Alteration of γδ T cell subsets in non-human primates transplanted with GGTA1 gene-deficient porcine blood vessels.

BACKGROUND: αGal-deficient xenografts are protected from hyperacute rejection during xenotransplantation but are still rejected more rapidly than allografts. Despite studies showing the roles of non-Gal antibodies and αß T cells in xenograft rejection, the involvement of γδ T cells in xenograft rejection has been limitedly investigated. METHODS: Six male cynomolgus monkeys were transplanted with porcine vessel xenografts from wild-type (n = 3) or GGTA1 knockout (n = 3) pigs. We measured the proportions and T cell receptor (TCR) repertoires of blood γδ T cells before and after xenotransplant. Grafted porcine vessel-infiltrating immune cells were visualized at the end of experiments. RESULTS: Blood γδ T cells expanded and infiltrated into the graft vessel adventitia following xenotransplantation of α-Gal-deficient pig blood vessels. Pre- and post-transplant analysis of γδ TCR repertoire revealed a transition in δ chain usage post-transplantation, with the expansion of several clonotypes of δ1, δ3, or δ7 chains. Furthermore, the distinctions between pre- and post-transplant δ chain usages were more prominent than those observed for γ chain usages. CONCLUSION: γδ TCR repertoire was significantly altered by xenotransplantation, suggesting the role of γδ T cells in sustained xenoreactive immune responses.

Urine Exosomal bkv-miR-B1-5p and BK Virus Nephropathy in Kidney Transplant Recipients.

BACKGROUND: Urine exosomal bkv-miR-B1-5p is associated with BK virus (BKV) nephropathy (BKVN); however, its posttransplantation changes and predictability for BKVN have not been determined in kidney transplant recipients (KTRs). METHODS: Urine exosomal bkv-miR-B1-5p and urine and plasma BKV DNA were measured at 2 weeks and 3, 6, and 12 months posttransplant in 83 KTRs stratified into biopsy-proven or presumptive BKVN, BKV viruria, and no evidence of BKV reactivation. Joint model, multivariable Cox model and receiver operating characteristic curve (ROC) were used to investigate the association of each assay with the following events: a composite of biopsy-proven or presumptive BKVN, and biopsy-proven BKVN. RESULTS: Urine exosomal bkv-miR-B1-5p and urine and plasma BKV DNA showed similar posttransplant time-course changes. Joint models incorporating serial values demonstrated significant associations of all assays with the events, and Cox analyses using single time point values at 2 weeks posttransplant showed that only urine exosomal bkv-miR-B1-5p was significantly associated with the events, although it did not outperform urine BKV DNA in ROC analyses. CONCLUSIONS: Urine exosomal bkv-miR-B1-5p was associated with BKVN as were urine and plasma BKV DNA loads on serial follow-up, and might have potential as a predictive marker for BKVN during the early posttransplant period. CLINICAL TRIALS REGISTRATION: Clinical Research Information Service (https://cris.nih.go.kr/cris/), KCT0001010.

Augmented humoral and cellular immunity against severe acute respiratory syndrome coronavirus 2 after breakthrough infection in kidney transplant recipients who received 3 doses of coronavirus disease 2019 vaccine.

Diminished immune response to coronavirus disease 2019 (COVID-19) vaccines and breakthrough infection (BI) is a major concern for solid organ transplant recipients. Humoral and cellular immune responses of kidney transplant (KT) recipients after a third COVID-19 vaccination were investigated compared to matched health care workers. Anti-severe acute respiratory syndrome coronavirus 2 spike protein antibody and severe acute respiratory syndrome coronavirus 2 specific interferon-gamma releasing assay (IGRA) were assessed. A total of 38 KT recipients, including 20 BI and 18 noninfection, were evaluated. In the KT BI group, antibody titers were significantly increased (median 5 to 724, binding antibody units/mL (P = 0.002) after the third vaccination, but IGRA responses were negligible. After BI, antibody titers increased (median 11 355 binding antibody unit/mL; P < 0.001) and there was a significant increase of IGRA responses to spike proteins (Spike1-Nil, median 0.05 to 0.41 IU/mL; P = 0.009). Antibody titers and IGRA responses were significantly higher in the BI than in the noninfection group after 6 months. Immune responses were stronger in the health care worker than in the KT cohort, but the gap became narrower after BI. In conclusion, KT recipients who experienced BI after 3 COVID-19 vaccinations acquired augmented humoral and cellular immune responses.

Auxiliary liver xenotransplantation technique in a transgenic pig-to-non-human primate model: A surgical approach to prolong survival.

Xenotransplantation using pigs' liver offers a potentially alternative method to overcome worldwide donor shortage, or more importantly as a bridge to allotransplantation. However, it has been challenged by profound thrombocytopenia and fatal coagulopathy in non-human primate models. Here we suggest that a left auxiliary technique can be a useful method to achieve extended survival of the xenograft. Fifteen consecutive liver xenotransplants were carried out in a pig-to-cynomolgus model. Right auxiliary technique was implemented in two cases, orthotopic in eight cases, and left auxiliary in five cases. None of the right auxiliary recipients survived after surgery due to hemorrhage during complex dissection between the primate's right lobe and inferior vena cava. Orthotopic recipients survived less than 7 days secondary to profound thrombocytopenia and coagulopathy. Two out of five left auxiliary xenotransplants survived more than 3 weeks without uncontrolled thrombocytopenia or anemia, with one of them surviving 34 days, the longest graft survival reported to date. Left auxiliary xenotransplant is a feasible approach in non-human primate experiments, and the feared risk of thrombocytopenia and coagulopathy can be minimized. This may allow for longer evaluation of the xenograft and help better understand histopathological and immunological changes that occur following liver xenotransplantation.

Factors to consider during anesthesia in patients undergoing preemptive kidney transplantation: a propensity-score matched analysis.

BACKGROUND: International guidelines have recommended preemptive kidney transplantation (KT) as the preferred approach, advocating for transplantation before the initiation of dialysis. This approach is advantageous for graft and patient survival by avoiding dialysis-related complications. However, recipients of preemptive KT may undergo anesthesia without the opportunity to optimize volume status or correct metabolic disturbances associated with end-stage renal disease. In these regard, we aimed to investigate the anesthetic events that occur more frequently during preemptive KT compared to nonpreemptive KT. METHODS: This is a single-center retrospective study. Of the 672 patients who underwent Living donor KT (LDKT), 388 of 519 who underwent nonpreemptive KT were matched with 153 of 153 who underwent preemptive KT using propensity score based on preoperative covariates. The primary outcome was intraoperative hypotension defined as area under the threshold (AUT), with a threshold set at a mean arterial blood pressure below 70 mmHg. The secondary outcomes were intraoperative metabolic acidosis estimated by base excess and serum bicarbonate, electrolyte imbalance, the use of inotropes or vasopressors, intraoperative transfusion, immediate graft function evaluated by the nadir creatinine, and re-operation due to bleeding. RESULTS: After propensity score matching, we analyzed 388 and 153 patients in non-preemptive and preemptive groups. The multivariable analysis revealed the AUT of the preemptive group to be significantly greater than that of the nonpreemptive group (mean ± standard deviation, 29.7 ± 61.5 and 14.5 ± 37.7, respectively, P = 0.007). Metabolic acidosis was more severe in the preemptive group compared to the nonpreemptive group. The differences in the nadir creatinine value and times to nadir creatinine were statistically significant, but clinically insignificant. CONCLUSION: Intraoperative hypotension and metabolic acidosis occurred more frequently in the preemptive group during LDKT. These findings highlight the need for anesthesiologists to be prepared and vigilant in managing these events during surgery.

Recoverability of Diabetic Nephropathy of Donor Kidney After Kidney Transplantation.

Some kidney donors have diabetes, and little of their natural course of diabetic nephropathy (DN) is known. The aim of this study was to analyze the changes in pathologic lesions in the diabetic donor kidney after KT by performing protocol biopsy two weeks and one year after KT. This retrospective study included 103 patients who underwent KT, with kidneys from donors with a history of diabetes mellitus (DM). Among them, data of 34 patients who underwent biopsy two weeks and one year after KT were reviewed. Biopsy specimens were reviewed using light microscopy and electron microscopy. Glomerular basement membrane (GBM) thickness at 2 weeks and 1 year was compared. Biopsy showed that DN occurred in 29 of the 34 patients. Only trivial histological changes were observed in 22 patients (64.7%), including 5 patients who did not show DN. At one year after transplantation, there was no change in the DN histologic class in 26 patients (76.5%), and there was no statistically significant difference in the change in GBM thickness. This pattern was observed regardless of the recipient's DM or glycemic control. With this understanding, clinicians can use kidneys from DM donors with more comfort, thereby reducing the kidney discard rate.

Pretransplant and Posttransplant Alcohol Consumption and Outcomes in Kidney Transplantation: A Prospective Multicenter Cohort Study.

The impact of pretransplant and posttransplant alcohol consumption on outcomes in kidney transplant recipients (KTRs) is uncertain. Self-reported alcohol consumption was obtained at the time of transplant and 2 years after transplant in a prospective cohort study. Among 907 KTRs, 368 (40.6%) were drinkers at the time of transplant. Compared to non-drinkers, alcohol consumption did not affect the risk of death-censored graft failure (DCGF), biopsy-proven acute rejection (BPAR), cardiovascular events, or all-cause mortality. Compared to persistent non-drinkers, the development of DCGF, BPAR, cardiovascular events, all-cause mortality, or posttransplant diabetes mellitus was not affected by the alcohol consumption pattern (persistent, de novo, or stopped drinking) over time. However, de novo drinkers had a significantly higher total cholesterol (p < 0.001) and low-density lipoprotein cholesterol levels (p = 0.005) compared to persistent non-drinkers 5 years after transplant, and had significantly higher total cholesterol levels (p = 0.002) compared to the stopped drinking group 7 years after transplant, even after adjusting for the use of lipid-lowering agents, age, sex, and body mass index. Although pretransplant and posttransplant alcohol consumption were not associated with major outcomes in KTRs during the median follow-up of 6.0 years, a new start of alcohol use after KT results in a relatively poor lipid profile. Clinical Trial Registration: clinicaltrials.gov, identifier NCT02042963.

Kidney Transplantation From Deceased Donors With Bloodstream Infection: A Multicenter Retrospective Study.

BACKGROUND: The use of organs from donors with infection is limited because of the possibility of transmission. We aimed to investigate the transmission after deceased donor transplantation with bloodstream infection (BSI). METHODS: A retrospective study of patients undergoing kidney or pancreas transplantation at five tertiary centers in Korea from January 2009 and November 2019 was performed. We analyzed the outcomes after transplantation from deceased donors with BSI. RESULTS: Eighty-six recipients received transplantation from 69 donors with BSI. The most common isolated pathogens from donors were Gram-positive bacteria (72.0%), followed by Gram-negative bacteria (22.7%), and fungi (5.3%). Appropriate antimicrobial agents were used in 47.8% of donors before transplantation. Transmission occurred only in 1 of 83 recipients (1.2%) from bacteremic donors and 1 of 6 recipients (16.7%) from fungemic donors. One-year patient and graft survival was 97.5%and 96.3%, respectively. There was no significant difference in graft and patient survival between patients who received organs from infected donors and noninfected donors. CONCLUSION: Using organs from donors with bacteremia seems to be a safe option with low transmission risk. The overall prognosis of using organs from donors with BSI is favorable.

Management of Primary Retroperitoneal Sarcoma (RPS) in the Adult: An Updated Consensus Approach from the Transatlantic Australasian RPS Working Group.

BACKGROUND: Retroperitoneal soft tissue sarcomas comprise a heterogeneous group of rare tumors of mesenchymal origin that include several well-defined histologic subtypes. In 2015, the Transatlantic Australasian RPS Working Group (TARPSWG) published consensus recommendations for the best management of primary retroperitoneal sarcoma (RPS). Since then, through international collaboration, new evidence and knowledge have been generated, creating the need for an updated consensus document. METHODS: The primary aim of this study was to critically evaluate the current evidence and develop an up-to-date consensus document on the approach to these difficult tumors. The resulting document applies to primary RPS that is non-visceral in origin, with exclusion criteria as previously described. The relevant literature was evaluated and an international group of experts consulted to formulate consensus statements regarding the best management of primary RPS. A level of evidence and grade of recommendation were attributed to each new/updated recommendation. RESULTS: Management of primary RPS was considered from diagnosis to follow-up. This rare and complex malignancy is best managed by an experienced multidisciplinary team in a specialized referral center. The best chance of cure is at the time of primary presentation, and an individualized management plan should be made based on the 29 consensus statements included in this article, which were agreed upon by all of the authors. Whenever possible, patients should be enrolled in prospective trials and studies. CONCLUSIONS: Ongoing international collaboration is critical to expand upon current knowledge and further improve outcomes of patients with RPS. In addition, prospective data collection and participation in multi-institution trials are strongly encouraged.

Impact of recipient and donor smoking in living-donor kidney transplantation: a prospective multicenter cohort study.

The smoking status of kidney transplant recipients and living donors has not been explored concurrently in a prospective study, and the synergistic adverse impact on outcomes remains uncertain. The self-reported smoking status and frequency were obtained from recipients and donors at the time of kidney transplantation in a prospective multicenter longitudinal cohort study (NCT02042963). Smoking status was categorized as "ever smoker" (current and former smokers collectively) or "never smoker." Among 858 eligible kidney transplant recipients and the 858 living donors, 389 (45.3%) and 241 (28.1%) recipients were considered ever smokers at the time of transplant. During the median follow-up period of 6 years, the rate of death-censored graft failure was significantly higher in ever-smoker recipients than in never-smoker recipients (adjusted HR, 2.82; 95% CI 1.01-7.87; P = 0.048). A smoking history of >20 pack-years was associated with a significantly higher rate of death-censored graft failure than a history of ≤20 pack-years (adjusted HR, 2.83; 95% CI 1.19-6.78; P = 0.019). No donor smoking effect was found in terms of graft survival. The smoking status of the recipients and donors or both did not affect the rate of biopsy-proven acute rejection, major adverse cardiac events, all-cause mortality, or post-transplant diabetes mellitus. Taken together, the recipient's smoking status before kidney transplantation is dose-dependently associated with impaired survival.

The combination of area under the curve and percentage change in estimated glomerular filtration rate predicts long-term outcome of kidney transplants.

The development of surrogate markers for long-term outcomes of kidney transplant (KT) is a focus of attention. We examined the possibility of using a combination of the area under the curve of estimated glomerular filtration rate (eGFR) for 2 years (AUCeGFR2yrs ) and percent change in eGFR between 1 and 2 years after KT (% changeeGFR1/2yr ) as a surrogate marker. We compared the predictive power of death-censored graft failure with various combinations. The combination of >2% vs ≤2% for % changeeGFR1/2yr and >1300 vs ≤1300 mL/min/month for AUCeGFR2yr had the highest Harrell C-index (0.647; 95% confidence interval [95% CI], 0.604-0.690). The death-censored graft survival rate of the group with ≤2% changeeGFR1/2yr and ≤1300 mL/min/month AUCeGFR2yr was significantly lower than those of other groups. The AUC/% change eGFR had comparable predictive power to the previously identified marker ≥30% decline in eGFR between years 1 and 3 after KT (≤-30% changeeGFR1/3yr ) (Harrell's C-index = 0.645 [95% CI 0.628-0.662] for ≤-30% changeeGFR1/3yr ). The proposed combination might be useful as a surrogate marker in KT trials because it requires a shorter surveillance period than the established marker while having comparable predictive power.

Peripheral blood transcriptome analysis and development of classification model for diagnosing antibody-mediated rejection vs accommodation in ABO-incompatible kidney transplant.

The major obstacle to successful ABO blood group-incompatible kidney transplantation (ABOi KT) is antibody-mediated rejection (AMR). This study aimed to investigate transcriptional profiles through RNA sequencing and develop a minimally invasive diagnostic tool for discrimination between accommodation and early acute AMR in ABOi KT. Twenty-eight ABOi KT patients were selected: 18 with accommodation and 10 with acute AMR at the 10th day posttransplant protocol biopsy. Complete transcriptomes of their peripheral blood were analyzed by RNA sequencing. Candidate genes were selected by bioinformatics analysis, validated with quantitative polymerase chain reaction, and used to develop a classification model to diagnose accommodation. A total of 1385 genes were differentially expressed in accommodation compared with in AMR with P-adjusted < .05. Functional annotation and gene set enrichment analysis identified several immune-related and immunometabolic pathways. A 5-gene classification model including COX7A2L, CD69, CD14, CFD, and FOXJ3 was developed by logistic regression analysis. The model was further validated with an independent cohort and discriminated between accommodation and AMR with 92.7% sensitivity, 85.7% specificity, and 91.7% accuracy. Our study suggests that a classification model based on peripheral blood transcriptomics may allow minimally invasive diagnosis of acute AMR vs accommodation and subsequent patient-tailored immunosuppression in ABOi KT.

Hepatitis B reactivation after kidney transplantation in hepatitis B surface antigen-negative, core antibody-positive recipients.

Nowadays, intensive immunosuppressive therapy including rituximab is commonly used prior to kidney transplantation (KT), raising concerns over hepatitis B virus (HBV) reactivation among hepatitis B surface antigen (HBsAg)-negative and anti-hepatitis B core (HBc)-positive KT recipients. Recent practice guidelines suggested watchful monitoring or antiviral prophylaxis for the first 6-12 months, the period of maximal immunosuppression. However, the actual risk for HBV reactivation, and whether short-term antiviral therapy in the early period is necessary, remains unclear. A total of 449 HBsAg-negative and anti-HBc-positive KT recipients were analysed for HBV reactivation. During a median follow-up of 6.7 (interquartile range: 4.2-9.4) years, HBV reactivation was observed in 9 patients (2.0%). The median time of HBV reactivation from KT was 2.8 years (range: 1.4-11.5 years), with cumulative incidence rates of 0%, 1% and 2% for 1, 3 and 5 years, respectively. There were no severe adverse outcomes, including liver transplantation or mortality related to HBV reactivation. The risk of HBV reactivation was not high, even in anti-HBs-negative patients (n = 60, 4% at 5 years), ABO mismatch (n = 92, 4% at 5 years), use of rituximab (n = 66, 3% at 5 years) or plasmapheresis (n = 17, 7% at 5 years), and acute rejection (n = 169, 3% at 5 years). In conclusion, the HBV reactivation risk was not high and the time of detection was not clustered in the early post-KT period. Our findings favour continued watchful monitoring over antiviral prophylaxis in the early period.

Risk factors for development and mortality of invasive pulmonary Aspergillosis in kidney transplantation recipients.

Invasive pulmonary aspergillosis (IPA) is a high mortality opportunistic infection among kidney transplant recipients. This study assessed the risk factors and outcomes of IPA after KT. A retrospective study was conducted at a tertiary-care referral hospital in Korea. Electronic medical records of patients diagnosed with IPA after KT between February 1995 and March 2015 were reviewed. The control patients comprised two patients who received KT before and after each IPA case. Twenty-six cases were diagnosed with IPA among 1963 recipients at a median of 58 years old. The most common cause of end-stage renal disease was diabetic nephropathy. The median time to diagnosis was 161 days. Delayed graft function was associated with the development of IPA. The overall 12-week mortality rate of IPA was 57.5%. Serum GM level ≥ 2 and BAL GM level ≥ 5 were associated with 12-week mortality in the Kaplan-Meier survival analyses. Approximately half of IPA in KT recipients developed during the late posttransplant period (> 6 months), especially after treatment for acute rejection. Careful monitoring for IPA is required in patients with delayed graft function, DM, and who received rejection therapy. Higher serum and BAL GM were associated with 12-week mortality.

Dual kidney transplantation offers a safe and effective way to use kidneys from deceased donors older than 70 years.

PURPOSE: Dual kidney transplantation (DKT) offers a way to extend the use of kidneys from expanded criteria donors (ECDs). Here, we compared the outcomes of DKT with those of single kidney transplantation from standard criteria donors (SCDs) and ECDs. METHODS: In 2014, we began performing DKT using both kidneys from deceased donors greater than 70 years of age with one of two risk factors: serum creatinine (sCr) level over 3.0 mg/dl or eGFR under 30 ml/min. By 2017, we had performed 15 DKTs. We compared the outcomes of the 15 DKT recipients with those of 124 patients who received a kidney from an SCD and 80 patients who received a kidney from an ECD. RESULTS: Compared with ECDs and SCDs, DKT donors were older, had a higher diabetes burden, and a higher sCr level (p < 0.01, < 0.01, and 0.03, respectively). DKT recipients were also older and had a higher diabetes burden than recipients of kidneys from ECDs and SCDs (p < 0.01, both). DKT recipients had a lower nadir sCr and shorter duration to nadir sCr than single ECD KT recipients (p < 0.01and 0.04, respectively). CONCLUSIONS: The survival rates of DKT grafts were compatible with those of single KT grafts. Therefore, DKT may be considered a suitable an option to expand the donor pool.

Combination therapy with c-met inhibitor and TRAIL enhances apoptosis in dedifferentiated liposarcoma patient-derived cells.

BACKGROUND: Liposarcoma (LPS) is a tumor derived from adipose tissue, and has the highest incidence among soft tissue sarcomas. Dedifferentiated liposarcoma (DDLPS) is a malignant tumor with poor prognosis. Recurrence and metastasis rates in LPS remain high even after chemotherapy and radiotherapy following complete resection. Therefore, the development of advanced treatment strategies for LPS is required. In the present study, we investigated the effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment, and of combination treatment using TRAIL and a c-Met inhibitor on cell viability and apoptosis in LPS and DDLPS cell lines of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment, and of combination treatment using TRAIL and a c-Met inhibitor. METHODS: We analyzed cell viability after treatment with TRAIL and a c-Met inhibitor by measuring CCK8 and death receptor 5 (DR5) expression levels via fluorescence activated cell sorting (FACS) in both sarcoma cell lines and DDLPS patient-derived cells (PDCs). Moreover, we validated the effects of TRAIL alone and in combination with c-Met inhibitor on apoptosis in LPS cell lines and DDLPS PDCs via FACS. RESULTS: Our results revealed that combination treatment with a c-Met inhibitor and human recombinant TRAIL (rhTRAIL) suppressed cell viability and induced cell death in both sarcoma cell lines and DDLPS PDCs, which showed varying sensitivities to rhTRAIL alone. Also, we confirmed that treatment with a c-Met inhibitor upregulated DR5 levels in sarcoma cell lines and DDLPS PDCs. In both TRAIL-susceptible and TRAIL-resistant cells subjected to combination treatment, promotion of apoptosis was dependent on DR5 upregulation. CONCLUSION: From these results, our findings validated that DR5 up-regulation caused by combination therapy with a c-Met inhibitor and rhTRAIL enhanced TRAIL sensitization and promoted apoptosis. We propose the use of this approach to overcome TRAIL resistance and serve as a novel treatment strategy for clinical trials.

Coagulation biomarkers in healthy male Cynomolgus macaque monkeys (Macaca fascicularis).

We designed this study to define reference values of the cynomolgus monkey coagulation system, as the normal range of values has not been established. Measurement of coagulation function was determined by testing plasma samples from 30 healthy male cynomolgus monkeys. Prothrombin time (PT), PT activity, PT international normalized ratio (INR), activated prothrombin time (aPTT), antithrombin III activity, factor II, V, VII, VIII, IX, X, XI, and XII, protein C activity, protein S activity, and d-dimer were measured using standardized techniques. Mean age and body weight were 69.5 ± 11.8 months and 5.3 ± 0.8 kg, respectively. The mean PT, PT activity, PT INR, aPTT, and antithrombin III activities were 11.72 seconds (95% CI = 10.55-12.88), 143.4% (95% CI = 102.0-184.9), 0.85 (95% CI = 0.74-0.96), 28.2 seconds (95% CI = 23.24-33.09), and 99.7% (95% CI = 79.2-120.3), respectively. The mean activities of factors II, V, VII, VIII, IX, X, XI, and XII were 110.2% (95% CI = 88.8-131.5), 134.1% (95% CI = 73.0-195.2), 318.9% (95% CI = 185.0-452.9) 160.2% (95% CI = 96.9-261.3), 38.0% (95% CI = 20.9-55.1), 85.7% (95% CI = 61.4-110.0), 155.0% (95% CI = 81.4-228.6), and 353.7% (95% CI = 246.7-460.6), respectively. The mean activities of protein C and protein S were 195.7% (95% CI = 133.4-258.0) and 122.7% (95% CI = 83.2-162.3), respectively. The mean level of d-dimer was 1.80 µg/mL (95% CI = 0.27-3.33). Factors V (P = 0.008), IX (P = 0.002), and XI (P = 0.002), and protein S activity (P = 0.025) were positively correlated with age. Our study presented the baseline values of coagulation biomarkers of cynomolgus monkeys. Despite the similarity to previous published studies, more data are required to elucidate the age effect on coagulation biomarkers.

Reduced variability in tacrolimus pharmacokinetics following intramuscular injection compared to oral administration in cynomolgus monkeys: Investigating optimal dosing regimens.

Tacrolimus is one of the most commonly used immunosuppressive agents in animal models of transplantation. However, in these models, oral administration is often problematic due to the lowered compliance associated with highly invasive surgery and due to malabsorption in the intestinal tract. Therefore, we carried out a study to determine the pharmacokinetics of tacrolimus after intramuscular (IM) injection and to determine the optimal IM dosing regimens in primate models. Six male cynomolgus monkeys (Macaca fascicularis) were used in the study. Doses of 0.1 mg/kg and 5 mg were administered via IM injection and oral administration, respectively, once to determine single-dose pharmacokinetics and once daily for 5 days to determine multiple-dose pharmacokinetics. According to pharmacokinetic model estimates, the inter- and intra-individual variabilities in bioavailability following IM injection were remarkably reduced compared with those following oral administration. Monte Carlo simulations revealed that Cpeak, Ctrough and AUC would also have less variability following IM injection compared with oral administration. In this study, we found that the pharmacokinetic characteristics of tacrolimus were more constant following IM injection compared with oral administration. These results suggest that IM injection can be an alternative route of administration fin non-human primate model studies.

Optimal maximum duration for delaying salvage operation when recurrence of retroperitoneal liposarcoma is suspected: a single-center study.

BACKGROUND: This study was designed to identify the optimal maximum duration for delaying salvage operation when recurrence of retroperitoneal liposarcoma (LPS) is suspected. METHODS: Patients who underwent salvage operation at Samsung Medical Center for recurrent retroperitoneal LPS from January 2000 to December 2015 were reviewed. The time interval between recurrence and operation for recurrence was divided by 1, 2 or 3 months. A Cox proportional-hazards model was used to analyze factors related to disease-free survival along with recurrence-to-operation interval divided by 1, 2 or 3 months. RESULTS: The 1-, 3-, and 5-year disease-free survival rates were 43.2%, 15.6% and 13.4%, respectively. FNCLCC grade (p = 0.023) and recurrence-to-operation interval divided by 3 months (p = 0.003) were significant factors associated with recurrence. FNCLCC grade 2 (HR 1.940, CI 0.935-4.026, p = 0.238) and grade 3 (HR 4.049, CI 1.767-9.281, p = 0.007) showed increased risk compared to grade 1. Patients who underwent salvage operation more than 3 months after recurrence showed significantly increased risk of recurrence compared to patients within 3 months (HR 2.724, CI 1.391-5.337, p = 0.003). CONCLUSIONS: Based on our analysis of recurrence-free survival, salvage operation can be delayed for less than 3 months when recurrence is suspected. A short-term follow-up imaging study should be performed within this period.

Ectopic vascularized bone formation by human umbilical cord-derived mesenchymal stromal cells expressing bone morphogenetic factor-2 and endothelial cells.

Mesenchymal stromal cells (MSCs) isolated from numerous tissues including human fetal tissue are currently used in cell therapy and regenerative medicine. Among fetal tissues, the umbilical cord (UC) is one of the sources for both MSCs and endothelial cells (ECs). To establish ectopic vascularized bone tissue formation, UC-derived MSCs and ECs were isolated. UC-MSCs expressing human BMP-2 (hBMP-2-MSCs) were generated using an adenoviral system to promote bone formation. These cells were then transplanted with Matrigel into the subcutaneous tissue of an immune deficient NSG mouse, and bone tissue was analyzed after several weeks. The osteogenic differentiation ability of MSCs was elevated by transduction of the hBMP-2 expressing adenoviral system, and vascularization of bone tissue was enhanced by human umbilical vein endothelial cells (HUVEC). In this study, our results provide evidence that MSCs and HUVECs from human umbilical cord are suitable cells to investigate bone tissue engineering. The results also suggest that the co-transplantation of hBMP2-MSCs and HUVECs may be a simple and efficient strategy for improving tissue generation and angiogenesis in bone tissue engineering using stem cells.