Effect of oral D-tagatose on liver volume and hepatic glycogen accumulation in healthy male volunteers

Standard toxicity tests with high levels of D-tagatose showed a reversible enlargement of the liver in Sprague-Dawley rats without increase of liver enzymes. The present study tests the hypotheses that partial substitution of dietary sucrose by D-tagatose for 28 days increases the volume of human liver and the concentration of liver glycogen. Twelve healthy, male volunteers were studied in a double-blind crossover study with ingestion of D-tagatose (3x15 g daily) and placebo (sucrose, 3x15 g daily) for periods of 28 days each. Liver volume and glycogen concentration have been determined by magnetic resonance (MR) imaging and spectroscopy, which were accompanied by routine medical examinations. MR examinations before and after the treatments revealed no effects (P>0.05) of treatment, period, or subject for changes in liver volume or glycogen concentration. A steady increase of liver volumes, independent of the D-tagatose or placebo intake, has been observed over the study in parallel with a slight increase in body weight. The treatment with D-tagatose was not associated with clinically relevant changes of the examined clinico-chemical and hematological parameters, including liver enzymes and uric acid.

Norepinephrine to increase blood pressure in endotoxaemic pigs is associated with improved hepatic mitochondrial respiration

ABSTRACT: INTRODUCTION: Low blood pressure, inadequate tissue oxygen delivery and mitochondrial dysfunction have all been implicated in the development of sepsis-induced organ failure. This study evaluated the effect on liver mitochondrial function of using norepinephrine to increase blood pressure in experimental sepsis. METHODS: Thirteen anaesthetized pigs received endotoxin (Escherichia coli lipopolysaccharide B0111:B4; 0.4 mug/kg per hour) and were subsequently randomly assigned to norepinephrine treatment or placebo for 10 hours. Norepinephrine dose was adjusted at 2-hour intervals to achieve 15 mmHg increases in mean arterial blood pressure up to 95 mmHg. Systemic (thermodilution) and hepatosplanchnic (ultrasound Doppler) blood flow were measured at each step. At the end of the experiment, hepatic mitochondrial oxygen consumption (high-resolution respirometry) and citrate synthase activity (spectrophotometry) were assessed. RESULTS: Mean arterial pressure (mmHg) increased only in norepinephrine-treated animals (from 73 [median; range 69 to 81] to 63 [60 to 68] in controls [P = 0.09] and from 83 [69 to 93] to 96 [86 to 108] in norepinephrine-treated animals [P = 0.019]). Cardiac index and systemic oxygen delivery (DO2) increased in both groups, but significantly more in the norepinephrine group (P < 0.03 for both). Cardiac index (ml/min per.kg) increased from 99 (range: 72 to 112) to 117 (110 to 232) in controls (P = 0.002), and from 107 (84 to 132) to 161 (147 to 340) in norepinephrine-treated animals (P = 0.001). DO2 (ml/min per.kg) increased from 13 (range: 11 to 15) to 16 (15 to 24) in controls (P = 0.028), and from 16 (12 to 19) to 29 (25 to 52) in norepinephrine-treated animals (P = 0.018). Systemic oxygen consumption (systemic VO2) increased in both groups (P < 0.05), whereas hepatosplanchnic flows, DO2 and VO2 remained stable. The hepatic lactate extraction ratio decreased in both groups (P = 0.05). Liver mitochondria complex I-dependent and II-dependent respiratory control ratios were increased in the norepinephrine group (complex I: 3.5 [range: 2.1 to 5.7] in controls versus 5.8 [4.8 to 6.4] in norepinephrine-treated animals [P = 0.015]; complex II: 3.1 [2.3 to 3.8] in controls versus 3.7 [3.3 to 4.6] in norepinephrine-treated animals [P = 0.09]). No differences were observed in citrate synthase activity. CONCLUSION: Norepinephrine treatment during endotoxaemia does not increase hepatosplanchnic flow, oxygen delivery or consumption, and does not improve the hepatic lactate extraction ratio. However, norepinephrine increases the liver mitochondria complex I-dependent and II-dependent respiratory control ratios. This effect was probably mediated by a direct effect of norepinephrine on liver cells.

Distribution pattern of infrageniculate arterial obstructions in patients with diabetes mellitus and renal insufficiency - implications for revascularization

BACKGROUND: Diabetes mellitus (DM) and renal insufficiency (RI) were shown to be associated with an obstructive lesion pattern favouring distal lower limb arterial segments in patients with peripheral arterial disease (PAD). We hypothesized that presence of DM is associated with pronounced involvement of the tibioperoneal arteries, whereas RI predominantly affects the pedal arch. PATIENTS AND METHODS: A consecutive series of PAD patients (mean age 75 +/- 10 years, 40 women) with RI alone (n = 15), RI and DM (n = 25), DM alone (n = 25) and without RI or DM (n = 25) underwent diagnostic angiography. We analyzed the obstructive burden of different segments of the infrageniculate arterial tree using the Bollinger score as well as accessibility of pedal arteries for bypass surgery. RESULTS: In patients with DM and in patients with RI the mean total obstructive burden was higher in pedal as compared to tibioperoneal arteries (9.79 +/- 4.60 vs. 6.99 +/- 3.45, p = 0.03;10.50 +/- 5.53 vs. 6.88 +/- 4.12, p = 0.05, respectively). However, rates of patency of at least one pedal artery were significantly lower in patients with RI and RI/DM as compared to controls (47% and 48% vs. 80%, respectively; p = 0.007), whereas patency was comparable between patients with diabetes alone and controls (72% vs. 80%, ns). Rates of viability of pedal arteries as an attachment site for distal bypass was 80%, 68%, 47% and 44% in controls, patients with DM alone, RI alone and RI/DM, respectively (p = 0.0042). CONCLUSIONS: In contrast to previous anecdotal observations, both DM and RI are associated with a high atherosclerotic burden of the pedal arch in the present angiographic series. The presence of RI, however, is associated with a lower patency of the pedal arch as compared to the presence of DM alone, and more than fifty percent patients are unsuitable for distal bypass grafting.

Primary perivascular epithelioid cell tumor of the liver not related to hepatic ligaments: hepatic PEComa as an emerging entity

Primary perivascular epithelioid cell tumor (PEComa) of the liver is a very rare example of an emerging family of hepatic PEC tumors. Only few cases have been described so far. We report the case of a large but benign hepatic PEComa in a 53-year-old man without signs of tuberous sclerosis. In contrast to recently described PEC-derived liver tumors in children and young adults, this neoplasm was not related to the hepatic ligaments but had developed deeply within the liver substance. The neoplastic cells displayed the complete phenotype typical for PEComas, i.e. reactivity for several melanoma markers and for smooth muscle actin. The unique relationship of myoid tumor cells to the adventitia of blood vessels prompted us, in comparison with published findings obtained with angiomyolipomas, to comment on the possible origin of the still enigmatic perivascular epithelioid cells.

Treatment of intestinal and hepatic mucormycosis in an immunocompromized child

During ALL chemotherapy, a 4-year-old patient presented with febrile neutropenia and abdominal pain. Ultrasound examinations were repeatedly normal. Computerized tomography on day 7 demonstrated appendicitis and multiple hepatic foci identified as mucormycosis (Absidia corymbifera). Successful outcome was achieved by aggressive re-surgery, long-term antifungal therapy with serum level-monitored posaconazole, and recovery of neutrophil counts. Considering the interference of posaconazole with CYP3A4, vincristine was administered during 72 hr posaconazole windows. Pediatric intestinal mucormycosis, still associated with a >70% case-fatality rate, calls for early imaging and surgery to establish the diagnosis, reduce the fungal mass, and provide a rationale for using posaconazole.

P450 oxidoreductase deficiency - a new form of congenital adrenal hyperplasia

Patients with adrenal insufficiency, genital anomalies and bony malformations resembling the Antley- Bixler syndrome (a craniosynostosis syndrome), are likely to have P450 oxidoreductase (POR) deficiency. Since our first report in 2004, about 26 recessive POR mutations have been identified in 50 patients. POR is the obligate electron donor to all microsomal (type II) P450 enzymes, including the steroidogenic enzymes CYP17A1, CYP21A2 and CYP19A1. POR deficiency may cause disordered sexual development manifested as genital undervirilization in 46,XY newborns as well as overvirilization in those who are 46,XX. This may be explained by impaired aromatization of fetal androgens which may also lead to maternal virilization and low urinary estriol levels during pregnancy. A role for the alternate 'backdoor' pathway of androgen biosynthesis, leading to dihydrotestosterone production bypassing androstenedione and testosterone, has been suggested in POR deficiency but remains unclear. POR variants may play an important role in drug metabolism, as most drugs are metabolized by hepatic microsomal P450 enzymes. However, functional assays studying the effects of specific POR mutations on steroidogenesis showed that several POR variants impaired CYP17A1, CYP21A2 and CYP19A1 activities to different degrees, indicating that each POR variant must be studied separately for each potential target P450 enzyme. Thus, the impact of POR mutations on drug metabolism by hepatic P450s requires further investigation.

Shell brace for stage II posterior tibial tendon insufficiency

BACKGROUND: The nonoperative treatment of posterior tibial tendon insufficiency (PTTI) can lead to unsatisfactory functional results. Short-term results are available but the impact on the evolution of the deformity is not known. To address these problems, a new brace for the flexible Stage II deformity was developed, and midterm followup was obtained. MATERIALS AND METHOD: In a prospective case series, eighteen patients (mean age 64.2 years; range, 31 to 82; four male, 14 female) with flexible Stage II PTTI were fitted with the new custom-molded foot orthosis. At latest followup of a mean of 61.4 (range, 20 to 87) months, functional results were assessed with the AOFAS ankle hindfoot score and clinical or radiographic progression was recorded. RESULTS: The score improved significantly from a mean of 56 points (range, 20 to 64) to a mean of 82 points (range, 64 to 100, p < 0.001). Three patients (3/18, 16%) had a clinical progression to a fixed deformity (Stage III) and a radiographic increase of their deformity. All the other patients were satisfied with the brace's comfort and noted an improvement in their mobility. Complications were seen in three patients (3/18, 16%), and consisted of the development of calluses. CONCLUSION: The "shell brace" is a valuable option for nonoperative treatment of the flexible Stage II PTTI. Hindfoot flexibility was conserved throughout the observation period in all but three patients. Functional outcome and patient acceptance was above average. Problems were few, and closely associated with a progression to a fixed, Stage III deformity.

The role of purinergic signaling in the liver and in transplantation: effects of extracellular nucleotides on hepatic graft vascular injury, rejection and metabolism

Extracellular nucleotides (e.g. ATP, UTP, ADP) are released by activated endothelium, leukocytes and platelets within the injured vasculature and bind specific cell-surface type-2 purinergic (P2) receptors. This process drives vascular inflammation and thrombosis within grafted organs. Importantly, there are also vascular ectonucleotidases i.e. ectoenzymes that hydrolyze extracellular nucleotides in the blood to generate nucleosides (viz. adenosine). Endothelial cell NTPDase1/CD39 has been shown to critically modulate levels of circulating nucleotides. This process tends to limit the activation of platelet and leukocyte expressed P2 receptors and also generates adenosine to reverse inflammatory events. This vascular protective CD39 activity is rapidly inhibited by oxidative reactions, such as is observed with liver ischemia reperfusion injury. In this review, we chiefly address the impact of these signaling cascades following liver transplantation. Interestingly, the hepatic vasculature, hepatocytes and all non-parenchymal cell types express several components co-ordinating the purinergic signaling response. With hepatic and vascular dysfunction, we note heightened P2- expression and alterations in ectonucleotidase expression and function that may predispose to progression of disease. In addition to documented impacts upon the vasculature during engraftment, extracellular nucleotides also have direct influences upon liver function and bile flow (both under physiological and pathological states). We have recently shown that alterations in purinergic signaling mediated by altered CD39 expression have major impacts upon hepatic metabolism, repair mechanisms, regeneration and associated immune responses. Future clinical applications in transplantation might involve new therapeutic modalities using soluble recombinant forms of CD39, altering expression of this ectonucleotidase by drugs and/or using small molecules to inhibit deleterious P2-mediated signaling while augmenting beneficial adenosine-mediated effects within the transplanted liver.

Inverse thermodilution with conventional pulmonary artery catheters for the assessment of cerebral, hepatic, renal, and femoral blood flow

Assessment of regional blood flow changes is difficult in the clinical setting. We tested whether conventional pulmonary artery catheters (PACs) can be used to measure regional venous blood flows by inverse thermodilution (ITD). Inverse thermodilution was tested in vitro and in vivo using perivascular ultrasound Doppler (USD) flow probes as a reference. In anesthetized pigs, PACs were inserted in jugular, hepatic, renal, and femoral veins, and their measurements were compared with simultaneous USD flow measurements from carotid, hepatic, renal, and femoral arteries and from portal vein. Fluid boluses were injected through the PAC's distal port, and temperature changes were recorded from the proximally located thermistor. Injectates of 2 and 5 mL at 22 degrees C and 4 degrees C were used. Flows were altered by using a roller pump (in vitro), and infusion of dobutamine and induction of cardiac tamponade, respectively. In vitro: At blood flows between 400 mL . min-1 and 700 mL . min-1 (n = 50), ITD and USD correlated well (r = 0.86, P < 0.0001), with bias and limits of agreement of 3 +/- 101 mL . min-1. In vivo: 514 pairs of measurements had to be excluded from analysis for technical reasons, and 976 were analyzed. Best correlations were r = 0.87 (P < 0.0001) for renal flow and r = 0.46 (P < 0.0001) for hepatic flow. No significant correlation was found for cerebral and femoral flows. Inverse thermodilution using conventional PAC compared moderately well with USD for renal but not for other flows despite good in vitro correlation in various conditions. In addition, this method has significant technical limitations.

The role of muscle flap in preventing bronchus stump insufficiency after pneumonectomy for malignant pleural mesothelioma in high-risk patients

Bronchus stump insufficiency (BSI) is one of the major complications after pneumonectomy; we analyzed all patients who underwent extra pleural pneumonectomy (EPP) for malignant pleural mesothelioma (MPM) in order to detect the role of muscle flap (MF) on preventing early and late stump insufficiency. From January 2000 until December 2005, there were 42 patients admitted with MPM for further intervention at our institution. Thirty patients were suitable for surgery and thus received a multimodal treatment with neo-adjuvant chemotherapy using Cisplatin and Gemcitabin (Gemzar), EPP followed by 54 Gray (Gy) adjuvant radiotherapy. Data were collected from the surgical and oncological records. There were 37 male patients (88%), the median age was 65 years (range 40-83 years). Seven (17%) patients had concomitant diseases. Forty patients (95%) had asbestos exposition. The operative procedures were EPP with muscle flap through an anterolateral thoracotomy. Univariate and multivariate analyses were done. One patient (3%) died on the 2nd postoperative day due to lung embolism. Mild complications were noticed in the early postoperative phase in 8 (25%) patients. There was no early or late stump insufficiency during the 15-month follow-up. Surgical techniques using muscle flap seems to play a major role in the prevention of bronchus stump insufficiency especially after neo-adjuvant chemotherapy.

Microsomal triglyceride transfer protein polymorphism (-493G/T) is associated with hepatic steatosis in patients with chronic hepatitis C

BACKGROUND: Hepatic steatosis may promote progression of chronic hepatitis C (CHC). Microsomal triglyceride transfer protein (MTP) is required for assembly and secretion of ApoB lipoprotein and is implicated in hepatitis C virus (HCV)-related steatosis. The MTP -493G/T polymorphism may promote liver fat accumulation, but its role in HCV-related steatosis is still unclear. METHODS: Two hundred ninety-eight CHC patients were studied and genotyped for MTP -493G/T variants. Hepatic MTP mRNA expression and activity were determined in a subgroup. RESULTS: Patients with grades 2/3 steatosis were older, had a higher body mass index (BMI), more advanced fibrosis and lower MTP mRNA expression and carried more often HCV genotype 3 and the MTP T allele. Age, BMI, HCV-3 and MTP T allele [odds ratio (OR) 2.05; 95% confidence interval (CI) 1.2-3.53; P=0.009] were independent risk factors for steatosis grades 2/3, and in HCV genotype non-3 patients, the MTP T allele was the strongest predictor for steatosis grade 2/3 (OR 2.17; 95% CI 1.22-3.86; P=0.008). Moreover, TT carriers had higher high-density lipoprotein (65.6+/-14.6 vs 56.1+/-16.2 mg/dl; P=0.003) and apolipoprotein AI (1.80+/-0.3 vs 1.60+/-0.3 g/L; P=0.005) levels than G allele carriers. CONCLUSIONS: Chronic hepatitis C patients with the MTP -493T allele reveal higher grades of steatosis, indicating a relevant contribution to liver fat accumulation, particularly in HCV non-3 patients.

Extracts of Lindera obtusiloba induce antifibrotic effects in hepatic stellate cells via suppression of a TGF-beta-mediated profibrotic gene expression pattern

Liver fibrosis is characterized by high expression of the key profibrogenic cytokine transforming growth factor (TGF)-beta and the natural tissue inhibitor of metalloproteinases (TIMP)-1, leading to substantial accumulation of extracellular matrix. Liver fibrosis originates from various chronic liver diseases, such as chronic viral hepatitis that, to date, cannot be treated sufficiently. Thus, novel therapeutics, for example, those derived from Oriental medicine, have gained growing attention. In Korea, extracts prepared from Lindera obtusiloba are used for centuries for treatment of inflammation, improvement of blood circulation and prevention of liver damage, but experimental evidence of their efficacy is lacking. We studied direct antifibrotic effects in activated hepatic stellate cells (HSCs), the main target cell in the fibrotic liver. L. obtusiloba extract (135 mug/ml) reduced the de novo DNA synthesis of activated rat and human HSCs by about 90%, which was not accompanied by cytotoxicity of HSC, primary hepatocytes and HepG2 cells, pointing to induction of cellular quiescence. As determined by quantitative polymerase chain reaction, simultaneous treatment of HSCs with TGF-beta and L. obtusiloba extract resulted in reduction of TIMP-1 expression to baseline level, disruption of the autocrine loop of TGF-beta autoinduction and increased expression of fibrolytic matrix metalloproteinase (MMP)-3. In addition, L. obtusiloba reduced gelatinolytic activity of HSC by interfering with profibrogenic MMP-2 activity. Since L. obtusiloba extract prevented intracellular oxidative stress experimentally induced by tert-butylhydroperoxide, we concluded that the direct antifibrotic effect of L. obtusiloba extract might be mediated by antioxidant activity. Thus, L. obtusiloba, traditionally used in Oriental medicine, may complement treatment of chronic liver disease.

Granulocyte colony-stimulating factor increases hepatic sinusoidal perfusion during liver regeneration in mice

Conditioning with granulocyte colony-stimulating factor (G-CSF) promotes liver regeneration in an experimental small-for-size liver remnant mouse model. The mechanisms involved in this extraordinary G-CSF effect are unknown. The aim of this study was to investigate the influence of G-CSF on the hepatic microvasculature in the regenerating liver. The hepatic sinusoidal microvasculature and microarchitecture of the regenerating liver were evaluated by intravital microscopy in mice. Three experimental groups were compared: (1) unoperated unconditioned animals (control; n = 5), (2) animals conditioned with G-CSF 48 h after 60% partial hepatectomy (G-CSF-PH; n = 6), and (3) animals sham conditioned 48 h after 60% PH (sham-PH; n = 6). PH led to hepatocyte hypertrophy and increased hepatic sinusoidal velocity in the sham-PH and G-CSF-PH groups. Increased sinusoidal diameter and increased hepatic blood flow were observed in the G-CSF-PH group compared to the sham-PH and control groups. Furthermore, there was a strong positive correlation between spleen weight and hepatic sinusoidal diameter in the G-CSF-PH group. The increased hepatic blood flow could explain the observed benefit of G-CSF conditioning during liver regeneration. These results elucidate an unexplored aspect of pharmacological modulation of liver regeneration and motivate further experiments.

Pharmacological inhibition of integrin alphavbeta3 aggravates experimental liver fibrosis and suppresses hepatic angiogenesis

The vitronectin receptor integrin alphavbeta3 promotes angiogenesis by mediating migration and proliferation of endothelial cells, but also drives fibrogenic activation of hepatic stellate cells (HSCs) in vitro. Expecting antifibrotic synergism, we studied the effect of alphavbeta3 inhibition in two in vivo models of liver fibrogenesis. Liver fibrosis was induced in rats by way of bile duct ligation (BDL) for 6 weeks or thioacetamide (TAA) injections for 12 weeks. A specific alphavbeta3 (alphavbeta5) inhibitor (Cilengitide) was given intraperitoneally twice daily at 15 mg/kg during BDL or after TAA administration. Liver collagen was determined as hydroxyproline, and gene expression was quantified by way of quantitative polymerase chain reaction. Liver angiogenesis, macrophage infiltration, and hypoxia were assessed by way of CD31, CD68 and hypoxia-inducible factor-1alpha immunostaining. Cilengitide decreased overall vessel formation. This was significant in portal areas of BDL and septal areas of TAA fibrotic rats and was associated with a significant increase of liver collagen by 31% (BDL) and 27% (TAA), and up-regulation of profibrogenic genes and matrix metalloproteinase-13. Treatment increased gamma glutamyl transpeptidase in both models, while other serum markers remained unchanged. alphavbeta3 inhibition resulted in mild liver hypoxia, as evidenced by up-regulation of hypoxia-inducible genes. Liver infiltration by macrophages/Kupffer cells was not affected, although increases in tumor necrosis factor alpha, interleukin-18, and cyclooxygenase-2 messenger RNA indicated modest macrophage activation. CONCLUSION: Specific inhibition of integrin alphavbeta3 (alphavbeta5) in vivo decreased angiogenesis but worsened biliary (BDL) and septal (TAA) fibrosis, despite its antifibrogenic effect on HSCs in vitro. Angiogenesis inhibitors should be used with caution in patients with hepatic fibrosis.