Hepatic Encephalopathy

This article reviews hepatic encephalopathy (HE) in companion animals. Clinical signs and categories of hepatic disease likely to cause HE are discussed. Ammonia has a key role in pathogenesis and current concepts in body ammonia metabolism are reviewed. Inflammation and manganese accumulation are also thought to be important in pathogenesis. Treatment of HE in acute and chronic cases is discussed along with the rationale for current treatment recommendations. Potential avenues for new treatments and human treatments, which may be transferable to companion animals, are reviewed.

A computer model simulating human glucose absorption and metabolism in health and metabolic disease states

A computer model designed to simulate integrated glucose-dependent changes in splanchnic blood flow with small intestinal glucose absorption, hormonal and incretin circulation and hepatic and systemic metabolism in health and metabolic diseases e.g. non-alcoholic fatty liver disease, (NAFLD), non-alcoholic steatohepatitis, (NASH) and type 2 diabetes mellitus, (T2DM) demonstrates how when glucagon-like peptide-1, (GLP-1) is synchronously released into the splanchnic blood during intestinal glucose absorption, it stimulates superior mesenteric arterial (SMA) blood flow and by increasing passive intestinal glucose absorption, harmonizes absorption with its distribution and metabolism. GLP-1 also synergises insulin-dependent net hepatic glucose uptake (NHGU). When GLP-1 secretion is deficient post-prandial SMA blood flow is not increased and as NHGU is also reduced, hyperglycaemia follows. Portal venous glucose concentration is also raised, thereby retarding the passive component of intestinal glucose absorption.   Increased pre-hepatic sinusoidal resistance combined with portal hypertension leading to opening of intrahepatic portosystemic collateral vessels are NASH-related mechanical defects that alter the balance between splanchnic and systemic distributions of glucose, hormones and incretins.The model reveals the latent contribution of portosystemic shunting in development of metabolic disease. This diverts splanchnic blood content away from the hepatic sinuses to the systemic circulation, particularly during the glucose absorptive phase of digestion, resulting in inappropriate increases in insulin-dependent systemic glucose metabolism.  This hastens onset of hypoglycaemia and thence hyperglucagonaemia. The model reveals that low rates of GLP-1 secretion, frequently associated with T2DM and NASH, may be also be caused by splanchnic hypoglycaemia, rather than to intrinsic loss of incretin secretory capacity. These findings may have therapeutic implications on GLP-1 agonist or glucagon antagonist usage.

Invasive procedures with questionable indications

Insufficient coordination of medical research and partial isolation from the international scientific community can result in application of invasive methods without sufficient indications. Here is presented an overview of renal and pancreatic biopsy studies performed in the course of the operations of pancreatic blood shunting into the systemic blood flow in type 1 diabetic patients. Furthermore a surgical procedure of lung denervation as a treatment method of asthma as well as the use of bronchoscopy for research in asthmatics are discussed here. Today, the upturn in Russian economy enables acquisition of modern equipment; and medical research is on the increase. Under these circumstances, the purpose of this letter was to remind that, performing surgical or other invasive procedures, the risk-to-benefit ratio should be kept as low as possible.

Pioglitazone decreases portosystemic shunting by modulating inflammation and angiogenesis in cirrhotic and non-cirrhotic portal hypertensive rats

BACKGROUND & AIMS

Development of the portal-hypertensive syndrome is mediated by splanchnic inflammation and neoangiogenesis. Since peroxisome proliferator-activated receptor gamma (PPARγ) agonists like pioglitazone (PIO) regulate inflammatory response and inhibit angiogenesis in endothelial cells, we evaluated PIO as treatment for experimental portal hypertension.

METHODS

PIO (10 mg/kg) or vehicle (VEH) was administered from day 21-28 after bile duct ligation (BDL), from day 0-7 after partial portal vein ligation (PPVL) or sham-operation (SO), respectively. After treatment, systemic hemodynamics, splanchnic blood flow (SMABF), portal pressure (PP), and portosystemic shunting (PSS) were assessed. Splanchnic and hepatic tissues were analyzed for angiogenic and inflammatory markers.

RESULTS

BDL and PPVL showed significantly increased PP, SMABF, and PSS compared to SO-VEH rats. While PIO treatment did not decrease PP or SMABF, PSS was significantly reduced both in cirrhotic (BDL-VEH: 71% to BDL-PIO: 41%; p<0.001) and non-cirrhotic (PPVL-VEH: 62% to PPVL-PIO: 40%; p=0.041) rats. PIO (10 μM, in vitro) inhibited endothelial cell migration and significantly increased PPARγ activity in vivo. In BDL rats, PIO decreased hepatic mRNA levels of PPARγ (p=0.01) and PlGF (p=0.071), and splanchnic mRNA expression of PPARγ (p=0.017), PDGFβ (p=0.053) and TNFα (p=0.075). Accordingly, splanchnic protein expression of PPARγ (p=0.032), VEGFR2 (p=0.035), CD31 (p=0.060) and PDGFβ (p=0.066) were lower in BDL-PIO vs. BDL-VEH animals. In PPVL rats, PIO treatment decreased splanchnic gene expression of Ang2 (-12.4 fold), eNOS (-9.3 fold), PDGF (-7.0 fold), PlGF (-11.9 fold), TGFb (-8.3 fold), VEGF-A (-11.3 fold), VEGFR1 (-5.9 fold), IL1b (-14.4 fold), and IL6 (-9.6 fold).

CONCLUSIONS

Pioglitazone treatment decreases portosystemic shunting via modulation of splanchnic inflammation and neoangiogenesis. Pioglitazone should be assessed for potential beneficial effects in patients with portosystemic collaterals due to portal hypertension.