Co-administration of prostaglandin E1 with somatostatin attenuates acute liver damage after massive hepatectomy in rats via inhibition of inflammatory responses, apoptosis and endoplasmic reticulum stress

Combination drug therapy prevents CIAKI by suppressing ER stress-induced apoptosis

Contrast-induced acute kidney injury (CIAKI) is an important clinical complication that occurs after the application of contrast agent in percutaneous coronary intervention. The pathogenesis of CIAKI is complex. Studies have shown that cell apoptosis induced by endoplasmic reticulum stress (ERS) plays an important role in renal tubular injury in CIAKI. These findings suggest that atorvastatin, probucol and alprostadil can inhibit renal tubular cell apoptosis to prevent CIAKI. However, there is no specific research on the above effects of drug combinations. Therefore, this study aimed to establish a rat CIAKI model with meglumine diatrizoate and add drug intervention to compare the influence of combined drugs with that of atorvastatin alone on CIAKI via the inhibition of ERS-specific molecular chaperones. Fifty Wistar rats were randomly divided into 5 groups: Group A + CC (atorvastatin group, n = 10); Group PA + CC (probucol + atorvastatin group, n = 10); Group AA + CC (alprostadil + atorvastatin group, n = 10); Group PCC (contrast group, n = 10); and Group NCC (control group, n = 10). Among the five groups, Group PCC presented the significantly highest creatinine increase rate and protein and nucleic acid expression levels, with the most severe cell injury and apoptosis observed via HE and TUNEL staining. Compared with those in the atorvastatin group, the rate of increase in creatinine and protein expression in the combined treatment groups were decreased to some extent, and the histological morphology was also improved. This was especially evident in Group AA + CC. Renal cell apoptosis induced by the ERS pathway may play an important role in the pathogenesis of CIAKI induced by meglumine diatrizoate. Atorvastatin, probucol and alprostadil can prevent the occurrence of CIAKI, and the ERS-induced apoptosis pathway is involved in this mechanism. The protective effect of probucol or alprostadil combined with atorvastatin on CIAKI may be stronger than that of atorvastatin alone, with a greater effect of the combination of alprostadil and atorvastatin.

The Role of Endoplasmic Reticulum Stress Response in Liver Regeneration

Exposure to hepatotoxic chemicals is involved in liver disease-related morbidity and mortality worldwide. The liver responds to damage by triggering compensatory hepatic regeneration. Physical agent or chemical-induced liver damage disrupts hepatocyte proteostasis, including endoplasmic reticulum (ER) homeostasis. Post-liver injury ER experiences a homeostatic imbalance, followed by active ER stress response signaling. Activated ER stress response causes selective upregulation of stress response genes and downregulation of many hepatocyte genes. Acetaminophen overdose, carbon tetrachloride, acute and chronic alcohol exposure, and physical injury activate the ER stress response, but details about the cellular consequences of the ER stress response on liver regeneration remain unclear. The current data indicate that inhibiting the ER stress response after partial hepatectomy-induced liver damage promotes liver regeneration, whereas inhibiting the ER stress response after chemical-induced hepatotoxicity impairs liver regeneration. This review summarizes key findings and emphasizes the knowledge gaps in the role of ER stress in injury and regeneration.

Protective Effect of Alprostadil on Acute Pancreatitis in Rats via Inhibiting Janus Kinase 2 (JAK2)/STAT3 Signal Transduction Pathway

Background

Alprostadil can inhibit inflammation and reduce inflammation-related injury in many inflammatory diseases. However, the anti-inflammatory effect of alprostadil in decreasing acute pancreatitis (AP) injury remains unknow. This study aimed to investigate the possible protective effects and mechanism of alprostadil against AP in rats.

Material/Methods

Forty healthy Sprague-Dawley rats were randomly divided into a control group, an AP group, an AP-alprostadil group, an AP-AG490 group, and an AP-(alprostadil+AG490) group. An animal model of acute pancreatitis was established. The pathological changes of the pancreases in each group were observed. We assessed levels of malondialdehyde (MDA), superoxide dismutase (SOD), and myeloperoxidase (MPO), as well as serum IL-1β, IL-6, IL-10, and TNF-α. TUNEL assay was used to detect apoptosis of pancreatic cells. The proteins p-Jak2 and p-Stat3 were investigated by Western blot.

Results

Compared with the control group, pancreatic pathological score, pancreatic apoptosis, MDA, MPO, serum IL-1β, IL-6, and TNF-α levels were significantly higher in the AP group, and SOD levels were significantly decreased. Compared with the AP group, after treatment with alprostadil, AG490, and alprostadil+AG490, respectively, the pancreatic pathological score, apoptosis, MDA, MPO, serum IL-1β, IL-6, and TNF-α were significantly decreased in AP rats, while SOD levels were significantly increased. The protein levels of p-JAK2 and p-STAT3 were significantly upregulated in the AP group compared with the control group, and the protein levels of p-JAK2 and p-STAT3 after treatment with alprostadil, AG490, and alprostadil+AG490 were significantly decreased, and the effect of alprostadil+AG490 was the strongest.

Conclusions

Alprostadil can reduce pancreatic tissue damage, delay pancreatic cell apoptosis, and reduce inflammation and anti-oxidative stress by inhibiting the JAK2/STAT3 signal pathway, thus protecting the pancreas.

Alprostadil attenuates LPS-induced cardiomyocyte injury by inhibiting the Wnt5a/JNK/NF-κB pathway

Background

Clinical research has demonstrated that alprostadil has an anti-inflammatory effect; however, to date, its molecular mechanisms remain unclear. This study aimed to examine the anti-inflammatory activity and related mechanisms of alprostadil in lipopolysaccharide (LPS)-treated H9c2 cells.

Methods

Cell morphology was observed under an inverted light microscope, while cell viability was assessed with the 3‑(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay. Enzyme-linked immunosorbent assays (ELISA) were conducted to study biochemical indicators of cellular damage, such as released lactate dehydrase (LDH) and troponin, and inflammatory cytokine levels including interleukin-1β (IL-1β), IL-6, IL-17, and tumor necrosis factor-α (TNF-α). The mRNA expression levels of Wnt5a, c‑jun N‑terminal kinase (JNK), and nuclear factor kappa B (NF-κB) were further investigated by real-time quantitative polymerase chain reaction (RT-PCR). The effects of alprostadil on the Wnt5a/JNK/NF-κB pathway in H9c2 cells was examined by Western blotting.

Results

Alprostadil increased the cell viability of LPS-stimulated H9c2 cells, reduced LDH and troponin production, and attenuated IL-1β, IL-6, IL-17, and TNF-α secretion. Moreover, alprostadil reduced the mRNA expression of Wnt5a, JNK, and NF-κB and decreased the expression of Wnt5a, NF-κB, and the ratio of p‑JNK/JNK in H9c2 cells treated with LPS. The siWnt5a or JNK inhibitor SP600125 significantly augmented the inhibitory effects of alprostadil on the Wnt5a/JNK/NF-κB pathway.

Conclusion

Our results show that alprostadil has anti-inflammatory effects and could attenuate LPS-induced injury in H9c2 cardiomyocytes via the Wnt5a/JNK/NF-κB pathway.

Treatment of AECHB and Severe Hepatitis (Liver Failure)

This chapter describes the general treatment and immune principles and internal management for AECHB and HBV ACLF, including ICU monitoring, general supportive medications/nutrition/nursing, immune therapy, artificial liver supportive systems, hepatocyte/stem cell, and liver transplant, management for special populations, frequently clinical complications and the utilization of Chinese traditional medicines.

Early clinical indicators of severe hepatitis B include acratia, gastrointestinal symptoms, a daily increase in serum bilirubin >1 mg/dL, toxic intestinal paralysis, bleeding tendency and mild mind anomaly or character change, and the presence of other diseases inducing severe hepatitis. Laboratory indicators include T-Bil, PTA, cholinesterase, pre-albumin and albumin. The roles of immune indicators (such as IL-6, TNF-α, and fgl2), gene polymorphisms, HBV genotypes, and gene mutations as early clinical indicators.

Intensive Care Unit monitor patients with severe hepatitis include intracranial pressure, infection, blood dynamics, respiratory function, renal function, blood coagulation function, nutritional status and blood purification process. Nursing care should not only include routine care, but psychological and special care (complications).

Nutrition support and nursing care should be maintained throughout treatment for severe hepatitis. Common methods of evaluating nutritional status include direct human body measurement, creatinine height index (CHI) and subject global assessment of nutrition (SGA). Malnourished patients should receive enteral or parenteral nutrition support.

Immune therapies for severe hepatitis include promoting hepatocyte regeneration (e.g. with glucagon, hepatocyte growth factor and prostaglandin E1), glucocorticoid suppressive therapy, and targeting molecular blocking. Corticosteroid treatment should be early and sufficient, and adverse drug reactions monitored. Treatments currently being investigated are those targeting Toll-like receptors, NK cell/NK cell receptors, macrophage/immune coagulation system, CTLA-4/PD-1 and stem cell transplantation.

In addition to conventional drugs and radioiodine, corticosteroids and artificial liver treatment can also be considered for severe hepatitis patients with hyperthyreosis. Patients with gestational severe hepatitis require preventive therapy for fetal growth restriction, and it is necessary to choose the timing and method of fetal delivery. For patients with both diabetes and severe hepatitis, insulin is preferred to oral antidiabetic agents to control blood glucose concentration. Liver toxicity of corticosteroids and immune suppressors should be monitored during treatment for severe hepatitis in patients with connective tissue diseases including SLE, RA and sicca syndrome. Patient with connective tissue diseases should preferably be started after the antiviral treatment with nucleos(t)ide analogues.

An artificial liver can improve patients’ liver function; remove endotoxins, blood ammonia and other toxins; correct amino acid metabolism and coagulation disorders; and reverse internal environment imbalances. Non-bioartificial livers are suitable for patients with early and middle stage severe hepatitis; for late-stage patients waiting for liver transplantation; and for transplanted patients with rejection reaction or transplant failure. The type of artificial liver should be determined by each patient’s condition and previous treatment purpose, and patients should be closely monitored for adverse reactions and complications. Bio- and hybrid artificial livers are still under development.

MELD score is the international standard for choosing liver transplantation. Surgical methods mainly include the in situ classic type and the piggyback type; transplantation includes no liver prophase, no liver phase or new liver phase. Preoperative preparation, management of intraoperative and postoperative complications and postoperative long-term treatment are keys to success.

Severe hepatitis belongs to the categories of “acute jaundice”, “scourge jaundice”, and “hot liver” in traditional Chinese medicine. Treatment methods include Chinese traditional medicines, acupuncture and acupoint injection, external application of drugs, umbilical compress therapy, drip, blow nose therapy, earpins, and clysis. Dietary care is also an important part of traditional Chinese medicine treatment.

Protective Effect and Mechanism of Alprostadil in Acute Respiratory Distress Syndrome Induced by Oleic Acid in Rats

BACKGROUND This study investigated the role and mechanism of alprostadil in acute respiratory distress syndrome (ARDS) induced by oleic acid (OA) in rats. MATERIAL AND METHODS Sprague-Dawley rats were randomly divided into control, OA model, and OA + Alprostadil (2.5, 5, and 10 μg/kg, respectively) groups. The ARDS model was induced by femoral vein injection of OA, and alprostadil was administrated immediately. Lung injury was evaluated by lung wet-dry weight ratio (W/D) and histological analyses. Expressions of ACE, inflammatory mediators, apoptotic-related proteins, and proteins in the MAPKs and NF-κB signaling pathways were determined by Western blot or immunohistochemical staining. RESULTS Compared with the control group, the OA model group had significantly increased W/D, lung injury score, and collagen deposition at 3 h after OA injection. However, alprostadil (10 μg/kg) treatment significantly reduced OA-induced elevation of these indicators. Additionally, OA-induced expression of TNF-α and IL-1β were suppressed by alprostadil. The OA-induced activation of nuclear factor (NF) κB p65 was also reduced by alprostadil. Furthermore, we found that Alprostadil had an inhibitory effect on the phosphorylation of JNK, ERK1/2, and p38 MAPKs. Alprostadil inhibited Bax but increased Bcl-2, indicating a suppressive role in apoptosis. Remarkably increased expression of ACE in the OA model group was observed, which was decreased by alprostadil. CONCLUSIONS Alprostadil has a protective effect on ARDS induced by OA in rats, possibly through inhibiting apoptosis, suppressing the activation of MAPKs and NF-κB signaling pathways, and decreasing ACE protein expression. Therefore, the use of alprostadil in clinical ARDS treatment is promising.

Prostaglandin E1 protects hepatocytes against endoplasmic reticulum stress-induced apoptosis via protein kinase A-dependent induction of glucose-regulated protein 78 expression

AIM

To investigate the protective effect of prostaglandin E1 (PGE1) against endoplasmic reticulum (ER) stress-induced hepatocyte apoptosis, and to explore its underlying mechanisms.

METHODS

Thapsigargin (TG) was used to induce ER stress in the human hepatic cell line L02 and hepatocarcinoma-derived cell line HepG2. To evaluate the effects of PGE1 on TG-induced apoptosis, PGE1 was used an hour prior to TG treatment. Activation of unfolded protein response signaling pathways were detected by western blotting and quantitative real-time RT-PCR. Apoptotic index and cell viability of L02 cells and HepG2 cells were determined with flow cytometry and MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay.

RESULTS

Pretreatment with 1 μmol/L PGE1 protected against TG-induced apoptosis in both L02 cells and HepG2 cells. PGE1 enhanced the TG-induced expression of C/EBP homologous protein (CHOP), glucose-regulated protein (GRP) 78 and spliced X box-binding protein 1 at 6 h. However, it attenuated their expressions after 24 h. PGE1 alone induced protein and mRNA expressions of GRP78; PGE1 also induced protein expression of DNA damage-inducible gene 34 and inhibited the expressions of phospho-PKR-like ER kinase, phospho-eukaryotic initiation factor 2α and CHOP. Treatment with protein kinase A (PKA)-inhibitor H89 or KT5720 blocked PGE1-induced up-regulation of GRP78. Further, the cytoprotective effect of PGE1 on hepatocytes was not observed after blockade of GRP78 expression by H89 or small interfering RNA specifically targeted against human GRP78.

CONCLUSION

Our study demonstrates that PGE1 protects against ER stress-induced hepatocyte apoptosis via PKA pathway-dependent induction of GRP78 expression.

Impact of splenic artery ligation after major hepatectomy on liver function, regeneration and viability

It was reported that prevention of acute portal overpressure in small-for-size livers by inflow modulation results in a better postoperative outcome. The aim is to investigate the impact of portal blood flow reduction by splenic artery ligation after major hepatectomy in a murine model. Forty-eight rats were subjected to an 85% hepatectomy or 85% hepatectomy and splenic artery ligation. Both groups were evaluated at 24, 48, 72 and 120 post-operative hours: liver function, regeneration and viability. All methods and experiments were carried out in accordance with Coimbra University guidelines. Splenic artery ligation produces viability increase after 24 h, induces a relative decrease in oxidative stress during the first 48 hours, allows antioxidant capacity increment after 24 h, which is reflected in a decrease of half-time normalized liver curve at 48 h and at 72 h and in an increase of mitotic index between 48 h and 72 h. Splenic artery ligation combined with 85% hepatectomy in a murine model, allows portal inflow modulation, promoting an increase in hepatocellular viability and regeneration, without impairing the function, probably by inducing a less marked elevation of oxidative stress at first 48 hours.

PGA1-induced apoptosis involves specific activation of H-Ras and N-Ras in cellular endomembranes

The cyclopentenone prostaglandin A₁ (PGA₁) is an inducer of cell death in cancer cells. However, the mechanism that initiates this cytotoxic response remains elusive. Here we report that PGA₁ triggers apoptosis by a process that entails the specific activation of H- and N-Ras isoforms, leading to caspase activation. Cells without H- and N-Ras did not undergo apoptosis upon PGA₁ treatment; in these cells, the cellular demise was rescued by overexpression of either H-Ras or N-Ras. Consistently, the mutant H-Ras-C118S, defective for binding PGA₁, did not produce cell death. Molecular analysis revealed a key role for the RAF-MEK-ERK signaling pathway in the apoptotic process through the induction of calpain activity and caspase-12 cleavage. We propose that PGA₁ evokes a specific physiological cell death program, through H- and N-Ras, but not K-Ras, activation at endomembranes. Our results highlight a novel mechanism that may be of potential interest for tumor treatment.

Modulation of splanchnic circulation: Role in perioperative management of liver transplant patients

Splanchnic circulation is the primary mechanism that regulates volumes of circulating blood and systemic blood pressure in patients with cirrhosis accompanied by portal hypertension. Recently, interest has been expressed in modulating splanchnic circulation in patients with liver cirrhosis, because this capability might produce beneficial effects in cirrhotic patients undergoing a liver transplant. Pharmacologic modulation of splanchnic circulation by use of vasoconstrictors might minimize venous congestion, replenish central blood flow, and thus optimize management of blood volume during a liver transplant operation. Moreover, splanchnic modulation minimizes any high portal blood flow that may occur following liver resection and the subsequent liver transplant. This effect is significant, because high portal flow impairs liver regeneration, and thus adversely affects the postoperative recovery of a transplant patient. An increase in portal blood flow can be minimized by either surgical methods (e.g., splenic artery ligation, splenectomy or portocaval shunting) or administration of splanchnic vasoconstrictor drugs such as Vasopressin or terlipressin. Finally, modulation of splanchnic circulation can help maintain perioperative renal function. Splanchnic vasoconstrictors such as terlipressin may help protect against acute kidney injury in patients undergoing liver transplantation by reducing portal pressure and the severity of a hyperdynamic state. These effects are especially important in patients who receive a too small for size graft. Terlipressin selectively stimulates V1 receptors, and thus causes arteriolar vasoconstriction in the splanchnic region, with a consequent shift of blood from splanchnic to systemic circulation. As a result, terlipressin enhances renal perfusion by increasing both effective blood volume and mean arterial pressure.

Prostaglandin E₁ protects bone marrow-derived mesenchymal stem cells against serum deprivation-induced apoptosis

Mesenchymal stem cells (MSCs) have become a recent focus of experimental and clinical research regarding myocardial regeneration. However, the therapeutic potential of these cells is limited by poor survival. Prostaglandin E₁ (PGE₁) is known to have anti-inflammatory and anti-apoptotic effects on the myocardium. The aim of the present study was to determine whether PGE₁ could protect MSCs against serum deprivation (SD)-induced apoptosis. An SD model was used to induce apoptosis in MSCs in vitro. Apoptotic morphological changes were detected by Hoechst 33258 fluorescent nuclear staining; and Annexin V-fluorescein isothiocyanate/propidium iodide (PI) double staining and flow cytometry was used to quantify the rate of apoptosis. Western blot analysis was used to detect the expression levels of the apoptosis-associated proteins Bcl-2, Bax and caspase-3. The results of the present study demonstrated that SD induced apoptosis of MSCs, and that treatment with PGE₁ attenuated the morphological changes characteristic of apoptosis. Annexin V/PI staining showed that the rate of apoptosis gradually increased with the duration of ischemia. Furthermore, treatment with PGE₁ significantly reduced SD-induced apoptosis, decreased the protein expression levels of Bax and caspase-3, and increased the expression levels of Bcl-2. These data suggest that PGE₁ is able to influence the survival of MSCs under certain conditions. These results may aid in improving the therapeutic efficacy of MSC transplantation used to treat chronic ischemic heart disease.

Preventative effects of prostaglandin E1 in combination with iodized olive oil on liver fibrosis after transcatheter arterial chemoembolization in a rabbit model of CCl4-induced liver fibrosis

To explore the preventative effects of prostaglandin E1 (PGE1) on a rabbit model of CCl4-induced liver fibrosis after transcatheter arterial chemoembolization (TACE), we generated a rabbit model of CCl4-induced liver fibrosis by treatment with 40% CCl4 in iodized olive oil for 16 weeks. Body mass and serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein (TP), albumin (ALB), albumin:globulin ratio (A:G), total bilirubin (TBIL), and direct bilirubin (DBIL) were measured. After TACE, the levels of hyaluronic acid (HA), procollagen III (PC III), laminin (LN), and collagen IV (IV-C) were measured, and the severity of liver fibrosis as well as the morphology of liver tissues were determined. Body mass in the model group was significantly decreased from 10 to 16 weeks, and the serum levels of ALT, AST, TP, TBIL, and DBIL levels were significantly increased while the model was being generated; the levels of ALB and A:G were significantly decreased. After TACE, serum levels of HA, PC III, and LN in the group injected with 1.0 mL iodized olive oil (Group B) were higher than in the group that were injected with 1.0 mL iodized olive oil + 0.2 mL PGE1 (Group C), whereas the serum levels of IV-C were lower. The severity of liver fibrosis was ameliorated in Group C. The combination of PGE1 and iodized olive oil prevented the development of liver fibrosis following TACE.

Prostaglandin E1 for prevention and treatment of liver fibrosis progression after hepatic arterial embolization in a rabbit model

AIM: To investigate whether prostaglandin E1 (PGE1) has preventive and therapeutic effects on liver fibrosis progression after transcatheter hepatic arterial embolization in a rabbit model.

METHODS: Thirty rabbits were used to induce liver fibrosis with carbon tetrachloride (CCl₄), and transcatheter right hepatic arterial embolization was performed. The rabbits were divided into three groups randomly (groups A, B and C) and infused with 1 mL of 0.9% saline, 1 mL of lipiodol and 1 ml of lipiodol plus 0.2 mL of PGE1 via the right hepatic artery, respectively. Serum levels of hyaluronic acid (HA), laminin (LN), procollagen Ⅲ (PCⅢ), and collagen Ⅳ (Ⅳ-C) on postoperative days 2, 4, 6 and 8 were measured, and the animals were killed on postoperative day 8 to detect pathological changes in liver tissues.

RESULTS: Liver fibrosis was successfully induced in rabbits, and addition of PGE1 in hepatic arterial embolization significantly reduced serum levels of HA, LN, PCⅢ and Ⅳ-C, and alleviated hepatic histological abnormalities.

CONCLUSION: PGE1 can prevent liver fibrosis progression in rabbits after transcatheter hepatic arterial embolization with lipiodol.

Melatonin treatment reduces endoplasmic reticulum stress and modulates the unfolded protein response in rabbits with lethal fulminant hepatitis of viral origin

Hepatocyte apoptosis plays an important role in the development of fulminant hepatic failure (FHF). The objective of this study was to investigate whether endoplasmic reticulum (ER) stress and unfolded protein response (UPR) inhibition is an underlying mechanism of melatonin anti-apoptotic effects in an animal model of FHF of viral origin induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received melatonin at two concentrations of 10 mg/kg and 20 mg/kg at 0 hr, 12 hr and 24 hr postinfection. RHDV infection induced increased expression of CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin heavy chain binding protein (BiP/GRP78), glucose-regulated protein 94 (GRP94), phospho-c-Jun N-terminal kinase (JNK) and caspase-12. These effects were attenuated by melatonin. Double immunofluorescence staining showed colocalization of CHOP and cleaved caspase-3 in liver sections of RHDV-infected rabbits, while immunostaining decreased markedly with melatonin treatment. RHDV infection resulted in significant increases in the mRNA levels of activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), spliced X-box binding protein-1 (XBP1s) and tumor necrosis factor receptor-associated factor 2 (TRAF2). Melatonin attenuated the extent of the changes. Data obtained provide evidence that in rabbits with experimental infection by RHDV, reduction in apoptotic liver damage by melatonin is associated with attenuation of ER stress through a modulation of the three arms of UPR signaling and further support a potential hepatoprotective role of melatonin in FHF.