Management of pediatric lower extremity vascular trauma: adult vs pediatric level I trauma centers.

BACKGROUND: Pediatric lower extremity vascular injury (PLEVI) is uncommon and the availability of granular data is sparse. This study evaluated the surgical management of PLEVIs between a Level I adult (ATC) vs pediatric (PTC) trauma center. METHODS: We performed a retrospective review of PLEVIs (< 18 years) managed surgically between 01/2009-12/2022. Demographics and outcome data were obtained. Primary outcomes included amputation and fasciotomy rates. Secondary outcomes included type of vessel repair, mortality, and hospital length of stay. RESULTS: Seventy-nine patients were identified, 41 at the ATC and 38 at the PTC, totaling 112 vessels injured. ATC patients were older (median years 16.0 vs 12.5) and almost exclusively (97.6% vs 29.0%) gunshot wounds. Vascular surgeons managed 50% of injuries at the ATC vs 73.7% at the PTC (p = 0.10). Amputations were uncommon and not significantly different between centers. Seventeen patients (44.7%) required fasciotomies at the PTC vs 21 (51.2%) at the ATC (p = 0.56). Rates of vessel repair, ligation, grafting, mortality, and hospital length of stay were not significantly different. CONCLUSIONS: PLEVI can be managed safely at ATCs and PTCs with acceptable outcomes. However, important nuances in patient triage and management need to be considered. Multi-institutional comprehensive datasets are needed. LEVEL OF EVIDENCE:  Level III.

Powering up targeted protein degradation through active and passive tumour-targeting strategies: Current and future scopes.

Targeted protein degradation (TPD) has emerged as a prominent and vital strategy for therapeutic intervention of cancers and other diseases. One such approach involves the exploration of proteolysis targeting chimeras (PROTACs) for the selective elimination of disease-causing proteins through the innate ubiquitin-proteasome pathway. Due to the unprecedented achievements of various PROTAC molecules in clinical trials, researchers have moved towards other physiological protein degradation approaches for the targeted degradation of abnormal proteins, including lysosome-targeting chimeras (LYTACs), autophagy-targeting chimeras (AUTACs), autophagosome-tethering compounds (ATTECs), molecular glue degraders, and other derivatives for their precise mode of action. Despite numerous advantages, these molecules face challenges in solubility, permeability, bioavailability, and potential off-target or on-target off-tissue effects. Thus, an urgent need arises to direct the action of these degrader molecules specifically against cancer cells, leaving the proteins of non-cancerous cells intact. Recent advancements in TPD have led to innovative delivery methods that ensure the degraders are delivered in a cell- or tissue-specific manner to achieve cell/tissue-selective degradation of target proteins. Such receptor-specific active delivery or nano-based passive delivery of the PROTACs could be achieved by conjugating them with targeting ligands (antibodies, aptamers, peptides, or small molecule ligands) or nano-based carriers. These techniques help to achieve precise delivery of PROTAC payloads to the target sites. Notably, the successful entry of a Degrader Antibody Conjugate (DAC), ORM-5029, into a phase 1 clinical trial underscores the therapeutic potential of these conjugates, including LYTAC-antibody conjugates (LACs) and aptamer-based targeted protein degraders. Further, using bispecific antibody-based degraders (AbTACs) and delivering the PROTAC pre-fused with E3 ligases provides a solution for cell type-specific protein degradation. Here, we highlighted the current advancements and challenges associated with developing new tumour-specific protein degrader approaches and summarized their potential as single agents or combination therapeutics for cancer.

Management of complex pediatric and adolescent liver trauma: adult vs pediatric level 1 trauma centers.

PURPOSE: Management of high-grade pediatric and adolescent liver trauma can be complex. Studies suggest that variation exists at adult (ATC) vs pediatric trauma centers (PTC); however, there is limited granular comparative data. We sought to describe and compare the management and outcomes of complex pediatric and adolescent liver trauma between a level 1 ATC and two PTCs in a large metropolitan city. METHODS: A retrospective review of pediatric and adolescent (age < 21 years) patients with American Association for the Surgery of Trauma (AAST) Grade 4 and 5 liver injuries managed at an ATC and PTCs between 2016 and 2022 was performed. Demographic, clinical, and outcome data were obtained at the ATC and PTCs. Primary outcomes included rates of operative management and use of interventional radiology (IR). Secondary outcomes included packed red blood cell (pRBC) utilization, intensive care unit (ICU) length of stay (LOS), and hospital LOS. RESULTS: One hundred forty-four patients were identified, seventy-five at the ATC and sixty-nine at the PTC. The cohort was predominantly black (65.5%) males (63.5%). Six injuries (8.7%) at the PTC and forty-five (60%) injuries at the ATC were penetrating trauma. Comparing only blunt trauma, ATC patients had higher Injury Severity Score (median 37 vs 26) and ages (20 years vs 9 years). ATC patients were more likely to undergo operative management (26.7% vs 11.0%, p = 0.016) and utilized IR more (51.9% vs 4.8%, p < 0.001) compared to the PTC. The patients managed at the ATC required higher rates of pRBC transfusions though not statistically significant (p = 0.06). There were no differences in mortality, ICU, or hospital LOS. CONCLUSION: Our retrospective review of high-grade pediatric and adolescent liver trauma demonstrated higher rates of IR and operating room use at the ATC compared to the PTC in the setting of higher Injury Severity Score and age. While the PTC successfully managed > 95% of Grade 4/5 liver injuries non-operatively, prospective data are needed to determine the optimal algorithm for management in the older adolescent population. LEVEL OF EVIDENCE: Level IV.

Standardization of Antibiotic Management and Reduction of Opioid Prescribing in Pediatric Complicated Appendicitis: A Quality Improvement Initiative.

BACKGROUND: Appendicitis is one of the most common pediatric surgical procedures in the United States. However, wide variation remains in antibiotic prescribing and pain management across and within institutions. We aimed to minimize variation in antibiotic usage and decrease opioid prescribing at discharge for children with complicated appendicitis by implementation of a quality improvement (QI) initiative. METHODS: On December 1st, 2021, a QI initiative standardizing postoperative care for complicated appendicitis was implemented across a tertiary pediatric healthcare system with two main surgical centers. QI initiative focused on antibiotic and pain management. An extensive literature search was performed and a total of 20 articles matching our patient population were critically appraised to determine the best evidence-based interventions to implement. Antibiotic regimen included: IV or PO ceftriaxone/metronidazole immediately post-operatively and transition to PO amoxicillin-clavulanic acid for completion of 7-day total course at discharge. Discharge pain control regimen included acetaminophen, ibuprofen, as needed gabapentin, and no opioid prescription. Guideline compliance were closely monitored for the first six months following implementation. RESULTS: In the first 6-months post-implementation, compliance with use of ceftriaxone/metronidazole as initial post-operative antibiotics was 75.6 %. Transition to PO amoxicillin-clavulanic acid prior to discharge increased from 13.7 % pre-implementation to 73.7 % 6-months post-implementation (p < 0.001). Compliance with a 7-day course of antibiotics within the first 6-months post-implementation was 60 % across both sites. After QI intervention, overall opioid prescribing remained at 0 % at one surgical site and decreased from 17.6 % to 0 % at the second surgical site over the study timeframe (p < 0.001). CONCLUSION: Antibiotic use can be standardized and opioid prescribing minimized in children with complicated appendicitis using QI principles. Continued monitoring of the complicated appendicitis guideline is needed to assess for further progress in the standardization of post-operative care. STUDY TYPE: Quality improvement. LEVEL OF EVIDENCE: Level III.

Ferric Chloride-Induced Arterial Thrombosis and Sample Collection for 3D Electron Microscopy Analysis.

Cardiovascular diseases are a leading cause of mortality and morbidity worldwide. Aberrant thrombosis is a common feature of systemic conditions like diabetes and obesity, and chronic inflammatory diseases like atherosclerosis, cancer, and autoimmune diseases. Upon vascular injury, usually the coagulation system, platelets, and endothelium act in an orchestrated manner to prevent bleeding by forming a clot at the site of the injury. Abnormalities in this process lead to either excessive bleeding or uncontrolled thrombosis/insufficient antithrombotic activity, which translates into vessel occlusion and its sequelae. The FeCl3-induced carotid injury model is a valuable tool in probing how thrombosis initiates and progresses in vivo. This model involves endothelial damage/denudation and subsequent clot formation at the injured site. It provides a highly sensitive, quantitative assay to monitor vascular damage and clot formation in response to different degrees of vascular damage. Once optimized, this standard technique can be used to study the molecular mechanisms underlying thrombosis, as well as the ultrastructural changes in platelets in a growing thrombus. This assay is also useful to study the efficacy of antithrombotic and antiplatelet agents. This article explains how to initiate and monitor FeCl3-induced arterial thrombosis and how to collect samples for analysis by electron microscopy.

Trends in Adolescent Firearm-Related Injury: A Time Series Analysis.

BACKGROUND: Firearm-related injury (FRI) became the leading cause of death among children/adolescents in 2019. PURPOSE: This study sought to determine changes over time in the population of adolescents affected by FRI in Atlanta, Georgia, such that high risk cohorts could be identified. RESEARCH DESIGN: City-wide retrospective cohort review. STUDY SAMPLE: Adolescent victims (age 11-21 years of age) of FRI, defined by ICD9/10 codes, in Atlanta, Georgia. DATA ANALYSIS: Descriptive, multivariate and time series analysis. RESULTS: There were 1,453 adolescent FRI victims in this time period, predominantly Black (86%) and male (86.6%). Unintentional injury was higher among ages 11-14 years (43.1%) compared to 15-17 years (10.2%) and 18-21 years (9.3%) (P < .01). FRI affecting females increased at a rate of 8.1 injuries/year (P < .01), and unintentional injuries increased at by 7.6/year (P < .01). Mortality declined from 16% in 2016 to 7.7% in 2021. CONCLUSION: Our data provides evidence for firearm policy reform. Interventions should target prevention of intentional injury among AQ4 females and seek to reverse the trend in unintentional injuries.

miR-542-5p targets c-myc and negates the cell proliferation effect of SphK1 in intestinal epithelial cells.

Intestinal epithelial barrier defects occur commonly during a variety of pathological conditions, though their underlying mechanisms are not completely understood. Sphingosine-1-phosphate (S1P) has been shown to be a critical regulator of proliferation and of maintenance of an intact intestinal epithelial barrier, as is also sphingosine kinase 1 (SphK1), the rate-limiting enzyme for S1P synthesis. SphK1 has been shown to modulate its effect on intestinal epithelial proliferation through increased levels of c-myc. We conducted genome-wide profile analysis to search for differential microRNA expression related to overexpressed SphK1 demonstrating adjusted expression of microRNA 542-5p (miR-542-5p). Here, we show that miR-542-5p is regulated by SphK1 activity and is an effector of c-myc translation that ultimately serves as a critical regulator of the intestinal epithelial barrier. miR-542-5p directly regulates c-myc translation through direct binding to the c-myc mRNA. Exogenous S1P analogs administered in vivo protect murine intestinal barrier from damage due to mesenteric ischemia reperfusion, and damaged intestinal tissue had increased levels of miR-542-5p. These results indicate that miR-542-5p plays a critical role in the regulation of S1P-mediated intestinal barrier function, and may highlight a novel role in potential therapies.

Overcoming Cancer Drug Resistance Utilizing PROTAC Technology.

Cancer drug resistance presents a major barrier to continued successful treatment of malignancies. Current therapies inhibiting proteins indicated in cancer progression are consistently found to lose efficacy as a result of acquired drug resistance, often caused by mutated or overexpressed protein targets. By hijacking the cellular ubiquitin-proteasome protein degradation machinery, proteolysis-targeting chimeras (PROTACs) offer an alternative therapeutic modality to cancer treatments with various potential advantages. PROTACs specific for a number of known cancer targets have been developed in the last 5 years, which present new options for remission in patients with previously untreatable malignancies and provide a foundation for future-generation compounds. One notable advantage of PROTACs, supported by evidence from a number of recent studies, is that they can overcome some of the resistance mechanisms to traditional targeted therapies. More recently, some groups have begun researching the use of PROTACs to successfully degrade mutated targets conferring cancer resistance against first-line treatments. In this review, we focus on analyzing the developments in PROTACs geared towards cancer resistance and targets that confer it in the search for new and successful therapies.

Utility of ventriculogallbladder shunts in complex cases of hydrocephalus related to extreme prematurity.

OBJECTIVE: The management of hydrocephalus resulting from intraventricular hemorrhage related to extreme prematurity remains demanding. Given the complexities of controlling hydrocephalus in this population, less commonly used procedures may be required. The authors examined the utility of ventriculogallbladder (VGB) shunts in a series of such children. METHODS: The authors retrospectively reviewed the medical records of all children who underwent surgery for hydrocephalus in the period from 2011 through 2019 at Children's Healthcare of Atlanta. Six patients who underwent VGB shunt placement were identified among a larger cohort of 609 patients who had either a new shunt or a newly changed distal terminus site. The authors present an analysis of this series, including a case of laparoscopy-assisted distal VGB shunt revision. RESULTS: The mean age at initial shunt placement was 5.1 months (range 3.0-9.4 months), with patients undergoing a mean of 11.8 shunt procedures (range 5-17) prior to the initial VGB shunt placement at a mean age of 5.3 years (range 7.9 months-12.8 years). All 6 patients with VGB shunt placement had hydrocephalus related to extreme prematurity (gestational age < 28 weeks). At the time of VGB shunt placement, all had complex medical and surgical histories, including poor venous access due to congenital or iatrogenic thrombosis or thrombophlebitis and a peritoneum hostile to distal shunt placement related to severe necrotizing enterocolitis. VGB complications included 1 case of shunt infection, identified at postoperative day 6, and 2 cases of distal shunt failure due to retraction of the distal end of the VGB shunt. In all, there were 3 conversions back to ventriculoperitoneal or ventriculoatrial shunts due to the 2 previously mentioned complications, plus 1 patient who outgrew their initial VGB shunt. Three of 6 patients remain with a VGB shunt, including 1 who underwent laparoscopy-assisted distal shunt revision 110.5 months after initial VGB shunt insertion. CONCLUSIONS: Placement of VGB shunts should be considered in the armamentarium of procedures that may be used in the particularly difficult cohort of children with hydrocephalus related to extreme prematurity. VGB shunts show utility as both a definitive treatment and as a "bridge" procedure until the patient is larger and comorbid abdominal and/or vascular issues have resolved sufficiently to allow conversion back to ventriculoperitoneal or ventriculoatrial shunts, if needed.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) for temporization of hemorrhage in adolescent trauma patients.

BACKGROUND/PURPOSE: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as an alternative technique for traumatic hemorrhage control in the adult population. The purpose of this study is to describe the details of REBOA placement in adolescent trauma patients. METHODS: Patients 18 years of age or less who received REBOA for aortic occlusion (AO) from August 2013 to February 2017 at 2 urban tertiary care centers were included. RESULTS: 7 adolescent trauma patients received REBOA by trauma surgeons for both blunt (n = 4) and penetrating mechanisms (n = 3); mean age was 17 + 1.5 years, mean admission lactate 13.0 + 4.85 mmol/L, and mean Hgb 10.7 + 2.7 g/dL. 3 patients received REBOA through a 12Fr sheath and 4 through a 7Fr sheath. AO occurred mostly at the distal thoracic aorta (Zone I) (85.7%) and also in the distal abdominal aorta (Zone III) (14.3%). 57% of patients were in arrest with ongoing CPR at the time of REBOA. In-hospital mortality was 57%; all of these patients were in arrest at the time of REBOA, had return of spontaneous circulation (ROSC), and survived to the operating room. No complications from REBOA were identified. CONCLUSION: REBOA appears to be feasible for use in adolescents despite their smaller caliber vessels, even with use of a 12Fr sheath. REBOA results in improved physiology and can bridge adolescent trauma patients presenting in extremis to the operating room. TYPE OF STUDY: Treatment/therapeutic study LEVEL OF EVIDENCE: Level IV.

Can time to healing in pediatric blunt splenic injury be predicted?

BACKGROUND: Current consensus guidelines do not recommend routine follow-up imaging for blunt splenic injury (BSI) in children. However, repeat imaging is recommended based on persistent symptoms. Wide variation of practice continues to exist among surgeons. By defining the natural evolution of BSI, we sought to identify patients at higher risk for delayed healing who could benefit from outpatient imaging. METHODS: A retrospective review of all children with BSI at a Level 1 Pediatric Trauma Center was completed. Grade of injury, hospital course, laboratory values and follow-up imaging results were obtained. Injured spleens were classified as 'healed', 'healing' (with echogenic scar), or 'non-healing' with persistence of parenchymal abnormalities. RESULTS: Between 2000 and 2014, 222 patients with BSI were identified. Seven patients (3%) underwent immediate splenectomy. Packed red blood cell transfusion was required in 13 (6%) of the 222 patients, and 3 (2%) of 145 with isolated splenic injuries. Seventy-one percent of patients underwent additional imaging 2-74 weeks post-injury. A receiver operating characteristics (ROC) curve was used to establish the relationship between sensitivity and specificity of capturing non-healing spleens over time. Optimal timing for post-injury imaging for grades I-II was 7-8 weeks; healing of higher-grade injuries could not accurately be predicted. CONCLUSIONS: If return to full physical activity, in particular contact sports, is contingent upon documented healing of the splenic parenchyma after blunt trauma in the pediatric population, follow-up imaging for low-grade injuries is best obtained around 7-8 weeks. No such recommendations can be made for high-grade splenic injuries, as the exact time to healing cannot be predicted based on initial data. LEVEL OF EVIDENCE: IV. Diagnostic test.

Proposed clinical pathway for nonoperative management of high-grade pediatric pancreatic injuries based on a multicenter analysis: A pediatric trauma society collaborative.

BACKGROUND: Guidelines for nonoperative management (NOM) of high-grade pancreatic injuries in children have not been established, and wide practice variability exists. The purpose of this study was to evaluate common clinical strategies across multiple pediatric trauma centers to develop a consensus-based standard clinical pathway. METHODS: A multicenter, retrospective review was conducted of children with high-grade (American Association of Surgeons for Trauma grade III-V) pancreatic injuries treated with NOM between 2010 and 2015. Data were collected on demographics, clinical management, and outcomes. RESULTS: Eighty-six patients were treated at 20 pediatric trauma centers. Median age was 9 years (range, 1-18 years). The majority (73%) of injuries were American Association of Surgeons for Trauma grade III, 24% were grade IV, and 3% were grade V. Median time from injury to presentation was 12 hours and median ISS was 16 (range, 4-66). All patients had computed tomography scan and serum pancreatic enzyme levels at presentation, but serial enzyme level monitoring was variable. Pancreatic enzyme levels did not correlate with injury grade or pseudocyst development. Parenteral nutrition was used in 68% and jejunal feeds in 31%. 3Endoscopic retrograde cholangiopancreatogram was obtained in 25%. An organized peripancreatic fluid collection present for at least 7 days after injury was identified in 59% (42 of 71). Initial management of these included: observation 64%, percutaneous drain 24%, and endoscopic drainage 10% and needle aspiration 2%. Clear liquids were started at a median of 6 days (IQR, 3-13 days) and regular diet at a median of 8 days (IQR 4-20 days). Median hospitalization length was 13 days (IQR, 7-24 days). Injury grade did not account for prolonged time to initiating oral diet or hospital length; indicating that the variability in these outcomes was largely due to different surgeon preferences. CONCLUSION: High-grade pancreatic injuries in children are rare and significant variability exists in NOM strategies, which may affect outcomes and effective resource utilization. A standard clinical pathway is proposed. LEVEL OF EVIDENCE: Therapeutic/care management, level V (case series).

A protein-protein interaction dictates Borrelial infectivity.

Two Borrelia burgdorferi interacting proteins, BB0238 and BB0323, play distinct roles in pathogen biology and infectivity although a significance of their interaction remained enigmatic. Here we identified the polypeptide segment essential for BB0238-BB0323 interaction and examined how it supports spirochete infectivity. We show that the interaction region in BB0323 requires amino acid residues 22-200, suggesting that the binding encompasses discontinuous protein segments. In contrast, the interaction region in BB0238 spans only 11 amino acids, residues 120-130. A deletion of these 11 amino acids neither alters the overall secondary structure of the protein, nor affects its stability or oligomerization property, however, it reduces the post-translational stability of the binding partner, BB0323. Mutant B. burgdorferi isolates producing BB0238 lacking the 11-amino acid interaction region were able to persist in ticks but failed to transmit to mice or to establish infection. These results suggest that BB0238-BB0323 interaction is critical for post-translational stability of BB0323, and that this interaction is important for mammalian infectivity and transmission of B. burgdorferi. We show that saturation or inhibition of BB0238-BB0323 interaction could be studied in a luciferase assay, which could be amenable for future identification of small molecule inhibitors to combat B. burgdorferi infection.

Infection-derived lipids elicit an immune deficiency circuit in arthropods.

The insect immune deficiency (IMD) pathway resembles the tumour necrosis factor receptor network in mammals and senses diaminopimelic-type peptidoglycans present in Gram-negative bacteria. Whether unidentified chemical moieties activate the IMD signalling cascade remains unknown. Here, we show that infection-derived lipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) and 1-palmitoyl-2-oleoyl diacylglycerol (PODAG) stimulate the IMD pathway of ticks. The tick IMD network protects against colonization by three distinct bacteria, that is the Lyme disease spirochete Borrelia burgdorferi and the rickettsial agents Anaplasma phagocytophilum and A. marginale. Cell signalling ensues in the absence of transmembrane peptidoglycan recognition proteins and the adaptor molecules Fas-associated protein with a death domain (FADD) and IMD. Conversely, biochemical interactions occur between x-linked inhibitor of apoptosis protein (XIAP), an E3 ubiquitin ligase, and the E2 conjugating enzyme Bendless. We propose the existence of two functionally distinct IMD networks, one in insects and another in ticks.

Multicentre validation of a microRNA-based assay for diagnosing indeterminate thyroid nodules utilising fine needle aspirate smears.

AIMS: The distinction between benign and malignant thyroid nodules has important therapeutic implications. Our objective was to develop an assay that could classify indeterminate thyroid nodules as benign or suspicious, using routinely prepared fine needle aspirate (FNA) cytology smears. METHODS: A training set of 375 FNA smears was used to develop the microRNA-based assay, which was validated using a blinded, multicentre, retrospective cohort of 201 smears. Final diagnosis of the validation samples was determined based on corresponding surgical specimens, reviewed by the contributing institute pathologist and two independent pathologists. Validation samples were from adult patients (≥18 years) with nodule size >0.5 cm, and a final diagnosis confirmed by at least one of the two blinded, independent pathologists. The developed assay, RosettaGX Reveal, differentiates benign from malignant thyroid nodules, using quantitative RT-PCR. RESULTS: Test performance on the 189 samples that passed quality control: negative predictive value: 91% (95% CI 84% to 96%); sensitivity: 85% (CI 74% to 93%); specificity: 72% (CI 63% to 79%). Performance for cases in which all three reviewing pathologists were in agreement regarding the final diagnosis (n=150): negative predictive value: 99% (CI 94% to 100%); sensitivity: 98% (CI 87% to 100%); specificity: 78% (CI 69% to 85%). CONCLUSIONS: A novel assay utilising microRNA expression in cytology smears was developed. The assay distinguishes benign from malignant thyroid nodules using a single FNA stained smear, and does not require fresh tissue or special collection and shipment conditions. This assay offers a valuable tool for the preoperative classification of thyroid samples with indeterminate cytology.

Characterization of the Pro-Inflammatory Cytokine IL-1ß on Butyrate Oxidation in Colorectal Cancer Cells.

Cancer, in part, is driven, by alterations in cellular metabolism that promote cell survival and cell proliferation. Identifying factors that influence this shift in cellular metabolism in cancer cells is important. Interleukin-1ß (IL-1ß) is a pro-inflammatory cytokine that has been reported to be elevated in colorectal cancer patients. While much is known toward the effect of dietary nutrients on regulating inflammation and the inflammatory response, which includes cytokines such as IL-1ß, far less is understood how cytokines impact nutrient fate to alter cancer cell metabolism. Butyrate, a nutrient derived from the fermentation of dietary fiber in the colon, is the preferential exogenous energetic substrate used by non-cancerous colonocytes, but is used less efficiently by colorectal cancer cells. To test whether IL-1ß alters colonocyte energy metabolism, we measured butyrate oxidation in HCT116 colorectal cancer cells with and without IL-1ß. We hypothesize that IL-1ß will push cancerous colonocytes away from the utilization and oxidation of butyrate. In this study, we demonstrate that pretreatment of colorectal cancer cells with IL-1ß diminished butyrate oxidation and NADH levels. This effect was blocked with the interleukin receptor antagonist A (IL-1RA). Moreover, IL-1ß suppressed basal mitochondrial respiration and lowered the mitochondrial spare capacity. By using inhibitors to block downstream targets of the interleukin-1 receptor pathway, we show that p38 is required for the IL-1ß-mediated decrease in butyrate oxidation. These data provide insight into the metabolic effects induced by IL-1ß in colorectal cancer, and identify relevant targets that may be exploited to block the effects of this cytokine. J. Cell. Biochem. 118: 1614-1621, 2017. © 2016 Wiley Periodicals, Inc.

CANDIDATE GENES FOR LIMITING CHOLESTATIC INTESTINAL INJURY IDENTIFIED BY GENE EXPRESSION PROFILING.

The lack of bile flow from the liver into the intestine can have devastating complications including hepatic failure, sepsis and even death. This pathologic condition known as cholestasis can result from etiologies as diverse as total parenteral nutrition (TPN), hepatitis and pancreatic cancer. The intestinal injury associated with cholestasis has been shown to result in decreased intestinal resistance, increased bacterial translocation and increased endotoxemia. Anecdotal clinical evidence suggests a genetic predisposition to exaggerated injury. Recent animal research on two different strains of inbred mice demonstrating different rates of bacterial translocation with different mortality rates supports this premise. In this study, a microarray analysis of intestinal tissue following common bile duct ligation (CBDL) performed under general anesthesia on these same two strains of inbred mice was done with the goal of identifying the potential molecular mechanistic pathways responsible. Over 500 genes were increased more than 2.0 fold following CBDL. The most promising candidate genes included MUPs, Serpina1a and LCN-2. RT-PCR validated the microarray results for these candidate genes. In an in vitro experiment using differentiated intestinal epithelial cells, inhibition of MUP-1 by siRNA resulted in increased intestinal epithelial cell permeability. Diverse novel mechanisms involving the growth hormone pathway, the acute phase response and the innate immune response are thus potential avenues for limiting cholestatic intestinal injury. Changes in gene expression were at times found to be not only due to the CBDL but also due to the murine strain. Should further studies in cholestatic patients demonstrate inter-individual variability similar to what we have shown in mice, then a "personalized medicine" approach to cholestatic patients may become possible.

Sphingosine kinase 1 overexpression stimulates intestinal epithelial cell proliferation through increased c-Myc translation.

Sphingosine-1-phosphate (S1P), through mechanisms that are not completely understood, is shown to modulate cellular proliferation, which is critically important for maintaining the integrity of intestinal epithelium. Here, we show that increased S1P promotes proliferation in intestinal epithelial cells. We found that overexpression of sphingosine kinase 1 (SphK1), the rate-limiting enzyme for S1P synthesis, significantly increased cell proliferation and that this occurred through enhanced expression of c-Myc. Further, we found that the increased pattern of expression of c-Myc occurred predominantly due to its increased translation. The overexpressed SphK1 led to increased checkpoint kinase 2 and enhanced HuR phosphorylation which allowed for increased translation of c-Myc mRNA through HuR binding at the 3'-untranslated regions. Our findings demonstrate that S1P modulates intestinal cell proliferation and provides new insights as to the mechanistic actions of SphK1 and S1P in maintaining intestinal epithelial homeostasis.