Gender Issues in Transplantation

Sex and gender disparity in kidney transplantation: Historical and future perspectives

Sex and gender disparity exist in various stages of kidney transplantation. Females were found to be less likely to be referred for kidney transplant, complete pre-transplant evaluation, be placed on the waitlist, and receive a kidney transplant compared to their male counterparts. Interestingly, females comprise the majority of living kidney donors. This review explores the biological and psychosocial factors that contribute to sex and gender disparity in kidney transplantation and proposes ways to address the disparity.

Women's Access to Kidney Transplantation in France: A Mixed Methods Research Protocol

Kidney transplantation is the best renal replacement therapy (medically and economically) for eligible patients with end-stage kidney disease. Studies in some French regions and in other countries suggest a lower access to the kidney transplant waiting listing and also to kidney transplantation, once waitlisted, for women. Using a mixed methods approach, this study aims to precisely understand these potential sex disparities and their causes. The quantitative study will explore the geographic disparities, compare the determinants of access to the waiting list and to kidney transplantation, and compare the reasons and duration of inactive status on the waiting list in women and men at different scales (national, regional, departmental, and census-block). The qualitative study will allow describing and comparing women's and men's views about their disease and transplantation, as well as nephrologists' practices relative to the French national guidelines on waiting list registration. This type of study is important in the current societal context in which the reduction of sex/gender-based inequalities is a major social expectation.

An Analysis by the European Committee on Organ Transplantation of the Council of Europe Outlining the International Landscape of Donors and Recipients Sex in Solid Organ Transplantation

Discrepancies in donation and transplantation by sex and gender have previously been reported. However, whether such differences are invariably the inevitable, unintended outcome of a legitimate process has yet to be determined. The European Committee on Organ Transplantation of the Council of Europe (CD-P-TO) is the committee that actively promotes the development of ethical, quality and safety standards in the field of transplantation in Europe. Whilst the ultimate objective is to shed light on the processes underlying potential gender inequities in transplantation, our initial goal was to represent the distribution by sex among organ donors and recipients in the CD-P-TO Member States and observer countries. Our survey confirms previous evidence that, in most countries, men represent the prevalent source of deceased donors (63.3% in 64 countries: 60.7% and 71.9% for donation after brain and circulatory death, respectively). In contrast, women represent the leading source of organs recovered from living kidney and liver donors (61.1% and 51.2% in 55 and 32 countries, respectively). Across countries, most recovered organs are transplanted into men (65% in 57 countries). These observations may be explained, at least in part, by the higher burden of certain diseases in men, childbearing related immune sensitization in women, and donor-recipient size mismatch. Future research should establish whether gender-related socially-constructed roles and socioeconomic status may play a detrimental role reducing the access of women to transplantation.

Diabetes and Cardiovascular Risk in Renal Transplant Patients

End-stage kidney disease (ESKD) is a main public health problem, the prevalence of which is continuously increasing worldwide. Due to adverse effects of renal replacement therapies, kidney transplantation seems to be the optimal form of therapy with significantly improved survival, quality of life and diminished overall costs compared with dialysis. However, post-transplant patients frequently suffer from post-transplant diabetes mellitus (PTDM) which an important risk factor for cardiovascular and cardiovascular-related deaths after transplantation. The management of post-transplant diabetes resembles that of diabetes in the general population as it is based on strict glycemic control as well as screening and treatment of common complications. Lifestyle interventions accompanied by the tailoring of immunosuppressive regimen may be of key importance to mitigate PTDM-associated complications in kidney transplant patients. More transplant-specific approach can include the exchange of tacrolimus with an alternative immunosuppressant (cyclosporine or mammalian target of rapamycin (mTOR) inhibitor), the decrease or cessation of corticosteroid therapy and caution in the prescribing of diuretics since they are independently connected with post-transplant diabetes. Early identification of high-risk patients for cardiovascular diseases enables timely introduction of appropriate therapeutic strategy and results in higher survival rates for patients with a transplanted kidney.

Influence of Sex-Mismatch on Prognosis After Heart Transplantation

The influence of donor and recipient sex on prognosis after heart transplantation has been analyzed in single, multi-center studies, and international registries. In most of them, sex-mismatch was identified as a risk factor for the worst prognosis, especially in men recipients of female heart. This could be attributed to physiological differences between women and men, differences in complications rates after heart transplantation (rejection, cardiovascular allograft vasculopathy, and primary graft failure), and pulmonary hypertension of the recipient. Confounding variables as age, urgent transplantation, and size-mismatch should also be considered. When allocating a graft, sex-mismatch should be considered but its influence in long-term survival should be further explored.

Mitigating the Impact of Using Female Donor Hearts in Male Recipients Using BMI Difference

BACKGROUND

Heart transplantation is limited by the supply of donor organs. Previous studies have associated female donor to male recipient with decreased posttransplant survival. We wanted to evaluate whether this risk can be mitigated using higher donor than recipient body mass index (BMI).

METHODS

We performed a retrospective analysis of the Organ Procurement and Transplantation Network/United Network of Organ Sharing registry encompassing years 2005 to 2018 for all male adult recipients (>18 years of age) who underwent isolated heart transplantation with grafts from female donors. The association between donor and recipient BMI difference and recipient survival was evaluated using adjusted Cox proportional hazards modeling.

RESULTS

A total of 3788 male recipients who received female donor hearts met inclusion criteria for analysis. Maximally selected rank statistics identified donor minus recipient BMI of 1.5 kg/m² as a meaningful cutoff point in the analysis of recipient survival. Multivariable Cox proportional hazards analysis demonstrated that increasing donor BMI relative to recipient BMI up to this cutoff point was associated with improved survival (hazard ratio per 5-unit difference, 0.87; 95% confidence interval, 0.77-0.99). Above this cutoff point, increasing donor BMI relative to the recipient did not improve survival more than what was achieved by adding 1.5 of BMI difference (hazard ratio per 5-unit difference, 0.97; 95% confidence interval, 0.90-1.04).

CONCLUSIONS

Increasing donor BMI relative to recipient BMI up to 1.5 kg/m² greater than recipient BMI was associated with improved survival. BMI difference may be useful as a simple surrogate for predicted heart mass difference to help mitigate the impact of sex mismatch in heart transplantation.

Sex and Gender Bias in Kidney Transplantation: 3D Bioprinting as a Challenge to Personalized Medicine

In this article, we explore to what extent sex and gender differences may be reproduced in the 3D bioprinting of kidneys. Sex and gender differences have been observed in kidney function, anatomy, and physiology, and play a role in kidney donation and transplantation through differences in kidney size (sex aspect) and altruism (gender aspect). As a form of personalized medicine, 3D bioprinting might be expected to eliminate sex and gender bias. On the basis of an analysis of recent literature, we conclude that personalized techniques such as 3D bioprinting of kidneys alone do not mean that sex and gender bias does not happen. Therefore, sex and gender considerations should be included into every step of developing and using 3D-bioprinted kidneys: in the choice of design, cells, biomaterials, and X-chromosome-activated cells.

Understanding the sex disparity in living kidney donation

Living donors are the preferred source of organs for kidney transplantation, which is the treatment modality of choice for end-stage kidney disease. Health care systems widely promote living kidney donation. However, women are consistently overrepresented among living donors. The reasons behind the sex-based disparity in living kidney donation remain poorly understood. Compared to women, men possess a greater amount of kidney function, and the higher deceased donation rate among men reflects their higher overall kidney quality. A plausible medical explanation for the sex-based disparity in living kidney donation includes an uncompromising emphasis on preserving donor health, with less emphasis placed on organ quality, which is the main criterion in deceased donor selection. On the other hand, consent to deceased donation is also greater in women, indicating their greater desire to donate even though fewer women actually become deceased donors. Therefore, nonmedical reasons for the sex disparity in living donation must be sought. Increased empathic distress or emotional memory; a greater sense of responsibility, urgency, and impulsiveness with increased reaction to empathy; a different body image; and a different social status may all contribute to greater living kidney donation in women. Economic inequity may be the singular explanation when personal worth links to economic worth. To better understand the sex disparity in living kidney donation, we need better data on the reasons behind both nondonation and donor rejection after evaluation in clinical practice. Nondirected living kidney donation provides unique opportunities to minimize factors such as emotional distress, empathy, and impulsiveness. More liberal acceptance criteria for donors with isolated medical abnormalities and testing legitimate donor reimbursement strategies based on actual income levels rather than a fixed amount can assist in both ascertaining the reasons behind the sex disparity in living kidney donation and increasing overall living kidney donation rates.

Predictors of Organ Donation Among Patients With Brain Death in the Intensive Care Unit

INTRODUCTION

Despite the improved care of potential organ donors with probable brain death (BD) in the intensive care unit (ICU), few epidemiologic and clinical data are available in developing countries.

OBJECTIVES

To evaluate ICU patients with suspected BD aiming to identify factors possibly related to success (organ donation) or failure (nondonation).

METHODS

Retrospective cohort study, from the patient records of an adult ICU of a Brazilian teaching hospital for 12 months. Data were tabulated, and descriptive statistics and univariate and multivariate analyses were performed.

RESULTS

During the study period, 85 patients with acute neurologic diseases and suspected BD were admitted to the ICU and included for analysis. Of these, there were 9 organ donors (7 liver and 9 kidney donors); 77.7% were men, with a mean age of 39.6 years and admission Acute Physiology and Chronic Health Evaluation II of 25.5. Two-thirds of the patients were victims of trauma. The mean time between acute neurologic event and organ withdrawal was 269 hours. The main prognostic factors related to the success of organ donation were the maximum serum lactate and creatinine levels during ICU admission.

CONCLUSIONS

The main clinical factors correlated with nonevolution for organ donation among ICU patients with clinical suspicion of BD were related to patient severity and organic dysfunction: serum lactate and creatinine level. Clinical care and monitoring are emphasized to improve the efficiency of the donation process.

Few Gender Differences in Attitudes and Experiences after Live Kidney Donation, with Minor Changes Over Time

BACKGROUND We sought to study gender differences and differences over time with respect to demographics, relation to recipient, donor motives, and experiences of live kidney donation. MATERIAL AND METHODS In all, 455 consecutive live kidney donors, representing all of the donors at our center between 1974 and 2008 were considered for this study. There were 28 deceased donors and 14 donors who had moved abroad, leaving 413 donors; 387 (94%) agreed to participate in this study. A questionnaire was sent and the answers was analyzed for gender differences and, where relevant, for changes over time. RESULTS In all sub-periods, female donors made up the majority (55-62%), except for sibling donors (45%) and child-to-parent donors (40%). No significant gender differences were seen in perceived information given before donation. For males, it was more common that the recipient took the initiative to donate. For females, the motivation for donating was more frequently to help the recipient and because others wanted them to donate. For males, it was more common to feel a moral obligation. Post-operatively, females more frequently felt sad and experienced nausea, and more frequently felt that the donation had a positive impact on their lifes. With the introduction of minimally invasive surgical techniques, donors experienced fewer problems from the operation, with no gender difference. CONCLUSIONS Females donate more frequently than males, a difference that did not change over time. Only a few gender differences were seen in donor motives and the donation experience; however, these differences may be relevant to address the gender imbalance in kidney donations.

Mortality, rehospitalization, and post-transplant complications in gender-mismatched heart transplant recipients

BACKGROUND

Limited research has been published on outcomes in heart transplant (HT) recipients with gender-mismatched donors.

OBJECTIVE

Compare 3-year post-transplant outcomes in 2 groups of gender-mismatched HT recipients and a no-mismatch group.

METHODS

Sample: 347 HT recipients: 21.3% (74) received a heart from the opposite gender: Group 1: same gender donor/recipient (273, 78.7%); Group 2: female donor/male recipient (40, 11.5%); Group 3: male donor/female recipient (34, 9.8%).

OUTCOMES

mortality, hospitalization, and complications.

RESULTS

Female patients with male heart donors had shorter 3-year survival, were rehospitalized more days after HT discharge, and had more treated acute rejection episodes and cardiac allograft vasculopathy. No differences were found in: HT length of stay, respiratory failure, stroke, cancer, renal dysfunction, steroid-induced diabetes, number of IV-treated infections, or the timing of infection and rejection.

CONCLUSION

Female HT recipients with male donors had worse 3-year outcomes as compared to male-mismatch and no-mismatch groups.

[The effect of gender on the results of related kidney transplantation]

AIM

To define the effect of donor and recipient gender on the results of kidney transplantation from living related donor.

MATERIAL AND METHODS

Group of 271 patients who underwent kidney transplantation from living related donor was analyzed. There were 115 women and 156 men. Age varied from 1 to 63 years (mean 21.30±12.32). There were 127 children aged 1-18 years (mean 11.28±4.63) and 144 adults aged 19-63 years (mean 29.81±11.24). Donors included 162 women and 109 men. Overall survival was calculated using Kaplan-Mayer. Mortality and incidence of transplants failure were determined using Fisher's exact test.

RESULTS

All patients were divided into 2 groups depending on recipients' gender and then into 4 subgroups depending on gender of donors and recipients. Comparative statistical analysis showed that transplants survival was higher in women vs. men (T=2.7, p=0.007). Survival of patients was similar in both groups. Moreover it was the best in subgroup of recipients-women with kidneys from donors-men. Difference was statistically significant (T=2.16, p=0.03). There was no significant difference in all other cases.

CONCLUSION

The results of kidney transplantation are better in recipients-women than in men.

The impact of gender mismatching on early and late outcomes following heart transplantation

Aims

The role of donor/recipient gender matching on the long‐term rejection process and clinical outcomes following heart transplantation (HT) outcomes is still controversial. We aim to investigate the impact of gender matching on early and long‐term outcome HT.

Methods and results

The study population comprised 166 patients who underwent HT between 1991 and 2013 and were prospectively followed up in a tertiary referral centre. Early and late outcomes were assessed by the type of donor–recipient gender match (primary analysis: female donor–male recipient [FD–MR, n = 36] vs. male donor–male recipient [MD–MR, n = 109]). Early mortality, need for inotropic support, length of hospital stay, and major perioperative adverse events did not differ between the FD–MR and MD–MR groups. However, the FD–MR group experienced significantly higher rates of early major rejections per patient as compared with the MD–MR group (1.2 ± 1.6 vs. 0.4 ± 0.8; P = 0.001), higher rates of overall major rejections (16 vs. 5.5 per 100 person years; P < 0.05), and higher rate of cardiac allograft vasculopathy (43% vs. 20%; P = 0.01). Kaplan–Meier survival analysis showed that the cumulative probabilities of survival free of rejections and major adverse events were significantly higher in MD–MR group (P = 0.002 and 0.001, respectively). Multivariate analysis showed that FD–MR status was associated with >2.5‐fold (P = 0.03) increase in the risk for rejections and with a >3‐fold (P = 0.01) increase in the risk for major adverse events during follow‐up.

Conclusions

Donor–recipient gender mismatch is a powerful independent predictor of early and late rejections and long‐term major adverse events following HT.

Gender Mainstreaming and Transplant Surgery

BACKGROUND

Gender differences in medicine are gaining in importance. In transplant surgery, not only the patient's gender but also that of the donor play an important role in the outcome of transplantation due to sociocultural and genetic factors.

METHODS

This review article gives an overview of the latest investigations into gender-related influences in the field of visceral transplantation. For this purpose, a systematic review of the literature was performed.

RESULTS

In general, women are less often evaluated for and subjected to transplantation worldwide. Significantly poorer outcome can be observed in women with liver transplantation following hepatitis C cirrhosis. Furthermore, female renal grafts are less favorable in terms of outcome and survival. Gender disparities affect transplant medicine due to subtle gender-specific immunological factors. Sociocultural factors also lead to differences in the clinical treatment of men and women, which may influence overall survival.

CONCLUSION

For a better understanding of gender-specific differences in transplant medicine and a possible improvement in outcome, further research in this field is necessary.

Impact of donor-recipient sex match on long-term survival after heart transplantation in children: An analysis of 5797 pediatric heart transplants

The effect of donor-recipient sex matching on long-term survival in pediatric heart transplantation is not well known. Adult data have shown worse survival when male recipients receive a sex-mismatched heart, with conflicting results in female recipients. We analyzed 5795 heart transplant recipients ≤ 18 yr in the Scientific Registry of Transplant Recipients (1990-2012). Recipients were stratified based on donor and recipient sex, creating four groups: MM (N = 1888), FM (N = 1384), FF (N = 1082), and MF (N = 1441). Males receiving sex-matched donor hearts had increased unadjusted allograft survival at five yr (73.2 vs. 71%, p = 0.01). However, this survival advantage disappeared with longer follow-up and when adjusted for additional risk factors by multivariable Cox regression analysis. In contrast, for females, receiving a sex-mismatched heart was associated with an 18% higher risk of allograft loss over time compared to receiving a sex-matched heart (HR 1.18, 95% CI: 1.00-1.38) and a 26% higher risk compared to sex-matched male recipients (HR 1.26, 95% CI: 1.10-1.45). Females who receive a heart from a male donor appear to have a distinct long-term survival disadvantage compared to all other groups.

Gender in the allocation of organs in kidney transplants: meta-analysis

OBJECTIVE

To analyze whether gender influence survival results of kidney transplant grafts and patients.

METHODS

Systematic review with meta-analysis of cohort studies available on Medline (PubMed), LILACS, CENTRAL, and Embase databases, including manual searching and in the grey literature. The selection of studies and the collection of data were conducted twice by independent reviewers, and disagreements were settled by a third reviewer. Graft and patient survival rates were evaluated as effectiveness measurements. Meta-analysis was conducted with the Review Manager^® 5.2 software, through the application of a random effects model. Recipient, donor, and donor-recipient gender comparisons were evaluated.

RESULTS

: Twenty-nine studies involving 765,753 patients were included. Regarding graft survival, those from male donors were observed to have longer survival rates as compared to the ones from female donors, only regarding a 10-year follow-up period. Comparison between recipient genders was not found to have significant differences on any evaluated follow-up periods. In the evaluation between donor-recipient genders, male donor-male recipient transplants were favored in a statistically significant way. No statistically significant differences were observed in regards to patient survival for gender comparisons in all follow-up periods evaluated.

CONCLUSIONS

The quantitative analysis of the studies suggests that donor or recipient genders, when evaluated isolatedly, do not influence patient or graft survival rates. However, the combination between donor-recipient genders may be a determining factor for graft survival.

Sex differences in liver toxicity-do female and male human primary hepatocytes react differently to toxicants in vitro?

There is increasing amount of evidence for sex variation in drug efficiency and toxicity profiles. Women are more susceptible than men to acute liver injury from xenobiotics. In general, this is attributed to sex differences at a physiological level as well as differences in pharmacokinetics and pharmacodynamics, but neither of these can give a sufficient explanation for the diverse responses to xenobiotics. Existing data are mainly based on animal models and limited data exist on in vitro sex differences relevant to humans. To date, male and female human hepatocytes have not yet been compared in terms of their responses to hepatotoxic drugs. We investigated whether sex-specific differences in acute hepatotoxicity can be observed in vitro by comparing hepatotoxic drug effects in male and female primary human hepatocytes. Significant sex-related differences were found for certain parameters and individual drugs, showing an overall higher sensitivity of female primary hepatocytes to hepatotoxicants. Moreover, our work demonstrated that high content screening is feasible with pooled primary human hepatocytes in suspension.

Reparative effects of neural stem cells in neonatal rats with hypoxic-ischemic injury are not influenced by host sex

BACKGROUND

Gender is increasingly recognized as an important influence on brain development, disease susceptibility, and response to pharmacologic/rehabilitative treatments. In regenerative medicine, it remains entirely unknown whether there is an interaction between transplanted stem cells and host gender that might bias efficacy and safety in some patients but not others.

METHODS

We examined the role of recipient gender in a neonatal rat hypoxic-ischemic injury (HII) model, treated with female human neuronal stem cells (hNSCs), labeled with superparamagnetic iron oxide particles implanted into the contralateral cerebral ventricle. We monitored HII evolution (by magnetic resonance imaging, histopathology, behavioral testing) and hNSC fate (migration, replication, viability).

RESULTS

Recipient gender after implantation did not influence the volume or location of ischemic injury (1, 30, or 90 d) or behavior (90 d). Superparamagnetic iron oxide labeling did not influence HII evolution. Implantation had its greatest benefit on mild/moderate injuries, which remained stable rather than increasing as in severe HII as is the natural history for such lesions.

CONCLUSION

Our results suggest that hNSC treatment (including using hNSCs that are prelabeled with iron to allow tracking in real time by magnetic resonance imaging) would be equally safe and effective for male and female human newborns with mild-to-moderate HII.

The difficulty in defining extended donor criteria for liver grafts: the Eurotransplant experience

Donor criteria for liver grafts have been expanded because of organ shortage. Currently, no exact definitions for extended donor grafts have been established. The aim of this study was to analyze the impact of donor-specific risk factors, independent of recipient characteristics. In collaboration with Eurotransplant and European Liver Transplant Register, solely donor-specific parameters were correlated with 1-year survival following liver transplantation. Analyses of 4701 donors between 2000 and 2005 resulted in the development of a nomogram to estimate graft survival for available grafts. Predictions by nomogram were compared to those by Donor Risk Index (DRI). In the multivariate analysis, cold ischemic time (CIT), highest sodium, cause of donor death, γ-glutamyl transferase (γ-GT), and donor sex (female) were statistically significant factors for 3 months; CIT, γ-GT, and cause of donor death for 12-month survival. The median DRI of this study population was 1.45 (Q1: 1.17; Q3: 1.67). The agreement between the nomogram and DRI was weak (kappa = 0.23). Several donor-specific risk factors were identified for early survival after liver transplantation. The provided nomogram will support quick organ quality assessment. Nevertheless, this study showed the difficulties of determining an exact definition of extended criteria donors.

First-year clinical outcomes in gender-mismatched heart transplant recipients

BACKGROUND

Research indicates that gender mismatch of organ donor and recipient may adversely affect outcomes in heart transplant (HT) patients. However, there is a paucity of literature on gender-mismatched outcomes in patients receiving an HT, and only a few outcomes have been investigated.

OBJECTIVES

Objectives were to (1) determine if gender-mismatched HT recipients experienced decreased survival, more posttransplantation complications, and more days of hospitalization during the first postoperative year as compared with gender-matched recipients and (2) identify risk factors for decreased survival.

METHODS

Patients were 347 HT recipients; 21.3% (74) received a heart from the opposite gender. Three groups were compared: group 1: same gender donor-recipient (273 [78.7%]: 36 women, 237 men); group 2: female donor-male recipient (40 [11.5%]); group 3: male donor-female recipient (34 [9.8%]). Ten outcomes were compared with Kaplan-Meier survival analysis, logistic regression, and multivariate analysis of covariance, using a Bonferroni-adjusted P ≤ .005. Risk factors for decreased survival were examined with Cox regression.

RESULTS

Gender-mismatched HT patients with a male donor and a female recipient (group 3) had more treated acute rejections and were rehospitalized for more days after HT discharge during the first postoperative year as compared with gender-matched patients. No significant differences were found in 8 other first-year outcomes: number of deaths, survival time, hospital length of stay for HT surgery, cardiac allograft vasculopathy, severe renal dysfunction, new-onset steroid-induced diabetes, nonskin cancers, or the number of infections treated with an intravenous antibiotic. Risk factors for decreased year 1 survival were higher year 1 cholesterol, earlier intravenous-treated infection, severe renal dysfunction, earlier treated rejection, and diabetes (both preexisting and new-onset steroid-induced diabetes).

CONCLUSION

Gender-mismatched HT recipients had more complications due to rejection and higher resource utilization due to more rehospitalization during the first postoperative year as compared with gender-matched recipients. Therefore, these problem areas may provide targets for possible interventions.

Influence of donor-recipient gender mismatch on graft function and survival following lung transplantation

OBJECTIVES

In current practice, donors and recipients are not matched for gender in lung transplantation. However, some data have suggested a possible effect of gender combinations on lung transplant outcomes. We examined whether donor-recipient (D/R) gender mismatch is related to adverse outcomes after lung transplantation in terms of early and long-term graft function and survival.

METHODS

We reviewed 256 donors and lung transplant recipients over a 14-year period. Patients were distributed into four groups: Group A (D/R: female/female), Group B (D/R: male/male), Group C (D/R: female/male), Group D (D/R: male/female). Donor and recipient variables were compared among groups, including early graft function, 30-day mortality, freedom from bronchiolitis obliterans syndrome (BOS), and long-term survival.

RESULTS

Group A: 57 (22%), Group B: 99 (39%), Group C: 62 (24%), Group D: 38 (15%) transplants (P = 0.001). Donor age was 29 ± 14, 27 ± 12, 33 ± 13 and 23 ± 12 years for Groups A, B, C and D, respectively (P = 0.004). Recipient age was 31 ± 15, 44 ± 17, 42 ± 16 and 30 ± 16 years for Groups A, B, C and D, respectively (P = 0.000). PaO2/FiO2 (mmHg) 24 h post-transplant was: Group A: 276 ± 144, Group B: 297 ± 131, Group C: 344 ± 133 and Group D: 238 ± 138 (P = 0.015). Primary graft dysfunction developed in 23, 14, 17 and 21% of recipients from Groups A, B, C and D, respectively (P = 0.45). Operative mortality was 4.4, 6.5, 5.2 and 2%, for recipients from Groups A, B, C and D, respectively (P = 0.66). Freedom from BOS was 73, 59 and 36% for gender-matched transplants vs 76, 67 and 40% for gender-mismatched transplants at 3, 5 and 10 years, respectively (P = 0.618), without differences among groups. A non-significant survival benefit was observed for female recipients, irrespective of the donor gender.

CONCLUSIONS

Donor-recipient gender mismatch does not have a negative impact on early graft function and mortality following lung transplantation. There is a trend towards a survival benefit for female recipients, irrespective of the donor gender.

Gender-based analysis of outcome after heart transplantation

OBJECTIVES

Gender differences between donors and recipients might have an effect on outcome after heart transplantation. Literature and registries reveal controversial results. We reviewed 1000 heart transplantations at our center focusing on the influence of gender differences on short- and long-term outcome after heart transplantation.

MATERIALS AND METHODS

We performed a retrospective analysis of 1000 (960 primary and 40 redo-heart transplantations) between August 1981 and July 2008. In contrast to other studies, the data for gender differences (donor gender and recipient gender) were evaluated for recipient survival and survival conditional to early mortality.

RESULTS

Female donors are significantly older than male donors (females, 36.5 ± 14.5 years; males, 31.2 ± 13.8 years). One-year survival was significantly inferior in male recipients receiving female donor hearts (mR/fD: 73.7%) compared to females receiving male donor organs (fR/mD: 90.9%) (P = .045). Univariate analysis revealed that, for recipients who survived > 1 year, survival at 10 years was significantly greater for female donors and female recipients (90%) than it was for male donors and male recipients (72%; P = .034). Multivariate analysis showed that the gender combination with female donors and female recipients was an independent indicator for greater long-term survival (P = .04).

CONCLUSIONS

The gender combination of female donors and male recipients had a greater risk for early mortality after heart transplantation, and the combination of male donors and female recipients resulted in favorable short-term outcomes. In long-term follow-up, recipients of hearts from female donors had better survival, especially female recipients.

A GENS-based approach to cardiovascular pharmacology: impact on metabolism, pharmacokinetics and pharmacodynamics

Pharmacological outcomes depend on many factors, with many of them being sexually dimorphic. Thus, physiological gender/sex (GENS) differences can influence pharmacokinetics, pharmacodynamics and, thus, bioavailability and resulting in efficacy of treatment, meaning GENS differences should be an important consideration in therapeutics. In particular, drug response can change according to different hormonal environments. Therefore, GENS-specific differences have a particular clinical relevance in terms of drug delivery, especially for those substances with a narrow therapeutic margin. Since adverse effects are more frequent among women, safety is a key issue. Overall, the status of women, from a pharmacological point of view, is often different and less studied than that of men and deserves particular attention. Further studies focused on women's responses to drugs are necessary in order to make optimal pharmacotherapeutic decisions.

Effect of host sex and sex hormones on muscle-derived stem cell-mediated bone formation and defect healing

Muscle-derived stem cells (MDSCs) are known to exhibit sexual dimorphism, by donor sex, of osteogenic, chondrogenic, and myogenic differentiation potential in vitro. Moreover, host sex differences in the myogenic capacity of MDSCs in vivo are also observed. This study investigated the role of host sex and host sex hormones in MDSC-mediated bone formation and healing. Using unaltered male, castrated male, unaltered female, and ovariectomized female mice, both MDSC-mediated ectopic bone formation and cranial defect healing were examined. Male hosts, whether unaltered or castrated, form significantly larger volumes of MDSC-mediated ectopic bone than female hosts (either unaltered or ovariectomized), and no differences in ectopic bone volume were found between hosts of the same sex. In a cranial defect healing model, similar results were found-unaltered and castrated male hosts display larger volumes of bone formed when compared with unaltered and ovariectomized female hosts. However, in this healing model, some volume differences were found between hosts of the same sex. In both models, these differences were attributed to varying rates of endochondral bone formation in male and female hosts.

Risk factors that increase mortality after living donor liver transplantation

BACKGROUND

Female liver to male recipient is a well-accepted risk factor for graft loss in cadaveric liver transplantation. However, gender matching is infeasible because of an insufficient number of available donors. No studies have been performed on the role of gender in the field of living donor liver transplantation. This report investigates the effect of gender mismatch on the outcome of living donor liver transplantation.

METHODS

A total of 335 patients and donors were classified into four groups according to the following gender combinations: male donor to male recipient group (n=104), male donor to female recipient group (n=120), female donor to male recipient (FM) group (n=59), and female donor to female recipient group (n=52). Patient and graft survival were compared among the groups. We performed a multivariable analysis to identify the factors associated with patient mortality.

RESULTS

The 1-, 3-, 5-, and 10-year patient survival rates in the FM group were 80.6%, 66.8%, 61.8%, and 47.7%, respectively. The FM group showed significantly shorter patient survival compared with the other three groups. Independent risk factors for patient mortality were: FM group (P=0.006), pretransplant diabetes mellitus (P=0.001), and a model for end-stage liver disease score more than or equal to 20 (P=0.004).

CONCLUSIONS

Male recipients of transplants from female donors, pretransplant diabetes mellitus, and a model for end-stage liver disease score more than or equal to 20 have poor survival rates.

Donor-recipient sex mismatch portends poor 10-year outcomes in a single-center experience

BACKGROUND

Several studies have indicated that survival after heart transplantation is affected by donor-recipient sex matching. In most studies, male recipients of a female heart have the poorest survival rates, whereas survival of female recipients is not affected by donor sex. The purpose of the current study was to determine the long-term outcomes of recipients at a large single center on uniform immunosuppression therapy in the current era.

METHODS

We reviewed the records of 857 patients transplanted at a single center between 1994 and 2008. Patients were divided into 4 groups based on donor-recipient sex: male donor to male recipient (male/male, n = 506); female donor to female recipient (female/female, n = 113); male donor to female recipient (male/female, n = 106); and female donor to male recipient (female/male, n = 132). Ten-year outcomes were assessed for: survival; freedom from cardiac allograft vasculopathy (CAV); and freedom from non-fatal major adverse cardiac events (NF-MACE).

RESULTS

Ten-year actuarial survival was comparable in male/male and female/female groups, at 69% and 71%, respectively (p > 0.05). Compared with the male/male group, 10-year actuarial survival was significantly lower in the sex-mismatch groups: 58% in the male/female group (p = 0.03) and 59% in the female/male group (p = 0.01). There was no significant difference in 10-year freedom from CAV or NF-MACE among the groups.

CONCLUSIONS

Heart transplant patients with donor-recipient sex mismatch have lower survival, extending the results of prior studies to suggest that sex mismatch is undesirable in female, as well as male, recipients. This may impact donor selection and recipient wait time to transplantation.

Psychological distress as a negative survival factor for patients with hematologic malignancies who underwent allogeneic hematopoietic stem cell transplantation

STUDY OBJECTIVE

To evaluate the influence of distress on overall survival of patients with hematologic malignancies who underwent allogeneic stem cell transplantation (allo-SCT) and to analyze the possible risk factors for death.

DESIGN

Retrospective cohort study.

SETTING

Large tertiary care teaching hospital.

PATIENTS

Seventy-seven patients (aged ≥ 15 yrs) with hematologic malignancies who underwent allo-SCT between January 2000 and August 2007; 20 patients with distress history were matched in a 1:3 ratio with 57 patients without distress history.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was overall survival, defined as the time from allo-SCT to disease-related death or last date of follow-up. Secondary outcomes were time to hematologic recovery (absolute neutrophil count ≥ 500 cells/mm³) from day of allo-SCT, length of hospital stay, and opioid usage. Sociodemographic information and clinical characteristics were analyzed for possible risk factors. Patient history of psychological distress resulted in a significantly higher mortality rate in the first year after allo-SCT (hazard ratio [HR] 3.05, 95% confidence interval [CI] 1.48-6.28, p=0.001) and led to a shorter overall survival rate (HR 1.63, 95% CI 0.86-3.10, p=0.133). However, psychological distress had no effect on hospital length of stay, hematologic recovery time, opioid usage status, or dose of opioid analgesics used. Factors associated with death after allo-SCT in the univariate analysis (p<0.05) were high-relapse risk disease, umbilical cord blood SCT, total-body irradiation-containing conditioning regimen, and higher educational background. In the multivariate analysis, high relapse risk (HR 3.85, 95% CI 1.81-8.20, p<0.001) and total-body irradiation-containing conditioning regimen (HR 3.50, 95% CI 1.29-9.51, p=0.01) were identified as risk factors for death.

CONCLUSION

A history of psychological distress before allo-SCT, after adjusting for other patient- and disease-related prognostic factors, had a significant influence on early death in the first year after transplantation.

Stem cells and neuroprotection: understanding the players

The use of neuroprotective therapies begs the question of how such therapies could affect preexisting stem cell populations within the host, as well as those introduced through cell-replacement therapy. Multiple mechanisms may mediate stem cell responses to neuroprotectants such as host/donor age and gender, cellular lineage/differentiation status, and mitochondrial dynamics. Current therapeutic sources for stem cells are embryonic, somatic, or induced pluripotent, with very little known about the effects of gender, age, cell type, and mitochondrial dynamics. With the advent of therapies to stimulate and recruit endogenous stem cells or transplant donor cells into damage areas in the hopes of recuperative regeneration of lost neurons, it is important to discuss mechanisms that dictate the winning players in the neuroprotection game. This review will focus on our current understanding of the characteristics of renewing stem cells that may affect neuroprotection.

Repopulation of vascularized bone allotransplants with recipient-derived cells: detection by laser capture microdissection and real-time PCR

Mechanisms underlying successful composite tissue transplantation must include an analysis of transplant chimerism, which is little studied, particularly in calcified tissue. We have developed a new method enabling determination of lineage of selected cells in our model of vascularized bone allotransplantation. Vascularized femoral allotransplantation was performed from female Dark Agouti (DA) donor rats to male Piebald Virol Glaxo (PVG) recipients, representing a major histocompatibility mismatch. Four groups differed in use of immunosuppression (+/-2 weeks Tacrolimus) and surgical revascularization, by implantation of either a patent or a ligated saphenous arteriovenous (AV) bundle. Results were assessed at 18 weeks. Bone blood flow was measured by the hydrogen washout technique and transverse specimens were prepared for histology. Real-time PCR was performed on DNA from laser capture microdissected cortical bone regions to determine the extent of chimerism. To do so, we analyzed the relative expression ratio of the sex-determining region Y (Sry) gene, specific only for recipient male rat DNA, to the cyclophilin housekeeper gene. Substantial transplant chimerism was seen in cortical bone of all groups (range 77-97%). Rats without immunosuppression and with a patent AV bundle revealed significantly higher chimerism than those with immunosuppression and a ligated AV bundle, which maintained transplant cell viability. We describe a new method to study the extent of chimerism in rat vascularized bone allotransplants, including a sex-mismatched transplantation model, laser capture microdissection of selected bone regions, and calculation of the relative expression ratio.

The impact of donor-recipient sex matching on survival after orthotopic heart transplantation: analysis of 18 000 transplants in the modern era

INTRODUCTION

Single-institution series have suggested that men receiving orthotopic heart transplantation from female donors have decreased survival. No multi-institutional series has comprehensively addressed the issue of donor and recipient sex matching for both male and female orthotopic heart transplantation recipients.

METHODS AND RESULTS

We used data from the multi-institutional prospectively collected United Network for Organ Sharing open transplantation cohort to review 18 240 adult patients who received orthotopic heart transplantation from 1999 to 2007. Four donor recipient strata were identified (male donor/male recipient, N=10 750; female donor/female recipient, N=2201; male donor/female recipient, N=2121; and female donor/male recipient, N=3168). The primary end point of all cause posttransplant mortality was compared among groups using a Cox proportional hazard regression model with additional propensity adjustment. Female recipients, irrespective of donor sex, had 3.6% lower overall survival at 5 years posttransplant (P=0.003). Men who received organs from male donors had the highest cumulative survival at 5 years (74.5%). Men receiving female hearts had a 15% increase in the risk of adjusted cumulative mortality (hazard ratio, 1.15; 95% CI, 1.02 to 1.30; P=0.02). No significant increase in the relative hazard for death occurred for women receiving opposite sex donor organs (1.24; 0.92 to 1.35; P=0.31).

CONCLUSIONS

The United Network for Organ Sharing data set has provided a large sample examining donor recipient sex pairing in orthotopic heart transplantation. Men receiving organs for same sex donors have significantly improved short- and long-term survival. No survival advantage was seen for women with same sex donors.