Long-Term Clinical Outcomes of an Antibiotic-Coated Non-Cross-linked Porcine Acellular Dermal Graft for Abdominal Wall Reconstruction for High-Risk and Contaminated Wounds

BACKGROUND

Abdominal wall reconstruction in high-risk and contaminated cases remains a challenging surgical dilemma. We report long-term clinical outcomes for a rifampin-/minocycline-coated acellular dermal graft (XenMatrix™ AB) in complex abdominal wall reconstruction for patients with a prior open abdomen or contaminated wounds.

METHODS

Patients undergoing abdominal wall reconstruction at our institution at high risk for surgical site occurrence and reconstructed with XenMatrix™ AB with intent-to-treat between 2014 and 2017 were included. Demographics, operative characteristics, and outcomes were collected. The primary outcome was hernia recurrence. The secondary outcomes included length of stay, surgical site occurrence, readmission, morbidity, and mortality.

RESULTS

Twenty-two patients underwent abdominal wall reconstruction using XenMatrix™ AB during the study period. Two patients died while inpatient from progression of their comorbid diseases and were excluded. Sixty percent of patients had an open abdomen at the time of repair. All patients were from modified Ventral Hernia Working Group class 2 or 3. There were a total of four 30-day infectious complications including superficial cellulitis/fat necrosis (15%) and one intraperitoneal abscess (5%). No patients required reoperation or graft excision. Median clinical follow-up was 38.2 months with a mean of 35.2 +/- 18.5 months. Two asymptomatic recurrences and one symptomatic recurrence were noted during this period with one planning for elective repair of an eventration. Follow-up was extended by phone interview which identified no additional recurrences at a median of 45.5 and mean of 50.5 +/-12.7 months.

CONCLUSION

We present long-term outcomes for patients with high-risk and contaminated wounds who underwent abdominal wall reconstruction reinforced with XenMatrix™ AB to achieve early, permanent abdominal closure. Acceptable outcomes were noted.

Effect of Margin Status on Survival After Resection of Hilar Cholangiocarcinoma in the Modern Era of Adjuvant Therapies

INTRODUCTION

Studies have shown that for patients with hilar cholangiocarcinoma (HC), survival is associated with negative resection margins (R0). This requires increasingly proximal resection, putting patients at higher risk for complications, which may delay chemotherapy. For patients with microscopically positive resection margins (R1), the use of modern adjuvant therapies may offset the effect of R1 resection.

METHODS

Patients at our institution with HC undergoing curative-intent resection between January 2008 and July 2019 were identified by retrospective record review. Demographic data, operative details, tumor characteristics, postoperative outcomes, recurrence, survival, and follow-up were recorded. Patients with R0 margin were compared to those with R1 margin. Patients with R2 resection were excluded.

RESULTS

Seventy-five patients underwent attempted resection with 34 (45.3%) cases aborted due to metastatic disease or locally advanced disease. Forty-one (54.7%) patients underwent curative-intent resection with R1 rate of 43.9%. Both groups had similar rates of adjuvant therapy (56.5% vs. 61.1%, P = .7672). Complication rates and 30 mortality were similar between groups (all P > .05). Both groups had similar median recurrence-free survival (R0 29.2 months vs. R1 27.8 months, P = .540) and median overall survival (R0 31.2 months vs. R1 38.8 months, P = .736) with similar median follow-up time (R0 29.9 months vs. R1 28.5 months, P = .8864).

CONCLUSIONS

At our institution, patients undergoing hepatic resection for HC with R1 margins have similar recurrence-free and overall survival to those with R0 margins. Complications and short-term mortality were similar. This may indicate that with use of modern adjuvant therapies obtaining an R0 resection is not an absolute mandate.

Operative Microwave Ablation for the Multimodal Treatment of Neuroendocrine Liver Metastases

Background and Purpose: Operative microwave ablation (MWA) is a safe modality for treating hepatic tumors. The aim of this study is to present our 10-year, single-center experience of operative MWA for neuroendocrine liver metastases (NLM). Methods: A single-institution retrospective review of patients who underwent operative MWA for NLM was performed (2008-2018). Demographics, primary tumor site, operative approach, combined surgical operations, and carcinoid symptoms were recorded. Clinical outcomes for major complications, readmission, and mortality were analyzed 30 days postoperatively. Postablation imaging was evaluated for incomplete ablation/missed lesions, and surveillance imaging reviewed for local, regional, and metastatic recurrence. Results: Of the 50 patients (166 targeted lesions) who received MWA for NLM, 41 (82%) were treated with a minimally invasive approach, and 22 (44%) underwent MWA concomitant with hepatectomy and/or primary tumor resection. Within the study cohort 70% of patients were treated with curative intent with a 77% (27/35) success rate. Carcinoid symptoms were reported in 40% (20/50) of patients preoperatively, and MWA treatment improved symptoms in 19/20 patients. Incomplete ablation occurred in 1/166 treated lesions. Recurrence-free survival at 1 and 5 years was 86% and 28%, respectively. Overall survival at 1 and 5 years was 94% and 70%, respectively (median follow-up 32 months, range 0-116 months). Conclusion: Operative MWA is a versatile modality, which can be safe and effectively performed alone or combined with hepatectomy for NLM, preferably using a minimally invasive approach, to achieve symptom control and possibly improve survival.

Retrospective Validation of an Algorithmic Treatment Pathway for Necrotizing Pancreatitis

The role of surgical intervention for necrotizing pancreatitis has evolved; however, no widely accepted algorithm has been established to guide timing and optimal modality in the minimally invasive era. This study aimed to retrospectively validate an established institutional timing- and physiologic-based algorithm constructed from evidence-based guidelines in a high-volume hepatopancreatobiliary center. Patients with necrotizing pancreatitis requiring early (≤six weeks from symptom onset) or delayed (>six weeks) surgical intervention were reviewed over a four-year period (n = 100). Early intervention was provided through laparoscopic drain-guided retroperitoneal debridement (n = 15) after failed percutaneous drainage unless they required an emergent laparotomy (due to abdominal compartment syndrome, bowel necrosis/perforation, or hemorrhage) after which conservative, sequential open necrosectomy was performed (n = 47). Robot-assisted (n = 16) versus laparoscopic (n = 22) transgastric cystgastrostomy for the delayed management of walled-off pancreatic necrosis was compared, including patient factors, operative characteristics, and 90-day clinical outcomes. Major complications after early debridement were similarly high (open 25% and drain-guided 27%), yet 90-day mortality was low (open 8.5% and drain-guided 7.1%). Patient and operative characteristics and 90-day outcomes were statistically similar for robotic versus laparoscopic transgastric cystogastrostomy. Our evidence-based algorithm provides a stepwise approach for the management of necrotizing pancreatitis, emphasizing minimally invasive early and late interventions when feasible with low morbidity and mortality. Robot-assisted transgastric cystogastrostomy is an acceptable alternative to a laparoscopic approach for the delayed treatment of walled-off pancreatic necrosis.

Clinically Meaningful Laboratory Protocols Reduce Hospital Charges Based on Institutional and ACS-NSQIP® Risk Calculators in Hepatopancreatobiliary Surgery

Postoperative laboratory testing is an underrecognized but substantial contributor to health-care costs. We aimed to develop and validate a clinically meaningful laboratory (CML) protocol with individual risk stratification using generalizable and institution-specific predictive analytics to reduce laboratory testing and maximize cost savings for low-risk patients. An institutionally based risk model was developed for pancreaticoduodenectomy and hepatectomy, and an ACS-NSQIP®–based model was developed for distal pancreatectomy. Patients were stratified in each model to the CML by individual risk of major complications, readmission, or death. Clinical outcomes and estimated cost savings were compared with those of a historical cohort with standard of care. Over 34 months, 394 patients stratified to the CML for pancreaticoduodenectomy or hepatectomy saved an estimated $803,391 (44.4%). Over 13 months, 52 patients stratified to the CML for distal pancreatectomy saved an estimated $81,259 (30.5%). Clinical outcomes for 30-day major complications, readmission, and mortality were unchanged after implementation of either model. Predictive analytics can target low-risk patients to reduce laboratory testing and improve cost savings, regardless of whether an institutional or a generalized risk model is implemented. Broader application is important in patient-centered health care and should transition from predictive to prescriptive analytics to guide individual care in real time.

Prognostic impact of the Bismuth-Corlette classification: Higher rates of local unresectability in stage IIIb hilar cholangiocarcinoma

BACKGROUND

The Bismuth-Corlette (BC) classification is used to categorize hilar cholangiocarcinoma by proximal extension along the biliary tree. As the right hepatic artery crosses just behind the left bile duct, we hypothesized that BC IIIb tumors would have a higher likelihood of local unresectability due to involvement of the contralateral artery.

METHODS

A retrospective review of a prospectively maintained database identified patients with hilar cholangiocarcinoma taken to the operating room for intended curative resection between April 2008 and September 2016. Cases were assigned BC stages based on preoperative imaging.

RESULTS

Sixty-eight patients were included in the study. All underwent staging laparoscopy after which 16 cases were aborted for metastatic disease. Of the remaining 52 cases, 14 cases were explored and aborted for locally advanced disease. Thirty-eight underwent attempt at curative resection. After excluding cases aborted for metastatic disease, the chance of proceeding with resection was 55.6% for BC IIIb staged lesions compared to 80.0% of BC IIIa lesions and to 82.4% for BC I-IIIa staged lesions (P < 0.05). About 44.4% of BC IIIb lesions were aborted for locally advanced disease versus 17.6% of remaining BC stages.

CONCLUSIONS

When hilar cholangiocarcinoma is preoperatively staged as BC IIIb, surgeons should anticipate higher rates of locally unresectable disease, likely involving the right hepatic artery.

Experimental High-Frequency Irreversible Electroporation Using a Single-Needle Delivery Approach for Nonthermal Pancreatic Ablation In Vivo

PURPOSE

To investigate the feasibility of single-needle high-frequency irreversible electroporation (SN-HFIRE) to create reproducible tissue ablations in an in vivo pancreatic swine model.

MATERIALS AND METHODS

SN-HFIRE was performed in swine pancreas in vivo in the absence of intraoperative paralytics or cardiac synchronization using 3 different voltage waveforms (1-5-1, 2-5-2, and 5-5-5 [on-off-on times (μs)], n = 6/setting) with a total energized time of 100 μs per burst. At necropsy, ablation size/shape was determined. Immunohistochemistry was performed to quantify apoptosis using an anticleaved caspase-3 antibody. A numerical model was developed to determine lethal thresholds for each waveform in pancreas.

RESULTS

Mean tissue ablation time was 5.0 ± 0.2 minutes, and no cardiac abnormalities or muscle twitch was detected. Mean ablation area significantly increased with increasing pulse width (41.0 ± 5.1 mm² [range 32-66 mm²] vs 44 ± 2.1 mm² [range 38-56 mm²] vs 85.0 ± 7.0 mm² [range 63-155 mm²]; 1-5-1, 2-5-2, 5-5-5, respectively; p < 0.0002 5-5-5 vs 1-5-1 and 2-5-2). The majority of the ablation zone did not stain positive for cleaved caspase-3 (6.1 ± 2.8% [range 1.8-9.1%], 8.8 ± 1.3% [range 5.5-14.0%], and 11.0 ± 1.4% [range 7.1-14.2%] cleaved caspase-3 positive 1-5-1, 2-5-2, 5-5-5, respectively), with significantly more positive staining at the 5-5-5 pulse setting compared with 1-5-1 (p < 0.03). Numerical modeling determined a lethal threshold of 1114 ± 123 V/cm (1-5-1 waveform), 1039 ± 103 V/cm (2-5-2 waveform), and 693 ± 81 V/cm (5-5-5 waveform).

CONCLUSIONS

SN-HFIRE induces rapid, predictable ablations in pancreatic tissue in vivo without the need for intraoperative paralytics or cardiac synchronization.

Modifying Interhospital Hepatopancreatobiliary Transfers Based on Predictive Analytics: Moving from a Center of Excellence to a Health-Care System of Excellence

Regionalization of complex surgical care has increased interhospital transfers to quaternary centers within large health-care systems. Risk-based patient selection is imperative to improve resource allocation without compromising care. This study aimed to develop predictive models for identifying low-risk patients for transfer to a fully integrated satellite hepatopancreatobiliary (HPB) service in the northeast region of the health-care system. HPB transfers to the quaternary center over 15 months from hospitals in proximity to the satellite HPB center. A predictive tool was developed based on simple pretransfer variables and outcomes for 30-day major complications (Clavien grade ≥ 3), readmission, and mortality. Thresholds for "low risk" were set at different SDs below mean for each model. Predictive models were developed from 51 eligible northeast region patient transfers for major complications (Brier score 0.1948, receiver operator characteristic (ROC) 0.7123, P = 0.0009), readmission (Brier score 0.0615, ROC 0.7368, P = 0.0020), and mortality (Brier score 0.0943, ROC 0.7989, P = 0.0023). Thresholds set from 2 SD below the mean for all models identified 2 as "low risk." Adjusting the threshold for the serious complication model to only 1 SD below the mean increased the "low-risk" cohort to five patients. These models demonstrate an easy-to-use tool to assist surgeons in identifying low-risk patients for diversion to a fully integrated satellite center. Improved interhospital transfers within a region could begin a transition from centers of excellence toward health-care systems of excellence.

Modifying Interhospital Hepatopancreatobiliary Transfers Based on Predictive Analytics: Moving from a Center of Excellence to a Health-Care System of Excellence

Regionalization of complex surgical care has increased interhospital transfers to quaternary centers within large health-care systems. Risk-based patient selection is imperative to improve resource allocation without compromising care. This study aimed to develop predictive models for identifying low-risk patients for transfer to a fully integrated satellite hepatopancreatobiliary (HPB) service in the northeast region of the health-care system. HPB transfers to the quaternary center over 15 months from hospitals in proximity to the satellite HPB center. A predictive tool was developed based on simple pretransfer variables and outcomes for 30-day major complications (Clavien grade ≥ 3), readmission, and mortality. Thresholds for “low risk” were set at different SDs below mean for each model. Predictive models were developed from 51 eligible northeast region patient transfers for major complications (Brier score 0.1948, receiver operator characteristic (ROC) 0.7123, P = 0.0009), readmission (Brier score 0.0615, ROC 0.7368, P = 0.0020), and mortality (Brier score 0.0943, ROC 0.7989, P = 0.0023). Thresholds set from 2 SD below the mean for all models identified 2 as “low risk.” Adjusting the threshold for the serious complication model to only 1 SD below the mean increased the “low-risk” cohort to five patients. These models demonstrate an easy-to-use tool to assist surgeons in identifying low-risk patients for diversion to a fully integrated satellite center. Improved interhospital transfers within a region could begin a transition from centers of excellence toward health-care systems of excellence.

Clinically Meaningful Laboratory Protocols Reduce Hospital Charges Based on Institutional and ACS-NSQIP® Risk Calculators in Hepatopancreatobiliary Surgery

Postoperative laboratory testing is an underrecognized but substantial contributor to health-care costs. We aimed to develop and validate a clinically meaningful laboratory (CML) protocol with individual risk stratification using generalizable and institution-specific predictive analytics to reduce laboratory testing and maximize cost savings for low-risk patients. An institutionally based risk model was developed for pancreaticoduodenectomy and hepatectomy, and an ACS-NSQIP®-based model was developed for distal pancreatectomy. Patients were stratified in each model to the CML by individual risk of major complications, readmission, or death. Clinical outcomes and estimated cost savings were compared with those of a historical cohort with standard of care. Over 34 months, 394 patients stratified to the CML for pancreaticoduodenectomy or hepatectomy saved an estimated $803,391 (44.4%). Over 13 months, 52 patients stratified to the CML for distal pancreatectomy saved an estimated $81,259 (30.5%). Clinical outcomes for 30-day major complications, readmission, and mortality were unchanged after implementation of either model. Predictive analytics can target low-risk patients to reduce laboratory testing and improve cost savings, regardless of whether an institutional or a generalized risk model is implemented. Broader application is important in patient-centered health care and should transition from predictive to prescriptive analytics to guide individual care in real time.

Retrospective Validation of an Algorithmic Treatment Pathway for Necrotizing Pancreatitis

The role of surgical intervention for necrotizing pancreatitis has evolved; however, no widely accepted algorithm has been established to guide timing and optimal modality in the minimally invasive era. This study aimed to retrospectively validate an established institutional timing- and physiologic-based algorithm constructed from evidence-based guidelines in a high-volume hepatopancreatobiliary center. Patients with necrotizing pancreatitis requiring early (≤six weeks from symptom onset) or delayed (>six weeks) surgical intervention were reviewed over a four-year period (n = 100). Early intervention was provided through laparoscopic drain-guided retroperitoneal debridement (n = 15) after failed percutaneous drainage unless they required an emergent laparotomy (due to abdominal compartment syndrome, bowel necrosis/perforation, or hemorrhage) after which conservative, sequential open necrosectomy was performed (n = 47). Robot-assisted (n = 16) versus laparoscopic (n = 22) transgastric cystgastrostomy for the delayed management of walled-off pancreatic necrosis was compared, including patient factors, operative characteristics, and 90-day clinical outcomes. Major complications after early debridement were similarly high (open 25% and drain-guided 27%), yet 90-day mortality was low (open 8.5% and drain-guided 7.1%). Patient and operative characteristics and 90-day outcomes were statistically similar for robotic versus laparoscopic transgastric cystogastrostomy. Our evidence-based algorithm provides a stepwise approach for the management of necrotizing pancreatitis, emphasizing minimally invasive early and late interventions when feasible with low morbidity and mortality. Robot-assisted transgastric cystogastrostomy is an acceptable alternative to a laparoscopic approach for the delayed treatment of walled-off pancreatic necrosis.

Minimally Invasive Surgical Management as Effective First-Line Treatment of Large Pyogenic Hepatic Abscesses

Management of pyogenic hepatic abscesses (PHA) varies among surgeons and institutions. Recent studies have advocated for first-line percutaneous drainage (PD) of all accessible hepatic abscesses, with surgery reserved as rescue only. Our study aimed to internally validate an established multimodal algorithm for PHA at a high-volume hepatopancreatobiliary center. Patients treated by the hepatopancreatobiliary service for PHA were retrospectively reviewed from 2008 through 2018. The algorithm defined intended first-line treatment as antibiotics for type I abscesses (<3 cm), PD for type II (≥3, unilocular), and surgical intervention (minimally invasive drainage or resection, when possible) for type III (≥3 cm, multilocular). Outcomes were compared between patients who received first-line treatment following the algorithm versus alternate therapy. Of 330 patients with PHA, 201 met inclusion criteria. Type III abscesses had significantly lower failure following algorithmic approach with surgery compared with PD (4% vs 28%, P = 0.018). Type II abscesses failed first-line PD in 27 per cent (13/48) with 11 patients requiring surgical rescue, whereas first-line surgery failed in only 13 per cent (2/15). No deaths occurred after any surgical intervention, and there was no statistical difference in major complications between first-line surgical intervention and PD for type II or III abscesses. These results support the algorithmic approach and demonstrate that minimally invasive surgical intervention is a safe and effective modality for large PHA. We recommend that select patients with large, complex abscesses should be considered for a first-line minimally invasive surgical approach depending on surgical experience and available resources.

Minimally Invasive Surgical Management as Effective First-Line Treatment of Large Pyogenic Hepatic Abscesses

Management of pyogenic hepatic abscesses (PHA) varies among surgeons and institutions. Recent studies have advocated for first-line percutaneous drainage (PD) of all accessible hepatic abscesses, with surgery reserved as rescue only. Our study aimed to internally validate an established multimodal algorithm for PHA at a high-volume hepatopancreatobiliary center. Patients treated by the hepatopancreatobiliary service for PHA were retrospectively reviewed from 2008 through 2018. The algorithm defined intended first-line treatment as antibiotics for type I abscesses (<3 cm), PD for type II (≥3, unilocular), and surgical intervention (minimally invasive drainage or resection, when possible) for type III (≥3 cm, multilocular). Outcomes were compared between patients who received first-line treatment following the algorithm versus alternate therapy. Of 330 patients with PHA, 201 met inclusion criteria. Type III abscesses had significantly lower failure following algorithmic approach with surgery compared with PD (4% vs 28%, P = 0.018). Type II abscesses failed first-line PD in 27 per cent (13/48) with 11 patients requiring surgical rescue, whereas first-line surgery failed in only 13 per cent (2/15). No deaths occurred after any surgical intervention, and there was no statistical difference in major complications between first-line surgical intervention and PD for type II or III abscesses. These results support the algorithmic approach and demonstrate that minimally invasive surgical intervention is a safe and effective modality for large PHA. We recommend that select patients with large, complex abscesses should be considered for a first-line minimally invasive surgical approach depending on surgical experience and available resources.

Efficacy of a Laparoscopic Saline-Coupled Bipolar Sealer in Minimally Invasive Hepatobiliary Surgery

Hepatic resection presents unique surgical challenges to reduce blood loss during parenchymal division. The development of saline-coupled bipolar devices, in which hemostasis is achieved at lower temperatures than electrocautery or other bipolar sealing devices, have been employed for open hepatic resection. Saline-coupled bipolar devices have now become available for minimally invasive use. The goals of this study were to evaluate the feasibility and safety of a laparoscopic saline-coupled bipolar device for minimally invasive hepatectomy. Seventeen patients (median age 66 years, range 36-81) were consented for inclusion and enrolled. Patient demographics, intraoperative data, and surgeon feedback were collected. Seven robot-assisted partial hepatectomies, 9 laparoscopic partial hepatectomies, and 1 laparoscopic cholecystectomy with liver abscess resection were performed. Average operating time was 222 ± 33 minutes (median 188 minutes; range 61-564 minutes) with no difference between robotic versus laparoscopic time. Successful seals were achieved in all cases following application of 150 to 200 J energy (average 179 ± 3 J, average time to achieve a successful seal 9.3 ± 2.7 minutes). Estimated blood loss was 362 ± 74 mL (median 300 mL, range 5-1200 mL) and 3/17 patients received intraoperative blood transfusion. No bile leaks were detected in any of the patients. Median length of stay was 5 days (range 1-20 days), and there were no readmissions within 30 days. Postoperative morbidity occurred in 5/17 patients, all of which were Clavien Grade 1. There was no mortality within 90 days or complications requiring a return to the operating room, and there were no liver-specific morbidities. These data suggest the laparoscopic Aquamantys device represents a useful device for use in minimally invasive liver resection.

The impact of intraoperative goal-directed fluid therapy on complications after pancreaticoduodenectomy

Introduction

Optimal fluid balance is critical to minimize anastomotic edema in patients undergoing pancreaticoduodenectomy. We examined the effects of decreased fluid administration on rates of postoperative pancreatic leak and delayed gastric emptying.

Methods

Retrospective study of 105 patients undergoing pancreaticoduodenectomy at a single institution from January 2015 through July 2016. Stroke volume variation (SVV) was tracked and titrated during the procedure. A comparative analysis of postoperative complications was performed between patients with a median SVV < 12 during the extirpative and reconstructive phases of the procedure compared with patients with an SVV ≥ 12.

Results

Of 64 patients who met selection criteria, 42 (65.6%) had a SVV < 12 and 22 (34.4%) had a SVV ≥ 12. Patients with an SVV ≥ 12 during the extirpative phase of the procedure had lower rates of postoperative pancreatic leaks compared to patients with an SVV < 12 (5.9% vs 21.3%)). Patients with an SVV ≥ 12 during the extirpative phase had lower rates of postoperative delayed gastric emptying compared to patients with an SVV < 12 (41.2% vs 46.8%).

Conclusion

Goal-directed fluid restriction before the reconstructive phase of pancreaticoduodenectomy may contribute to lower postoperative rates of pancreatic leak and delayed gastric emptying.

•

Optimal fluid balance is critical to minimize anastomotic edema in patients undergoing pancreaticoduodenectomy.

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Fluid restriction before the reconstructive phase of pancreaticoduodenectomy may decrease pancreatic leak and delayed gastric emptying.

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Non-invasive hemodynamic monitoring systems offer the anesthesiologist a method to titrate intravascular fluid balance.

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Goal-directed fluid management is a recent clinical practice during pancreatic surgery that may help decrease postoperative complications.

Endocannabinoid degradation inhibition improves neurobehavioral function, blood-brain barrier integrity, and neuroinflammation following mild traumatic brain injury

Traumatic brain injury (TBI) is an increasingly frequent and poorly understood condition lacking effective therapeutic strategies. Inflammation and oxidative stress (OS) are critical components of injury, and targeted interventions to reduce their contribution to injury should improve neurobehavioral recovery and outcomes. Recent evidence reveals potential protective, yet short-lived, effects of the endocannabinoids (ECs), 2-arachidonoyl glycerol (2-AG) and N-arachidonoyl-ethanolamine (AEA), on neuroinflammatory and OS processes after TBI. The aim of this study was to determine whether EC degradation inhibition after TBI would improve neurobehavioral recovery by reducing inflammatory and oxidative damage. Adult male Sprague-Dawley rats underwent a 5-mm left lateral craniotomy, and TBI was induced by lateral fluid percussion. TBI produced apnea (17±5 sec) and a delayed righting reflex (479±21 sec). Thirty minutes post-TBI, rats were randomized to receive intraperitoneal injections of vehicle (alcohol, emulphor, and saline; 1:1:18) or a selective inhibitor of 2-AG (JZL184, 16 mg/kg) or AEA (URB597, 0.3 mg/kg) degradation. At 24 h post-TBI, animals showed significant neurological and -behavioral impairment as well as disruption of blood-brain barrier (BBB) integrity. Improved neurological and -behavioral function was observed in JZL184-treated animals. BBB integrity was protected in both JZL184- and URB597-treated animals. No significant differences in ipsilateral cortex messenger RNA expression of interleukin (IL)-1β, IL-6, chemokine (C-C motif) ligand 2, tumor necrosis factor alpha, cyclooxygenase 2 (COX2), or nicotinamide adenine dinucleotide phosphate oxidase (NOX2) and protein expression of COX2 or NOX2 were observed across experimental groups. Astrocyte and microglia activation was significantly increased post-TBI, and treatment with JZL184 or URB597 blocked activation of both cell types. These findings suggest that EC degradation inhibition post-TBI exerts neuroprotective effects. Whether repeated dosing would achieve greater protection remains to be examined.

Augmented central nitric oxide production inhibits vasopressin release during hemorrhage in acute alcohol-intoxicated rodents

Acute alcohol intoxication (AAI) attenuates the AVP response to hemorrhage, contributing to impaired hemodynamic counter-regulation. This can be restored by central cholinergic stimulation, implicating disrupted signaling regulating AVP release. AVP is released in response to hemorrhage and hyperosmolality. Studies have demonstrated nitric oxide (NO) to play an inhibitory role on AVP release. AAI has been shown to increase NO content in the paraventricular nucleus. We hypothesized that the attenuated AVP response to hemorrhage during AAI is the result of increased central NO inhibition. In addition, we predicted that the increased NO tone during AAI would impair the AVP response to hyperosmolality. Conscious male Sprague-Dawley rats (300-325 g) received a 15-h intragastric infusion of alcohol (2.5 g/kg + 300 mg·kg(-1)·h(-1)) or dextrose prior to a 60-min fixed-pressure hemorrhage (∼40 mmHg) or 5% hypertonic saline infusion (0.05 ml·kg(-1)·min(-1)). AAI attenuated the AVP response to hemorrhage, which was associated with increased paraventricular NO content. In contrast, AAI did not impair the AVP response to hyperosmolality. This was accompanied by decreased paraventricular NO content. To confirm the role of NO in the alcohol-induced inhibition of AVP release during hemorrhage, the nitric oxide synthase inhibitor, nitro-l-arginine methyl ester (l-NAME; 250 μg/5 μl), was administered centrally prior to hemorrhage. l-NAME did not further increase AVP levels during hemorrhage in dextrose-treated animals; however, it restored the AVP response during AAI. These results indicate that AAI impairs the AVP response to hemorrhage, while not affecting the response to hyperosmolality. Furthermore, these data demonstrate that the attenuated AVP response to hemorrhage is the result of augmented central NO inhibition.

Estrogen increases the sensitivity of ovariectomized rats to the disruptive effects produced by antagonism of D2 but not D1 dopamine receptors during performance of a response learning task

Estrogen impairs performance on some striatum-sensitive tasks of learning and memory. Evidence indicates that it may have these impairing effects by creating a bias to use hippocampally based strategies to solve tasks whether or not it is advantageous to do so. Estrogen may also exert direct effects in the striatum to affect performance on striatum-mediated procedural memory tasks. In spite of the robust effects that estrogen exerts on nigrostriatal dopaminergic neurons, the role of dopamine in the estrogen-induced effects on procedural memory tasks remains unexplored. The goal of the present study was to assess the independent and interactive effects of estrogen and dopamine antagonists on a striatum-mediated response learning task. Adult rats were ovariectomized and implanted with Silastic capsules containing 25% estradiol diluted in cholesterol or 100% cholesterol. Rats were trained to receive food rewards in an elevated plus maze by making a specified response (right or left turn). Following acquisition, dose-effect curves were determined for the D(1) dopamine receptor antagonist, SCH 23390, and the D(2) dopamine receptor antagonist, eticlopride. Estrogen did not significantly affect acquisition of the task and had no significant effect on the ability of SCH 23390 to disrupt performance on the task. However, estrogen significantly increased the sensitivity of the rats to the error-increasing effects of eticlopride. These results indicate that estrogen may differentially interact with D(1) and D(2) dopamine receptors to affect response learning. They also suggest that in addition to creating a bias to use hippocampally based strategies to solve tasks, estrogen may affect performance on procedural memory tasks through direct action on dopaminergic functioning.