A new bicornuate model of rat uterus transplantation.

INTRODUCTION: Uterus transplantation has revolutionized reproductive medicine for women with absolute uterine factor infertility, resulting in more than 40 reported successful live births worldwide to date. Small animal models are pivotal to refine this surgical and immunological challenging procedure aiming to enhance safety for both the mother and the child. MATERIAL AND METHODS: We established a syngeneic bicornuate uterus transplantation model in young female Lewis rats. All surgical procedures were conducted by an experienced and skilled microsurgeon who organized the learning process into multiple structured steps. Animals underwent meticulous preoperative preparation and postoperative care. Transplant success was monitored by sequential biopsies, monitoring graft viability and documenting histological changes long-term. RESULTS: Bicornuate uterus transplantation were successfully established achieving an over 70% graft survival rate with the passage of time. The bicornuate model demonstrated safety and feasibility, yielding outcomes comparable to the unicornuate model in terms of ischemia times and complications. Longitudinal biopsies were well-tolerated, enabling comprehensive monitoring throughout the study. CONCLUSIONS: Our novel bicornuate rat uterus transplantation model provides a distinctive opportunity for sequential biopsies at various intervals after transplantation and, therefore, comprehensive monitoring of graft health, viability, and identification of potential signs of rejection. Furthermore, this model allows for different interventions in each horn for comparative studies without interobserver differences contrary to the established unicornuate model. By closely replicating the clinical setting, this model stands as a valuable tool for ongoing research in the field of uterus transplantation, promoting further innovation and deeper insights into the intricacies of the uterus transplant procedure.

The Impact of T-cell Aging on Alloimmunity and Inflammaging.

Aging affects immunity broadly through changes caused by immunosenescence, clinically resulting in augmented susceptibility to infections, autoimmunity, and cancer. The most striking alterations associated with immunosenescence have been observed in the T-cell compartment with a significant shift toward a terminally differentiated memory phenotype taking on features of innate immune cells. At the same time, cellular senescence impairs T-cell activation, proliferation, and effector functions, compromising the effectiveness of immunity. In clinical transplantation, T-cell immunosenescence has been the main driver of less frequent acute rejections in older transplant recipients. This patient population, at the same time, suffers more frequently from the side effects of immunosuppressive therapy including higher rates of infections, malignancies, and chronic allograft failure. T-cell senescence has also been identified as an instigator of age-specific organ dysfunction through a process that has been coined "inflammaging," accelerating organ injury and potentially contributing to the limited lifetime of organ transplants. Here, we provide a summary of the latest evidence on molecular characteristics of T-cell senescence affecting alloimmunity and organ quality while dissecting the consequences of unspecific organ injury and immunosuppression on T-cell senescence. Rather than conceptualizing immunosenescence as a broad and general "weaker" alloimmune response, it appears critical to understand both mechanisms and clinical effects in detail as a basis to refine treatment.

Transplanting old organs promotes senescence in young recipients.

In clinical organ transplantation, donor and recipient ages may differ substantially. Old donor organs accumulate senescent cells that have the capacity to induce senescence in naïve cells. We hypothesized that the engraftment of old organs may induce senescence in younger recipients, promoting age-related pathologies. When performing isogeneic cardiac transplants between age-mismatched C57BL/6 old donor (18 months) mice and young and middle-aged C57BL/6 (3- or 12- month-old) recipients , we observed augmented frequencies of senescent cells in draining lymph nodes, adipose tissue, livers, and hindlimb muscles 30 days after transplantation. These observations went along with compromised physical performance and impaired spatial learning and memory abilities. Systemic levels of the senescence-associated secretory phenotype factors, including mitochondrial DNA (mt-DNA), were elevated in recipients. Of mechanistic relevance, injections of mt-DNA phenocopied effects of age-mismatched organ transplantation on accelerating aging. Single treatment of old donor animals with senolytics prior to transplantation attenuated mt-DNA release and improved physical capacities in young recipients. Collectively, we show that transplanting older organs induces senescence in transplant recipients, resulting in compromised physical and cognitive capacities. Depleting senescent cells with senolytics, in turn, represents a promising approach to improve outcomes of older organs.

Textbook Outcome after Gastrectomy for Gastric Cancer Is Associated with Improved Overall and Disease-Free Survival.

(1) Background: The complexity of the perioperative outcome for patients with gastric cancer is not well reflected by single quality metrics. To study the effect of the surgical outcome on survival, we have evaluated the relationship between textbook outcome (TO)-a new composite parameter-and oncological outcome. (2) Methods: All patients undergoing total gastrectomy or trans-hiatal extended gastrectomy for gastric cancer with curative intent between 2017 and 2021 at our institution were included. TO was defined by negative resection margins (R0); collection of ≥25 lymph nodes; the absence of major perioperative complications (Clavien-Dindo ≥ 3); the absence of any reintervention; absence of unplanned ICU re-admission; length of hospital stay < 21 days; absence of 30-day readmission and 30-day mortality. We evaluated factors affecting TO by multivariate logistic regression. The correlation between TO and long-term survival was assessed using a multivariate cox proportional-hazards model. (3) Results: Of the patients included in this study, 52 (52.5 %) achieved all TO metrics. Open surgery (p = 0.010; OR 3.715, CI 1.334-10.351) and incomplete neoadjuvant chemotherapy (p = 0.020, OR 4.278, CI 1.176-15.553) were associated with failure to achieve TO on multivariate analysis. The achievement of TO significantly affected overall survival (p = 0.015). TO (p = 0.037, OD 0.448, CI 0.211-0.954) and CCI > 4 (p = 0.034, OR 2.844, CI 1.079-7.493) were significant factors affecting DFS upon univariate analysis. In multivariate analysis, CCI > 4 (p = 0.035, OR 2.605, CI 0.983-6.905) was significantly associated with DFS. (4) Conclusions: We identified patient- and procedure-related factors influencing TO. Importantly, achieving TO is strongly associated with improved long-term survival in gastric cancer patients and merits further focus on surgical quality improvement efforts.

Sex as a biological variable: Mechanistic insights and clinical relevance in solid organ transplantation.

Biological sex affects immunity broadly, with recognized effects on the incidence and severity of autoimmune diseases, infections, and malignancies. Consequences of sex on alloimmunity and outcomes in solid organ transplantation are less well defined. Clinical studies have shown that donor and recipient sex independently impact transplant outcomes, which are further modified by aging. Potential mechanisms have thus far not been detailed and may include hormonal, genetic, and epigenetic components. Here, we summarize relevant findings in immunity in addition to studies in clinical and experimental organ transplantation detailing the effects of biological sex on alloimmunity. Understanding both clinical impact and mechanisms is expected to provide critical insights on the complexity of alloimmune responses, with the potential to fine-tune treatment and allocation while providing a rationale to include both sexes in transplant research.

Hepatic artery reconstruction using an operating microscope in pediatric liver transplantation-Is it worth the effort?

INTRODUCTION: In pediatric liver transplantation (pLT), hepatic artery thrombosis (HAT) is associated with inferior transplant outcome. Hepatic artery reconstruction (HAR) using an operating microscope (OM) is considered to reduce the incidence of HAT. METHODS: HAR using an OM was compared to a historic cohort using surgical loupes (SL) in pLT performed between 2009 and 2020. Primary endpoint was the occurrence of HAT. Secondary endpoints were 1-year patient and graft survival determined by Kaplan-Meier analysis and complications. Multivariate analysis was used to identify independent risk factors for HAT and adverse events. RESULTS: A total of 79 pLTs were performed [30 (38.0%) living donations; 49 (62.0%) postmortem donations] divided into 23 (29.1%) segment 2/3, 32 (40.5%) left lobe, 4 (5.1%) extended right lobe, and 20 (25.3%) full-size grafts. One-year patient and graft survival were both 95.2% in the OM group versus 86.2% and 77.8% in the SL group (p = .276 and p = .077). HAT rate was 0% in the OM group versus 24.1% in the SL group (p = .013). One-year patient and graft survival were 64.3% and 35.7% in patient with HAT, compared to 93.9% and 92.8% in patients with no HAT (both p < .001). Multivariate analysis revealed HAR with SL (p = .022) and deceased donor liver transplantation (DDLT) (p = .014) as independent risk factors for HAT. The occurrence of HAT was independently associated with the need for retransplantation (p < .001) and biliary leakage (p = .045). CONCLUSION: In pLT, the use of an OM is significantly associated to reduce HAT rate, biliary complications, and graft loss and outweighs the disadvantages of delayed arterial perfusion and prolonged warm ischemia time (WIT).

The effect of age on short-term and mid-term outcomes after thoracoscopic Ivor Lewis esophagectomy: a propensity score-matched analysis.

BACKGROUND: The number of elderly patients diagnosed with esophageal cancer rises. Current information about outcomes in elderly patients undergoing thoracoscopic Ivor Lewis esophagectomy is limited. The objective of this study was to evaluate the influence of age on short-and mid-term outcomes after thoracoscopic Ivor Lewis esophagectomy. METHODS: A retrospective review of 188 patients with esophageal cancer undergoing thoracoscopic Ivor Lewis esophagectomy between August 2014 and July 2019 was performed. Patients were divided into patients aged > 75 years (elderly group (EG), n = 37) and patients ≤ 75 years (younger group (YG), n = 151) and matched using propensity-score matching. Baseline characteristics, length of hospital stay, mortality and major postoperative complications (Clavien-Dindo ≥ grade III) were compared. RESULTS: After matching 74 patients remained (n = 37 in each group). Postoperatively, no significant differences in major and overall complications, intra-hospital and 30-day mortality, disease-free or overall survival up to 3 years after surgery were noted. The incidence of pulmonary complications (65% vs. 38%) and pneumonia (54% vs. 30%) was significantly higher and the median hospital length of stay (12 vs. 14 days) significantly longer in the EG versus YG. CONCLUSION: Thoracoscopic Ivor Lewis esophagectomies resulted in acceptable postoperative major morbidity and mortality without compromising 3-years overall and disease-free survival in elderly compared to younger patients with esophageal cancer. However, the incidence of postoperative pulmonary complications was higher in patients aged over 75 years.

Immunosuppression after uterus transplantation.

PURPOSE OF REVIEW: Clinical uterus transplantation (UTx) is growing rapidly. The procedure represents the only therapy for women with absolute uterine factor infertility to give birth to a biological baby. Immunosuppression after UTx needs to carefully balance effects with the healthy mother and baby. Unique for UTx is the 'temporary' character of the procedure with a transplant hysterectomy being performed after delivery. Most of the practice on immunosuppression in UTx is currently based on the experience in solid organ transplantation (SOT). RECENT FINDINGS: Clinical UTx-trials have been performed in centers worldwide during the recent years and experience on immunosuppression has accumulated. SUMMARY: Immunosuppression in UTx has been successfully applied as maintenance treatment in addition to effectively treating acute T- and B-cell mediated rejections. Understanding the biology of UTx in more detail is expected to refine future approaches.

Recipient sex and estradiol levels affect transplant outcomes in an age-specific fashion.

Sex-specific influences have been shown for a variety of diseases. Whether donor or recipient sex and sex hormone levels impact alloimmune responses remains unclear. In unifactorial and multifactorial analyses of more than 400 000 SRTR listed kidney transplant patients, we found that younger female recipients had an inferior death-censored graft survival that was independent of donor sex. In contrast, graft survival was superior in older female recipients, suggesting the impact of recipient sex hormones over chromosomal sex mismatches. Those clinical changes were delineated in experimental skin and heart transplant models showing a prolongation of graft survival in ovariectomized young female recipients. In contrast, graft survival was comparable in ovariectomized and naïve old female recipients. Young ovariectomized mice showed reduced amounts and a compromised T cell proliferation. Deprivation of female hormones dampened the production of interferon (IFN)-γ and interleukin (IL)-17+ by CD4+ T cells while augmenting systemic counts of Tregs. Increasing estradiol concentrations in vitro promoted the switch of naïve CD4+ T cells into Th1 cells; high physiological estradiol concentrations dampening Th1 responses, promoted Tregs, and prolonged graft survival. Thus, clinical observations demonstrate age-specific graft survival patterns in female recipients. Estrogen levels, in turn, impact the fate of T cell subsets, providing relevant and novel information on age- and sex-specific alloimmunity.

Senolytics prevent mt-DNA-induced inflammation and promote the survival of aged organs following transplantation.

Older organs represent an untapped potential to close the gap between demand and supply in organ transplantation but are associated with age-specific responses to injury and increased immunogenicity, thereby aggravating transplant outcomes. Here we show that cell-free mitochondrial DNA (cf-mt-DNA) released by senescent cells accumulates with aging and augments immunogenicity. Ischemia reperfusion injury induces a systemic increase of cf-mt-DNA that promotes dendritic cell-mediated, age-specific inflammatory responses. Comparable events are observed clinically, with the levels of cf-mt-DNA elevated in older deceased organ donors, and with the isolated cf-mt-DNA capable of activating human dendritic cells. In experimental models, treatment of old donor animals with senolytics clear senescent cells and diminish cf-mt-DNA release, thereby dampening age-specific immune responses and prolonging the survival of old cardiac allografts comparable to young donor organs. Collectively, we identify accumulating cf-mt-DNA as a key factor in inflamm-aging and present senolytics as a potential approach to improve transplant outcomes and availability.

Outcome after pediatric liver transplantation for staged abdominal wall closure with use of biological mesh-Study with long-term follow-up.

Abdominal wall closure after pediatric liver transplantation (pLT) in infants may be hampered by graft-to-recipient size discrepancy. Herein, we describe the use of a porcine dermal collagen acellular graft (PDCG) as a biological mesh (BM) for abdominal wall closure in pLT recipients. Patients <2 years of age, who underwent pLT from 2011 to 2014, were analyzed, divided into definite abdominal wall closure with and without implantation of a BM. Primary end-point was the occurrence of postoperative abdominal wall infection. Secondary end-points included 1- and 5-year patient and graft survival and the development of abdominal wall hernia. In five out of 21 pLT recipients (23.8%), direct abdominal wall closure was achieved, whereas 16 recipients (76.2%) received a BM. BM removal was necessary in one patient (6.3%) due to abdominal wall infection, whereas no abdominal wall infection occurred in the no-BM group. No significant differences between the two groups were observed for 1- and 5-year patient and graft survival. Two late abdominal wall hernias were observed in the BM group vs none in the no-BM group. Definite abdominal wall closure with a BM after pLT is feasible and safe when direct closure cannot be achieved with comparable postoperative patient and graft survival rates.