The social network of carbon monoxide in medicine

Networking between cells is critical for proper functioning of the cellular milieu and is mediated by cascades of highly regulated and overlapping signaling molecules. The enzyme heme oxygenase-1 (HO-1) generates three separate signaling molecules through the catalysis of heme - carbon monoxide (CO), biliverdin, and iron - each of which acts via distinct molecular targets to influence cell function, both proximally and distally. This review focuses on state-of-the art developments and insights into the impact of HO-1 and CO on the innate immune response, the effects of which are responsible for an ensemble of functions that help regulate complex immunological responses to bacterial sepsis and ischemia/reperfusion injury. HO-1 exemplifies an evolutionarily conserved system necessary for the cellular milieu to adapt appropriately, function properly, and ensure survival of the organism.

A consolidated biovigilance system for blood, tissue and organs: one size does not fit all

Biovigilance systems to assess and analyze risks for disease transmission through the transfer of organs, tissue, cells and blood between people is part of administrative oversight and has impact upon clinical practice and policy. In 2009, a formal recommendation by the Public Health Service requested that Health and Human Services fund and support efforts to consolidate national biovigilance efforts. There are differences in the biovigilance issues involved in organ and tissue donation/transplantation. If disease avoidance is made the dominant principle guiding organ donor testing, an unintended consequence may be an increase in deaths on the waiting list. We propose that overall benefit for the organ transplant recipient, tempered by patient informed awareness of limited organ availability and assessment processes, should be the guiding principle of such a system.

Clinical pathways in transplantation: a review and examples from Beth Israel Deaconess Medical Center

Clinical pathways (CP) have been developed to aid in the management of many surgical and medical conditions. Studies show the benefits of CP on outcomes including reduction in length of stay (LOS), morbidity, costs, and improvement in patient satisfaction (Arch Surg 2008: 394: 31; J Eval Clin Pract 2007: 13: 920; Arch Otolaryngol Head Neck Surg 2000: 126: 322; Circulation 2000: 101: 461; BMC Pulm Med 2006: 6: 22; Int J Health Care Qual Assur 2006: 19: 237; Am J Med Qual 2005: 20: 83; Am J Surg 2006: 192: 399; Am Surg 2005: 71: 152). Reports of CP in solid organ transplantation are lacking, possibly given the complexity of the transplant procedures that entail a complex, multidisciplinary pre-operative evaluation, inpatient, and post-operative time frames. We have developed CP from presentation for transplant evaluation to post-transplant follow-up for liver, kidney, and pancreas transplantation and live kidney and live liver donation and are making them available online for viewing. Our CPs encompass the pre-operative, peri-operative, and post-operative period, including both outpatient and inpatient care. We propose that transplantation is an ideal forum for successful implementation of CP, given the rigorous process that centers are subject to for CMS approval and the ample opportunity for improving our patients' lives by improvement in and streamlining of the entire process of clinical care from end-stage organ failure to post-transplant long-term management. Our CPs can be found at http://bidmc.org/CentersandDepartments/Departments/TransplantInstitute/TransplantClinicalPathways.aspx.

Is Model for End-Stage Liver Disease score associated with quality of life after liver transplantation?

CONTEXT

The Model for End-Stage Liver Disease (MELD) is used to predict short-term mortality of patients on the liver transplant waiting list and to allocate deceased donor livers for transplantation.

OBJECTIVE

To examine the relationship between MELD score before transplant and quality of life and other functional status indicators after transplant.

DESIGN, SETTING, AND PATIENTS

Two-hundred sixty-five adults from 2 transplant programs completed quality-of-life measures 1 year after transplantation. A subcohort (n = 115) also completed quality-of-life assessments before transplant. Clinical parameters at the time of transplantation were collected from their medical records.

MAIN OUTCOME MEASURES

Short Form-36 Health Survey, version 2; Transplant Symptom Frequency Questionnaire.

RESULTS

Patients with MELD scores greater than 25 at transplantation had significantly higher scores on the Short Form-36 general health (P = .004) and physical component summary (P = .02) than did patients with MELD scores of 25 or less. However, scores on the Transplant Symptom Frequency Questionnaire did not vary significantly by MELD score. Child-Turcotte-Pugh (CTP) score, a measure of disease severity, was significantly associated with total symptom frequency after transplant (P = .03) but was not correlated with any domains on the Short Form-36. In the subcohort of 115 patients, a MELD score greater than 25 at the time of transplantation was associated with greater improvement in physical functioning (11.3 vs 4.8, P = .02), role functioning-physical (10.7 vs 4.7, P = .04), general health (11.9 vs 5.5, P = .03), vitality (10.4 vs 5.2, P = .02), and physical component summary (12.3 vs 5.4, P = .01) relative to patients with MELD scores of 15 to 25.

CONCLUSIONS

The relationship between disease severity before transplant and quality of life after transplant is different depending on the index of disease severity used (MELD vs CTP) and whether the assessment of quality of life is general or specific to transplant-related symptoms.

Rational rationing or discrimination: balancing equity and efficiency considerations in kidney allocation

After 6 years of deliberation, the Organ Procurement and Transplantation Network recently released a concept document proposing changes to the kidney allocation algorithm, sparking a heated debate about priority-setting of scarce health resources and discrimination. Proponents of the proposal argue that it will result in an additional 15,223 life years following transplant annually for recipients, yet the benefit will not be equally distributed and will likely benefit younger patients. Critics argue that the new model will promote age discrimination and may lead to a further decrease in live kidney donation. If true, these concerns could undermine fairness and damage public trust in the organ allocation system. We address these objections and consider their merit, highlighting both benefits and shortcomings of the proposal. We argue that, despite weaknesses of the proposal and the importance of maintaining consistency in patient and provider expectations over time, the proposal represents a needed first step in balancing equity and efficiency.

Patients' expectations and success criteria for liver transplantation

Patient-reported outcomes are important to consider when the relative success of liver transplantation (LT) is being evaluated. Our primary objective was to examine the expectations for LT and the criteria for its success across 4 domains of functioning (pain, fatigue, emotional distress, and interference with daily activities) from the perspective of patients who were wait-listed for LT. One hundred four adult patients with a mean wait-list time of 16.5 ± 13 months completed a semistructured interview with a modified version of the Patient-Centered Outcomes Questionnaire (PCOQ). The patients reported moderate usual levels of pain, fatigue, emotional distress, and interference with daily activities (mean rating range = 3.8-6.2), and they attached great importance to improvements in these domains after LT (mean rating range = 7.3-8.0). Patients considered a mean reduction in pain of 33% to be a successful LT outcome. A reduction in fatigue of 56%, a reduction in emotional distress of 44%, and a reduction in interference with daily activities of 54% represented successful LT across these domains. Patients with more severe illness had higher expectations for fatigue (r = -0.30, P = 0.002) and interference with daily activities (r = -0.24, P = 0.015). Cluster and correlational analyses provided support for the validity of the PCOQ with LT patients. Our findings underscore the importance and value of using patient-centered assessments to better understand the ways in which patients prioritize LT outcomes and define transplantation success. Patient-centered assessments have the potential to facilitate provider-patient communication by helping patients to prioritize their goals for LT and make informed choices on the basis of those priorities.

Quality of life and psychosocial functioning of spouse/partner caregivers before and after liver transplantation

Spouse/partner caregivers of liver transplant (LTx) patients play an important role both before and after transplantation. However, very little research has examined the quality of life (QOL), caregiving strain, and psychological functioning of these caregivers. In this study, we examined these outcomes and their correlates in 86 (49 pre-LTx, 38 post-LTx) spouse/partner caregivers. The physical QOL of caregivers was not impaired, and numerous caregiving benefits were identified (e.g., realizing what is important in life, discovering one's own inner strength, giving emotional support to the patient). However, a relatively high proportion of both pre-LTx and post-LTx caregivers had clinically low mental QOL (29% and 35%, respectively), low life satisfaction (45% and 32%, respectively), and high caregiving strain (59% and 81%, respectively). Both pre- and post-LTx caregivers, particularly women, had more total mood disturbance than a normative sample. Higher caregiving strain was significantly correlated with lower mental QOL, lower life satisfaction, and more mood disturbance. Overall, findings suggest that caregiving strain is prominent through the LTx spectrum. There is a need for prospective research to identify the patterns of caregiver outcomes over time and to examine the benefits of clinical interventions for caregivers.

Patients' willingness to accept expanded criteria donor liver transplantation

Utilization of livers from expanded criteria donors (ECD) is one strategy to overcome the severe organ shortage. The decision to utilize an ECD liver is complex and fraught with uncertainty for both providers and patients. We assessed patients' willingness to accept ECD liver transplantation (LTx) and acceptable 1-year mortality risk. One hundred eight patients listed for LTx were asked to rate their willingness to accept ECD LTx and the associated 1-year mortality risk they were willing to accept. Also, patients completed the SF-36v2 and sociodemographic and health information was gathered from their medical records. Patients reported significantly higher willingness to accept standard criteria donor (SCD) versus ECD LTx (t = 13.8, p < 0.001), with more than one-third of patients reporting low willingness to accept ECD LTx. Relative to our center's 10% SCD LTx 1-year mortality rate, most patients (71%) were willing to accept moderately or substantially higher 1-year mortality risk for ECD LTx. In multivariable analyses, higher lab MELD score and white race were significant independent predictors of both ECD willingness and ECD increased mortality risk acceptability. Findings highlight the importance of assessing patients' willingness to pursue ECD LTx and the relative mortality risks they are willing to accept.

Carbon monoxide enhances early liver regeneration in mice after hepatectomy

Hepatocyte proliferation early after liver resection is critical in restoring liver mass and preserving function as the liver regenerates. Carbon monoxide (CO) generated by heme oxygenase-1 (HO-1) strongly influences cellular proliferation and both HO-1 and CO are accepted hepatoprotective molecules. Mice lacking functional HO-1 were unable to mount an appropriate regenerative response following partial hepatectomy (PHTx) compared to wildtype controls. We therefore hypothesized that exogenous administration of CO at low, nontoxic concentrations would modulate hepatocyte (HC) proliferation and liver regeneration. Animals treated with a low concentration of CO 1 hour prior to 70% hepatectomy demonstrated enhanced expression of hepatocyte growth factor (HGF) in the liver compared to controls that correlated with a more rapid onset of HC proliferation as measured by phospho-histone3 staining, increased expression of cyclins D1 and E, phosphorylated retinoblastoma, and decreased expression of the mitotic inhibitor p21. PHTx also increased activation of the HGF receptor c-Met, which was detected more then 9 hours earlier in the livers of CO-treated mice. Blockade of c-Met resulted in abrogation of the CO effects on HC proliferation. Corresponding with increased HC proliferation, treatment with CO maintained liver function with normal prothrombin times versus a 2-fold prolongation in controls. In a lethal 85% PHTx, CO-treated mice showed a greater survival rate compared to controls. In vitro, CO increased HGF expression in hepatic stellate cells, but not HC, and when cocultured together led to increased HC proliferation. In summary, we demonstrate that administration of exogenous CO enhances rapid and early HC proliferation and, importantly, preserves function following PHTx. Taken together, CO may offer a viable therapeutic option to facilitate rapid recovery following PHTx.

Social Adaptability Index predicts access to kidney transplantation

Identifying the group of subjects prone to disparities in access to kidney transplantation is important for developing potential interventions. Data from the United States Renal Data System (January 1, 1990-September 1, 2007; n = 3407) were used to study association between the Social Adaptability Index (SAI; based upon employment, marital status, education, income, and substance abuse) and outcomes (time to being placed on the waiting list and time to being transplanted once listed). Patients were 56.9 ± 16.1 yr old, 54.2% men, 64.2% white, and 50.4% had diabetes. SAI was higher in whites (7.4 ± 2.4) than African Americans (6.5 ± 2.6) [ANOVA, p < 0.001] and greater in men (7.4 ± 2.4) than in women (6.7 ± 2.5) [T-test, p < 0.001]. In multivariate model, greater SAI (range 0-12) was associated with increased likelihood of being placed on the waiting list (hazard ratio [HR] 1.19 [95% CI 1.15-1.23] per each point of increase in SAI, p < 0.001) and greater likelihood of receiving a transplant once listed (HR of 1.06 [95% CI 1.03-1.09] per point of increase in SAI, p < 0.001). Similar trends were observed in most of the subgroups (based upon race, sex, diabetic status, age, comorbidities, and donor type). SAI is associated with access to renal transplantation in patients with end-stage renal disease; it may be used to indentify individuals at risk of healthcare disparities.

Fatigue and sleep quality before and after liver transplantation

CONTEXT

Recent publications suggest that fatigue and sleep disturbance are problems in patients with chronic liver disease and in liver transplant recipients.

OBJECTIVES

To characterize the severity and nature of fatigue and sleep quality before and after liver transplantation, to examine the relationship between fatigue/ sleep quality and quality of life, and to identify their multivariate correlates.

DESIGN, SETTINGS, AND PARTICIPANTS

Cross-sectional survey administered to 110 patients before and 95 patients after liver transplantation at 2 transplant centers.

MAIN OUTCOME MEASURES

Fatigue and sleep quality.

RESULTS

Most pretransplant (86%) and posttransplant (76%) patients experienced high fatigue severity. Correlates of pretransplant fatigue severity were being female (odds ratio [OR] = 0.22, P = .04), higher body mass index (OR = 1.07, P = .04), higher mood disturbance (OR = 1.05, P = .02), and poor sleep quality (OR = 0.26, P = .02). Correlates of posttransplant fatigue severity were use of sleep medications in the past month (OR = 0.51, P = .02) and higher mood disturbance (OR = 1.06, P = .004). Seventy-three percent of pretransplant and 77% of posttransplant patients were classified as having poor sleep quality. Higher body mass index (OR = 1.06, P = .05), sleep medications (OR = 0.43, P = .03), and more mood disturbance (OR = 1.04, P = .007) were predictive of poor sleep quality in pretransplant patients, whereas higher body mass index (OR = 1.07, P = .04) and more anxious mood (OR = 1.28, P = .03) were predictive of poor sleep quality in posttransplant patients.

CONCLUSION

A very high proportion of both pretransplant and posttransplant patients experience clinically severe fatigue levels. Prospective research is necessary to identify causal mechanisms of these disorders and to evaluate strategies to reduce fatigue severity and improve sleep quality.

Intraoperative administration of inhaled carbon monoxide reduces delayed graft function in kidney allografts in Swine

Ischemia/reperfusion injury and delayed graft function (DGF) following organ transplantation adversely affect graft function and survival. A large animal model has not been characterized. We developed a pig kidney allograft model of DGF and evaluated the cytoprotective effects of inhaled carbon monoxide (CO). We demonstrate that donor warm ischemia time is a critical determinant of DGF as evidenced by a transient (4-6 days) increase in serum creatinine and blood urea nitrogen following transplantation before returning to baseline. CO administered to recipients intraoperatively for 1 h restored kidney function more rapidly versus air-treated controls. CO reduced acute tubular necrosis, apoptosis, tissue factor expression and P-selectin expression and enhanced proliferative repair as measured by phosphorylation of retinol binding protein and histone H3. Gene microarray analyses with confirmatory PCR of biopsy specimens showed that CO blocked proinflammatory gene expression of MCP-1 and heat shock proteins. In vitro in pig renal epithelial cells, CO blocks anoxia-reoxygenation-induced cell death while promoting proliferation. This large animal model of DGF can be utilized for testing therapeutic strategies to reduce or prevent DGF in humans. The efficacy of CO on improving graft function posttransplant validates the model and offers a potentially important therapeutic strategy to improve transplant outcomes.

Increasing time delay from presentation until surgical referral for hepatobiliary malignancies

BACKGROUND

Studies have shown that delayed treatment of several non-hepatobiliary (HB) malignancies is associated with adverse effects on disease progression and survival. Delayed treatment of HB malignancies has not been thoroughly investigated.

METHODS

We performed a retrospective institutional review of patients referred to the Hepatobiliary Surgery Service at Beth Israel Deaconess Medical Center (BIDMC) for hepatobiliary malignancies from 2002 to 2008. Primary outcomes included the time delays (TD) in patient workup. Secondary outcomes were reasons for delay as well as disparities in TD based on demographic factors.

RESULTS

Multivariate-adjusted linear regression showed a significant trend of increasing time from presentation until referral to a HB surgeon over the 7-year period (P= 0.001). There were no differences in TD by gender, age or education level. Multivariate-adjusted linear regression showed a significant trend of increasing number of imaging tests performed prior to referral [computerized tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and ultrasound and endoscopic ultrasound (US/EUS)] (P < 0.001). Multivariate-adjusted linear regression in resectable patients showed a significant difference in overall length of survival in those with a TD1 > 30 days compared with those with a TD1 (TD from presentation until referral) <30 days (P = 0.042).

CONCLUSIONS

Delays were associated with an increase in imaging studies and delays adversely affect survival in resected patients. Referring physicians are encouraged to expedite the evaluation and early referral of all patients to an HB surgeon for evaluation and treatment.

Fatigue and Sleep Quality before and after Liver Transplantation

Context

Recent publications suggest that fatigue and sleep disturbance are problems in patients with chronic liver disease and in liver transplant recipients.

Objectives

To characterize the severity and nature of fatigue and sleep quality before and after liver transplantation, to examine the relationship between fatigue/sleep quality and quality of life, and to identify their multivariate correlates.

Design, Settings, and Participants

Cross-sectional survey administered to 110 patients before and 95 patients after liver transplantation at 2 transplant centers.

Main Outcome Measures

Fatigue and sleep quality.

Results

Most pretransplant (86%) and posttransplant (76%) patients experienced high fatigue severity. Correlates of pretransplant fatigue severity were being female (odds ratio [OR] = 0.22, P= .04), higher body mass index (OR = 1.07, P= .04), higher mood disturbance (OR=1.05, P= .02), and poor sleep quality (OR=0.26, P= .02). Correlates of posttransplant fatigue severity were use of sleep medications in the past month (OR = 0.51, P= .02) and higher mood disturbance (OR = 1.06, P = .004). Seventy-three percent of pretransplant and 77% of posttransplant patients were classified as having poor sleep quality. Higher body mass index (OR = 1.06, P= .05), sleep medications (OR=0.43, P= .03), and more mood disturbance (OR=1.04, P = .007) were predictive of poor sleep quality in pretransplant patients, whereas higher body mass index (OR=1.07, P= .04) and more anxious mood (OR=1.28, P = .03) were predictive of poor sleep quality in posttransplant patients.

Conclusion

A very high proportion of both pretransplant and posttransplant patients experience clinically severe fatigue levels. Prospective research is necessary to identify causal mechanisms of these disorders and to evaluate strategies to reduce fatigue severity and improve sleep quality.