Understanding necrotizing enterocolitis endotypes and acquired intestinal injury phenotypes from a historical and artificial intelligence perspective

Necrotizing enterocolitis (NEC) remains a devastating disease in preterm and term neonates. Despite significant progress made in understanding NEC pathogenesis over the last 50 years, the inability of current definitions to discriminate the various pathophysiological processes underlying NEC has led to an umbrella term that limits clinical and research progress. In this mini review, we provide a historical perspective on how NEC definitions and pathogenesis have evolved to our current understanding of NEC endotypes. We also discuss how artificial intelligence-based approaches are influencing our knowledge of risk-factors, classification and prognosis of NEC and other neonatal intestinal injury phenotypes.

Bolus Vasopressor Use for Air Medical Rapid Sequence Intubation: The Vasopressor Intravenous Push to Enhance Resuscitation Trial

BACKGROUND

Rapid sequence intubation (RSI) may compromise perfusion because of the use of sympatholytic medications as well as subsequent positive pressure ventilation. The use of bolus vasopressor agents may reverse hypotension and prevent arrest.

METHODS

This was a prospective, observational study enrolling air medical patients with critical peri-RSI hypotension (systolic blood pressure [SBP] < 90 mm Hg) to receive either arginine vasopressin (aVP), 2 U intravenously every 5 minutes, for trauma patients or phenylephrine (PE), 200 μg intravenously every 5 minutes, for nontrauma patients. The main outcome measures included an increase in SBP, a reversal of hypotension, and the occurrence of dysrhythmia or hypertension (SBP > 160 mm Hg) within 20 minutes of vasopressor administration.

RESULTS

A total of 523 patients (344 aVP and 179 PE) were enrolled over 2 years. An increase in SBP was observed in 326 aVP patients (95%), with reversal of hypotension in 272 patients (79%). An increase in SBP was observed in 171 PE patients (96%), with reversal of hypotension in 148 patients (83%). A low rate of rebound hypertension was observed for both aVP and PE patients.

CONCLUSION

Both aVP and PE appear to be safe and effective for treating critical hypotension in the peri-RSI period.

Hepatic circadian and differentiation factors control liver susceptibility for fatty liver disease and tumorigenesis

Hepatocellular carcinoma (HCC) is a leading cause of cancer deaths, and the most common primary liver malignancy to present in the clinic. With the exception of liver transplant, treatment options for advanced HCC are limited, but improved tumor stratification could open the door to new treatment options. Previously, we demonstrated that the circadian regulator Aryl Hydrocarbon-Like Receptor Like 1 (ARNTL, or Bmal1) and the liver-enriched nuclear factor 4 alpha (HNF4α) are robustly co-expressed in healthy liver but incompatible in the context of HCC. Faulty circadian expression of HNF4α- either by isoform switching, or loss of expression- results in an increased risk for HCC, while BMAL1 gain-of-function in HNF4α-positive HCC results in apoptosis and tumor regression. We hypothesize that the transcriptional programs of HNF4α and BMAL1 are antagonistic in liver disease and HCC. Here, we study this antagonism by generating a mouse model with inducible loss of hepatic HNF4α and BMAL1 expression. The results reveal that simultaneous loss of HNF4α and BMAL1 is protective against fatty liver and HCC in carcinogen-induced liver injury and in the "STAM" model of liver disease. Furthermore, our results suggest that targeting Bmal1 expression in the absence of HNF4α inhibits HCC growth and progression. Specifically, pharmacological suppression of Bmal1 in HNF4α-deficient, BMAL1-positive HCC with REV-ERB agonist SR9009 impairs tumor cell proliferation and migration in a REV-ERB-dependent manner, while having no effect on healthy hepatocytes. Collectively, our results suggest that stratification of HCC based on HNF4α and BMAL1 expression may provide a new perspective on HCC properties and potential targeted therapeutics.

A Transcriptomic Response to Lactiplantibacillus plantarum-KCC48 against High-Fat Diet-Induced Fatty Liver Diseases in Mice

The most prevalent chronic liver disorder in the world is fatty liver disease caused by a high-fat diet. We examined the effects of Lactiplantibacillus plantarum-KCC48 on high-fat diet-induced (HFD) fatty liver disease in mice. We used the transcriptome tool to perform a systematic evaluation of hepatic mRNA transcripts changes in high-fat diet (HFD)-fed animals and high-fat diet with L. plantarum (HFLPD)-fed animals. HFD causes fatty liver diseases in animals, as evidenced by an increase in TG content in liver tissues compared to control animals. Based on transcriptome data, 145 differentially expressed genes (DEGs) were identified in the liver of HFD-fed mice compared to control mice. Moreover, 61 genes were differentially expressed in the liver of mice fed the HFLPD compared to mice fed the HFD. Additionally, 43 common DEGs were identified between HFD and HFLPD. These genes were enriched in metabolic processes, retinol metabolism, the PPAR signaling pathway, fatty acid degradation, arachidonic metabolism, and steroid hormone synthesis. Taking these data into consideration, it can be concluded that L. plantarum-KCC48 treatment significantly regulates the expression of genes involved in hepatosteatosis caused by HFD, which may prevent fatty liver disease.

Necrotizing Enterocolitis in Children with Congenital Heart Disease: A Literature Review

Infants with congenital heart disease (CHD) are at an increased risk of developing necrotising enterocolitis (NEC), a serious inflammatory intestinal condition classically associated with prematurity. CHD not only increases the risk of NEC in preterm infants but is one of the most commonly implicated risk factors in term infants. Existing knowledge on the topic is limited largely to retrospective studies. This review acts to consolidate existing knowledge on the topic in terms of disease incidence, pathophysiology, risk factors, outcomes and the complex relationship between NEC and enteral feeds. Potential preventative strategies, novel biomarkers for NEC in this population, and the role of the intestinal microbiome are all explored. Numerous challenges exist in the study of this complex multifactorial disease which arise from the heterogeneity of the affected population and its relative scarcity. Nevertheless, its high related morbidity and mortality warrant renewed interest in identifying those infants most at risk and implementing strategies to reduce the incidence of NEC in infants with CHD.

The impact of perioperative inotropes on the incidence of pancreatic leak following pancreaticoduodenectomy

Backgrounds/Aims

Pancreatic leak and fistula formation following pancreatic resection is a dreaded complication associated with significant morbidity and mortality. The perioperative use of inotropes has been implicated in anastomotic dehiscence in other types of gastrointestinal surgery but their impact in pancreatic surgery remains unclear and a potentially modifiable risk factor for pancreatic leak. This study aims to assess the impact of perioperative inotrope infusion on the incidence of pancreatic leak following pancreaticoduodenectomy.

Methods

Retrospective data analysis of all patients undergoing pancreaticoduodenectomy at a tertiary HPB institute. Multivariate analysis and regression models assessed the impact of inotrope use against other known risk factors such as pancreatic duct size and gland texture. Pancreatic fistulae were graded as per ISGPF as Grade A (biochemical leak), Grade B and Grade C fistula.

Results

One-hundred and twenty-three (123) patients were included. A total of 52 patients (42%) developed a leak (29 grade A, 15 grade B, and 8 Grade C). In the fistula group, 28 patients (55%) received perioperative inotropes compared to 26 (35%) in the no fistula group. On univariate analysis, patients receiving inotropes (p=0.04) and patients with a soft pancreatic texture (p=0.003) had a statistically higher incidence of developing a pancreatic fistula of any grade. On multivariate analysis, only inotrope use was associated with an increased risk of developing a pancreatic fistula of any grade (OR 2.46, p=0.026), independent of pancreatic texture and pancreatic duct size.

Conclusions

Perioperative inotrope use is associated with an increase incidence of pancreatic leak following pancreaticoduodenectomy and should therefore be used judiciously.

Vasopressin and nitroglycerin decrease portal and hepatic venous pressure and hepato-splanchnic blood flow

BACKGROUND

Various methods are used to reduce venous blood pressure in the hepato-splanchnic circulation, and hence minimise blood loss during liver surgery. Previous studies show that combination of vasopressin and nitroglycerin reduces portal pressure and flow in patients with portal hypertension, and in this study we investigated this combination in patients with normal portal pressure.

METHOD

In all, 13 patients were studied. Measurements were made twice to confirm baseline (C1 and BL), during vasopressin infusion 4.8 U/h (V), and during vasopressin infusion combined with nitroglycerin infusion (V + N). Portal venous pressure (PVP), hepatic venous pressure (HVP), central haemodynamics and arterial and venous blood gases were obtained at each measuring point, and portal (splanchnic) and hepato-splanchnic blood flow changes were calculated.

RESULTS

Vasopressin alone did not affect PVP, whereas HVP increased slightly. In combination with nitroglycerin, PVP decreased from 10.1 ± 1.6 to 8.9 ± 1.3 mmHg (P < 0.0001), and HVP decreased from 7.9 ± 1.9 to 6.2 ± 1.3 mmHg (P = 0.001). Vasopressin reduced portal blood flow by 47 ± 19% and hepatic venous flow by 11 ± 18%, respectively. Addition of nitroglycerin further reduced portal- and hepatic flow by 55 ± 13% and 30 ± 13%, respectively. Vasopressin alone had minor effects on central haemodynamics, whereas addition of nitroglycerin reduced cardiac index (3.2 ± 0.7 to 2.7 ± 0.5; P < 0.0001). The arterial-portal vein lactate gradient was unaffected.

CONCLUSION

The combination of vasopressin and nitroglycerin decreases portal pressure and hepato-splanchnic blood flow, and could be a potential treatment to reduce bleeding in liver resection surgery.

Increased Intraoperative Vasopressor Use as Part of an Enhanced Recovery After Surgery Pathway for Pancreatectomy Does Not Increase Risk of Pancreatic Fistula

Purpose: Enhanced recovery after surgery (ERAS) pathways are increasingly implemented. Goal directed fluid therapy (GDFT) is a core component of ERAS pathways that limit excessive volume administration and is associated with increased use of intraoperative vasopressors. Vasopressor effects on anastomotic healing and pancreatic fistula are inconclusive. We hypothesized that intraoperative vasopressor use in an ERAS GDFT algorithm would not increase risk of pancreatic fistulas. Methods: We reviewed all adult patients undergoing pancreatectomy at an academic institution from January 2013 to February 2016, before and after implementation of an ERAS pathway in July 2014. Retrospective chart review was performed. Log-binomial regression, weighted by stabilized inverse probability-of-treatment weights, estimated effect of ERAS and intraoperative vasopressors on fistula risk. Results: One hundred thirty two patients met inclusion criteria: 74 (56.1%) in the ERAS cohort. No significant differences in overall leak risk (risk ratio [RR] 0.89, 95% confidence interval [CI] 0.38-2.09) were observed between the ERAS and pre-ERAS cohorts. Similarly, vasopressor infusions, independent of ERAS pathway, did not significantly increase the risk of anastomotic leaks (RR 1.19, 95% CI 0.52-2.72). Conclusions: Increased use of vasopressor infusions as part of an ERAS pathway for pancreatic surgery is not associated with an increase in the risk of clinically significant pancreatic fistulas.

Early and sustained vasopressin infusion augments the hemodynamic efficacy of restrictive fluid resuscitation and improves survival in a liver laceration model of hemorrhagic shock

BACKGROUND

Current management of hemorrhagic shock favors restrictive fluid resuscitation before control of the bleeding source. We investigated the additional effects of early and sustained vasopressin infusion in a swine model of hemorrhagic shock produced by liver laceration.

METHODS

Forty male domestic pigs (32-40 kg) had a liver laceration inflicted with an X-shaped blade clamp, 32 received a second laceration at minute 7.5, and 24 received two additional lacerations at minute 15. Using a two-by-two factorial design, animals were randomized 1:1 to receive vasopressin infusion (0.04 U/kg per minute) or vehicle intraosseously from minute 7 until minute 240 and 1:1 to receive isotonic sodium chloride solution (12 mL/kg) intravenously at minute 30 or no fluids.

RESULTS

Kaplan-Meier curves showed greater survival after vasopressin with isotonic sodium chloride solution (8/10) compared to vasopressin without isotonic sodium chloride solution (4/10), vehicle with isotonic sodium chloride solution (3/10), or vehicle without isotonic sodium chloride solution (3/10), but the differences were not statistically significant (p = 0.095 by log-rank test). However, logistic regression showed vasopressin to elicit a statistically significant benefit on survival (p = 0.042). Vasopressin augmented mean aortic pressure between 10 and 20 mm Hg without intensifying the rate of bleeding from liver laceration, which was virtually identical to that of vehicle-treated animals (33.9 ± 5.1 and 33.8 ± 4.8 mL/kg). Vasopressin increased systemic vascular resistance and reduced transcapillary fluid extravasation, augmenting the volume of isotonic sodium chloride solution retained (6.5 ± 2.7 vs 2.4 ± 2.0 mL/kg by minute 60). The cardiac output and blood flow to the myocardium, liver, spleen, kidney, small bowel, and skeletal muscle at minute 120 and minute 180 were comparable or higher in the vasopressin group.

CONCLUSIONS

Early and sustained vasopressin infusion provided critical hemodynamic stability during hemorrhagic shock induced by liver laceration and increased the hemodynamic efficacy of restrictive fluid resuscitation without intensifying bleeding or compromising organ blood flow resulting in improved 240-minute survival.

Altered hepatic lipid metabolism in mice lacking both the melanocortin type 4 receptor and low density lipoprotein receptor

Obesity is often associated with dyslipidemia and hepatosteatosis. A number of animal models of non-alcoholic fatty liver disease (NAFLD) are established but they significantly differ in the molecular and biochemical changes depending on the genetic modification and diet used. Mice deficient for melanocortin type 4 receptor (Mc4r^mut) develop hyperphagia, obesity, and subsequently NAFLD already under regular chow and resemble more closely the energy supply-driven obesity found in humans. This animal model was used to assess the molecular and biochemical consequences of hyperphagia-induced obesity on hepatic lipid metabolism. We analyzed transcriptome changes in Mc4r^mut mice by RNA sequencing and used high resolution ¹H magic angle spinning NMR spectroscopy and MALDI-TOF mass spectrometry to assess changes in the lipid composition. On the transcriptomic level we found significant changes in components of the triacylglycerol metabolism, unsaturated fatty acids biosynthesis, peroxisome proliferator-activated receptor signaling pathways, and lipid transport and storage compared to the wild-type. These findings were supported by increases in triacylglycerol, monounsaturated fatty acid, and arachidonic acid levels. The transcriptome signatures significantly differ from those of other NAFLD mouse models supporting the concept of hepatic subphenotypes depending on the genetic background and diet. Comparative analyses of our data with previous studies allowed for the identification of common changes and genotype-specific components and pathways involved in obesity-associated NAFLD.

Portal venular constriction during anaphylactic shock in anesthetized rats

Hepatic venoconstriction occurs in rat anaphylactic hypotension. However, the exact venoconstrictive site remains unknown, and we therefore attempted to determine its location by using hepatic venography and histology. Anaphylaxis was induced in anesthetized Sprague-Dawley rats by i.v. administration of ovalbumin antigen. Venography of the portal vein (n = 8) was obtained at baseline and maximal hepatic venoconstriction. We separately examined photomicrographs of the liver sections. Along with systemic hypotension, portal venous pressure increased to a peak of 28 ± 3 cm- H2O at 2 min after antigen injection. Post-antigen portal venography revealed that 40% of portal venuls (76 vessels/total 188 vessels) with diameters from 160 to 300 μm were not visualized, suggesting that stenosis or obliteration occurred distally. The corresponding upstream portal vessels exhibited markedly bulging. Stenosis was also observed in some portal branches with diameters from 180 to 420 μm (9%; 17 vessels/total 188 vessels). Light microscopically, most portal venules with an estimated baseline diameter less than 110 μm showed stenosis, but statistically significant stenosis was found in those with baseline diameters of 20-70 μm. In conclusion, anaphylactic hepatic venoconstriction occurs over a wide range of portal veins with diameters less than 420 μm, and occurs markedly in portal venules with diameters less than 70 μm in anesthetized rats.