Parenteral nutrition-associated liver injury and increased GRP94 expression prevented by ω-3 fish oil-based lipid emulsion supplementation

GRP94 Inhabits the Immortalized Porcine Hepatic Stellate Cells Apoptosis under Endoplasmic Reticulum Stress through Modulating the Expression of IGF-1 and Ubiquitin

Endoplasmic reticulum stress (ERS) is closely related to the occurrence and progression of metabolic liver disease. The treatment targeting glucose-regulated protein 94 (GRP94) for liver disease has gotten much attention, but the specific effect of GRP94 on hepatocyte apoptosis is still unclear. So far, all the studies on GRP94 have been conducted in mice or rats, and little study has been reported on pigs, which share more similarities with humans. In this study, we used low-dose (LD) and high-dose (HD) tunicamycin (TM) to establish ERS models on piglet livers and immortalized porcine hepatic stellate cells (HSCs). On the piglet ERS model we found that ERS could significantly (p < 0.01) stimulate the secretion and synthesis of insulin-like growth factor (IGF-1), IGF-1 receptor (IGF-1R), and IGF-binding protein (IGFBP)-1 and IGFBP-3; however, with the increase in ERS degree, the effect of promoting secretion and synthesis significantly (p < 0.01) decreased. In addition, the ubiquitin protein and ubiquitination-related gene were significantly increased (p < 0.05) in the LD group compared with the vehicle group. The protein level of Active-caspase 3 was significantly increased (p < 0.01) in the HD group, however, the TUNEL staining showed there was no significant apoptosis in the piglet liver ERS model. To explore the biofunction of ER chaperone GRP94, we used shRNA to knock down the expression of GRP94 in porcine HSCs. Interestingly, on porcine HSCs, the knockdown of GRP94 significantly (p < 0.05) decreased the secretion of IGF-1, IGFBP-1 and IGFBP-3 under ERS, but had no significant effect on these under normal condition, and knockdown GRP94 had a significant (p < 0.01) effect on the UBE2E gene and ubiquitin protein from the analysis of two-way ANOVA. On porcine HSCs apoptosis, the knockdown of GRP94 increased the cell apoptosis in TUNEL staining, and the two-way ANOVA analysis shows that knockdown GRP94 had a significant (p < 0.01) effect on the protein levels of Bcl-2 and Caspase-3. For CCK-8 assay, ERS had a significant inhibitory(p < 0.05) effect on cell proliferation when treated with ERS for 24 h, and both knockdown GRP94 and ERS had a significant inhibitory(p < 0.05) effect on cell proliferation when treated with ERS for 36 h and 48 h. We concluded that GRP94 can protect the cell from ERS-induced apoptosis by promoting the IGF-1 system and ubiquitin. These results provide valuable information on the adaptive mechanisms of the liver under ERS, and could help identify vital functional genes to be applied as possible diagnostic biomarkers and treatments for diseases induced by ERS in the future.

Animal Fats in Rabbit Feeding – A Review

The purpose of this article is to overview the history of feeding rabbits with different types of animal fats, and to discuss their effects on rabbit performance and quality of their products. Other aspects of the inclusion of various animal fats in rabbit diets are also described. This article is based on the analysis of relevant scientific literature and presents animal fats fed to rabbits, such as beef tallow, butter, pork lard, poultry fat, fish oil, krill oil, oil extracted from insect larvae, mixtures of various animal fats, and mixtures of animal and vegetable fats. The reported papers describe the effect of fats on growth performance, lactation, rearing performance, meat quality, and health status of rabbits. It is notable that in many cases, various animal fats were often an integral part of numerous diets or were included in control diets. The presented information demonstrates that animal fat can be fed to rabbits at 2–4% of the diet without negative effects on reproductive performance, growth performance and quality of meat obtained. Rabbits were used as model animals in many studies in which fat was added to balance the diets and to increase their energy value, especially when investigating various cardiovascular and obesity-related diseases.

Investigation of the cardiotoxic effects of parenteral nutrition in rabbits

INTRODUCTION

Parenteral nutrition (PN) is used for the intravenous delivery of nutrients to patients who cannot take food orally. However, it is not clear whether PN also negatively impacts cardiac tissue. The present empirical study investigated the cardiac effects of PN in rabbits.

METHODS

The effects of PN were examined in three groups of rabbits: animals in the PN + fasting group (n = 14) had been fully fasted before receiving a full PN dose via an intravenous central catheter; the PN + oral feeding group (n = 14) received half of the daily calorie requirement as a half dose of PN via an intravenous central catheter; the third group consisted of controls (n = 14) with full enteral feeding and full enteral fluid intake with no PN and no central venous catheter. At the end of the 10-day study period, the rabbits were subjected to echocardiographic examination and euthanized. Blood and tissue samples were obtained from all groups. DNA was isolated from nucleated blood cells. Tissue samples were examined by both light and electron microscopy, relative telomere length was determined from DNA, and blood samples were analyzed biochemically.

RESULTS

At the end of the study, there were no statistically significant differences in weight change between the three groups. Echocardiography revealed minimally impaired diastolic function in the PN + fasting group compared to the other groups. Biochemical and histopathological analyses, relative telomere length determination, and electron micrographs showed significant cardiac damage in the PN + fasting group but not in the PN + oral feeding group or the control group. The blood biochemical analyses showed hyperglycemia and a low insulin level in the PN + fasting group but not in the other two groups.

CONCLUSIONS

A combination of PN and fasting may damage the cardiac muscle cells of rabbits via a mechanism involving hyperglycemia and oxidative stress. Additional enteral feeding may protect against the destructive effects of PN on cardiac tissue.

Prediction of Bronchopulmonary Dysplasia in Preterm Infants Using Postnatal Risk Factors

Objective: To identify postnatal risk factors for bronchopulmonary dysplasia (BPD) development in preterm infants with gestational age ≤32 weeks. Methods: Seventy-two preterm infants(30 with BPD and 42 non-BPD controls) admitted in the neonatal intensive care unit (NICU) of the Children's Hospital of Soochow University during 2017 were enrolled in this prospective longitudinal study. Perinatal clinical data, a neonatal critical illness score (NCIS), different soluble B7-H3(sB7-H3), and interleukin-18 (IL-18) levels by days after birth were collected. An early predictive model for BPD development was established based on clinical data using multiple logistic regression analysis. And the sensitivity and specificity of the model were assesed by ROC curve. Results: Electrolyte disturbances, hemodynamically significant patent ductus arteriosus (hs-PDA), and the age that infants achieved 120 kcal/kg.d via enteral feeding ≥40 days after birth were found to be associated with the BPD pathogenesis. Serum sB7-H3, IL-18, and NCIS were significantly higher in the BPD group compared to the non-BPD group (p < 0.05). BPD group had significantly lower enteral fluid and caloric intake compared to the non-BPD group at 1, 7, 14, and 28 days after birth. The risk factors were analyzed by multiple logistic regression and a predictive model of a combination of sB7-H3 (day 7), IL-18 (day 14), NCIS, and clinical risk factors was evaluated via ROC curve with an area under the curve (AUC) of 0.960 having sensitivity of 86.7% and a specificity of 97.6%, respectively. Conclusion: The causes of BPD are multifactorial postnatal risk factors. And the combination of sB7-H3 (day 7), IL-18 (day 14), NCIS, and clinical risk factors (electrolyte disturbances, hs-PDA, and the age that infants achieved 120 kcal/kg.d via enteral feeding ≥40 days after birth) might be served as an optimal predictive model for the occurrence of BPD.

Effects of Sex, Drinking History, and Omega-3 and Omega-6 Fatty Acids Dysregulation on the Onset of Liver Injury in Very Heavy Drinking Alcohol-Dependent Patients

BACKGROUND

Heavy alcohol consumption frequently causes liver inflammation/injury, and certain fatty acids (FAs) may be involved in this liver pathology. In this study, we evaluated the association of heavy drinking and the changes in the FA levels involved in the ω-6 (pro-inflammatory) and ω-3 (anti-inflammatory) state in alcohol-dependent (AD) patients who had no clinical manifestations of liver injury. We aimed to identify sex-based differences in patients with mild or no biochemical evidence of liver injury induced by heavy drinking.

METHODS

A total of 114 heavy drinking AD female and male patients aged 21 to 65 years without clinical manifestations of liver injury, who were admitted to an alcohol dependence treatment program, were grouped by the alanine aminotransferase (ALT) levels: ≤40 IU/l, as no liver injury (GR.1), and >40 IU/l, as mild liver injury (GR.2). Patients were actively drinking until the day of admission. Comprehensive metabolic panel, comprehensive FA panel, and drinking history data were evaluated.

RESULTS

Elevated ALT and aspartate aminotransferase (AST) showed close association with markers of heavy alcohol intake. In the patients with mild biochemical liver injury (GR.2), females showed significantly higher AST level than males. Significant association of AST and total drinks in past 90 days (TD90) in females, and AST and heavy drinking days in past 90 days (HDD90) in males was observed. The ω-6:ω-3 ratio showed a significant pro-inflammatory response only in females with mild liver injury (GR.2) when adjusted by drinking history marker, TD90. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were increased in males with liver injury, while females did not show any comparable rise in EPA; and DHA levels were lower.

CONCLUSIONS

Measures of heavy drinking, TD90 and HDD90, predicted changes in liver injury. Changes in the ω-3 and ω-6 FA levels and the ω-6:ω-3 ratio showed a pro-inflammatory shift in patients with biochemical liver injury with a significant effect in females. Changes in FAs involved in the inflammatory state may represent one mechanism for liver inflammation/injury in response to heavy alcohol drinking.

Total Parenteral Nutrition-Induced Cholestasis: Prevention and Management

When cholestasis occurs in patients receiving total parenteral nutrition, it is the result of many pathogenic pathways converging on the hepatic acinus. The result may be a temporary rise in liver function tests. The resulting fibrosis, portal hypertension, and jaundice are hallmarks of type 3 intestinal-associated liver disease to which children are more susceptible than adults. The key to prevention is in identifying high-risk scenarios, meticulous monitoring, and personalized prescription of parenteral nutrition solutions combined with an active approach in reducing the impact of inflammatory events when they occur by prompt use of antibiotics and line locks.

Differential Impacts of Soybean and Fish Oils on Hepatocyte Lipid Droplet Accumulation and Endoplasmic Reticulum Stress in Primary Rabbit Hepatocytes

Parenteral nutrition-associated liver disease (PNALD) is a severe ailment associated with long-term parenteral nutrition. Soybean oil-based lipid emulsions (SOLE) are thought to promote PNALD development, whereas fish oil-based lipid emulsions (FOLE) are thought to protect against PNALD. This study aimed to investigate the effects of SOLE and FOLE on primary rabbit hepatocytes. The results reveal that SOLE caused significant endoplasmic reticulum (ER) and mitochondrial damage, ultimately resulting in lipid droplets accumulation and ER stress. While these deleterious events induce hepatocyte injury, FOLE at high doses cause only minor ER and mitochondrial damage, which has no effect on hepatic function. SOLE also significantly upregulated glucose-regulated protein 94 mRNA and protein expression. These data indicate that SOLE, but not FOLE, damage the ER and mitochondria, resulting in lipid droplets accumulation and ER stress and, finally, hepatocyte injury. This likely contributes to the differential impacts of SOLE and FOLE on PNALD development and progression.

Hepatic Overexpression of GRP94 in a Rabbit Model of Parenteral Nutrition-Associated Liver Disease

Objective. To use a rabbit model of parenteral nutrition-associated liver disease (PNALD) to study changes of the endoplasmic reticulum stress (ERS) marker glucose regulatory protein 94 (GRP94) and determine its role in the pathogenesis of PNALD. Methods. A rabbit PNALD model total parenteral nutrition (TPN) group was established. A corresponding control group received breast-feeding for one week. Serum biochemical parameters were measured and liver histological examinations were performed. The level of GRP94 mRNA and protein were measured. Results. The results showed that the serum TBIL, DBIL, and γ-GT levels in the TPN group were significantly higher than those in the control group, while levels of serum ALB in TPN group were significantly lower than those in the control group. The immunohistochemistry results showed that the protein expression level of GRP94 in the liver of TPN group was significantly increased compared with the control group. The RT-PCR results showed that the level of GRP94 mRNA in the liver of the TPN group was significantly higher compared with the control group. Conclusions. The mRNA and protein levels of GRP94 in the TPN group were both significantly increased, indicating that ERS may be directly related to the occurrence and development of PNALD.

Endoplasmic Reticulum Stress Is Implicated in Intestinal Failure-Associated Liver Disease

BACKGROUND

Intestinal failure-associated liver disease (IFALD) is the most serious consequence of long-term parenteral nutrition for intestinal failure. Little is known about the pathogenesis of IFALD, although many of the risk factors are also linked to endoplasmic reticulum stress (ERS). We propose that ERS may have a role in the development of IFALD.

METHODS

Archived liver tissue from patients with early and late IFALD, as well as from normal controls, was used for RNA extraction and immunohistochemistry to demonstrate the presence of ERS markers.

RESULTS

Mean relative RNA levels of glucose regulatory protein 78 in normal liver (n = 3), early IFALD (n = 15), and late IFALD (n = 5) were 0.5, 37.86, and 212.11, respectively. Mean relative expression of ERDj4 (ER DnaJ homologue 4, a downstream ERS effector) in normal liver, early IFALD, and late IFALD was 5.51, 216.68, and 213.22, respectively. The degree of splicing of X-box binding protein 1 in IFALD compared with normal liver was significantly higher (mean, 0.0779 normal, 0.102 early IFALD, 0.2063 late IFALD).

CONCLUSIONS

This is the first description of ERS in IFALD. This information may open up new therapeutic possibilities in the form of chemical chaperones known to ameliorate ERS.