Platelets prevent acute liver damage after extended hepatectomy in pigs. J Hepatobiliary Pancreat Sci. 2010;17:855-864. [PMID: 20734209 DOI: 10.1007/s00534-010-0276-2]

Surgical Models of Liver Regeneration in Pigs: A Practical Review of the Literature for Researchers

The remarkable capacity of regeneration of the liver is well known, although the involved mechanisms are far from being understood. Furthermore, limits concerning the residual functional mass of the liver remain critical in both fields of hepatic resection and transplantation. The aim of the present study was to review the surgical experiments regarding liver regeneration in pigs to promote experimental methodological standardization. The Pubmed, Medline, Scopus, and Cochrane Library databases were searched. Studies evaluating liver regeneration through surgical experiments performed on pigs were included. A total of 139 titles were screened, and 41 articles were included in the study, with 689 pigs in total. A total of 29 studies (71% of all) had a survival design, with an average study duration of 13 days. Overall, 36 studies (88%) considered partial hepatectomy, of which four were an associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). Remnant liver volume ranged from 10% to 60%. Only 2 studies considered a hepatotoxic pre-treatment, while 25 studies evaluated additional liver procedures, such as stem cell application, ischemia/reperfusion injury, portal vein modulation, liver scaffold application, bio-artificial, and pharmacological liver treatment. Only nine authors analysed how cytokines and growth factors changed in response to liver resection. The most used imaging system to evaluate liver volume was CT-scan volumetry, even if performed only by nine authors. The pig represents one of the best animal models for the study of liver regeneration. However, it remains a mostly unexplored field due to the lack of experiments reproducing the chronic pathological aspects of the liver and the heterogeneity of existing studies.

Platelet and liver regeneration after liver surgery

The success of liver surgery, including resection and transplantation, is largely dependent on the ability of the liver to regenerate. Despite substantial improvement in surgical techniques and perioperative care, one of the main concerns is post-hepatectomy liver failure and early allograft dysfunction, both of which are associated with impaired liver regeneration. Recent studies have demonstrated the positive role of platelets in promoting liver regeneration and protecting hepatocytes; however, the underlying mechanisms responsible for these effects are not fully understood. In this review, we updated the accumulated evidence of the role of platelets in promoting liver regeneration, with a focus on liver resection and liver transplantation. The goal of these studies was to support the clinical implementation of platelet agents, such as thrombopoietin receptor agonists, to augment liver regeneration after liver surgery. This "platelet therapy" may become a treatment choice for post-hepatectomy liver failure and early allograft dysfunction.

Systematic review and meta-analysis of thrombocytopenia as a predictor of post-hepatectomy liver failure

BACKGROUND

We performed a systematic review and meta-analysis to assess whether thrombocytopenia constituted a risk factor for post-hepatectomy liver failure (PHLF).

METHODS

We searched MEDLINE and EMBASE from inception until February the 17th, 2018 for studies reporting cases of PHLF in patients with and without thrombocytopenia (defined as a platelet count below 100 or 150 (G/l)) and/or platelet counts in patients with and without PHLF. Pooled odd ratios for PHLF, as well as mean difference in platelet counts between patients with and without PHLF, were obtained by random effects models. Robustness was tested by subgroups and leave-one out sensitivity analyses. Heterogeneity was assessed using the Q-test and quantified based on I² value.

RESULTS

We included 15 studies representing 3966 patients. Pooled odds ratio for PHLF in thrombocytopenic patients was 3.71 (95% CI: 2.51 to 5.48; I² = 0%). Pooled odds ratio was 5.53 (95% CI: 2.85 to 10.48) when pooling only studies based on preoperative platelet count, and 3.13 (95% CI: 1.75 to 5.58) when pooling studies including only patients without liver cirrhosis. The pooled mean difference in platelet counts between patients with and without PHLF was -21.2 (G/l) (95% CI: -36.1 to 6.4) in disfavor of patients with PHLF. When pooling only patients with various qualities of liver tissue, the pooled mean difference was 0.6 (G/l) (95% CI: -21.1 to 22.2).

CONCLUSION

Preoperative and/or postoperative thrombocytopenia constitute significant risk factors for PHLF in cirrhotic and non-cirrhotic patients.

Platelet-rich plasma as a potential therapeutic approach against lead nitrate- and/or gamma radiation-induced hepatotoxicity

Because of the potential regenerative and cytoprotective effects of its content of numerous bioactive growth factors and cytokines, platelet-rich plasma (PRP) became an attractive biomaterial for therapeutic purposes. Therefore, the current study was designed to investigate the potential therapeutic effect of PRP against lead nitrate- and/or γ-radiation-induced hepatotoxicity. To do so, hepatotoxicity was induced in rats by intraperitoneal administration of lead nitrate (7.5 mg/kg) thrice weekly for two consecutive weeks and/or a whole-body γ-irradiation at a single dose of 6 Gy. Activated PRP (0.5 ml/kg) was injected subcutaneously 24 h after the last dose of lead nitrate and/or γ-irradiation and continued twice weekly for three successive weeks. Lead nitrate intoxication and/or γ-irradiation resulted in a significant elevation of serum alanine transaminase and aspartate transaminase activities accompanied with a significant decrease in serum levels of total protein and albumin. Further, a significant increase in malondialdehyde level and nitric oxide content accompanied with a significant decrease in the reduced glutathione content and the enzyme activities of glutathione-S-transferase, superoxide dismutase, and catalase were observed. Additionally, hepatic extracellular signal-regulated kinase (ERK) and Akt signaling pathways were stimulated. PRP treatment notably ameliorated the induced cell injury, reduced the intracellular oxidative and interestingly increased the upregulation of phosphorylated ERK1/2 and Akt. Moreover, PRP treatment relieved lead nitrate and/or γ-radiation-induced hepatic histological damages. In conclusion, this study sheds the light on a probable therapeutic role of PRP against lead nitrate- and/or γ-radiation-induced hepatotoxicity which might attribute to its ability to activate ERK and Akt signaling pathways.

Low Preoperative Platelet Count Predicts Risk of Subclinical Posthepatectomy Liver Failure in Right Lobe Donors for Liver Transplantation

Living donor right hepatectomy (LDRH) is a common procedure in adult-to-adult living donor liver transplantation, but it is associated with a higher risk of posthepatectomy liver failure (PHLF) compared with left hepatectomy because of a smaller remnant. We identified risk factors for PHLF and other complications in LDRH, verified the appropriateness of the criteria, and explored the possibility of adjusting the minimum remnant liver volume (RLV) based on individual risk. Between October 2005 and November 2017, 254 donors undergoing LDRH at Kyoto University Hospital were enrolled. Clinical data were collected retrospectively. All complications were graded according to the Clavien-Dindo classification. No donors had grade 4 or 5 complications or clinically significant grade B or C PHLF. Grade A PHLF occurred in 30 donors (11.8%). Male sex (P = 0.01), lower preoperative platelet count (PLT; P = 0.01), higher prothrombin time-international normalized ratio (P = 0.03), higher total bilirubin (P = 0.01), smaller RLV (P = 0.03), and greater blood loss (P = 0.04) were associated with increased risk of PHLF in the univariate analysis, whereas PLT, RLV, and blood loss remained significant in the multivariate analysis. Grade 2 or 3 complications were observed in 32 (12.6%) donors. Higher body mass index (BMI; P = 0.002) and larger blood loss (P = 0.02) were identified as risk factors for complications (Clavien-Dindo grade ≥ 2) in univariate analysis. Only BMI remained significant in the multivariate analysis. In conclusion, LDRH is performed safely with acceptable morbidity under the current criteria. Minimum RLV may be marginally adjusted by PLT and reducing intraoperative blood loss minimizes PHLF risk. Liver Transplantation 00 000-000 2018 AASLD.

Thrombocytopenia after liver transplantation: Should we care?

Transient thrombocytopenia is a common phenomenon after liver transplantation. After liver transplantation (LT), platelet count decreases and reaches a nadir on postoperative days 3-5, with an average reduction in platelet counts of 60%; platelet count recovers to preoperative levels approximately two weeks after LT. The putative mechanisms include haemodilution, decreased platelet production, increased sequestration, medications, infections, thrombosis, or combination of these processes. However, the precise mechanisms remain unclear. The role of platelets in liver transplantation has been highlighted in recent years, and particular attention has been given to their effects beyond hemostasis and thrombosis. Previous studies have demonstrated that perioperative thrombocytopenia causes poor graft regeneration, increases the incidence of postoperative morbidity, and deteriorates the graft and decreases patient survival in both the short and long term after liver transplantation. Platelet therapies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist, platelet transfusion, splenectomy, and intravenous immunoglobulin treatment might have a potential for improving graft survival, however clinical trials are lacking. Further studies are warranted to detect direct evidence on whether thrombocytopenia is the cause or result of poor-graft function and postoperative complications, and to determine who needs platelet therapies in order to prevent postoperative complications and thus improve post-transplant outcomes.

Swine used in the medical university: overview of 20 years of experience

Center for Development of Advanced Medical Technology (CDAMTec) in Jichi Medical University was established in 2009. It is the first educational research facility specialized for medical research and training using swine in Japan. Preclinical studies on large animals are essential prior to clinical trials to develop regenerative medical products and medical equipment. We have continued comprehensively considering using miniature swine for experiments to develop advanced medical technologies and train physicians with advanced clinical abilities, while paying attention to animal welfare. The center plays a pioneering role in this field by accumulating know-how such as (1) Construction and effective utilization of research facilities, (2) Procurement of quality animal resources, (3) Education and training of technical staff, (4) Establishment of support system for physicians and researchers. We now open up widely these expertise and foundation for medical research and training not only within our university but also outside the university, so as to move faster to practical use of advanced medical technology and contribute to human health and welfare.

Mesenchymal stem cells correct haemodynamic dysfunction associated with liver injury after extended resection in a pig model

In patients, acute kidney injury (AKI) is often due to haemodynamic impairment associated with hepatic decompensation following extended liver surgery. Mesenchymal stem cells (MSCs) supported tissue protection in a variety of acute and chronic diseases, and might hence ameliorate AKI induced by extended liver resection. Here, 70% liver resection was performed in male pigs. MSCs were infused through a central venous catheter and haemodynamic parameters as well as markers of acute kidney damage were monitored under intensive care conditions for 24 h post-surgery. Cytokine profiles were established to anticipate the MSCs’ potential mode of action. After extended liver resection, hyperdynamic circulation, associated with hyponatraemia, hyperkalaemia, an increase in serum aldosterone and low urine production developed. These signs of hepatorenal dysfunction and haemodynamic impairment were corrected by MSC treatment. MSCs elevated PDGF levels in the serum, possibly contributing to circulatory homeostasis. Another 14 cytokines were increased in the kidney, most of which are known to support tissue regeneration. In conclusion, MSCs supported kidney and liver function after extended liver resection. They probably acted through paracrine mechanisms improving haemodynamics and tissue homeostasis. They might thus provide a promising strategy to prevent acute kidney injury in the context of post-surgery acute liver failure.

Porcine model characterizing various parameters assessing the outcome after acetaminophen intoxication induced acute liver failure

AIM

To investigate the changes of hemodynamic and laboratory parameters during the course of acute liver failure following acetaminophen overdose.

METHODS

Eight pigs underwent a midline laparotomy following jejunal catheter placement for further acetaminophen intoxication and positioning of a portal vein Doppler flow-probe. Acute liver failure was realized by intrajejunal acetaminophen administration in six animals, two animals were sham operated. All animals were invasively monitored and received standardized intensive care support throughout the study. Portal blood flow, hemodynamic and ventilation parameters were continuously recorded. Laboratory parameters were analysed every eight hours. Liver biopsies were sampled every 24 h following intoxication and upon autopsy.

RESULTS

Acute liver failure (ALF) occurred after 28 ± 5 h resulted in multiple organ failure and death despite maximal support after further 21 ± 1 h (study end). Portal blood flow (baseline 1100 ± 156 mL/min) increased to a maximum flow of 1873 ± 175 mL/min at manifestation of ALF, which was significantly elevated (P < 0.01). Immediately after peaking, portal flow declined rapidly to 283 ± 135 mL/min at study end. Thrombocyte values (baseline 307 × 10³/µL ± 34 × 10³/µL) of intoxicated animals declined slowly to values of 145 × 10³/µL ± 46 × 10³/µL when liver failure occurred. Subsequent appearance of severe thrombocytopenia in liver failure resulted in values of 11 × 10³/µL ± 3 × 10³/µL preceding fatality within few hours which was significant (P > 0.01).

CONCLUSION

Declining portal blood flow and subsequent severe thrombocytopenia after acetaminophen intoxication precede fatality in a porcine acute liver failure model.

Prognostic impact of postoperative low platelet count after liver transplantation

BACKGROUND

The positive impact of platelets has been recently implicated in liver transplantation (LT). The aim of this study was to determine the risk factors for graft loss and mortality after LT, focusing on perioperative platelet counts.

METHODS

We reviewed all deceased donor LT from 2000 to 2012 and enrolled 975 consecutive recipients. The risk factors for graft loss and mortality were analyzed by multivariate analysis, using Cox's regression model.

RESULTS

Using cutoff values acquired by receiver operating characteristics curve analysis, multivariate analyses determined that viral hepatitis C (hazard ratio [HR]=1.32), donor age >40 (HR=1.33), higher peak serum alanine aminotransferase (HR=1.01), reoperation within 30 days (HR=1.51), and platelet count <72 500/μL on postoperative day (POD) 5 (HR=1.30) were independent risk factors for graft loss. Viral hepatitis C (HR=1.33), reoperation within 30 days (HR=1.35), and platelet count <72 500/μL on POD 5 (HR=1.38) were independent risk factors for mortality.

CONCLUSION

A low platelet count on POD 5 was associated with graft loss and mortality after LT. Platelet count <72 500/μL on POD 5 can be a predictor of poor graft and overall survival. Maintaining higher postoperative platelet counts could potentially improve graft and overall survival rates.

The beneficial role of simultaneous splenectomy after extended hepatectomy: experimental study in pigs

BACKGROUND

The role of hepatic hemodynamic modulation in the development of "small-for-size" syndrome (SFSS) after extended hepatectomy (EH) or living-donor liver transplantation is still controversial. We have designed an experimental study to investigate the effect of hemodynamic parameters of the liver circulation on the development of SFSS after EH in a porcine model.

METHODS

Eighteen pigs were randomly divided into two groups: group A has received EH (75%-80%) without splenectomy, and group B with EH and simultaneous splenectomy was carried out. Portal hemodynamics, liver function tests, histologic findings, injury and survival rates were compared between groups A and B.

RESULTS

The 7-d survival rate in the splenectomy group was significantly improved compared with group A (88.9% versus 44.4%, P < 0.05). Portal vein pressure, portal vein flow, and liver function tests in the splenectomy group were significantly lower than in group A immediately after splenectomy and postoperatively until the day of sacrifice. Histologic findings in group A clearly illustrate severe inflammation, bridging necrosis, ischemic cholangitis, and severe congestion, while in group B there were less serious histologic changes.

CONCLUSIONS

Our experimental study indicates that perioperative portal modulation can successfully prevent the manifestation of SFSS after EH. Therefore, by focusing on "flow" rather than on "size," researchers may understand better the pathophysiology of this syndrome.

Effects of platelet-rich plasma on liver regeneration in CCl4-induced hepatotoxicity model

Numerous bioactive growth factors and cytokines in platelet-rich plasma (PRP) have recently made it an attractive biomaterial for therapeutic purposes. These growth factors have the potential to regenerate the injured tissues. The aim of this study was to investigate the therapeutic effects of PRP in hepatotoxic animal model. Hepatotoxicity was induced in rats by oral administration of 4 mL/kg/week of CCl₄ diluted 1:1 in corn oil for 10 weeks. To confirm the hepatotoxicity, 24 h after the last CCl₄ administration, blood samples were collected via cardiac puncture to assess the serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, albumin, total protein, and total bilirubin. Twenty-four hours after blood collection, the experimental animals received a single injection of PRP (1 mL) via the anterior mesenteric vein. One week later, all biochemical tests were performed again, and the rats were scarified and their livers were removed, prepared histologically, and stained. The stereological analyses were performed to evaluate the effects of PRP on histopathological features of CCl₄-treated livers. The results were compared statistically with the corresponding control and CCl₄+normal saline (NS)-treated animals. A significant decrease in the number and volume of hepatocytes (p = 0.01), and also a reduction in the volume of sinusoids (p = 0.001) and connective tissue (p = 0.04), were observed in the PRP-treated animals compared with the CCl₄+NS-treated ones. Our findings demonstrated that application of PRP had beneficial effects on CCl₄-induced fibrosis; however, it had detrimental effects on the total number of hepatocytes and the volume of hepatocytes and sinusoidal spaces.

New drug delivery system for liver sinusoidal endothelial cells for ischemia-reperfusion injury

AIM: To investigate the cytoprotective effects in hepatic ischemia-reperfusion injury, we developed a new formulation of hyaluronic acid (HA) and sphingosine 1-phophate.

METHODS: We divided Sprague-Dawley rats into 4 groups: control, HA, sphingosine 1-phosphate (S1P), and HA-S1P. After the administration of each agent, we subjected the rat livers to total ischemia followed by reperfusion. After reperfusion, we performed the following investigations: alanine aminotransferase (ALT), histological findings, TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining, and transmission electron microscopy (TEM). We also investigated the expression of proteins associated with apoptosis, hepatoprotection, and S1P accumulation.

RESULTS: S1P accumulated in the HA-S1P group livers more than S1P group livers. Serum ALT levels, TUNEL-positive hepatocytes, and expression of cleaved caspase-3 expression, were significantly decreased in the HA-S1P group. TEM revealed that the liver sinusoidal endothelial cell (LSEC) lining was preserved in the HA-S1P group. Moreover, the HA-S1P group showed a greater increase in the HO-1 protein levels compared to the S1P group.

CONCLUSION: Our results suggest that HA-S1P exhibits cytoprotective effects in the liver through the inhibition of LSEC apoptosis. HA-S1P is an effective agent for hepatic ischemia/reperfusion injury.

Platelet increases survival in a model of 90% hepatectomy in rats

BACKGROUND & AIMS

Ninety per cent hepatectomy in rodents is a model for acute liver failure. It has been reported that platelets have a strong effect enhancing liver regeneration, because of the production of several growth factors such as serotonin. The aim of this study was to investigate the role of microencapsulated platelets on 90% hepatectomy in rats.

METHODS

Platelets (PLT) were microencapsulated in sodium alginate and implanted in the peritoneum of rats after 90% partial hepatectomy (PH). Control group received empty capsules (EC). Animals were euthanized at 6, 12, 24, 48 and 72 h post PH (n=9-12/group/time) to evaluate liver regeneration rate, mitotic index, liver content, serum and tissue levels of Interleukin 6 (IL-6) and serotonin and its receptor 5-hydroxytryptamine type 2B (5Ht2b). Survival rate in 10 days was evaluated in a different set of animals (n=20/group).

RESULTS

Platelets group showed the highest survival rate despite the lowest liver regeneration rate at any time point. Mitotic and BrdU index showed no difference between groups. However, the number of hepatocytes was higher and the internuclear distance was shorter for PLT group. Liver dry weight was similar in both groups indicating that water was the main responsible factor for the weight difference. Gene expression of IL-6 in the liver was significantly higher in EC group 6 h after PH, whereas 5Ht2b was up-regulated at 72 h in PLT group.

CONCLUSIONS

Platelets enhance survival of animals with 90% PH, probably by an early protective effect on hepatocytes and the increase in growth factor receptors.

Laparoscopic left hepatectomy in swine: a safe and feasible technique

A purely laparoscopic four-port approach was created for left hepatectomy in pigs. A polyethylene loop was placed on the left two hepatic lobes for traction and lift. Next, penetrating ligation of the lobes using of a double row of silk sutures was performed to control bleeding. A direct hepatic transection was completed using a monopolar hook electrode without meticulous dissection of the left hepatic vein. The raw surface of the liver was coagulated and sealed with fibrin glue. Lobes were retrieved through an enlarged portal. Laparoscopic hepatic lobectomy was completed in all pigs without the use of specialized instruments and with a mean operative time of 179 ± 9 min. No significant perioperative complications were observed. The average weight of each resected lobe was 180 ± 51 g. Complete blood count as well as serum organics and enzyme levels normalized after about 2 weeks. During necropsy, adhesion of the hepatic raw surface to the gastric wall and omentum were observed. No other abnormalities were identified. This minimally invasive left hepatectomy technique in swine could serve as a useful model for investigating liver diseases and regeneration, and offer preclinical information to improve hepatobiliary surgical procedures.

Signal transduction of platelet-induced liver regeneration and decrease of liver fibrosis

Platelets contain three types of granules: alpha granules, dense granules, and lysosomal granules. Each granule contains various growth factors, cytokines, and other physiological substances. Platelets trigger many kinds of biological responses, such as hemostasis, wound healing, and tissue regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and improving liver fibrosis. The regenerative effect of liver by platelets consists of three mechanisms; i.e., the direct effect on hepatocytes, the cooperative effect with liver sinusoidal endothelial cells, and the collaborative effect with Kupffer cells. Many signal transduction pathways are involved in hepatocyte proliferation. One is activation of Akt and extracellular signal-regulated kinase (ERK)1/2, which are derived from direct stimulation from growth factors in platelets. The other is signal transducer and activator of transcription-3 (STAT3) activation by interleukin (IL)-6 derived from liver sinusoidal endothelial cells and Kupffer cells, which are stimulated by contact with platelets during liver regeneration. Platelets also improve liver fibrosis in rodent models by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cyclic adenosine monophosphate (cyclic AMP) is increased by adenosine through its receptors on hepatic stellate cells, resulting in inactivation of these cells. Adenosine is produced by the degradation of adenine nucleotides such as adenosine diphosphate (ADP) and adenosine tri-phosphate (ATP), which are stored in abundance within the dense granules of platelets.

Effect of Platelet-Rich Plasma on CCl4-Induced Chronic Liver Injury in Male Rats

Platelet-rich plasma (PRP) has been of great concern to the scientists and doctors who are involved in wound healing and regenerative medicine which focuses on repairing and replacing damaged cells and tissues. Growth factors of platelet-rich plasma are cost-effective, available, and is more stable than recombinant human growth factors. Given these valuable properties, we decided to assess the effect of PRP on CCl4-induced hepatotoxicity on rats. The rats received CCl4 (1 mL/kg, i.p. 1 : 1 in olive oil) twice per week for 8 weeks. Five weeks after CCl4 injection, the rats also received PRP (0.5 mL/kg, s.c.) two days a week for three weeks. Twenty-four hours after last CCl4 injection, the animals bled and their livers dissected for biochemical and histopathological studies. Blood analysis was performed to evaluate enzyme activity. The results showed that PRP itself was not toxic for liver and could protect the liver from CCl4-induced histological damages and attenuated oxidative stress by increase in glutathione content and decrease in lipid peroxidative marker of liver tissue. The results of the present study lend support to our beliefs in hepatoprotective effects of PRP.

Platelet therapy: A novel strategy for liver regeneration, anti-fibrosis, and anti-apoptosis

Platelets contain bio-physiological substances, including insulin-like growth factor-1, vascular endothelial growth factor, platelet-derived growth factor, hepatocyte growth factor, serotonin, transforming growth factor-β, adenosine diphosphate, adenosine tri-phosphate, and epidermal growth factor. Platelets have conventionally been considered to exacerbate the inflammatory response and liver injury. Recently, platelets were discovered to have a positive impact on the liver. In this review, we present experimental and clinical evidence indicating that platelets accelerate liver regeneration and have anti-fibrosis and anti-apoptosis activity, and we detail the mechanisms of action. Platelets accelerate liver regeneration by three different mechanisms: (1) a direct effect on hepatocytes, (2) a cooperative effect with liver sinusoidal endothelial cells, and (3) a collaborative effect with Kupffer cells. Platelets exert anti-fibrotic activity by deactivating hepatic stellate cells via the adenosine-cyclic adenosine 5’-monophosphate signaling pathway. Platelets prevent hepatocyte apoptosis by activating the Akt pathway and up-regulating Bcl-xL, which suppresses caspase-3 activation. Platelet therapy with thrombopoietin, thrombopoietin receptor agonists, and platelet transfusion has the advantages of convenience and cost-efficiency over other treatments. We propose that in the future, platelet therapy will play a promising role in the treatment of the various liver disorders that currently challenge the surgical field, such as liver failure after a massive hepatectomy, hepatectomy of a cirrhotic liver, and small grafts in liver transplantation.

Risk factors and nursing strategies for severe acute pancreatitis complicated with multiple organ dysfunction syndrome

AIM: To explore the risk factors and nursing strategies for severe acute pancreatitis (SAP) complicated with multiple organ dysfunction syndrome (MODS).

METHODS: Clinical data for 134 patients with SAP were retrospectively analyzed. Based on the presence of MODS or not, the patients were divided into two groups, those complicated with or without MODS. Risk factors and nursing strategies for SAP with MODS were then analyzed.

RESULTS: Logistic regression analysis demonstrated that shock, biliary obstruction, hyperlipidemia, hypoxemia, lung infection, pleural effusion, abdominal cavity room partition syndrome and Ranson's score, APACHE II score, and CT score were independent risk factors for SAP complicated with MODS (OR = 1.193, 1.016, 1.004, 1.193, 1.049, 1.055, 1.081, 1.100, 1.027, all P < 0.05). Nursing for SAP with MODS should focus on monitoring the patient's vital signs and strengthening the management of respiratory function, renal function, blood coagulation function and intestinal function.

CONCLUSION: Awareness of risk factors for SAP complicated with MODS should be raised to conduct active intervention to improve prognosis. Optimization of nursing management of SAP complicated with MODS can help reduce mortality.

Novel therapy for liver regeneration by increasing the number of platelets

Platelets are the smallest blood constitutes which contain three types of granules; alpha granules, dense granules, and lysosomal granules. Each granule contains various biophysiological substances such as growth factors, cytokines, etc. Platelets have been conventionally viewed as a trigger of inflammatory responses and injury in the liver. Some studies revealed that platelets have strong effects on promoting liver regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and describes three different mechanisms involved; (1) the direct effect on hepatocytes, where platelets translocate to the space of Disse and release growth factors through direct contact with hepatocytes, (2) the cooperative effect with liver sinusoidal endothelial cells, where the dense concentration of sphingosine-1-phosphate in platelets induces excretion of interleukin-6 from liver sinusoidal endothelial cells, and (3) the collaborative effect with Kupffer cells, where the functions of Kupffer cells are enhanced by platelets.

The pig as a model for translational research: overview of porcine animal models at Jichi Medical University

To improve the welfare of experimental animals, investigators seek to respect the 3R principle (Replacement, Reduction, and Refinement). Even when large animal studies are essential before moving to clinical trials, it is important to look for ways to reduce the number of experimental animals used. At the Center for the Development of Advanced Medical Technology, we consider ‘medical’ pigs to be ideal preclinical model systems.

We have been using both wild-type and genetically modified pigs. We began using this approach about 10 years ago with a ‘total pig system’ to model human health and disease for the purposes of both medical skill education and the development of new devices and therapeutic strategies.

At our Center, medical students and residents use pigs to gain experience with surgical skills and train for emergency procedures after appropriate simulation training. Senior clinicians have also used these models to advance the development of innovative tools for endo- and laparoscopic procedures. The Center focuses on translational research for organ transplantation and stem cell therapy. Several pig models have been established for liver, intestine, kidney, pancreas, and lung transplantation. Mesenchymal stromal cells have been established in green fluorescent protein- and red fluorescent protein-transgenic pigs and tested to trans-differentiate organogenesis. A program to establish induced pluripotent stem cells in the pig is ongoing at our Center.

Here, we review our 10 years of activity in this field. Based on our experience in surgical education and research, experimental pigs are valuable models in translational research.