Excess glutamate in the cerebrospinal fluid in bacterial meningitis

We investigated possible neurotoxic components in the cerebrospinal fluid (CSF) of patients with bacterial meningitis. On murine cerebellar neuronal cell cultures, CSF exerted a dose-dependent toxic effect, which was attenuated by the NMDA receptor antagonist MK-801. Glutamate concentrations in the CSF of patients with bacterial meningitis were measured by an enzymatic assay and found to be significantly elevated (p < 0.001) as compared to viral meningitis and non-inflammatory neurological diseases. The concentration of glutamate in the CSF of patients with bacterial meningitis varied considerably and correlated with the severity of the disease as scored by the Glasgow Coma Scale. Cells in the CSF, mainly comprising polymorphonuclear granulocytes, did not release any glutamate into the culture medium, whereas blood monocytes produced remarkable amounts. These findings implicate an important role of monocytic inflammatory cells in bacterial meningitis by the release of glutamate, which may contribute to neuronal cell death.

Activated recombinant factor VII in orthotopic liver transplantation

Orthotopic liver transplantation (OLT) is affected by important alterations of hemostasis. The aim of this study was to evaluate the efficacy of recombinant factor VII activated (rFVIIa) to reduce intraoperative bleeding during OLT.

METHODS

Twenty OLT patients were assigned in double-blind way to a rFVIIa group or a control group. Inclusion criteria were hemoglobin > 8 g/dL: INR > 1,5 and fibrinogen > 100 mg/dL. We administered a single bouls of rFVIIa (40 microg/kg) or placebo. We determined INR, partial thromboplastin time, fibrinogen, ATIII, and blood cell counts. Blood products were administered as follows: 4 units of fresh frozen plasma when INR > 1.5, and 1 unit of RBC for Hb < 10 g/dL. The study ended 6 hours after the bolus.

RESULTS

No thromboembolic events occurred. The INR was different between rFVIIa group and the controls at T0 (1.9 vs 1.6 P < .021) and during T1 (1.2 vs 1.6 P < .004). The total transfused red blood cells was 300 mL +/- 133 in rFVIIa group and 570 mL +/- 111 in control group (P < .017). The total fresh frozen plasma was 600 mL +/- 154 in rFVIIa group and 1400 mL +/- 187 in control group (P < .001). Total blood loss was greater in the control group than the rFVIIa group: 1140 mL +/- 112 vs 740 mL +/- 131 (P < .049).

DISCUSSION

The use of rFVIIa during OLT can reduce the risk of bleeding during surgery. The literature has described cases who did not benefit from the treatment. An adequate cut-off of INR, allowed us to treat only patients at greater bleeding risk.

Incidence of fungal infections in a solid organ recipients dedicated intensive care unit

Invasive fungal infections are a significant cause of morbidity and mortality for patients undergoing solid organ transplantation. Our aim was to evaluate the incidence of invasive fungal infections in solid organ recipients within a dedicated intensive care unit (ICU).

MATERIALS AND METHODS

From May 2002 to May 2005, 278 patients undergoing solid organ transplantation (105 liver, 142 kidney, 20 lung, 2 combined liver-kidney, 9 combined pancreas-kidney) were admitted to our posttransplant intensive care unit. We retrospectively analyzed data obtained from the ICU stay. Fungal infection was defined by positivity of normally sterile biological samples and by elevated positivity of normally non sterile biological samples. We did not consider superficial fungal infections and asymptomatic colonizations.

RESULTS

Forty-six patients (16.5%) developed a fungal infection; at least one mycotic agent was isolated from each patient. Candida albicans was the most common pathogen, isolated from 71 % of infected patients (33 of 46). Infected patients showed a mortality rate of 35%, while that for non infected recipients was 3.5%. Total length of ICU stay was the most significant risk factor among infected patients (30.26 days vs 5.04 days P < .0001). Mean time between transplantation and first positive samples was 6.17 days (SD 8.88).

CONCLUSION

Fungal infections in solid organ transplant patients are a major issue because of their associated morbidity and mortality. Candida albicans was the most common pathogen and total length of ICU stay was the most important risk factor.

Pediatric renal transplantation: anesthesia and perioperative complications

The appropriate choice of anesthesia for patients (pts) undergoing renal transplantation (Ktx) requires minimal toxicity and accurate monitoring for pts at high risk for metabolic, cardiovascular, and respiratory perioperative complications. We evaluated the anesthetic management and postoperative follow-up in pediatric Ktx performed in the last 12 years in our institution. From 1988 to 1999, 75 ASA class II-III pts (45 males, 22 females) younger than 18 years scheduled for Ktx were studied: 49 received a graft from a cadaveric donor (CD) and 26 from a living donor (LD). All pts were treated with dialysis within 24 h before the procedure. Standard monitoring consisted of an electrocardiogram, central venous pressure, non-invasive arterial pressure, pulse oximetry, and inspiratory and expiratory gas analysis. If necessary, an arterial cannula and pediatric pulmonary catheter were introduced. Anesthesia was induced with sodium thiopental, propofol, halothane, or sevoflurane and maintained with isoflurane and/or fentanyl and droperidol in O2:N2O (FiO2 0.4%). As muscle relaxants atracurium or cisatracurium besilate were used, except in allergic pts, in whom vecuronium or rocuronium bromide was administered. Dopamine, 20% mannitol, and furosemide were used to increase diuresis. Continuous morphine and ketoralac infusions were used for postoperative pain relief. The surgical technique was the same in all cases. Complications and renal-function (RF) recovery were evaluated relating to CD and LD using the chi-square test; differences in mean anesthesia and surgical time were evaluated by Student's t-test; survival curves were calculated from the day of Ktx to death or last follow-up and estimated by the Kaplan-Meier method. Values of P below 0.05 were considered significant. Postoperative immunosuppressive therapy was based on cyclosporine together with other conventional drugs. Mean anesthesia time was 228 +/- 65 min. Mean kidney ischemia time for CD was 16.5 +/- 4 h. Four pts (3 CD, 1 LD) died within 72 h postoperatively: 3 due to cardiac failure and 1 to metabolic coma. Six pts showed cardiovascular and 3 had infective complications, all successfully treated. Three pts (2 CD, 1 LD) died within 2 to 12 months after, surgery; 10 (6 CD, 4 LD) had graft failure and are still alive on dialysis; 58 (38 CD, 20 LD) are alive in good health after a mean follow-up of 57.6 +/- 36.6 months (range 12-120 months). Fifteen of 26 pts younger than 12 years (21 CD and 5 LD) recovered RF intraoperatively (10 CD, 5 LD); 1 with CD and 1 with LD showed postoperative graft failure and 2 with CD died within 72 h postoperatively, 22 (18 CD and 4 LD) are alive in good health. This group showed no statistical difference compared to pts older than 12 years. Of 16 pts (15 CD and 1 LD) with body weight (BW) less than 25 kg, 6 showed intraoperative (5 CD, 1 LD) recovery of RF. The 3 deaths were all in CD pts, 2 within 72 h and one 2 months after surgery; only 1 LD had postoperative graft failure. Twelve pts (75%) (12 CD, 80%) are alive in good health. Compared to pts with BW of 25 kg or more, this group showed lower intraoperative recovery of RF (P < or = 0.05). No peri- and postoperative complications occurred in all 26 LD pts (100%). Recent advances in surgery, anesthesia, immunosuppression, and antimicrobial prophylaxis have made Ktx a more predictable procedure even in pediatric pts. For high-risk pts, mortality and morbidity can be controlled by accurate surgical, anesthetic, and postoperative management. Pts younger than 12 years and with BW less than 25 kg are more likely to develop peri- and postoperative complications.

Cloning, expression and functional characterization of the full-length murine ADAMTS13

Functional deficiency or absence of the human von Willebrand factor (VWF)-cleaving protease (VWF-cp), recently termed ADAMTS13, has been shown to cause acquired and congenital thrombotic thrombocytopenic purpura (TTP), respectively. As a first step towards developing a small animal model of TTP, we have cloned the complete (non-truncated) murine Adamts13 gene from BALB/c mice liver poly A+ mRNA. Murine ADAMTS13 is a 1426-amino-acid protein with a high homology and similar structural organization to the human ortholog. Transient expression of the murine Adamts13 cDNA in HEK 293 cells yielded a protein with a molecular weight of approximately 180 kDa which degraded recombinant murine VWF (rVWF) in a dose-dependent manner. The cleavage products of murine rVWF had the expected size of 140 and 170 kDa. Murine ADAMTS13 was inhibited by EDTA and the plasma from a TTP patient.

Clinical effects of direct hemoperfusion using a polymyxin-B immobilized column in solid organ transplanted patients with signs of severe sepsis and septic shock. A pilot study

BACKGROUND

Polymyxin B (PMX-B) is a polycationic antibiotic, known to bind the lipid A portion of endotoxin, a cell wall component found exclusively in gram negative bacteria (GNB). An extracorporeal hemoperfusion device (TORAYMYXIN) has been developed: PMX is covalently bound on the surface of an insoluble carrier material so that the endotoxin can be inactivated in the blood without exerting its toxicity on the brain and kidney. The aim of this study was to clarify the efficacy, safety and clinical effects of direct hemoperfusion with an immobilized polymyxin-B fiber column (DHP-PMX) in solid organ transplanted patients with severe sepsis or septic shock.

METHODS

From June 2004 to May 2005, 15 patients (10 men and 5 women), mean age 55 years old (46-65 range), underwent kidney or liver transplantation and developed severe sepsis or septic shock, as defined by the Consensus Conference of American College Physicians/Society of Critical Care Medicine (ACCP/SCCM) criteria. GNB were detected in all the patients receiving conventional treatments including antibiotic therapy, vasopressive or inotropic agents, and ventilation support. The DHP-PMX treatment was performed three times in each patient. Hemodynamic and respiratory parameters, dosage of vasopressor/inotropic drugs were assessed at baseline and after each treatment.

RESULTS

No adverse events occurred. From baseline to 3rd treatment, mean arterial pressure (MAP) was increased (from 63+/-5 to 83+/-4 mmHg), while the dosage of dobutamine (from 7.5+/-3 to 3+/-2 mcg/kg/min) and noradrenaline (from 1.3+/-0.45 to 0.05+/-0.02 mcg/kg/min) were reduced. The PaO2/FiO2 ratio increased (from 234+/-38.47 to 290+/-107.48 mmHg).

CONCLUSION

The use of DHP-PMX in association with conventional therapy may be an important aid in patients with sepsis.

Clinical effects of use polymyxin B fixed on fibers in liver transplant patients with severe sepsis or septic shock

Polymyxin B (PMX-B) is a polycationic antibiotic, known to bind the lipid A portion of endotoxin, a cell wall component exclusively found in gram-negative bacteria (GNB). An extracorporeal hemoperfusion device (TORAYMYXIN) has been developed: PMX is covalently bound to the surface of an insoluble carrier material to inactivate endotoxin in blood without exerting toxicity on the brain or the kidney. The aim of this study was to evaluate the efficacy, safety, and clinical effects of direct hemoperfusion with an immobilized polymyxin B fiber column (DHP-PMX) among liver transplant patients with severe sepsis or septic shock.

METHODS

From June 2004 to May 2005, 10 patients (6 men and 4 women) of overall mean age of 55 years (46-65 range) underwent orthotopic liver transplantation (OLT) and developed severe sepsis or septic shock according to The Consensus Conference of American College Physicians/Society of Critical Care Medicine (ACCP/SCCM) criteria. GNB were detected in all treated patients who received conventional antibiotic therapy, vasopressor or inotropic agents, and ventilatory support. The DHP-PMX treatment was performed three times in each patient. Hemodynamic and respiratory parameters and dosages of vasopressor or inotropic drugs were assessed at baseline and after each treatment.

RESULTS

No adverse events occurred. From baseline to the third treatment the mean arterial pressure increased from 64 +/- 5 mm Hg to 89 +/- 4 mm Hg); while the dosages of dobutamine and norepinephrine were reduced: 6.4 to 1 mcg/kg/min and 1.3 to 0.001 mcg/kg per min, respectively. The PaO(2)/FiO(2) ratio increased: 214 to 291 mm Hg.

CONCLUSION

The use of DHP-PMX may be an important aid in patients with sepsis in association with conventional therapy.

Modifications of Intracranial Pressure After Molecular Adsorbent Recirculating System Treatment in Patients With Acute Liver Failure: Case Reports

Cerebral dysfunction may be fatal in patients with acute liver failure (ALF); intracranial pressure (ICP) monitoring may be mandatory to direct measures to prevent further cerebral edema. Recently the introduction of dialysis with the molecular adsorbent recirculating system (MARS) has improved the outcomes among patients with ALF. The aim of this study was to evaluate ICP changes after MARS treatment among patients with ALF.

METHODS

Three patients -- 14, 18 and 16 years old -- were admitted to the ICU for acute liver failure induced by HBV in two cases and by acetaminophen in the other one. Because of Glasgow Coma Score (GCS) <8, they were intubated and ventilated to protect the airway and maintain moderate hypocapnia. Invasive monitoring of intracranial pressure MARS treatments were performed in all patients.

RESULTS

The patients received MARS treatments every day after their admission to liver transplantation. After MARS therapy the ICP decreased on average from 21 to 7 mm Hg. Significant hemodynamic modifications were not observed and their neurological conditions improved.

CONCLUSION

MARS treatment improved the clinical pictures of these patients increasing the available time to obtain an urgent liver graft.

Technical note: Validation of an automated system for monitoring and restricting water intake in group-housed beef steers

The Insentec Roughage Intake Control (RIC) system has been validated for the collection of water intake; however, this system has not been validated for water restriction. The objective of this validation was to evaluate the agreement between direct observations and automated intakes collected by the RIC system under both ad libitum and restricted water conditions. A total of 239 crossbred steers were used in a 3-d validation trial, which assessed intake values generated by the RIC electronic intake monitoring system for both ad libitum water intake ( = 122; BASE) and restricted water intake ( = 117; RES). Direct human observations were collected on 4 Insentec water bins for three 24-h periods and three 12-h periods for BASE and RES, respectively. An intake event was noted by the observer when the electronic identification of the animal was read by the transponder and the gate lowered, and starting and ending bin weights were recorded for each intake event. Data from direct observations across each validation period were compared to automated observations generated from the RIC system. Missing beginning or ending weight values for visual observations occasionally occurred due to the observer being unable to capture the value before the monitor changed when bin activity was high. To estimate the impact of these missing values, analyses denoted as OBS were completed with the incomplete record coded as missing data. These analyses were contrasted with analyses where observations with a single missing beginning or end weight (but not both) were assumed to be identical to that which was recorded by the Insentec system (OBS). Difference in mean total intake across BASE steers was 0.60 ± 2.06 kg OBS (0.54 ± 1.99 kg OBS) greater for system observations than visual observations. The comparison of mean total intake across the 3 RES validation days was 0.53 ± 2.30 kg OBS (0.13 ± 1.83 kg OBS) greater for system observations than direct observations. Day was not a significant source of error in this study ( > 0.05). These results indicate that the system was capable of limiting water of individual animals with reasonable accuracy, although errors are slightly higher during water restriction than during ad libitum access. The Insentec system is a suitable resource for monitoring individual water intake of growing, group-housed steers under ad libitum and restricted water conditions.

Outcome of a Modified Sympathicotomy for Cardiac Neuromodulation of Untreatable Ventricular Tachycardia

OBJECTIVES

This study aimed to describe the preliminary results of a modified sympathicotomy for cardiac sympathetic denervation (CSD), which may reduce the predictive risk and intraoperative surgical time of the procedure.

BACKGROUND

CSD, in patients with refractory ventricular tachycardia (VT), is comprehensively recognized as an important treatment option for patients with structural heart disease as well as congenital inherited arrhythmia syndrome.

METHODS

We consecutively enrolled 5 patients with refractory VT. Baseline demographic, medical, and surgical data as well as arrhythmia outcomes and procedural complications were evaluated.

RESULTS

A total of 5 patients (mean age: 67.4 years) were enrolled for the treatment of refractory VT with a modified CSD technique. In 3 of 5 patients, an overall reduction in VT burden (ranging from 75% to 100%) and VT number was observed after the CSD despite an in-hospital early recurrence.

CONCLUSIONS

A modified CSD (sympathicotomy T2-T5) with stellate ganglion sparing and the use of unipolar radiofrequency is feasible, effective, and safe in the setting of untreatable VT.

Extracorporeal Circulation With Low Systemic Heparinization During Lung Transplantation

BACKGROUND

Some lung transplantation (LT) recipients suffer from pulmonary hypertension and right ventricular dysfunction or failure requiring extracorporeal circulation (ECC) to avoid catastrophic complications during surgery. The extracorporeal support usually requires systemic heparinization which is potentially associated with important side effects. We performed eight LT using preheparinized ECC circuits and an oxygenator associated with a lower level of systemic heparinization without evidence of perioperative complications.

PATIENTS AND METHODS

From May 2002 to May 2005, 8 patients (5 men and 3 women) of mean age 22.5 +/- 9.5 years underwent bilateral sequential lung transplantation (BSLT) for cystic fibrosis (n = 6) or idiopathic pulmonary fibrosis (n = 2). All procedures were performed with ECC through a femoro-femoral veno-arterial bypass with preheparinized circuits and an oxygenator.

RESULTS

No intraoperative mortality occurred. The mean ECC time was 147.8 +/- 31.3 minutes and the mean heparin administered was 3525 +/- 969.16 UI. No coagulopathy or thrombotic events were observed perioperatively.

CONCLUSIONS

Our study confirmed the efficacy and safety of prehepanized circuits and oxygenator for femoro-femoral veno-arterial bypass during LT for patients with severe pulmonary hypertension requiring ECC.

United Nations Development Program solicits funds from corporations

The Global Sustainable Development Facility (GSDF) project, a collaboration between the U.N. Development Program and a variety of global corporate sponsors, some with poor human rights, labor, and environmental records, has come under criticism from prestigious nongovernmental organizations around the world. A letter to James Gustave Speth, Administrator of the U.N. Development Program, expresses concern about the threat posed by the GSDF project to the independence and credibility of the U.N. Development Program.

Fenoldopam and Gastric Tonometry During Orthotopic Liver Transplantation

The aim of this study was to evaluate the effects of continuous infusion of fenoldopam on splanchnic perfusion in orthotopic liver transplant (OLT) recipients.

PATIENTS AND METHODS

We enrolled 40 patients of mean age 57+/-16 years who underwent (OLT). They were randomly divided into two double blinded groups; continuous fenoldopam (0.06 mcg/kg per minute) or placebo infusion. Hemodynamics, gastric tonometry, urine output, renal function parameters, and diuretics use were collected during selected phases of the surgery and postoperatively every 12 hours for 72 hours in the intensive care unit.

RESULTS

No significant differences were observed between the two groups concerning hemodynamics, though in the fenoldopam group we observed increased splanchnic perfusion during the whole study period but particularly after arterial unclamping (pHi 7,31+/-0.04 vs 7.28+/-0.05; P < .05) and at 48 hours after surgery (pHi 7.49+/-0.15 vs 7.39+/-0.15; P < .05). Creatinine and blood urea nitrogen values were slightly higher in the placebo group, but this data did not reach statistical significance, while higher doses of furosemide were administered to the placebo group to maintain a urinary output over 200 mL/hour during the whole study.

DISCUSSION

In this study we observed that continuous fenoldopam infusion (0.06 mg/kg per minute) improved splanchnic perfusion without affecting systemic pressure.

CONCLUSION

Patients undergoing OLT have altered splanchnic perfusion related to cirrhosis, surgical manipulation, and fluid shifts during and after surgery. The use of a splanchnic vasodilator drug improved outcomes in these patients.

Outcome of a modified sympathicotomy for cardiac neuromodulation of untreatable ventricular tachycardia

Funding Acknowledgements

Type of funding sources: None.

OBJECTIVES This study aimed to describe the results of a modified sympathicotomy (uniportal VATs with stellate ganglion sparing) for cardiac sympathetic denervation (CSD) in the setting of untreatable ventricular tachycardia.

BACKGROUND. CSD, in patients with refractory ventricular tachycardia (VT), is comprehensively recognized as an important treatment option for patients with structural heart disease as well as congenital inherited arrhythmia syndrome. A recent case series demostrated  the feasibility of the modified technique.

METHODS We consecutively enrolled 8 patients with refractory VT. Baseline demographic, medical, and surgical data as well as arrhythmia outcomes and procedural complications were evaluated.

RESULTS A total of 8 patients ( 7 pts NIDCM, 1 pt IDCM with mean age:68+-8 years) were enrolled for the treatment of refractory VT with a modified CSD technique. Mean sympathicotomy length were 7.3 (SD 3) min per side. 3/8 patients underwent monolateral (LCSD) sympathicotomy due to strong adesion in the right pleural cavity. Mean follow up was 13 months (SD 6). No complication occurred during the sympathicotomy. An overall reduction in VT burden and VT number was observed after the CSD despite an in-hospital early recurrence in 3 patients.

CONCLUSIONS A modified CSD (sympathicotomy T2–T5) with stellate ganglion sparing and the use of unipolar radiofrequency is feasible, effective, and safe in the setting of untreatable VT. Abstract Figure. VT trend

Non-Intubated Thoracic Surgery: Standpoints and Perspectives

Non-intubated video-assisted thoracic surgery (NI-VATS) combines the advantages of a non-intubated surgery with the benefits of a minimally invasive approach. First, NI-VATS is performed in the case of fragile patients when general anesthesia and/or orotracheal intubation can be foreseen as inconvenient. However, NI-VATS indications have been increasingly extended to different patient conditions, considering the increasingly assessed safety and feasibility of the procedure. Currently, the NI-VATS approach is used worldwide for different thoracic surgery procedures, including the management of malignant pleural effusion, surgical treatment of empyema, anatomical and non-anatomical lung resection, and other indications. In fact, this approach has shown to be less impactful than VATS under general anesthesia, allowing for shortened hospitalization and faster recovery after surgery. Besides, NI-VATS is associated with fewer pulmonary complications, less respiratory distress, and a mild systemic inflammatory reaction. For these reasons, this approach should be considered not only in patients with poor cardiac or respiratory function (general functional reserve), but also in other eligible conditions.

We explored the anesthetic and surgical aspects of such an approach, including the management of analgesia, cough reflex, depth of sedation, and intraoperative technical issues to put this approach in perspective.

Cardiac sympathetic denervation for untreatable ventricular tachycardia in structural heart disease. Strengths and pitfalls of evolving surgical techniques

Cardiac sympathetic denervation (CSD) is a valuable option in the setting of refractory ventricular arrhythmias in patient with structural heart disease. Since the procedure was introduced for non structural heart disease patients the techniques evolved and were modified to be adopted in several settings. In this state-of-the-art article we revised different techniques, their rationale, strengths, and pitfalls.

Intraoperative use of extracorporeal CO2 removal (ECCO2R) and emergency ECMO requirement in patients undergoing lung transplant: a case-matched cohort retrospective study

BACKGROUND

The use of extracorporeal carbon dioxide removal (ECCO₂R) is less invasive than extracorporeal membrane oxygenation (ECMO), and intraoperative control of gas exchange could be feasible. The aim of this study in intermediate intraoperative severity patients undergoing LT was to assess the role of intraoperative ECCO₂R on emergency ECMO requirement in patients.

METHODS

Thirty-eight consecutive patients undergoing lung transplantation (LT) with "intermediate" intraoperative severity in the intervals 2007 to 2010 or 2011 to 2014 were analyzed as historical comparison of case-matched cohort retrospective study. The "intermediate" intraoperative severity was defined as the development of intraoperative severe respiratory acidosis with maintained oxygenation function (i.e., pH <7.25, PaCO₂ >60 mmHg, and PaO₂/FiO₂ >150), not associated with hemodynamic instability. Of these 38 patients, twenty-three patients were treated in the 2007-2010 interval by receiving "standard intraoperative treatment," while 15 patients were treated in the 2011-2014 interval by receiving "standard intraoperative treatment + ECCO₂R."

RESULTS

ECMO requirement was more frequent among patients that received "standard intraoperative treatment" alone than in those treated with "standard intraoperative treatment + ECCO₂R" (17/23 vs. 3/15; p = 0.004). The use of ECCO₂R improved pH and PaCO₂ while mean pulmonary artery pressure (mPAP) decreased.

CONCLUSION

In intermediate intraoperative severity patients, the use of ECCO₂R reduces the ECMO requirement.

Sex differences in cardio-oncology: utilizing a genetic variant as a therapeutic target doxorubicin-induced cardiomyopathy

Introduction

Doxorubicin is an anthracycline used as a chemotherapeutic drug for the treatment of a wide range of adult and pediatric cancers. Doxorubicin is associated with an increased risk of cardiomyopathy and heart failure with up to 10% of patients developing cardiac complications. A GWAS conducted of 1,191 patients from the N9831 clinical trial identified that cardiac gene expression and genetic variants of TRPC6 were associated with a decline in left ventricular ejection fraction (LVEF) (p=0.005 and p=1.6x10–6, respectively). TRPC6 is a non-selective cation channel expressed in heart and vascular tissue. TRPC6 participates in the pathogenesis of cardiac hypertrophy as a pathological response to chronic mechanical stress. Chronic activation has been found to promote cardiac fibrosis leading to heart failure.

Purpose

TRPC6 variants could be associated with increased risk of doxorubicin-induced cardiotoxicity. Data/tests to determine which patients may progress to cardiomyopathy and heart failure are currently lacking and there are no targeted treatments to prevent cardiomyopathy in these patients.

Methods

In preliminary in vivo data, B6.129 wild-type mice or TRPC6 knockout mice were treated with either 6x intraperitoneal saline or 4mg/kg doxorubicin injections (cumulative dose of 24mg/kg).

Results

We found doxorubicin increased cardiac vacuolation (male, p≤0.001 and female, p≤0.05) in WT mice compared to controls. Higher HW/BW ratio was observed in male TRPC6 knock out mice compared to wild-type mice when both were treated with doxorubicin (males, p=0.005 and females, p=0.19). Additionally, we found that doxorubicin-induced cardiac injury was significantly reduced in TRPC6 knock-out mice compared to wild-type mice based on reduced vacuolation (p=0.0004 males, p=0.03 females), with the effect being greater in male mice than female mice. Furthermore, a significant decrease in stroke volume (p=0.007), diastolic volume (p=0.01) and cardiac output (p=0.004) in wild-type male mice treated with doxorubicin compared to control and TRPC6 knock-out mice.

Our in vitro preliminary data show that inhibition of TRPC6 using the TRPC6 inhibitor GsMTx-4 in human iPSC-derived cardiomyocytes significantly reduced doxorubicin-induced apoptosis (p&lt;0.0001). Further we treated male mice with the TRPC6 inhibitor, GsMTx4, and found that they had less global longitudinal cardiac strain (p=0.04) and higher ejection fraction (p=0.01) compared to mice who were only treated with doxorubicin. Histologically we found that mice given the TRPC6 inhibitor had less fibrosis as measured by Trichrome stained heart sections (p=0.004) which could account for improvements in cardiac function.

Conclusion

TRPC6 could be a novel therapeutic target in the prevention of chemotherapy-induced cardiomyopathy and heart failure. Additionally genetic mapping of TRCP6 functional variants may provide a new screening tool to determine increased risk of developing heart failure.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): Mayo Clinic