinolysis within compartments and improve survival in polymicrobial peritonitis.

Liver protection by hypothermic perfusion at different temperatures during total vascular exclusion.

INTRODUCTION: In situ hypothermic perfusion (HP) can be applied to attenuate ischemia and reperfusion (I/R) injury during liver resection under total vascular exclusion (TVE). This study examines the protective effect of cooling by HP at 20 and 28 degrees C as compared with no HP during TVE in a porcine liver I/R model. METHODS: Twenty-one pigs underwent 60 min TVE of the liver followed by 24 h reperfusion. HP was performed via the portal vein using ringerlactate solution of 4 degrees C. Pigs were assigned to three groups: TVE without HP (no-HP, n=9), TVE with HP at 28 degrees C (HP-28, n=6) and TVE with HP at 20 degrees C (HP-20, n=6). RESULTS: Perfusion volumes during TVE were 5.1+/-0.5 and 17.3+/-1.7 l in HP-28 and HP-20, respectively (P<0.05). Aspartate aminotransferase (AST) after 24 h reperfusion was 1172+/-440 U/l in no-HP as compared with 223+/-69 and 180+/-22 U/l in HP-28 and HP-20, respectively (P<0.05). No differences in liver function or histopathology were found between the HP-28 and HP-20 groups. CONCLUSIONS: HP at 20 degrees C is equally effective in preserving liver function and preventing hepatocellular injury under TVE as compared with HP at 28 degrees C. HP at 28 degrees C is advised, because of the lesser perfusion volume necessary for cooling of the liver.

Imaging of liver function with dedicated animal dynamic pinhole scintigraphy in rats.

BACKGROUND: Non-invasive evaluation of liver function in small animal models remains a challenge. Hepatobiliary scintigraphy (HBS) enables the assessment of total and regional liver function for both uptake and excretion in larger species. AIM: To validate quantitative liver function assessment with dedicated pinhole HBS in rats. To illustrate an application of this technique, liver function was assessed in two surgical models of liver regeneration. METHODS: HBS was performed in 12 rats with 99mTc-mebrofenin on a dedicated animal pinhole gamma camera. The hepatic uptake rate was calculated twice by different observers to establish a normal range and the reproducibility of processing. The degree of hepatocellular injury and synthesis function were assessed by serum liver tests. Liver function was compared with liver weight. Subsequently, three groups of three rats were scanned on three separate days to assess the reproducibility of HBS. Finally, to illustrate an application of this technique, liver function was assessed in two surgical models of liver regeneration. RESULTS: HBS in rats was feasible without mortality. The mean liver uptake rate was 77.29+/-1.29% . min(-1). Calculation of the liver uptake (% . min(-1)) was highly reproducible (r=0.95, P<0.001). There was a good correlation between liver weight and function measured by HBS at baseline and after partial resection (r=0.94, P<0.001). CONCLUSION: HBS offers a unique combination of functional liver uptake and excretion assessment with the ability to determine the liver function reserve before and after an intervention in rats.

Bovine intestinal alkaline phosphatase attenuates the inflammatory response in secondary peritonitis in mice.

Lipopolysaccharide (LPS) contributes importantly to morbidity and mortality in sepsis. Bovine intestinal alkaline phosphatase (BIAP) was demonstrated to detoxify LPS through dephosphorylation. LPS injection combined with BIAP reduced inflammation and improved survival in various experimental settings. In this study, single-dose intravenous administration of BIAP (0.15 IU/g) was applied in a murine cecal ligation and puncture (CLP) model of polymicrobial sepsis. Saline was given as control (S group). Treatment with BIAP prior to CLP (prophylaxis; BIAP-P group) or shortly after (early treatment; BIAP-ET group) reduced cytokine concentrations in plasma and peritoneal lavage fluid (PLF). Tumor necrosis factor-alpha peak levels decreased from 170 pg/ml (S) to 57.5 (BIAP-P) and 82.5 (BIAP-ET) in plasma and in PLF from 57.5 pg/ml (S) to 35.3 (BIAP-P) and 16.8 (BIAP-ET) (all, P < 0.05). Peak interleukin-6 levels in plasma decreased from 19.3 ng/ml (S) to 3.4 (BIAP-P) and 11.5 (BIAP-ET) and in PLF from 32.6 ng/ml (S) to 13.4 (BIAP-P) and 10.9 (BIAP-ET) (all, P < 0.05). Macrophage chemoattractant protein 1 peak levels in plasma decreased from 2.0 ng/ml (S) to 1.0 (BIAP-P) and 0.7 (BIAP-ET) and in PLF from 6.4 (S) to 2.3 (BIAP-P) and 1.3 ng/ml (BIAP-ET) (all, P < 0.05). BIAP-treated groups showed decreased transaminase activity in plasma and decreased myeloperoxidase activity in the lung, indicating reduced associated hepatocellular and pulmonary damage. Survival was not significantly altered by BIAP in this single-dose regimen. In polymicrobial secondary peritonitis, both prophylactic and early BIAP treatment attenuates the inflammatory response both locally and systemically and reduces associated liver and lung damage.

Improved rat liver preservation by hypothermic continuous machine perfusion using polysol, a new, enriched preservation solution.

For experimental machine perfusion (MP) of the liver, the modified University of Wisconsin solution (UW-G) is most often used. In our search for an enriched MP preservation solution, Polysol was developed. Polysol is enriched with various amino acids, vitamins, and other nutrients for the liver metabolism. The aim of this study was to compare Polysol with UW-G for MP preservation of the liver. Rat livers were preserved during 24 hours with hypothermic MP using UW-G (n = 5) or Polysol (n = 5). Hepatocellular damage (aspartate aminotransferase [AST], alanine aminotransferase [ALT], lactate dehydrogenase [LDH], alpha-glutathione-S-transferase [alpha-GST]) and bile production were measured during 60 minutes of reperfusion (37 degrees C) with Krebs-Henseleit buffer. Control livers were reperfused after 24 hours of cold storage in UW (n = 5). MP using UW-G or Polysol showed less liver damage when compared with controls. Livers machine perfused with Polysol showed less enzyme release when compared to UW-G. Bile production was higher after MP using either UW-G or Polysol compared with controls. In conclusion, machine perfusion using Polysol results in better quality liver preservation than cold storage with UW and machine perfusion using UW-G.

Kidney growth in normal and diabetic mice is not affected by human insulin-like growth factor binding protein-1 administration.

Insulin-like growth factor I (IGF-I) accumulates in the kidney following the onset of diabetes, initiating diabetic renal hypertrophy. Increased renal IGF-I protein content, which is not reflected in messenger RNA (mRNA) levels, suggests that renal IGF-I accumulation is due to sequestration of circulating IGF-I rather than to local synthesis. It has been suggested that IGF-I is trapped in the kidney by IGF binding protein 1 (IGFBP-1). We administered purified human IGFBP-1 (hIGFBP-1) to nondiabetic and diabetic mice as three daily sc injections for 14 days, starting 6 days after induction of streptozotocin diabetes when the animals were overtly diabetic. Markers of early diabetic renal changes (i.e., increased kidney weight, glomerular volume, and albuminuria) coincided with accumulation of renal cortical IGF-I despite decreased mRNA levels in 20-day diabetic mice. Human IGFBP-1 administration had no effect on increased kidney weight or albuminuria in early diabetes, although it abolished renal cortical IGF-I accumulation and glomerular hypertrophy in diabetic mice. Increased IGF-I levels in kidneys of normal mice receiving hIGFBP-1 were not reflected on kidney parameters. IGFBP-1 administration in diabetic mice had only minor effects on diabetic renal changes. Accordingly, these results did not support the hypothesis that IGFBP-1 plays a major role in early renal changes in diabetes.

Preoperative assessment of postoperative remnant liver function using hepatobiliary scintigraphy.

UNLABELLED: Hepatic resection is the therapy of choice for malignant and symptomatic benign hepatobiliary tumors. The concept of remnant liver volume (RLV) has been introduced and can be assessed with CT. However, inhomogeneous liver function distribution and a lack of correlation between morphologic hypertrophy and functional recovery fuelled the enthusiasm for functional imaging. The aim of the present study was to assess liver function reserve (LFR) and remnant liver function (RLF) before and after major liver surgery with hepatobiliary scintigraphy (HBS) and to compare scintigraphic results with volumetric CT data and indocyanine-green (ICG) clearance test results. Furthermore, HBS was used to assess functional recovery of liver function, and results were compared with volumetric data. METHODS: Fifteen patients with a partial liver resection were included. HBS was performed before, 1 d after, and 3 mo after surgery. ICG clearance and CT were performed before and 3 mo after surgery. Liver function determined with HBS was compared with ICG and volumetric data. RESULTS: Liver function determination using HBS was highly reproducible. A strong positive association (r = 0.84) was found between LFR determined with HBS and ICG clearance. Little or no association (r = 0.27) was found between CT volumetric analysis and corresponding ICG clearance. A strong positive association (r = 0.95) was found between the RLF determined preoperatively on HBS and the actually measured value postoperatively. A weak positive association (r = 0.61) was found between functional liver regeneration and liver volume regeneration in the 3 mo after partial liver resection. CONCLUSION: HBS offers a unique combination of functional liver uptake and excretion with the ability to assess the preoperative LFR and to estimate the RLF preoperatively. Determination of the RLF instead of the RLV might clarify some of the discrepancies observed in the literature between RLV and clinical outcome in patients with an inhomogeneous liver function. Finally, liver function regeneration can be monitored using HBS.

Inhibition of coagulation and inflammation by activated protein C or antithrombin reduces intestinal ischemia/reperfusion injury in rats.

OBJECTIVE: To examine whether administration of activated protein C or antithrombin reduces local splanchnic derangement of coagulation and inflammation and attenuates intestinal dysfunction and injury following intestinal ischemia/reperfusion. DESIGN: Randomized prospective animal study. SETTING: University research institute. SUBJECTS: Adult male Wistar rats, weighing 300-325 g (n = 72). INTERVENTIONS: Rats were subjected to superior mesenteric artery occlusion consisting of 20 or 40 mins of ischemia and 3 hrs of reperfusion. A randomized intravenous administration of vehicle (0.9% NaCl), heparin, antithrombin, or activated protein C was performed during ischemia, 15 mins before reperfusion. Coagulation and fibrinolysis variables obtained from portal blood were correlated with mucosal fibrin deposition (determined by anti-rat fibrin antibody staining), intestinal function (glucose/water clearance), and intestinal injury (histologic evaluation by Park/Chiu score). MEASUREMENTS AND MAIN RESULTS: Activated protein C- or antithrombin-treated animals demonstrated less ischemia/reperfusion-induced intestinal dysfunction and histologic changes compared with control animals, whereas intravenous administration of heparin only showed less histologic derangement. Activated protein C- or antithrombin-treated animals showed less thrombin generation, fibrin degradation products, and fibrin deposition compared with control animals, as confirmed by histologic examination, whereas heparin administration showed only a limited reduction of portal fibrin degradation product concentrations. Furthermore, activated protein C or antithrombin administration markedly inhibited the inflammatory response, as reflected by reduced interleukin-6 plasma concentrations to baseline values, whereas heparin had no effect. CONCLUSIONS: Administration of activated protein C or antithrombin inhibited local and systemic derangement of coagulation and inflammation following intestinal ischemia/reperfusion, diminished mucosal fibrin deposition, and attenuated ischemia/reperfusion-induced intestinal injury. These observations suggest that activated protein C or antithrombin reduces ischemia/reperfusion-induced intestinal injury, both through their anticoagulant and anti-inflammatory effects.

Enhancement of endogenous fibrinolysis does not reduce local fibrin deposition, but modulates inflammation upon intestinal ischemia and reperfusion.

This study investigated the contribution of endogenous suppression of fibrinolysis and increased fibrin deposition to intestinal dysfunction and injury in a rat model of intestinal ischemia/reperfusion (I/R), as fibrinolytic inhibition may lead to thrombotic obstructions that compromise microcirculation and promote intestinal injury. Circulatory fibrinolysis was enhanced by intravenous administration of recombinant tissue plasminogen activator (rt-PA) or by inhibition of PAI-I by administration of MA-33H1F7. Coagulation and fibrinolysis parameters obtained from portal blood were correlated to fibrin deposition (determined by anti-rat fibrin antibody staining), intestinal function (glucose/water clearance) and intestinal injury (histological evaluation by Park/Chiu score). Enhanced circulatory fibrinolytic activity, as evidenced by increased portal plasma plasminogen activator activity, elevated fibrin degradation products and decreased levels of PAI-I, did not reduce mucosal fibrin deposition and microthrombosis in postischemic intestinal tissue. Furthermore, rt-PA or anti-PAI-I antibody administration did not attenuate I/R-induced intestinal injury or dysfunction, as demonstrated by intestinal histopathology scores of 4.8+/-0.2 and 4.7+/-0.3 (control I/R group 4.7+/-0.2) and glucose clearances of 47+/-6 and 46+/-9 micro L/min g (control I/R group 30+/-8 micro L/min. g) after 40 minutes of intestinal ischemia and 3 hours of reperfusion, respectively. However, both interventions resulted in decreased levels of interleukin-6, which may indicate fibrin-induced modulation of inflammation. Attempts to enhance the fibrinolytic activity (either by rt-PA or by anti-PAI-I administration), indicated by increased portal plasma levels of released FDP, failed to decrease mucosal fibrin deposition and to attenuate intestinal I/R injury. Based on our observations and previous reports, the contribution of suppressed endogenous fibrinolysis to microcirculatory fibrin deposition and I/R-injury may be of limited importance.

High-protein induced renal enlargement is growth hormone independent.

BACKGROUND: Growth hormone (GH) and insulin-like growth factors (IGFs) have been postulated as pathogenic factors in several forms of renal growth, including that induced by high-protein (HP) diets. Compensatory renal growth (CRG) following renal uninephrectomy is strictly GH dependent, while the exact role of GH as a regulating factor in HP induced renal growth has not been fully clarified. METHODS: To elucidate a possible direct role for GH in HP-induced renal growth, we examined the effect of a newly developed specific GH-receptor (GHR) antagonist (B2036-PEG) on renal growth and renal GH/IGF-system expression in HP-fed mice. RESULTS: Mice fed a HP diet (45% protein) for one week demonstrated renal hypertrophy and increased renal IGF-I. GH receptor antagonist (GHRA) treatment neither modified renal IGF-I nor abolished the renal hypertrophy. In contrast, however, GHRA administration did modify renal mRNA expression of many members of the GH and IGF systems. CONCLUSIONS: The major new finding is that HP-induced renal growth in adult mice is GH independent.