The effect of denervation on liver regeneration in partially hepatectomized rats

Development of the nervous system in mouse liver

BACKGROUND

The role of the hepatic nervous system in liver development remains unclear. We previously created functional human micro-hepatic tissue in mice by co-culturing human hepatic endodermal cells with endothelial and mesenchymal cells. However, they lacked Glisson’s sheath [the portal tract (PT)]. The PT consists of branches of the hepatic artery (HA), portal vein, and intrahepatic bile duct (IHBD), collectively called the portal triad, together with autonomic nerves.

AIM

To evaluate the development of the mouse hepatic nervous network in the PT using immunohistochemistry.

METHODS

Liver samples from C57BL/6J mice were harvested at different developmental time periods, from embryonic day (E) 10.5 to postnatal day (P) 56. Thin sections of the surface cut through the hepatic hilus were examined using protein gene product 9.5 (PGP9.5) and cytokeratin 19 (CK19) antibodies, markers of nerve fibers (NFs), and biliary epithelial cells (BECs), respectively. The numbers of NFs and IHBDs were separately counted in a PT around the hepatic hilus (center) and the peripheral area (periphery) of the liver, comparing the average values between the center and the periphery at each developmental stage. NF-IHBD and NF-HA contacts in a PT were counted, and their relationship was quantified. SRY-related high mobility group-box gene 9 (SOX9), another BEC marker; hepatocyte nuclear factor 4α (HNF4α), a marker of hepatocytes; and Jagged-1, a Notch ligand, were also immunostained to observe the PT development.

RESULTS

HNF4α was expressed in the nucleus, and Jagged-1 was diffusely positive in the primitive liver at E10.5; however, the PGP9.5 and CK19 were negative in the fetal liver. SOX9-positive cells were scattered in the periportal area in the liver at E12.5. The Jagged-1 was mainly expressed in the periportal tissue, and the number of SOX9-positive cells increased at E16.5. SOX9-positive cells constructed the ductal plate and primitive IHBDs mainly at the center, and SOX-9-positive IHBDs partly acquired CK19 positivity at the same period. PGP9.5-positive bodies were first found at E16.5 and HAs were first found at P0 in the periportal tissue of the center. Therefore, primitive PT structures were first constructed at P0 in the center. Along with remodeling of the periportal tissue, the number of CK19-positive IHBDs and PGP9.5-positive NFs gradually increased, and PTs were also formed in the periphery until P5. The numbers of NFs and IHBDs were significantly higher in the center than in the periphery from E16.5 to P5. The numbers of NFs and IHBDs reached the adult level at P28, with decreased differences between the center and periphery. NFs associated more frequently with HAs than IHBDs in PTs at the early phase after birth, after which the number of NF-IHBD contacts gradually increased.

CONCLUSION

Mouse hepatic NFs first emerge at the center just before birth and extend toward the periphery. The interaction between NFs and IHBDs or HAs plays important roles in the morphogenesis of PT structure.

Daikenchuto improved perioperative nutritional status of the patients with colorectal cancer: A prospective open-labeled randomized exploratory study

Background and aims

The aim of this study is to exploratively evaluate the effect of Tsumura Daikenchuto Extract Granules (DKT, TJ-100) on abdominal symptoms, body weight, and nutritional function following colorectal cancer surgery.

Methods

The subjects included 20 patients for curative resection of colorectal cancer. A TJ-100 administration group (n = 10) and non-administration group (n = 10) were randomized and compared. In the administration group, TJ-100 was administered from 2 days prior to surgery up to 12 weeks following surgery. The endpoints included body weight gain, Gastrointestinal Symptom Rating Scale (GSRS), and blood biochemical factors. For the purpose of observing safety, drug adverse events were evaluated including liver function tests.

Results

Excluding one patient, we compared 9 cases in the administration group and 10 cases in the non-administration group. No obvious adverse events were observed in any of the cases. In the comparison of body weight gain, the TJ-100 administration group showed significantly higher values at 2, 4, and 12 weeks following the surgery. There was a tendency for lower stable GSRS scores in the administration group overall, with no statistically significant difference.

Conclusion

It is suggested that TJ-100 can be safely administered in the perioperative period for cases undergoing colorectal cancer surgery, potentially preventing weight loss during the early postoperative period.

Liver sympathetic denervation reverses obesity-induced hepatic steatosis

KEY POINTS

Non-alcoholic fatty liver disease, characterized in part by elevated liver triglycerides (i.e. hepatic steatosis), is a growing health problem. In this study, we found that hepatic steatosis is associated with robust hepatic sympathetic overactivity. Removal of hepatic sympathetic nerves reduced obesity-induced hepatic steatosis. Liver sympathetic innervation modulated hepatic lipid acquisition pathways during obesity.

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) affects 1 in 3 Americans and is a significant risk factor for type II diabetes mellitus, insulin resistance and hepatic carcinoma. Characterized in part by excessive hepatic triglyceride accumulation (i.e. hepatic steatosis), the incidence of NAFLD is increasing - in line with the growing obesity epidemic. The role of the autonomic nervous system in NAFLD remains unclear. Here, we show that chronic hepatic sympathetic overactivity mediates hepatic steatosis. Direct multiunit recordings of hepatic sympathetic nerve activity were obtained in high fat diet and normal chow fed male C57BL/6J mice. To reduce hepatic sympathetic nerve activity we utilized two approaches including pharmacological ablation of the sympathetic nerves and phenol-based hepatic sympathetic nerve denervation. Diet-induced NAFLD was associated with a nearly doubled firing rate of the hepatic sympathetic nerves, which was largely due to an increase in efferent nerve traffic. Furthermore, established high fat diet-induced hepatic steatosis was effectively reduced with pharmacological or phenol-based removal of the hepatic sympathetic nerves, independent of changes in body weight, caloric intake or adiposity. Ablation of liver sympathetic nerves was also associated with improvements in liver triglyceride accumulation pathways including free fatty acid uptake and de novo lipogenesis. These findings highlight an unrecognized pathogenic link between liver sympathetic outflow and hepatic steatosis and suggest that manipulation of the liver sympathetic nerves may represent a novel therapeutic strategy for NAFLD.

Efficiency of herbal medicine Dai-kenchu-to on portal blood flow in rat models

Introduction

To clarify the influence of Dai-Kenchu-To (DKT) on portal blood flow (PBF), PBF was continuously measured with Doppler ultrasound.

Methods

Normal liver rats were divided into a DKT 90 mg/kg, DKT 270 mg/kg administered group, and control, while cirrhotic liver rats were divided into a DKT-LC 90 mg/kg administered group and Control-LC. The PBF was measured after the administration of either DKT or water for 60 min by laser Doppler flowmetry system.

Results

The PBF in the DKT 90 increased approximately 10 min after DKT was administrated, and elevated levels were maintained for approximately 10 min. A comparison of the increase in PBF by the calculating the area under the curve (AUC) revealed that flow was significantly higher in the DKT 90 compared to either the control or the DKT 270 (p < 0.05). The cirrhotic liver group showed stable PBF in both the DKT-LC and Control-LC. The AUC, revealed no significant difference between the DKT-LC and Control-LC.

Discussion

DKT induced an increase in PBF in normal livers; however, its effects were insufficient to increase PBF in the cirrhotic livers. No increase in the portal blood flow in the cirrhotic liver rats was probably the result of the cirrhotic liver, which had fibrotic change, and, therefore, may not have had sufficient compliance to accept the increasing blood flow volume from the intestinal tract.

Conclusion

We suggested DKT has the potential to protect the liver by increasing PBF when the liver has either normal or mild to moderate dysfunction.

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Effect of DKT to PBF.

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Normal and cirrhotic liver.

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Continuous observation of PBF.

Effect of aging on norepinephrine-related proliferative response in primary cultured periportal and perivenous hepatocytes

Norepinephrine (NE) amplifies the mitogenic effect of EGF in a rat liver through the adrenergic receptor coupled with G protein, Ghα. Ghα is also known as a transglutaminase 2 (TG2), whose cross-linking activity is implicated in hepatocyte growth. Recently, we found that NE-induced amplification of EGF-induced DNA synthesis in hepatocytes obtained from perivenous regions of liver is caused by inhibiting the downregulation of EGF receptor (EGFR) by TG2. In the present study, we investigated the effect of aging on NE-related proliferative response. Hepatocytes were obtained from the liver of 7- and 90-wk-old rats. To examine this in detail, periportal hepatocytes (PPH) and perivenous hepatocytes (PVH) were isolated using the digitonin/collagenase perfusion technique. EGF or NE receptor binding was analyzed by Scatchard analysis. Changes in NE-induced DNA synthesis, G protein activity, and TG2 activity were measured. NE slightly potentiated [125I]EGF binding to EGFR, and EGF-induced DNA synthesis in PVH but not in PPH. [3H]NE binding studies indicated that PVH have a greater number of receptors than PPH, and that the number of receptors in both subpopulations increased with aging. NE-induced changes in G protein activity and TG2 activity in 90-wk-old rats were slight compared with 7-wk-old rats. These results suggest that NE results in a slight recovery effect on the age-related decline in EGF-induced DNA synthesis because of incomplete switching of the function from TG2 to Ghα.

Role of the autonomic nervous system in rat liver regeneration

To study the regulatory role of autonomic nervous system in rat regenerating liver, surgical operations of rat partial hepatectomy (PH) and its operation control (OC), sympathectomy combining partial hepatectomy (SPH), vagotomy combining partial hepatectomy (VPH), and total liver denervation combining partial hepatectomy (TDPH) were performed, then expression profiles of regenerating livers at 2 h after operation were detected using Rat Genome 230 2.0 array. It was shown that the expressions of 97 genes in OC, 230 genes in PH, 253 genes in SPH, 187 genes in VPH, and 177 genes in TDPH were significantly changed in biology. The relevance analysis showed that in SPH, genes involved in stimulus response, immunity response, amino acids and K(+) transport, amino acid catabolism, cell adhesion, cell proliferation mediated by JAK-STAT, Ca(+), and platelet-derived growth factor receptor, cell growth and differentiation through JAK-STAT were up-regulated, while the genes involved in chromatin assembly and disassembly, and cell apoptosis mediated by MAPK were down-regulated. In VPH, the genes associated with chromosome modification-related transcription factor, oxygen transport, and cell apoptosis mediated by MAPK pathway were up-regulated, but the genes associated with amino acid catabolism, histone acetylation-related transcription factor, and cell differentiation mediated by Wnt pathway were down-regulated. In TDPH, the genes related to immunity response, growth and development of regenerating liver, cell growth by MAPK pathway were up-regulated. Our data suggested that splanchnic and vagal nerves could regulate the expressions of liver regeneration-related genes.

Norepinephrine modulates the zonally different hepatocyte proliferation through the regulation of transglutaminase activity

A neurotransmitter, norepinephrine (NE), amplifies the mitogenic effect of epidermal growth factor (EGF) in the liver by acting on the alpha(1)-adrenergic receptor coupled with G protein, Galpha(h). However, the molecular mechanism is not well understood. Galpha(h) is known as a transglutaminase 2 (TG2), a cross-linking enzyme implicated in hepatocyte proliferation. We investigated the effect of NE on EGF-induced cell proliferation and TG2 activity using hepatocytes isolated in periportal and perivenous regions of the liver, which differ in proliferative capacity. Periportal hepatocytes (PPH) and perivenous hepatocytes (PVH) were isolated by the digitonin-collagenase perfusion technique. EGF or NE receptor binding was analyzed by Scatchard analysis. Changes in NE-induced DNA synthesis, EGF receptor (EGFR) dimerization and phosphorylation, and TG2 activity were measured. NE enhanced EGF-induced DNA synthesis, EGF-induced EGFR dimerization, and its phosphorylation in PVH but not in PPH. [(3)H]NE binding studies indicated that PVH was found to have a greater affinity and number of receptors than PPH. Furthermore, NE treatment decreased TG2 activity and increased phospholipase C activity in PVH although TG2 level showed no change. These results suggest that NE-induced amplification of EGF-induced DNA synthesis especially in PVH is caused by upregulation of EGFR activation through the switching of function from TG2 to Galpha(h).

Role of splanchnic hemodynamics in liver regeneration after living donor liver transplantation

The aim of this study was to investigate the changes in splanchnic hemodynamics after LDLT and their relationship with graft regeneration. Eighteen patients with LDLT December 2006 and June 2008 were enrolled, and color Doppler ultrasonography was performed preoperatively and on postoperative days (PODs) 1, 3, 5, 7, 30, and 90 after transplantation. The changes in the portal blood flow mean velocity (PBV) and portal blood flow volume (PBF) were monitored, and their effects on hepatic function were observed simultaneously. Graft sizes were measured on PODs 7, 30, and 90 after the operation. The regeneration rates of grafts were calculated. PBF increased in the recipient group from 1081.17 +/- 277.50 to 2171.44 +/- 613.15 mL/minute, and PBV increased from 15.01 +/- 5.67 to 56.00 +/- 22.11 cm/s; they were both significantly higher than those in the donor group (P < 0.01). On POD 1, serum aspartic aminotransferase, alanine aminotransferase, and total bilirubin all peaked; however, these indices in patients with PBF/graft weight (GW) > 300 mL/minute . 100 g were significantly higher than those in patients with PBF/GW < 300 mL/minute . 100 g. Livers in the recipient group regenerated rapidly. The graft regeneration rate reached 119.40% +/- 28.21% as early as 1 month post-transplantation. PBF and PBV on PODs 1 and 3 were greatly related to liver regeneration at 30 days. The portal venous flow in patients with portal hypertension after LDLT showed a high perfusion state, which could promote graft regeneration, but PBF/GW after the operation should be controlled below 300 mL/minute . 100 g in order to protect grafts from hyperperfusion injury.

Human liver stem cell-derived microvesicles accelerate hepatic regeneration in hepatectomized rats

Several studies indicate that adult stem cells may improve the recovery from acute tissue injury. It has been suggested that they may contribute to tissue regeneration by the release of paracrine factors promoting proliferation of tissue resident cells. However, the factors involved remain unknown. In the present study we found that microvesicles (MVs) derived from human liver stem cells (HLSC) induced in vitro proliferation and apoptosis resistance of human and rat hepatocytes. These effects required internalization of MVs in the hepatocytes by an alpha(4)-integrin-dependent mechanism. However, MVs pre-treated with RNase, even if internalized, were unable to induce hepatocyte proliferation and apoptosis resistance, suggesting an RNA-dependent effect. Microarray analysis and quantitative RT-PCR demonstrated that MVs were shuttling a specific subset of cellular mRNA, such as mRNA associated in the control of transcription, translation, proliferation and apoptosis. When administered in vivo, MVs accelerated the morphological and functional recovery of liver in a model of 70% hepatectomy in rats. This effect was associated with increase in hepatocyte proliferation and was abolished by RNase pre-treatment of MVs. Using human AGO2, as a reporter gene present in MVs, we found the expression of human AGO2 mRNA and protein in the liver of hepatectomized rats treated with MVs. These data suggested a translation of the MV shuttled mRNA into hepatocytes of treated rats. In conclusion, these results suggest that MVs derived from HLSC may activate a proliferative program in remnant hepatocytes after hepatectomy by a horizontal transfer of specific mRNA subsets.