Rescue Allocation Modes in Eurotransplant Kidney Transplantation: Recipient Oriented Extended Allocation Versus Competitive Rescue Allocation-A Retrospective Multicenter Outcome Analysis

BACKGROUND

Whenever the kidney standard allocation (SA) algorithms according to the Eurotransplant (ET) Kidney Allocation System or the Eurotransplant Senior Program fail, rescue allocation (RA) is initiated. There are 2 procedurally different modes of RA: recipient oriented extended allocation (REAL) and competitive rescue allocation (CRA). The objective of this study was to evaluate the association of patient survival and graft failure with RA mode and whether or not it varied across the different ET countries.

METHODS

The ET database was retrospectively analyzed for donor and recipient clinical and demographic characteristics in association with graft outcomes of deceased donor renal transplantation (DDRT) across all ET countries and centers from 2014 to 2021 using Cox proportional hazards methods.

RESULTS

Seventeen thousand six hundred seventy-nine renal transplantations were included (SA 15 658 [89%], REAL 860 [4.9%], and CRA 1161 [6.6%]). In CRA, donors were older, cold ischemia times were longer, and HLA matches were worse in comparison with REAL and especially SA. Multivariable analyses showed comparable graft and recipient survival between SA and REAL; however, CRA was associated with shorter graft survival. Germany performed 76% of all DDRTs after REAL and CRA and the latter mode reduced waiting times by up to 2.9 y.

CONCLUSIONS

REAL and CRA are used differently in the ET countries according to national donor rates. Both RA schemes optimize graft utilization, lead to acceptable outcomes, and help to stabilize national DDRT programs, especially in Germany.

Comparable cellular and humoral immunity upon homologous and heterologous COVID-19 vaccination regimens in kidney transplant recipients

Background

Kidney transplant recipients (KTRs) are at high risk for a severe course of coronavirus disease 2019 (COVID-19); thus, effective vaccination is critical. However, the achievement of protective immunogenicity is hampered by immunosuppressive therapies. We assessed cellular and humoral immunity and breakthrough infection rates in KTRs vaccinated with homologous and heterologous COVID-19 vaccination regimens.

Method

We performed a comparative in-depth analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific T-cell responses using multiplex Fluorospot assays and SARS-CoV-2-specific neutralizing antibodies (NAbs) between three-times homologously (n = 18) and heterologously (n = 8) vaccinated KTRs.

Results

We detected SARS-CoV-2-reactive T cells in 100% of KTRs upon third vaccination, with comparable frequencies, T-cell expression profiles, and relative interferon γ and interleukin 2 production per single cell between homologously and heterologously vaccinated KTRs. SARS-CoV-2-specific NAb positivity rates were significantly higher in heterologously (87.5%) compared to homologously vaccinated (50.0%) KTRs (P < 0.0001), whereas the magnitudes of NAb titers were comparable between both subcohorts after third vaccination. SARS-CoV-2 breakthrough infections occurred in equal numbers in homologously (38.9%) and heterologously (37.5%) vaccinated KTRs with mild-to-moderate courses of COVID-19.

Conclusion

Our data support a more comprehensive assessment of not only humoral but also cellular SARS-CoV-2-specific immunity in KTRs to provide an in-depth understanding about the COVID-19 vaccine–induced immune response in a transplant setting.

Kidney Transplantation Outcome Predictions (KTOP): A Risk Prediction Tool for Kidney Transplants from Brain-dead Deceased Donors Based on a Large European Cohort

BACKGROUND

European kidney donation shortages mandate efficient organ allocation by optimizing the prediction of success for individual recipients.

OBJECTIVE

To develop the first European online risk tool for kidney transplant outcomes on the basis of recipient-only and recipient plus donor characteristics.

DESIGN, SETTING, AND PARTICIPANTS

We used individual recipient and donor risk factors and three outcomes (death, death with functioning graft [DWFG], and graft loss) for 32 958 transplants within the Eurotransplant kidney allocation system and the Eurotransplant senior program between January 2006 and May 2018 in eight European countries to develop and validate a risk tool.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cox proportional-hazards models were used to analyze the association of risk factors with overall patient mortality, and proportional subdistribution hazard regression models for their association with graft loss and DWFG. Prediction models were developed with recipient-only and recipient-donor risk factors. Sensitivity analyses based on time-specific area under the receiver operating characteristic curve (AUC) with leave-one-country-out validation were performed and calibration plots were generated.

RESULTS AND LIMITATIONS

The 10-yr cumulative incidence rate was 37% for mortality, 12% for DWFG, and 41% for graft loss. In recipient-donor models the leading risk factors for mortality were recipient diabetes (hazard ratio [HR] 10.73), retransplantation (HR 3.08 per transplant), and recipient age (HR 1.08). Effects were similar for DWFG. For graft loss, diabetes (subdistributional HR [SHR] 1.32), increased donor age (SHR 1.02), and prolonged cold ischemia time (SHR 1.02) had increased SHRs. All p values were <0.001.

CONCLUSIONS

Previously identified risk factors for outcomes following kidney transplants allow for outcome prediction with 10-yr AUC values of up to 0.81.

PATIENT SUMMARY

Using European data, we estimated individual risks to predict the success of kidney transplants and support physicians in decision-making. An online tool is now available (https://riskcalc.org/ktop/) for predicting kidney transplant outcomes both before and after a donor has been identified.

softALPPS - A novel, individual procedure for patients with advanced liver tumors

BACKGROUND

The first-line therapy for liver malignancies is a radical extended liver resection. This high-risk operation has a high incidence of post-hepatectomy liver failure (PHLF) due to a small future liver remnant (FLR). One of the procedures to increase the FLR is the associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) which is still associated with high morbidity and mortality. Here, we present a new, less invasive ALPPS variant that may be associated with lower morbidity.

METHODS

SoftALPPS is characterized by reduced trauma to the liver tissue and individual adaptation to the patient's health constitution. In softALPPS, portal vein embolization (PVE) is performed instead of portal vein ligation (PVL) after complete recovery of liver function. In addition, a non-absorbable foil was avoided in order to be able to extend the interval to step two or skip step two when required.

RESULTS

Four patients successfully underwent softALPPS. Two of these patients have been followed-up for over a year (one patient with Klatskin tumor, one patient with extensive HCC). Both patients show no evidence of recurrence after 12 months and are in good medical condition. The other two patients who recently had surgery are also doing well.

CONCLUSION

SoftALPPS offers the chance to curatively resect patients with high tumor burden of the liver even when the FLR is inadequate. This individual therapy method can give patients the possibility of complete tumor resection and can help to reduce perioperative morbidity.

Kidney Transplantation After Rescue Allocation-the Eurotransplant Experience: A Retrospective Multicenter Outcome Analysis

BACKGROUND

At Eurotransplant (ET), kidneys are transferred to "rescue allocation" (RA), whenever the standard allocation (SA) algorithms Eurotransplant Kidney Allocation System (ETKAS) and Eurotransplant Senior Program (ESP) fail. We analyzed the outcome of RA.

METHODS

Retrospective patient clinical and demographic characteristics association analyses were performed with graft outcomes for 2422 recipients of a deceased donor renal transplantation (DDRT) after RA versus 25 481 after SA from 71 centers across all ET countries from 2006 to 2018.

RESULTS

Numbers of DDRTs after RA increased over the time, especially in Germany. RA played a minor role in ESP versus ETKAS (2.7% versus 10.4%). RA recipients and donors were older compared with SA recipients and donors, cold ischemia times were longer, waiting times were shorter, and the incidence of primary nonfunction was comparable. Among ETKAS recipients, HLA matching was more favorable in SA (mean 3.7 versus 2.5). In multivariate modeling, the incidence of graft loss in ETKAS recipients was reduced in RA compared with SA (subdistribution hazard ratio, 0.80; 95% confidence interval [0.70-0.91], P < 0.001), whereas other outcomes (mortality, death with functioning graft (DwFG)) were not significantly different. None of the 3 outcomes were significantly different when comparing RA with SA within the ESP program.

CONCLUSIONS

Facing increased waiting times and mortality on dialysis due to donor shortage, this study reveals encouragingly positive DDRT outcomes following RA. This supports the extension of RA to more patients and as an alternative tool to enable transplantation in patients in countries with prohibitively long waiting times or at risk of deterioration.

The Kidney Donor Profile Index (KDPI) Correlates With Histopathologic Findings in Post-reperfusion Baseline Biopsies and Predicts Kidney Transplant Outcome

Background

The increasing organ shortage in kidney transplantation leads to the necessity to use kidneys previously considered unsuitable for transplantation. Numerous studies illustrate the need for a better decision guidance rather than only the classification into kidneys from standard or expanded criteria donors referred to as SCD/ECD-classification. The kidney donor profile index (KDPI) exhibits a score utilizing a much higher number of donor characteristics. Moreover, graft biopsies provide an opportunity to assess organ quality.

Methods

In a single center analysis 383 kidney transplantations (277 after deceased and 106 after living donation) performed between January 1st, 2006, and December 31st, 2016, retrospectively underwent SCD/ECD and KDPI scoring. Thereby, the quality of deceased donor kidneys was assessed by using the KDPI and the living donor kidneys by using the living KDPI, in the further analysis merged as (L)KDPI. Baseline biopsies taken 10 min after the onset of reperfusion were reviewed for chronic and acute lesions. Survival analyses were performed using Kaplan-Meier analysis and Cox proportional hazards analysis within a 5-year follow-up.

Results

The (L)KDPI correlated with glomerulosclerosis (r = 0.30, p < 0.001), arteriosclerosis (r = 0.33, p < 0.001), interstitial fibrosis, and tubular atrophy (r = 0.28, p < 0.001) as well as the extent of acute tubular injury (r = 0.20, p < 0.001). The C-statistic of the (L)KDPI concerning 5-year death censored graft survival was 0.692. Around 48% of ECD-kidneys were classified as (L)KDPI<85%. In a multivariate Cox proportional hazard analysis including (preformed) panel reactive antibodies, cold ischemia time, (L)KDPI, and SCD/ECD-classification, the (L)KDPI was significantly associated with risk of graft loss (hazard ratio per 10% increase in (L)KDPI: 1.185, 95% confidence interval: 1.033–1.360, p = 0.025). Survival analysis revealed decreased death censored (p < 0.001) and non-death censored (p < 0.001) graft survival in kidneys with an increasing (L)KDPI divided into groups of <35, 35–85, and >85%, respectively.

Conclusion

With a higher granularity compared to the SCD/ECD-classification the (L)KDPI is a promising tool to judge graft quality. The correlation with chronic and acute histological lesions in post-reperfusion kidney biopsies underlines the descriptive value of the (L)KDPI. However, its prognostic value is limited and underlines the urgent need for a more precise prognostic tool adopted to European kidney transplant conditions.

Kidney transplantation after rescue allocation-meticulous selection yields the chance for excellent outcome

BACKGROUND

The small number of organ donors forces transplant centres to consider potentially suboptimal kidneys for transplantation. Eurotransplant established an algorithm for rescue allocation (RA) of kidneys repeatedly declined or not allocated within 5 h after procurement. Data on the outcomes and benefits of RA are scarce to date.

METHODS

We conducted a retrospective 8-year analysis of transplant outcomes of RA offers based on our in-house criteria catalogue for acceptance and decline of organs and potential recipients.

RESULTS

RA donors and recipients were both older compared with standard allocation (SA). RA donors more frequently had a history of hypertension, diabetes or fulfilled expanded criteria donor key parameters. RA recipients had poorer human leucocyte antigen (HLA) matches and longer cold ischaemia times (CITs). However, waiting time was shorter and delayed graft function, primary non-function and biopsy-proven rejections were comparable to SA. Five-year graft and patient survival after RA were similar to SA. In multivariate models accounting for confounding factors, graft survival and mortality after RA and SA were comparable as well.

CONCLUSIONS

Facing relevant comorbidities and rapid deterioration with the risk of being removed from the waiting list, kidney transplantation after RA was identified to allow for earlier transplantation with excellent outcome. Data from this survey propose not to reject categorically organs from multimorbid donors with older age and a history of hypertension or diabetes to aim for the best possible HLA matching and to carefully calculate overall expected CIT.

Survival data on timing of resection of liver metastases in colorectal cancer patients

Between 2007 and 2016, 140 consecutive patients who underwent resection of colorectal cancer with simultaneous liver metastases at a single university hospital were retrospectively analysed. In order to gather information regarding potential survival differences for n = 68 simultaneous versus n = 72 staged resections of the colorectal primary tumor and the liver metastases, Clinical, histopathological, serological, and survival data were compared for those two patient groups. The rate of simultaneous tumor resections increased from approximately 25% in 2007 to >75% in 2016. There was no difference in tumor specific survival for patients with simultaneous vs. staged resection (p = 0.631). This effect continued after excluding patients with extrahepatic metastases (p = 0.440). Further, neoadjuvant treatment did not lead to differences in the tumor-specific survival (p = 0.123). Factors associated with an increased tumor-specific survival were low ASA score (p < 0.001), low number of tumor-affected lymph nodes (p < 0.001), histological grading G1/2 (p = 0.001), and a low number of liver metastases (p = 0.044). There was no significant survival difference for the primary tumor stage (pT), the Clavien-Dindo complication rate, the resection status (R0), and minor versus major hepatectomies.

Simultaneous Versus Staged Resection of Colorectal Cancer Liver Metastasis: A Retrospective Single-Center Study

BACKGROUND

For patients with colorectal cancer and synchronous liver metastasis, either a simultaneous, or a two-staged resection of the primary tumor and the liver metastases is possible. There are currently no guidelines preferring one approach to the other.

MATERIAL AND METHODS

Consecutive patients who underwent hepatic resection at our university hospital from 2007-2016 were included. Clinical, histopathologic, serologic, and survival data were analyzed. The primary end point was tumor-specific survival for patients with simultaneous versus staged resections.

RESULTS

Of all 140 patients, 68 underwent simultaneous resection and 72 underwent staged resection. The characteristics of both groups were comparable. Patients with simultaneous resections had a shorter duration of cumulative operation time (299 versus 460 min; P = 0.003) and a shorter cumulative length of hospital stay (23 versus 43 d; P = 0.002). Perioperative mortality (P = 0.257) did not differ significantly; however, patients with simultaneous resections had higher rates of grade 2 complications according to Clavien-Dindo (P < 0.001). Tumor-specific 1-y survival was 85 ± 5% for simultaneous and 83 ± 5% for staged resection (P = 0.631). On multivariable analysis, pT4 (P = 0.038), pN3 (P = 0.003), and G3/4 (P = 0.041) of the primary tumor and postoperative complications (Clavien-Dindo 3/4/5, P = 0.003) were poor prognostic factors regarding tumor-specific survival.

CONCLUSIONS

This is one of the largest and most thoroughly documented retrospective single-center studies of consecutive patients with synchronous hepatic metastases. Simultaneous resection of colorectal cancer together with hepatic metastases is a safe procedure in selected patients and does not have a significant influence on long-term survival.

BRG1 promotes hepatocarcinogenesis by regulating proliferation and invasiveness

The chromatin remodeler complex SWI/SNF plays an important role in physiological and pathological processes. Brahma related gene 1(BRG1), a catalytic subunit of the SWI/SNF complex, is known to be mutated in hepatocellular carcinoma (HCC). However, its role in HCC remains unclear. Here, we investigate the role of BRG1 on cell growth and invasiveness as well as its effect on the expression of putative target genes. Expression of BRG1 was examined in human liver tissue samples and in HCC cell lines. In addition, BRG1 was silenced in human HCC cell lines to analyse cell growth and invasiveness by growth curves, colony formation assay, invasion assay and the expression of putative target genes. BRG1 was found to be significantly increased in HCC samples compared to non-HCC samples. In addition, a declined proliferation rate of BRG1-silenced human HCC cell lines was associated with a decrease of expression of cyclin family members. In line with a decreased invasiveness of BRG1-siRNA-treated human HCC cell lines, down-regulation of MMP7 was detected. These results support the hypothesis that overexpression of BRG1 increases cell growth and invasiveness in HCC. Furthermore, the data highlight cyclin B, E and MMP7 to be associated with BRG1 during hepatocarcinogenesis.

Impact of NKT Cells and LFA-1 on Liver Regeneration under Subseptic Conditions

Background

Activation of the immune system in terms of subseptic conditions during liver regeneration is of paramount clinical importance. However, little is known about molecular mechanisms and their mediators that control hepatocyte proliferation. We sought to determine the functional role of immune cells, especially NKT cells, in response to partial hepatectomy (PH), and to uncover the impact of the integrin lymphocyte function-associated antigen-1 (LFA-1) on liver regeneration in a subseptic setting.

Methods

Wild-type (WT) and LFA-1^-/- mice underwent a 2/3 PH and low-dose lipopolysaccharid (LPS) application. Hepatocyte proliferation, immune cell infiltration, and cytokine profile in the liver parenchyma were determined.

Results

Low-dose LPS application after PH results in a significant delay of liver regeneration between 48h and 72h, which is associated with a reduced number of CD3⁺ cells within the regenerating liver. In absence of LFA-1, an impaired regenerative capacity was observed under low-dose LPS application. Analysis of different leukocyte subpopulations showed less CD3⁺NK1.1⁺ NKT cells in the liver parenchyma of LFA-1^-/- mice after PH and LPS application compared to WT controls, while CD3^-NK1.1⁺ NK cells markedly increased. Concordantly with this observation, lower levels of NKT cell related cytokines IL-12 and IL-23 were expressed in the regenerating liver of LFA-1^-/- mice, while the expression of NK cell-associated CCL5 and IL-10 was increased compared to WT mice.

Conclusion

A subseptic situation negatively alters hepatocyte proliferation. Within this scenario, we suggest an important impact of NKT cells and postulate a critical function for LFA-1 during processes of liver regeneration.

Heparin-induced thrombocytopenia in solid organ transplant recipients: The current scientific knowledge

Exposure to heparin is associated with a high incidence of immunization against platelet factor 4 (PF4)/heparin complexes. A subgroup of immunized patients is at risk of developing heparin-induced thrombocytopenia (HIT), an immune mediated prothrombotic adverse drug effect. Transplant recipients are frequently exposed to heparin either due to the underlying end-stage disease, which leads to listing and transplantation or during the transplant procedure and the perioperative period. To review the current scientific knowledge on anti-heparin/PF4 antibodies and HIT in transplant recipients a systematic PubMed literature search on articles in English language was performed. The definition of HIT is inconsistent amongst the publications. Overall, six studies and 15 case reports have been published on HIT before or after heart, liver, kidney, and lung transplantation, respectively. The frequency of seroconversion for anti-PF4/heparin antibodies ranged between 1.9% and 57.9%. However, different methods to detect anti-PF4/heparin antibodies were applied. In none of the studies HIT-associated thromboembolic events or fatalities were observed. More importantly, in patients with a history of HIT, reexposure to heparin during transplantation was not associated with thrombotic complications. Taken together, the overall incidence of HIT after solid organ transplantation seems to be very low. However, according to the current knowledge, cardiac transplant recipients may have the highest risk to develop HIT. Different alternative suggestions for heparin-free anticoagulation have been reported for recipients with suspected HIT albeit no official recommendations on management have been published for this special collective so far.

Procalcitonin ratio and on-demand relaparotomy for septic peritonitis: validation of the focus index (FI)

PURPOSE

Secondary peritonitis remains challenging to manage and some recent evidence suggests that on-demand relaparotomy is more appropriate than planned relaparotomy. This study was designed to validate the predictive power of postoperative procalcitonin (PCT) changes in relation to elimination of the septic abdominal focus.

METHODS

In this prospective trial, postoperative PCT serum levels were monitored in 234 surgical patients with secondary peritonitis. The PCT ratio on postoperative days (PODs) 1 and 2 (focus index; FI) was calculated and correlated with the success of the operation.

RESULTS

A cutoff value of 1.1 was calculated for the FI. Values below 1.1 indicated insufficient elimination of the focus and values above 1.1 correlated with effective treatment. The optimal time for first PCT sampling was found to be 12-24 h after the index operation. After the respective data cleanup, successful elimination of the intraabdominal focus could be confirmed, with a sensitivity of 93 % and a specificity of 71 %.

CONCLUSIONS

The FI is a single parameter-based reliable predictor of successful surgical eradication and strengthens the on-demand relaparotomy concept as the method of choice to treat secondary peritonitis.

The cannabinoid receptor 2 is involved in acute rejection of cardiac allografts

AIMS

Acute rejection of cardiac allografts is a major risk factor limiting survival of heart transplant recipients. Rejection is triggered by dendritic cell (DC) mediated activation of host T cells, amongst others CD4(+) T helper (TH)1- and TH17 cells. The cannabinoid receptor 2 (CB2) is an important modulator of cellular immune responses. However, its role in cardiac allograft rejection has not been studied so far.

MAIN METHODS

Here, we examined the effect of CB2 on cytokine release by mature DCs and its impact on CD4(+) T cell differentiation by utilizing in vitro generated bone marrow-derived DCs (BM-DCs) and CD4(+) T cells from CB2 knockout (Cnr2(-/-)) mice. We further assessed the functional role of CB2 in acute allograft rejection using Cnr2(-/-) mice in a fully major histocompatibility complex-mismatched mouse cardiac transplantation model.

KEY FINDINGS

Cardiac allograft rejection was accelerated in Cnr2(-/-) mice compared to wild type recipients. In vitro stimulation of BM-DCs showed enhanced secretion of the pro-inflammatory cytokines interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF) and the immunomodulatory cytokine TGF-β. Furthermore, secretion of the TH1/TH17 promoting cytokines IL-12 and IL-23 was increased in Cnr2(-/-) BM-DCs. In addition, Cnr2(-/-) CD4(+) T cells showed an enhanced capacity to differentiate into interferon (IFN)-γ- or IL-17-producing effector cells.

SIGNIFICANCE

These results demonstrate that CB2 modulates in vitro cytokine responses via DCs and directly via its influence on TH1/TH17 differentiation. These findings and the fact that allograft rejection is enhanced in Cnr2(-/-) mice suggest that CB2 may be a promising therapeutic target in organ transplantation.

Anti-platelet factor 4/heparin antibodies in patients with impaired graft function after liver transplantation

BACKGROUND

Heparin, the standard perioperative anticoagulant for the prevention of graft vessel thrombosis in patients undergoing liver transplantation (LT), binds to the chemokine platelet factor 4 (PF4). Antibodies that are formed against the resulting PF4/heparin complexes can induce heparin-induced thrombocytopenia. LT is a clinical situation that allows the study of T-cell dependency of immune responses because T-cell function is largely suppressed pharmacologically in these patients to prevent graft rejection.

OBJECTIVES

To investigate the immune response against PF4/heparin complexes in patients undergoing LT.

PATIENTS AND METHODS

In this prospective cohort study, 38 consecutive patients undergoing LT were systematically screened for anti-PF4/heparin antibodies (enzyme immunoassay and heparin-induced platelet aggregation assay), platelet count, liver function, and engraftment.

RESULTS

At baseline, 5 (13%) of 38 patients tested positive for anti-PF4/heparin IgG (non-platelet-activating) antibodies. By day 20, an additional 5 (15%) of 33 patients seroconverted for immunoglobulin G (two platelet-activating) antibodies. No patient developed clinical heparin-induced thrombocytopenia. Two of six patients with graft function failure had anti-PF4/heparin IgG antibodies at the time of graft function failure. Graft liver biopsy samples from these patients showed thrombotic occlusions of the microcirculation.

CONCLUSIONS

Anti-PF4/heparin IgG antibodies are generated despite strong pharmacologic suppression of T cells, indicating that T cells likely have a limited role in the immune response to PF4/heparin complexes in humans.

Extended postinterventional tumor necrosis-implication for outcome in liver transplant patients with advanced HCC

Background

Locoregional interventional bridging therapy (IBT) is an accepted neoadjuvant approach in liver transplant candidates with hepatocellular carcinoma (HCC). However, the prognostic value of IBT in patients with advanced HCC is still undefined.

Aim

The aim of this trial was to evaluate the impact of postinterventional tumor necrosis on recurrence-free long-term survival after liver transplantation (LT) in patients with HCC, especially focusing on those exceeding the Milan criteria on pretransplant radiographic imaging.

Patients and Methods

A total of 93 consecutive liver transplant candidates with HCC were included in this trial. In 36 patients, tumors were clinically staged beyond Milan criteria prior LT. Fifty-nine patients underwent IBT by transarterial chemoembolization or radiofrequency ablation pretransplantation. Postinterventional tumor necrosis rate as assessed at liver explant pathology was correlated with outcome post-LT.

Results

There was no significant difference in 5-year tumor-free survival rate between the IBT- and the non-IBT subpopulation (78% versus 68%, P = 0.25). However, tumor response following IBT (≥50% tumor necrosis rate at explant pathology) resulted in a significantly better outcome 5 years post-LT (96%) than tumor non-response to IBT (<50% tumor necrosis rate at explant pathology; 21%; P<0.001). Five-year recurrence-free survival rate was 80% in Milan Out patients with extended post-IBT tumor necrosis versus 0% in Milan Out patients without tumor response to IBT (P<0.001). None of macromorphological HCC features, but only the absence of increased ¹⁸F-fluoro-deoxy-glucose (¹⁸FDG) uptake on pretransplant positron emission tomography (PET) was identified as independent predictor of postinterventional tumor response (P<0.001).

Conclusion

Our results implicate that extended postinterventional tumor necrosis promotes recurrence-free long-term survival in patients with HCC beyond standard criteria. Pretransplant PET assessment may identify those patients with advanced HCC that will benefit from post-IBT tumor response and may, thereby, achieve excellent posttransplant outcome.

Mixed antagonist response and sepsis severity-dependent dysbalance of pro- and anti-inflammatory responses at the onset of postoperative sepsis

It has been postulated that an early systemic inflammatory response syndrome (SIRS) and a subsequent compensatory anti-inflammatory response syndrome (CARS) occur sequentially in sepsis. Co-existence of both is referred to as mixed antagonist response syndrome (MARS). Pro- and anti-inflammatory cytokine production was investigated in patients with postoperative sepsis, a murine peritonitis model and in vitro to further delineate the interaction of hyper- and hypo-inflammation in sepsis. IL-6 and IL-10 were measured in serum samples from 80 patients on d1 and d2 of postoperative sepsis and were similarly determined at various time points after induction of septic peritonitis in mice. Cytokine production of RAW264 macrophages was stimulated in vitro using TLR agonists. IL-6 and IL-10 were measured in supernatants. All cytokine measurements were performed by ELISA. In patients, the initial phase of the immune response to sepsis was characterized by a concomitant elevation of serum IL-6 and IL-10 levels. IL-10 levels were correlated with IL-6 levels in an exponential manner (p<0.001), which could be confirmed in a mouse model of septic peritonitis. In vitro experiments revealed that the observed exponential correlation may occur as function of TLR signaling intensity. Early postoperative sepsis seems to be characterized by a primary MARS. Sepsis severity was positively correlated with a disproportionate elevation of the anti-inflammatory response relative to the pro-inflammatory response, a pattern reminiscent of TLR-driven responses. Detailed characterization of immune responses in sepsis may help to direct standard therapies and to develop effective immunomodulatory strategies.

Palliative interventional and surgical therapy for unresectable pancreatic cancer

Palliative treatment concepts are considered in patients with non-curatively resectable and/or metastasized pancreatic cancer. However, patients without metastases, but presented with marginally resectable or locally non-resectable tumors should not be treated by a palliative therapeutic approach. These patients should be enrolled in neoadjuvant radiochemotherapy trials because a potentially curative resection can be achieved in approximately one-third of them after finishing treatment and restaging. Within the scope of best possible palliative care, resection of the primary cancer together with excision of metastases represents a therapeutic option to be contemplated in selected cases. Comprehensive palliative therapy is based on treatment of bile duct or duodenal obstruction for certain locally unresectable or metastasized advanced pancreatic cancer. However, endoscopic or percutaneous stenting procedures and surgical bypass provide safe and highly effective therapeutic alternatives. In case of operative drainage of the biliary tract (biliodigestive anastomosis), the prophylactic creation of a gastro-intestinal bypass (double bypass) is recommended. The decision to perform a surgical versus an endoscopic procedure for palliation depends to a great extent on the tumor stage and the estimated prognosis, and should be determined by an interdisciplinary team for each patient individually.

[Diagnosis and surgical treatment of pancreatic cancer]

Despite sustained efforts, intensive research has not been proven successful to reveal risk factors, which relevantly influence early diagnostics or effective treatment of pancreatic carcinoma. Principally, it must be noted, that currently no ideal tumor marker exists for the (early) detection of pancreatic carcinoma. The most important imaging modalities are high-resolution computed tomography, abdominal ultrasound, and endosonography. Surgical procedures in therapy have become more and more standardised and lead to a decrease in morbidity and mortality on the one hand and to an increase in resectability on the other hand. Pylorus-preserving partial pancreaticoduodenectomy is the treatment of choice for a tumor of the pancreatic head, whereas resection of the left pancreas (including splenectomy) is the standard therapy for carcinomas of the pancreatic tail. In all cases, a local systematic lymphadenectomy is mandatory; hence the prognostic gain of an extended lymphadenectomy remains indeterminate. An infiltration of mesenteric and portal veins does not prevent respectability, as long as by venous resection an R0 status can be achieved. However arterial involvement in general excludes resection. Patients with marginally resectable or locally non-resectable tumors should be recruited into neoadjuvant radiochemotherapy trials since one third of these patients could be considered for potentially curative resection. However the majority of pancreatic cancer patients show locally unresectable or metastasized disease and therefore palliative treatment concepts are needed. Both, endoscopic or percutaneous stenting procedures and operative bypass surgery, are safe and reach high success rates.

[Unresectable pancreatic cancer--palliative interventional and surgical treatment]

In most cases pancreatic cancer appears in a non-curatively resectable stage at time the diagnosis is made. Thus, palliative treatment concepts come to the fore in these patients. Patients without metastases, but presenting with marginally resectable or locally non-resectable tumours should not be treated in a palliative therapeutic scheme. These patients should be enrolled in neoadjuvant radiochemotherapy trials. After finishing treatment and restaging, a potentially curative resection can be achieved in approximately one-third of these patients. Within the scope of the best possible palliative care, excision of metastases together with resection of the primary cancer represents a therapeutic option to be contemplated in selected cases. For distinct locally unresectable or metastasised advanced pancreatic cancer, treatment of bile duct or duodenal obstruction is an essential part of the comprehensive palliative therapy. However, both endoscopic / percutaneous stenting procedures and surgical bypass makeshifts constitute safe and highly effective therapeutic alternatives in this context. In the case of operative drainage of the biliary tract the prophylactic creation of a gastro-intestinal bypass (double bypass) is recommended. The decision on a surgical versus an endoscopic procedure for palliation depends considerably on the tumour stage and the estimated prognosis and has to be determined interdisciplinary and individually in each case.

Combined immunosuppressive and antibiotic therapy improves bacterial clearance and survival of polymicrobial septic peritonitis

Effective immunosuppressive therapy is essential to prevent transplant rejection but renders patients vulnerable to opportunistic infections. The present study investigates the effects of common immunosuppressive drugs on the course of septic peritonitis in an experimental mouse model. We show that treatment with a combination of tacrolimus, mycophenolate mofetil, and methylprednisolone resulted in highly elevated lethality of septic peritonitis. When immunosuppressive drugs were combined with antibiotic therapy, however, mice were almost completely protected. The combination of mycophenolate mofetil and methylprednisolone was shown to be required and sufficient to improve outcome of septic peritonitis in the presence of antibiotic therapy. Combined immunosuppressive and antibiotic therapy, but not antibiotic therapy alone, resulted in enhanced bacterial clearance. These beneficial effects were linked to an elevated expression of activation markers and an increased production of reactive oxygen metabolites by peritoneal neutrophils and correlated with a reduced messenger RNA expression of the inhibitory cytokine IL-22. In contrast, systemic or peritoneal levels of IL-10, IL-12, TNF-alpha, keratinocyte chemoattractant, and monocyte chemoattractant protein 1, and splenic messenger RNA levels of IFN-gamma were not influenced by the immunosuppressive therapy. These results therefore suggest that combined immunosuppressive and antibiotic therapy may improve bacterial clearance and survival of septic peritonitis by a mechanism that involves enhanced activation and antimicrobial activity of neutrophils and reduced production of IL-22.

Liver transplantation in the rat: single-center experience with technique, long-term survival, and functional and histologic findings

OBJECTIVE

Orthotopic liver transplantation (OLT) in rats is frequently used as an experimental model. Numerous surgical techniques have been developed that enable the investigator to conduct clinically relevant studies. The objective of this study was to develop a rat model of acute and chronic rejection, to explicitly study technical modifications of vascular anastomoses with precision, and to examine histopathologic and functional changes in the graft.

MATERIALS AND METHODS

With DA-(RT1av1) rats as donors and Lewis-(RT1) rats as recipients, arterialized OLT was performed using a combined suture, cuff, and splint method. Recipients were divided into 5 groups: syngeneic control rats (group 1), allogeneic control rats (group 2), allogeneic OLT rats with low-dose tacrolimus (FK506) immunosuppression (group 3), allogeneic OLT rats with high-dose tacrolimus immunosuppression (group 4), and allogeneic OLT rats with high-dose tacrolimus immunosuppression and retrograde reperfusion via the infrahepatic caval vein (group 5). After OLT, serum parameters were determined and hepatic biopsy specimens were sampled. We examined the effects of acute rejection with or without immunosuppression therapy at histopathologic evaluation.

RESULTS

Liver grafts in syngeneic and allogeneic rats (groups 1, 2, 4, and 5) demonstrated normal serum parameters and histopathologic findings at 10 days after OLT, and 93% survival at 3 months. The simplified technique using 1 suture and 2 cuff anastomoses provided the best short- and long-term survival after OLT in all groups. Retrograde perfusion via the infrahepatic caval vein resulted in lower postoperative liver enzyme values.

CONCLUSION

The present model is feasible, enabling comprehensive preclinical experimental research on liver transplantation. Furthermore, we provide helpful instructions for learning this surgical technique.

[Middle segmental pancreatic resection: an organ-preserving option for benign lesions]

Benign and low malignant tumors of the middle pancreatic segment can be resected by extended pancreaticoduodenectomy or distal pancreatic resection. Both procedures involve unavoidably extensive loss of normal pancreatic parenchyma, leading to deteriorated endocrine and exocrine pancreatic function. Segmental pancreatic resection represents an organ-preserving surgical procedure. Normal pancreatic tissue can be preserved as only the tumor with a pancreatic segment is resected. Several reports confirm lower mortality and minimal risk of postoperative endocrine or exocrine insufficiency than with standard pancreatic resections. The indication should be limited exclusively to benign or low malignant pancreatic tumors, metastases from other tumors, and focal chronic pancreatitis, as this type of resection cannot be deemed oncologic. Segmental pancreatic resections are technically more demanding and therefore should be performed in experienced centers.

Calculated withdrawal of low-dose immunosuppression based on a detailed immunological monitoring after kidney transplantation between monocygotic twins

BACKGROUND

Pretransplant screening in living donor kidney transplantation includes human leukocyte antigen matching, and panel reactive antibody analysis, whereas T cell mediated anti-donor reactivity is not assessed routinely. We investigated T cell reactivity after living related kidney transplantation between two monocygotic twins and in consequence correlated the withdrawal of individual immunosuppressive medication with immunological findings.

METHODS

Immunosuppression consisted of mycophenolate mofetil, glucocorticoid single shot, and induction therapy with antithymocyte immunoglobulin.

RESULTS

FACS analysis of recipient peripheral blood cells revealed a normal haemogram after transplantation, showing non-activated CD4 and CD8 cells. Mixed lymphocyte reaction did not reveal donor-specific T cell activity. IFN-gamma and IL-10 ELISA of supernatants of recipient cells cocultivated with donor cells support the lack of Th1 and Th2 cell differentiation.

CONCLUSION

Based on immunological findings on days 5 and 20 MMF-therapy was reduced and stopped. Immunological monitoring on day 90 confirmed the absence of immune reactions directed against donor tissue.

Nitric oxide inhibition and consecutive Aspisol application show a prolonged survival of orthotopic transplanted livers in a rat model

BACKGROUND

It is generally accepted that nitric oxide (NO) plays a crucial role in acute rejection caused by inflammatory responses. Therefore, the purpose of this study was to investigate the effect on survival following arterialized orthotopic rat liver transplantations (o-RLTx) of NO inhibition and consequent blockade of platelet aggregation by application of Aspisol.

MATERIALS AND METHODS

Inbred LEWIS-(RT(1)) rats underwent arterialized o-RLTx under ether anesthesia with DA-(RT1av1) rats as organ donors. After liver transplantation, serum parameters were determined and hepatic biopsy specimens were sampled on postoperative days 5, 8, 10, 30, and 90. Sixty-one rats were divided into 5 groups: syngenic controls (group I, n = 12); allogenic controls (group II, n = 11); allogenic with FK506 immunosuppression (group III, n = 12); allogenic with AGH-treatment (group IV, n = 13); and allogenic with AGH/low- dose Aspisol treatment for 5 days after liver transplantation (group V, n = 13) (Bayer, Leverkusen, Germany).

RESULTS

Rats of group V with AGH/low-dose Aspisol treatment showed significantly longer graft survival (18.2 days +/- 1.8 days) compared with group II rats with untreated grafts (11.3 days +/- 1.7 days) the allogenic group IV with AGH treatment (11.2 days +/- 1.8 days; P < .05). Histological examination revealed moderate graft rejection among the AGH-treated group IV; however, marked platelet aggregation in sinusoids was present, which was not observed in the AGH/low-dose Aspisol-treated animals (group V).

CONCLUSION

Our data suggested that simultaneous treatment with AGH/low-dose Aspisol leads to a significant increase in survival and inhibition of platelet aggregation in the graft after orthotopic liver transplantation.

High-risk constellation in living renal transplantation

There is only limited information about recipient risk factors for graft survival in living- donor kidney transplantation. This study aimed to investigate prognostic factors and their impact on living-related and unrelated renal transplant recipients. From October 2000 until October 2004, 81 adult living-related renal transplantations were performed at our institution. Using multivariate analysis, the association of the following variables with kidney graft outcome was studied: ages of donors and recipients, gender and body mass index, cold and warm ischemia, HLA mismatches, identity and compatibility of blood group, duration of dialysis, cytomegalovirus (CMV) status, recipient original disease, surgical and general complications, and status of retransplantation. Multivariate analysis revealed significant reduction of graft function and graft survival in recipients with retransplantation, more than 4 mismatches, and a high body mass index. Thus, living-donor kidney transplantation can be regarded as a safe and standardized operation relating to surgical technique, but further consideration of the recipient body mass index and the number of mismatches are recommended during the preparation for transplantation.

CCR4-deficient mice show prolonged graft survival in a chronic cardiac transplant rejection model

Chronic graft rejection mediated by cellular immune responses still poses a serious clinical problem in transplant surgery. Chemokines coordinate the recruitment of leukocytes in inflammatory and immune responses. Their precise functions in the rejection of allografts are still ill defined. This study investigates the role of chemokine receptor 4 (CCR4) in acute and chronic cardiac allograft rejection in mice. Allogeneic hearts were transplanted into CCR4 deficient (CCR4(-/-)) and control recipients. Reverse transcription-PCR showed transcription of macrophage-derived chemokine and thymus and activation-regulated chemokine, the cognate chemokine ligands of CCR4, within the graft. Compared to wild-type controls, acute allograft rejection in CCR4(-/-) recipients was only slightly prolonged. In contrast, in a gallium nitrate chronic cardiac allograft rejection model, cardiac graft survival was significantly prolonged in CCR4(-/-) recipients. A relative increase in the percentage of graft infiltrating CD8(+) T cells in CCR4(-/-) recipients was observed 30 days after transplantation and was accompanied by a decrease in CD4(+) T cells. Moreover, the percentage of NK1.1(+)CD3(+) graft-infiltrating cells was significantly reduced on day 5 and day 30 post transplantation. These findings indicate that CCR4 is involved in the recruitment of NK1.1(+)CD3(+) cells into cardiac allografts and clearly establish an important and novel role for CCR4 in chronic graft rejection.