Renal outcome and plasma methylmalonic acid levels after isolated or combined liver or kidney transplantation in patients with methylmalonic acidemia: A multicenter analysis

BACKGROUND

Methylmalonic acidemia (MMAemia) is characterized by accumulation of methylmalonic acid (MMA) in all body tissues. To minimize disease-related complications, isolated kidney (KTx), liver (LTx) or combined liver-kidney transplantation (LKTx) have been suggested. However, the impact of these different transplant strategies on outcome are unclear.

METHODS

In this multicenter retrospective observational study, we compared plasma MMA levels and estimated glomerular filtration rate (eGFR) data of 83 patients. Sixty-eight patients (82%) had a mut⁰-type MMAemia, one patient had a mut^--type MMAemia, and seven (7.3%) had an inherited defect in cobalamin metabolism (cblA- or cblB-type MMAemia). Median observation period was 3.7 years (0-15.1 years).

RESULTS

Twenty-six (31%) patients underwent KTx, 24 (29%) LTx and 33 (40%) LKTx. Posttransplant, mean plasma MMA concentration significantly decreased in all three cohorts; but at month 12, plasma MMA in KTx (1372 ± 1101 μmol/L) was 7.8-fold higher than in LTx (176 ± 103 μmol/L; P < 0.001) and 6.4-fold higher than in LKTx (215 ± 110 μmol/L; P < 0.001). Comparable data were observed at month 24. At time of transplantation, mean eGFR in KTx was 18.1 ± 24.3 mL/min/1.73 m², in LTx 99.8 ± 29.9 mL/min/1.73 m², and in LKTx 31.5 ± 21.2 mL/min/1.73 m². At month 12 posttransplant, mean eGFR in KTx (62.3 ± 30.3 mL/min/1.73 m²) was 33.4% lower than in LTx (93.5 ± 18.3 mL/min/1.73 m²; P = 0.0053) and 25.4% lower than in LKTx (83.5 ± 26.9 mL/min/1.73 m²; P = 0.0403).

CONCLUSIONS

In patients with isolated MMAemia, LTx and LKTx lead to markedly lower plasma MMA levels during the first 2 years posttransplant than KTx and are associated with a better preservation of kidney function. LTx should therefore be part of the transplant strategy in MMAemia.

Sequential Stem Cell-Kidney Transplantation in Schimke Immuno-osseous Dysplasia

Lifelong immunosuppression is required for allograft survival after kidney transplantation but may not ultimately prevent allograft loss resulting from chronic rejection. We developed an approach that attempts to abrogate immune rejection and the need for post-transplantation immunosuppression in three patients with Schimke immuno-osseous dysplasia who had both T-cell immunodeficiency and renal failure. Each patient received sequential transplants of αβ T-cell-depleted and CD19 B-cell-depleted haploidentical hematopoietic stem cells and a kidney from the same donor. Full donor hematopoietic chimerism and functional ex vivo T-cell tolerance was achieved, and the patients continued to have normal renal function without immunosuppression at 22 to 34 months after kidney transplantation. (Funded by the Kruzn for a Kure Foundation.).

The Tabula Sapiens: A multiple-organ, single-cell transcriptomic atlas of humans

Molecular characterization of cell types using single-cell transcriptome sequencing is revolutionizing cell biology and enabling new insights into the physiology of human organs. We created a human reference atlas comprising nearly 500,000 cells from 24 different tissues and organs, many from the same donor. This atlas enabled molecular characterization of more than 400 cell types, their distribution across tissues, and tissue-specific variation in gene expression. Using multiple tissues from a single donor enabled identification of the clonal distribution of T cells between tissues, identification of the tissue-specific mutation rate in B cells, and analysis of the cell cycle state and proliferative potential of shared cell types across tissues. Cell type-specific RNA splicing was discovered and analyzed across tissues within an individual.

Complement-Binding Donor-Specific Anti-HLA Antibodies: Biomarker for Immunologic Risk Stratification in Pediatric Kidney Transplantation Recipients

Antibody-mediated rejection is a common cause of early kidney allograft loss but the specifics of antibody measurement, therapies and endpoints have not been universally defined. In this retrospective study, we assessed the performance of risk stratification using systematic donor-specific antibody (DSA) monitoring. Included in the study were children who underwent kidney transplantation between January 1, 2010 and March 1, 2018 at Stanford, with at least 12-months follow-up. A total of 233 patients were included with a mean follow-up time of 45 (range, 9–108) months. Median age at transplant was 12.3 years, 46.8% were female, and 76% had a deceased donor transplant. Fifty-two (22%) formed C1q-binding de novo donor-specific antibodies (C1q-dnDSA). After a standardized augmented immunosuppressive protocol was implemented, C1q-dnDSA disappeared in 31 (58.5%). Graft failure occurred in 16 patients at a median of 54 (range, 5–83) months, of whom 14 formed dnDSA. The 14 patients who lost their graft due to rejection, all had persistent C1q-dnDSA. C1q-binding status improved the individual risk assessment, with persistent; C1q binding yielding the strongest independent association of graft failure (hazard ratio, 45.5; 95% confidence interval, 11.7–177.4). C1q-dnDSA is more useful than standard dnDSA as a noninvasive biomarker for identifying patients at the highest risk of graft failure.

Comparison of combined heart‒liver vs heart-only transplantation in pediatric and young adult Fontan recipients

BACKGROUND

Indications for a heart‒liver transplantation (HLT) for Fontan recipients are not well defined. We compared listing characteristics, post-operative complications, and post-transplant outcomes of Fontan recipients who underwent HLT with those of patients who underwent heart-only transplantation (HT). We hypothesized that patients who underwent HLT have increased post-operative complications but superior survival outcomes compared with patients who underwent HT.

METHODS

We performed a retrospective review of Fontan recipients who underwent HLT or HT at a single institution. Characteristics at the time of listing, including the extent of liver disease determined by laboratory, imaging, and biopsy data, were compared. Post-operative complications were assessed, and the Kaplan‒Meier survival method was used to compare post-transplant survival. Univariate regression analyses were performed to identify the risk factors for increased mortality and morbidity among patients who underwent HT.

RESULTS

A total of 47 patients (9 for HLT, 38 for HT) were included. Patients who underwent HLT were older, were more likely to be on dual inotrope therapy, and had evidence of worse liver disease. Whereas ischemic time was longer for the group who underwent HLT, post-operative complications were similar. Over a median post-transplant follow-up of 17 (interquartile range: 5-52) months, overall mortality for the cohort was 17%; only 1 patient who underwent HLT died (11%) vs 7 patients who underwent HT (18%) (p = 0.64). Among patients who underwent HT, cirrhosis on pre-transplant imaging was associated with worse outcomes.

CONCLUSIONS

Despite greater inotrope need and more severe liver disease at the time of listing, Fontan recipients undergoing HLT have post-transplant outcomes comparable with those of patients undergoing HT. HLT may offer a survival benefit for Fontan recipients with liver disease.

Predictors of Outcomes of Patients Referred to a Transplant Center for Urgent Liver Transplantation Evaluation

Liver transplantation (LT) is definitive treatment for end-stage liver disease. This study evaluated factors predicting successful evaluation in patients transferred for urgent inpatient LT evaluation. Eighty-two patients with cirrhosis were transferred for urgent LT evaluation from January 2016 to December 2018. Alcohol-associated liver disease was the common etiology of liver disease (42/82). Of these 82 patients, 35 (43%) were declined for LT, 27 (33%) were wait-listed for LT, 5 (6%) improved, and 15 (18%) died. Psychosocial factors were the most common reasons for being declined for LT (49%). Predictors for listing and receiving LT on multivariate analysis included Hispanic race (odds ratio [OR], 1.89; P = 0.003), Asian race (OR, 1.52; P = 0.02), non-Hispanic ethnicity (OR, 1.49; P = 0.04), hyponatremia (OR, 1.38; P = 0.04), serum albumin (OR, 1.13; P = 0.01), and Model for End-Stage Liver Disease (MELD)-Na (OR, 1.02; P = 0.003). Public insurance (i.e., Medicaid) was a predictor of not being listed for LT on multivariate analysis (OR, 0.77; P = 0.02). Excluding patients declined for psychosocial reasons, predictors of being declined for LT on multivariate analysis included Chronic Liver Failure Consortium (CLIF-C) score >51.5 (OR, 1.26; P = 0.03), acute-on-chronic liver failure (ACLF) grade 3 (OR, 1.41; P = 0.01), hepatorenal syndrome (HRS) (OR, 1.38; P = 0.01), and respiratory failure (OR, 1.51; P = 0.01). Predictors of 3-month mortality included CLIF-C score >51.5 (hazard ratio [HR], 2.52; P = 0.04) and intensive care unit (HR, 8.25; P < 0.001). Conclusion: MELD-Na, albumin, hyponatremia, ACLF grade 3, HRS, respiratory failure, public insurance, Hispanic race, Asian race, and non-Hispanic ethnicity predicted liver transplant outcome. Lack of psychosocial support was a major reason for being declined for LT. The CLIF-C score predicted being declined for LT and mortality.

Acute kidney injury and chronic kidney disease after combined heart-liver transplant in patients with congenital heart disease: A retrospective case series

Although it is known that children undergoing heart transplantation are at increased risk for both AKI and CKD, renal function following CHLT remains understudied. All pediatric CHLT patients from 2006 to 2019 were included. The prevalence of AKI in the first 7 post-operative days, renal recovery at 30 post-operative days, and CKD were ascertained. AKI was defined as an increase in creatinine greater than 1.5 times baseline, and CKD, as an eCrCl less than 90 mL/min/1.73 m² . The need for RRT was also analyzed. 10 patients were included, with an average age of 20 years and an average listing time of 130 days. Preoperatively, the median eCrCl was 91.12 mL/min/m² (IQR 70.51, 127.75 min/mL/m² ). 5 (50%) patients had CKD, with 4 at stage 2 and 1 at stage 3. AKI occurred post-operatively in 3 of 9 (33%) patients: 2 at stage 1 and 1 at stage 2. 2 (67%) resolved by 7 days. Of the 5 patients who reached their 1-year follow-up, 1 (20%) had stage 3 CKD. Among 2 patients, neither had CKD at 5 years. One patient required RRT 2 weeks after CHLT. Despite an increased prevalence of preoperative CKD, patients undergoing CHLT have a lower AKI prevalence than those receiving an isolated heart or liver transplant. Of those with AKI, early renal recovery is common, although at 1 year CKD remains present in 20%. Among long-term survivors, normal renal function is achievable.

Does liver biopsy accurately measure fibrosis in Fontan-associated liver disease? A comparison of liver biopsy pre-combined heart and liver transplant and liver explant post-transplant

The accuracy of liver biopsy to stage fibrosis due to Fontan-associated liver disease (FALD) remains unclear. We compared the results of biopsy pre-combined heart and liver transplantation (CHLT) to the results of whole liver explant. Liver biopsy and explants from 15 Fontan patients (ages 16-49, median 28 years) were retrospectively reviewed. Staging was as follows: stage 0: no fibrosis, stage 1: pericellular fibrosis, stage 2: bridging fibrosis, and stage 3: regenerative nodules. There is no stage 4. Clinical characteristics including Model of End-stage Liver Disease eXcluding INR and Varices, Ascites, Splenomegaly, and Thrombocytopenia (VAST) scores were collected, and descriptive statistics and Mann-Whitney U tests were used to analyze the data. All patients had biopsies with at least bridging fibrosis, and all had nodularity on explant; transjugular biopsy never overestimated fibrosis. Explant showed higher-grade fibrosis (stage 3) than pre-CHLT biopsy (stage 2) in 6 of 15 patients and equal grade of fibrosis (stage 3) in 9 of 15 patients. Though clinical characteristics varied significantly, VAST score was ≥2 in all but two patients. Transjugular liver biopsy does not overestimate and can underestimate fibrosis in Fontan patients undergoing CHLT, likely due to the patchy nature of fibrosis in FALD.

Pulsed focused ultrasound enhances the therapeutic effect of mesenchymal stromal cell-derived extracellular vesicles in acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is characterized by rapid failure of renal function and has no curative therapies. Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) are known to carry therapeutic factors, which have shown promise in regenerative medicine applications, including AKI. However, there remains an unmet need to optimize their therapeutic effect. One potential avenue of optimization lies in pulsed focused ultrasound (pFUS), where tissues-of-interest are treated with sound waves. pFUS has been shown to enhance MSC therapy via increased cell homing, but its effects on cell-free EV therapy remain largely unexplored.

METHODS

We combine pFUS pretreatment of the kidney with MSC-derived EV therapy in a mouse model of cisplatin-induced AKI.

RESULTS

EVs significantly improved kidney function, reduced injury markers, mediated increased proliferation, and reduced inflammation and apoptosis. While pFUS did not enhance EV homing to the kidney, the combined treatment resulted in a superior therapeutic effect compared to either treatment alone. We identified several molecular mechanisms underlying this synergistic therapeutic effect, including upregulation of proliferative signaling (MAPK/ERK, PI3K/Akt) and regenerative pathways (eNOS, SIRT3), as well as suppression of inflammation.

CONCLUSION

Taken together, pFUS may be a strategy for enhancing the therapeutic efficacy of MSC-derived EV treatment for the treatment of AKI.

Complementing Human Behavior Assessment by Leveraging Personal Ubiquitous Devices and Social Links: An Evaluation of the Peer-Ceived Momentary Assessment Method

BACKGROUND

Ecological momentary assessment (EMA) enables individuals to self-report their subjective momentary physical and emotional states. However, certain conditions, including routine observable behaviors (eg, moods, medication adherence) as well as behaviors that may suggest declines in physical or mental health (eg, memory losses, compulsive disorders) cannot be easily and reliably measured via self-reports.

OBJECTIVE

This study aims to examine a method complementary to EMA, denoted as peer-ceived momentary assessment (PeerMA), which enables the involvement of peers (eg, family members, friends) to report their perception of the individual's subjective physical and emotional states. In this paper, we aim to report the feasibility results and identified human factors influencing the acceptance and reliability of the PeerMA.

METHODS

We conducted two studies of 4 weeks each, collecting self-reports from 20 participants about their stress, fatigue, anxiety, and well-being, in addition to collecting peer-reported perceptions from 27 of their peers.

RESULTS

Preliminary results showed that some of the peers reported daily assessments for stress, fatigue, anxiety, and well-being statistically equal to those reported by the participant. We also showed how pairing assessments of participants and peers in time enables a qualitative and quantitative exploration of unique research questions not possible with EMA-only based assessments. We reported on the usability and implementation aspects based on the participants' experience to guide the use of the PeerMA to complement the information obtained via self-reports for observable behaviors and physical and emotional states among healthy individuals.

CONCLUSIONS

It is possible to leverage the PeerMA method as a complement to EMA to assess constructs that fall in the realm of observable behaviors and states in healthy individuals.

Understanding Health Care Utilization and Mortality After Emergency General Surgery in Patients With Underlying Liver Disease

BACKGROUND

Mortality and complications are not well defined nationally for emergency general surgery (EGS) patients presenting with underlying all-cause liver disease (LD).

STUDY DESIGN

We analyzed the 2012-2014 National Inpatient Sample for adults (aged ≥ 18 years) with a primary EGS diagnosis. Underlying LD included International Classification of Diseases, Ninth Revision, Clinical Modification codes for alcoholic and viral hepatitis, malignancy, congenital etiologies, and cirrhosis. The primary outcome was mortality; secondary outcomes included complications, operative intervention, and costs.

RESULTS

Of the 6.8 million EGS patients, 358 766 (5.3%) had underlying LD. 59.1% had cirrhosis, 6.7% had portal hypertension, and 13.7% had ascites. Compared with other EGS patients, EGS-LD patients had higher mean costs ($12 847 vs $10 234, P < .001). EGS-LD patients were less likely to have surgery (26.1% vs 37.0%, P < .001) but for those who did, mortality was higher (4.8% vs 1.8%, P < .001). Risk factors for mortality included ascites (adjusted odds ratio [aOR] = 2.68, P < .001), dialysis (aOR = 3.44, P < .001), sepsis (aOR = 8.97, P < .001), and respiratory failure requiring intubation (aOR = 10.40, P < .001). Odds of death increased in both surgical (aOR = 4.93, P < .001) and non-surgical EGS-LD patients (aOR = 2.56, P < .001).

CONCLUSIONS

Underlying all-cause LD among EGS patients is associated with increased in-hospital mortality, even in the absence of surgical intervention.

HSP70-Mediated NLRP3 Inflammasome Suppression Underlies Reversal of Acute Kidney Injury Following Extracellular Vesicle and Focused Ultrasound Combination Therapy

Acute kidney injury (AKI) is the abrupt loss of renal function, for which only supportive therapies exist. Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) have been shown to be therapeutically effective in treating AKI by spurring endogenous cell proliferation and survival while suppressing inflammation. Pre-treating kidneys with pulsed focused ultrasound (pFUS) has also been shown to enhance MSC therapy for AKI, but its role in MSC-derived EV therapy remains unexplored. Using a mouse model of cisplatin-induced AKI, we show that combination therapy with pFUS and EVs restores physiological and molecular markers of kidney function, more so than either alone. Both pFUS and EVs downregulate heat shock protein 70 (HSP70), the NLRP3 inflammasome, and its downstream pro-inflammatory cytokines IL-1β and IL-18, all of which are highly upregulated in AKI. In vitro knockdown studies suggest that HSP70 is a positive regulator of the NLRP3 inflammasome. Our study therefore demonstrates the ability of pFUS to enhance EV therapy for AKI and provides further mechanistic understanding of their anti-inflammatory and regenerative effects.

Successful liver transplantation in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a fatal disorder characterized by progressive gastrointestinal dysmotility, peripheral neuropathy, leukoencephalopathy, skeletal myopathy, ophthalmoparesis, and ptosis. MNGIE stems from deficient thymidine phosphorylase activity (TP) leading to toxic elevations of plasma thymidine. Hematopoietic stem cell transplant (HSCT) restores TP activity and halts disease progression but has high transplant-related morbidity and mortality. Liver transplant (LT) was reported to restore TP activity in two adult MNGIE patients. We report successful LT in four additional MNGIE patients, including a pediatric patient. Our patients were diagnosed between ages 14 months and 36 years with elevated thymidine levels and biallelic pathogenic variants in TYMP. Two patients presented with progressive gastrointestinal dysmotility, and three demonstrated progressive peripheral neuropathy with two suffering limitations in ambulation. Two patients, including the child, had liver dysfunction and cirrhosis. Following LT, thymidine levels nearly normalized in all four patients and remained low for the duration of follow-up. Disease symptoms stabilized in all patients, with some manifesting improvements, including intestinal function. No patient died, and LT appeared to have a more favorable safety profile than HSCT, especially when liver disease is present. Follow-up studies will need to document the long-term impact of this new approach on disease outcome. Take Home Message: Liver transplantation is effective in stabilizing symptoms and nearly normalizing thymidine levels in patients with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) and may have an improved safety profile over hematopoietic stem cell transplant.

Reversing Acute Kidney Injury Using Pulsed Focused Ultrasound and MSC Therapy: A Role for HSP-Mediated PI3K/AKT Signaling

Acute kidney injury (AKI) is characterized by a sudden failure of renal function, but despite increasing worldwide prevalence, current treatments are largely supportive, with no curative therapies. Mesenchymal stromal cell (MSC) therapy has been shown to have a promising regenerative effect in AKI but is limited by the ability of cells to home to damaged tissue. Pulsed focused ultrasound (pFUS), wherein target tissues are sonicated by short bursts of sound waves, has been reported to enhance MSC homing by upregulating local homing signals. However, the exact mechanism by which pFUS enhances MSC therapy remains insufficiently explored. In this study, we studied the effect of bone marrow-derived MSCs (BM-MSCs), in conjunction with pFUS, in a mouse model of cisplatin-induced AKI. Here, BM-MSCs improved kidney function, reduced histological markers of kidney injury, decreased inflammation and apoptosis, and promoted cellular proliferation. Surprisingly, whereas pFUS did not upregulate local cytokine expression or improve BM-MSC homing, it did potentiate the effect of MSC treatment in AKI. Further analysis linked this effect to the upregulation of heat shock protein (HSP)20/HSP40 and subsequent phosphatidylinositol 3-kinase (PI3K)/Akt signaling. In summary, our results suggest that pFUS and BM-MSCs have independent as well as synergistic therapeutic effects in the context of AKI.

The role of ultrasound in enhancing mesenchymal stromal cell-based therapies

Mesenchymal stromal cells (MSCs) have been a popular platform for cell‐based therapy in regenerative medicine due to their propensity to home to damaged tissue and act as a repository of regenerative molecules that can promote tissue repair and exert immunomodulatory effects. Accordingly, a great deal of research has gone into optimizing MSC homing and increasing their secretion of therapeutic molecules. A variety of methods have been used to these ends, but one emerging technique gaining significant interest is the use of ultrasound. Sound waves exert mechanical pressure on cells, activating mechano‐transduction pathways and altering gene expression. Ultrasound has been applied both to cultured MSCs to modulate self‐renewal and differentiation, and to tissues‐of‐interest to make them a more attractive target for MSC homing. Here, we review the various applications of ultrasound to MSC‐based therapies, including low‐intensity pulsed ultrasound, pulsed focused ultrasound, and extracorporeal shockwave therapy, as well as the use of adjunctive therapies such as microbubbles. At a molecular level, it seems that ultrasound transiently generates a local gradient of cytokines, growth factors, and adhesion molecules that facilitate MSC homing. However, the molecular mechanisms underlying these methods are far from fully elucidated and may differ depending on the ultrasound parameters. We thus put forth minimal criteria for ultrasound parameter reporting, in order to ensure reproducibility of studies in the field. A deeper understanding of these mechanisms will enhance our ability to optimize this promising therapy to assist MSC‐based approaches in regenerative medicine.

Impact of Pretransplant Donor BK Viruria in Kidney Transplant Recipients

BACKGROUND

BK virus (BKV) is a significant cause of nephropathy in kidney transplantation. The goal of this study was to characterize the course and source of BKV in kidney transplant recipients.

METHODS

We prospectively collected pretransplant plasma and urine samples from living and deceased kidney donors and performed BKV polymerase chain reaction (PCR) and immunoglobulin G (IgG) testing on pretransplant and serially collected posttransplant samples in kidney transplant recipients.

RESULTS

Among deceased donors, 8.1% (17/208) had detectable BKV DNA in urine prior to organ procurement. BK viruria was observed in 15.4% (6/39) of living donors and 8.5% (4/47) of deceased donors of recipients at our institution (P = .50). BKV VP1 sequencing revealed identical virus between donor-recipient pairs to suggest donor transmission of virus. Recipients of BK viruric donors were more likely to develop BK viruria (66.6% vs 7.8%; P < .001) and viremia (66.6% vs 8.9%; P < .001) with a shorter time to onset (log-rank test, P < .001). Though donor BKV IgG titers were higher in recipients who developed BK viremia, pretransplant donor, recipient, and combined donor/recipient serology status was not associated with BK viremia (P = .31, P = .75, and P = .51, respectively).

CONCLUSIONS

Donor BK viruria is associated with early BK viruria and viremia in kidney transplant recipients. BKV PCR testing of donor urine may be useful in identifying recipients at risk for BKV complications.

Emerging role of stem cell-derived extracellular microRNAs in age-associated human diseases and in different therapies of longevity

Organismal aging involves the progressive decline in organ function and increased susceptibility to age-associated diseases. This has been associated with the aging of stem cell populations within the body that decreases the capacity of stem cells to self-renew, differentiate, and regenerate damaged tissues and organs. This review aims to explore how aging is associated with the dysregulation of stem cell-derived extracellular vesicles (SCEVs) and their corresponding miRNA cargo (SCEV-miRNAs), which are short non-coding RNAs involved in post-transcriptional regulation of target genes. Recent evidence has suggested that in aging stem cells, SCEV-miRNAs may play a vital role regulating various processes that contribute to aging: cellular senescence, stem cell exhaustion, telomere length, and circadian rhythm. Hence, further clarifying the age-dependent molecular mechanisms through which SCEV-miRNAs exert their downstream effects may inform a greater understanding of the biology of aging, elucidate their role in stem cell function, and identify important targets for future regenerative therapies. Additionally, current studies evaluating therapeutic role of SCEVs and SCEV-miRNAs in treating several age-associated diseases are also discussed.

Stem cell-derived extracellular vesicles: role in oncogenic processes, bioengineering potential, and technical challenges

Extracellular vesicles (EVs) are cellular-derived versatile transporters with a specialized property for trafficking a variety of cargo, including metabolites, growth factors, cytokines, proteins, lipids, and nucleic acids, throughout the microenvironment. EVs can act in a paracrine manner to facilitate communication between cells as well as modulate immune, inflammatory, regenerative, and remodeling processes. Of particular interest is the emerging association between EVs and stem cells, given their ability to integrate complex inputs for facilitating cellular migration to the sites of tissue injury. Additionally, stem cell-derived EVs can also act in an autocrine manner to influence stem cell proliferation, mobilization, differentiation, and self-renewal. Hence, it has been postulated that stem cells and EVs may work synergistically in the process of tissue repair and that dysregulation of EVs may cause a loss of homeostasis in the microenvironment leading to disease. By harnessing the property of EVs for delivery of small molecules, stem cell-derived EVs possess significant potential as a platform for developing bioengineering approaches for next-generation cancer therapies and targeted drug delivery methods. Although one of the main challenges of clinical cancer treatment remains a lack of specificity for the delivery of effective treatment options, EVs can be modified via genetic, biochemical, or synthetic methods for enhanced targeting ability of chemotherapeutic agents in promoting tumor regression. Here, we summarize recent research on the bioengineering potential of EV-based cancer therapies. A comprehensive understanding of EV modification may provide a novel strategy for cancer therapy and for the utilization of EVs in the targeting of oncogenic processes. Furthermore, innovative and emerging new technologies are shifting the paradigm and playing pivotal roles by continually expanding novel methods and materials for synthetic processes involved in the bioengineering of EVs for enhanced precision therapeutics.

"I Must Try Harder": Design Implications for Mobile Apps and Wearables Contributing to Self-Efficacy of Patients With Chronic Conditions

Background

Diverse wellness-promoting mobile health technologies, including mobile apps and wearable trackers, became increasingly popular due to their ability to support patients' self-management of health conditions. However, the patient's acceptance and use depend on the perceived experience and the app appropriateness to the patient's context and needs. We have some understating of the experience and factors influencing the use of these technologies in the general public, but we have a limited understanding of these issues in patients.

Objective

By presenting results from an explorative study, this paper aims to identify implications for the design of mobile apps and wearables to effectively support patients' efforts in self-management of health with a special emphasis on support for self-efficacy of activities contributing to health.

Methods

An explorative mixed-method study involving 200 chronically ill patients of Stanford Medical Center (Stanford, CA, United States) was conducted between mid-2016 and end of 2018. Amongst these, 20 patients were involved in a 4-weeks study, in which we collected the underlying wearable device use logs (e.g., Fitbit) and subjective use experience [via an Ecological Momentary Assessment (EMA)], as well as patients' momentary perception of general self-efficacy in their natural environments and different daily contexts.

Results

The results indicate that mobile apps for health and wearables have the potential to enable better self-management and improve patients' wellbeing but must be further refined to address different human aspects of their use. Specifically, the apps/wearables should be easier to use, more personalized and context-aware for the patient's overall routine and lifestyle choices, as well as with respect to the momentary patient state (e.g., location, type of people around) and health(care) needs. Additionally, apps and devices should be more battery efficient and accurate; providing timely, non-judgmental feedback and personalized advice to the patients anywhere-anytime-anyhow. These results are mapped on major sources of the individuals' self-efficacy.

Conclusion

Our results show how the apps/wearables that are aimed at supporting the patients' self-management should be designed to leverage and further improve the patients' general self-efficacy and self-efficacy of activities contributing to chronic disease management.

Two infants with bilateral renal agenesis who were bridged by chronic peritoneal dialysis to kidney transplantation

Bilateral renal agenesis is associated with severe oligohydramnios and was considered incompatible with postnatal life due to severe pulmonary hypoplasia. The use of renal replacement therapy was limited by significant morbidity and mortality associated with dialysis in very young infants with major pulmonary pathology. In the United States, there is a tremendous controversy about whether or not the use of prenatal amniotic fluid infusions provides a benefit to fetuses with bilateral renal agenesis. One of the critical issues identified is that there are, as yet, no children reported who had achieved long-term survival. Previous reports all indicated these children died shortly after birth or after unsuccessful peritoneal dialysis. We present two infants with a prenatal diagnosis of bilateral renal agenesis whose mothers elected to undergo prenatal amnioinfusions. One was born at 28 weeks with a birthweight of 1230 g and the other born at 34 weeks with a birthweight of 1940 g. We present the details of both cases, with initial management on chronic peritoneal dialysis, which started shortly after birth, as a bridge to living related kidney transplants.

Mesenchymal stem cells confer chemoresistance in breast cancer via a CD9 dependent mechanism

The development of chemotherapy drug resistance remains a significant barrier for effective therapy in several cancers including breast cancer. Bone marrow-derived mesenchymal stem cells (BMMSCs) have previously been shown to influence tumor progression and the development of chemoresistance. In the present study, we showed that when GFP labelled BMMSCs and RFP labelled HCC1806 cells are injected together in vivo, they create tumors which contain a new hybrid cell that has characteristics of both BMMSCs and HCC1806 cells. By labelling these cells prior to their injection, we were then able to isolate new hybrid cell from harvested tumors using FACS (DP-HCC1806:BMMSCs). Interestingly, when DP-HCC1806:BMMSCs were then injected into the mammary fat pad of NOD/SCID mice, they produced xenograft tumors which were smaller in size, and exhibited resistance to chemotherapy drugs (i.e. doxorubicin and 5-fluorouracil), when compared tumors from HCC1806 cells alone. This chemoresistance was shown to associated with an increased expression of tetraspanins (CD9, CD81) and drug resistance proteins (BCRP, MDR1). Subsequent siRNA-mediated knockdown of BMMSC-CD9 in DP-HCC1806:BMMSCs resulted in an attenuation of doxorubicin and 5-fluorouracil chemoresistance associated with decreased BCRP and serum cytokine expression (CCL5, CCR5, CXCR12). Our findings suggest that within the tumor microenvironment, CD9 is responsible for the crosstalk between BMMSCs and HCC1806 breast cancer cells (via CCL5, CCR5, and CXCR12) which contributes to chemoresistance. Hence, BMMSC-CD9 may serve as an important therapeutic target for the treatment of breast cancer.

Short-term outcomes of en bloc combined heart and liver transplantation in the failing Fontan

Patients with failing Fontan physiology and liver cirrhosis are being considered for combined heart and liver transplantation. We performed a retrospective review of our experience with en bloc combined heart and liver transplantation in Fontan patients > 10 years old from 2006 to 18 per Institutional Review Board approval. Six females and 3 males (median age 20.7, range 14.2-41.3 years) underwent en bloc combined heart and liver transplantation. Indications for heart transplant included ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, and/or lymphatic abnormalities. Indication for liver transplant included portal hypertension and cirrhosis. Median Fontan/single ventricular end-diastolic pressure was 18/12 mm Hg, respectively. Median Model for End-Stage Liver Disease excluding International Normalized Ratio score was 10 (7-26), eight patients had a varices, ascites, splenomegaly, thrombocytopenia score of ≥ 2, and all patients had cirrhosis. Median cardiopulmonary bypass and donor ischemic times were 262 (178-307) and 287 (227-396) minutes, respectively. Median intensive care and hospital stay were 19 (5-96) and 29 (13-197) days, respectively. Survival was 100%, and rejection was 0% at 30 days and 1 year post-transplant. En bloc combined heart and liver transplantation is an acceptable treatment in the failing Fontan patient with liver cirrhosis.

Ferumoxytol Is Not Retained in Kidney Allografts in Patients Undergoing Acute Rejection

PURPOSE

To evaluate whether ultrasmall superparamagnetic iron oxide nanoparticle (USPIO)-enhanced magnetic resonance imaging (MRI) can detect allograft rejection in pediatric kidney transplant patients.

PROCEDURES

The USPIO ferumoxytol has a long blood half-life and is phagocytosed by macrophages. In an IRB-approved single-center prospective clinical trial, 26 pediatric patients and adolescents (age 10-26 years) with acute allograft rejection (n = 5), non-rejecting allografts (n = 13), and normal native kidneys (n = 8) underwent multi-echo T2* fast spoiled gradient-echo (FSPGR) MRI after intravenous injection (p.i.) of 5 mg Fe/kg ferumoxytol. T2* relaxation times at 4 h p.i. (perfusion phase) and more than 20 h p.i. (macrophage phase) were compared with biopsy results. The presence of rejection was assessed using the Banff criteria, and the prevalence of macrophages on CD163 immunostains was determined based on a semi-quantitative scoring system. MRI and histology data were compared among patient groups using t tests, analysis of variance, and regression analyses with a significance threshold of p < 0.05.

RESULTS

At 4 h p.i., mean T2* values were 6.6 ± 1.5 ms for native kidneys and 3.9 ms for one allograft undergoing acute immune rejection. Surprisingly, at 20-24 h p.i., one rejecting allograft showed significantly prolonged T2* relaxation times (37.0 ms) compared to native kidneys (6.3 ± 1.7 ms) and non-rejecting allografts (7.6 ± 0.1 ms). Likewise, three additional rejecting allografts showed significantly prolonged T2* relaxation times compared to non-rejecting allografts at later post-contrast time points, 25-97 h p.i. (p = 0.008). Histological analysis revealed edema and compressed microvessels in biopsies of rejecting allografts. Allografts with and without rejection showed insignificant differences in macrophage content on histopathology (p = 0.44).

CONCLUSION

After ferumoxytol administration, renal allografts undergoing acute rejection show prolonged T2* values compared to non-rejecting allografts. Since histology revealed no significant differences in macrophage content, the increasing T2* value is likely due to the combined effect of reduced perfusion and increased edema in rejecting allografts.

When does vesicoureteral reflux in pediatric kidney transplant patients need treatment?

PURPOSE

The treatment of VUR in children with UTI has changed significantly, due to studies showing that antibiotic prophylaxis does not decrease renal scarring. As children with kidney transplants are at higher risk for UTI, we investigated if select patients with renal transplant VUR could be managed without surgery.

MATERIALS AND METHODS

A total of 18 patients with VUR into their renal grafts were identified, and 319 patients underwent transplantation from 2006 to 2016. The cause for the detection of the VUR, treatment, and graft function was reviewed.

RESULTS

Six boys and 12 girls were identified, 13 of whom had grade 3 or 4 VUR into the renal graft. Nine patients presented with hydronephrosis or abnormal renal biopsy: eight were successfully managed with antibiotic prophylaxis and bladder training, one developed UTI and underwent Dx/HA subureteric injection. Nine patients presented with recurrent febrile UTI, only one was successfully managed without surgery. Only 2 of 9 (22%) patients who underwent Dx/HA injection had resolution of their reflux. Of the remaining seven, five required open ureteral reimplantation (two for obstruction), one lost the graft due to rejection, and one had significant hydronephrosis. eGFR was similar between the hydronephrosis, UTI, and abnormal renal biopsy groups at all times.

CONCLUSION

Patients with transplant VUR and recurrent febrile UTI are more likely to require surgical therapy, but the complication and failure rate for Dx/HA injection is significant. Patients with transplant VUR without febrile UTI can be successfully managed with bladder training and temporary antibiotic prophylaxis.

1586. Prevalence and Significance of Pre-transplant BK Viremia and Viruria in Deceased and Living Kidney Donors and Kidney Transplant Recipients

Background

BK virus (BKV) is a major cause of nephropathy in kidney transplantation. Pre-transplant BKV shedding in the donor or recipient may increase the risk for developing BKV viremia in kidney transplant recipients.

Methods

From August 2016 to December 2017, we prospectively performed pre-transplant BKV DNA PCR testing on plasma and urine samples from deceased kidney donors procured through Donor Network West, our local organ procurement organization and third largest in the country. We also simultaneously performed pre-transplant BKV DNA PCR testing of plasma and urine from living kidney donors and adult kidney transplant recipients as well as post-transplant surveillance testing of recipients at Stanford University Medical Center.

Results

BKV DNA PCR testing of plasma and urine samples from 212 deceased kidney donors revealed 17 donors that were positive (16 in urine, 1 in plasma; 8.02% BKV DNA detection). Fifty of these specimens went to Stanford kidney transplant recipients, including four donors with BKV viruria (8.00%). During the study period, we obtained complete pre-transplant donor and recipient pairings for 47 deceased and 39 living adult kidney transplant recipients. Of these 86 kidney recipients, none had detectable BKV DNA in pre-transplant donor or recipient plasma specimens, while 10 (four deceased, six living) had BKV DNA detected in the urine. The majority (9/10) were positive in the donor urine, with one positive in the recipient and one in both the recipient and donor. After a minimum follow-up of 5 months, three (30%) had developed BKV viremia, compared with three of the 76 (3.9%, P = 0.009) with negative pre-transplant BKV DNA. The rate of BKV viruria was not significantly different between deceased and living kidney donors (4/47 (8.5%) vs. 6/39 (15.4%), P = 0.32).

Conclusion

In one of the largest cohorts in the United States that also includes deceased donor testing, we demonstrate that pre-transplant BKV viruria, particularly of the donor, is associated with development of BKV viremia in kidney transplant recipients. Pre-transplant BKV DNA screening in the urine of kidney donors (deceased and living) may be useful in predicting risk for BKV viremia.

Disclosures

All authors: No reported disclosures.

Orthotopic Liver Transplantation After Stereotactic Body Radiotherapy for Pediatric Hepatocellular Carcinoma with Central Biliary Obstruction and Nodal Involvement

Here we describe the case of a 10-year-old boy with a history of chronic hepatitis B who was diagnosed with hepatocellular carcinoma (HCC) with a large central hepatic mass and metastatic disease in a celiac lymph node. His tumor was unresectable, due to location and lack of clear margins, and he could not receive chemotherapy due to elevated bilirubin. He was treated with stereotactic body radiotherapy (SBRT) to the primary site and involved nodal region. After completing radiotherapy, his total bilirubin level fell below 1.0 mg/dL, allowing him to begin systemic therapy with cisplatin and doxorubicin. At three months after SBRT, his bilirubin was 0.1 mg/dL, alpha-fetoprotein (AFP) was 88 ng/mL, and imaging demonstrated a decrease in tumor size (total volume 28.7 cc), with no evidence of local or distant disease progression. He then developed distant disease within the liver, but his disease remained controlled at the primary site and nodes that had been treated with SBRT. He underwent orthotopic liver transplantation (OLT) with an uneventful operative course and remains with no evidence of disease at seven months after OLT. This is one of the first reported cases of successful downstaging of pediatric HCC with nodal involvement to allow for OLT, and it argues for consideration of similar patients for OLT.

Transarterial chemoembolization in children to treat unresectable hepatocellular carcinoma

Children with unresectable HCC have a dismal prognosis and few approved treatment options. TACE is an effective treatment option for adults with HCC, but experience in children is very limited. Retrospective analysis was performed of 8 patients aged 4-17 years (4 male, mean 12.5 years) who underwent TACE for unresectable HCC. Response to TACE was evaluated by change in AFP, RECIST and tumor volume, PRETEXT, and transplantation eligibility by UCSF and Milan criteria. Post-procedure mean follow-up was 8.2 years. Mean overall change in tumor volume for the 8 patients was 51%. Percent change in AFP ranged from a decrease of 100% to an increase of 89.3%, with a mean change of -49.6%. Two patients did not undergo resection or transplantation and died of progressive disease. Six patients underwent orthotopic liver transplantation with mean first TACE-to-transplant interval of 141 days (range 11-514). Following transplantation, 5 patients were alive at the end of the follow-up period and one died of recurrent disease. Based on our initial experience, TACE for children with unresectable HCC appears to be a safe and effective method for managing hepatic tumor burden and for downstaging and bridging to liver transplantation.

Prenatal treatment of ornithine transcarbamylase deficiency

PURPOSE OF STUDY

Patients with neonatal urea cycle defects (UCDs) typically experience severe hyperammonemia during the first days of life, which results in serious neurological injury or death. Long-term prognosis despite optimal pharmacological and dietary therapy is still poor. The combination of intravenous sodium phenylacetate and sodium benzoate (Ammonul®) can eliminate nitrogen waste independent of the urea cycle. We report attempts to improve outcomes for males with severe ornithine transcarbamylase deficiency (OTCD), a severe X-linked condition, via prenatal intravenous administration of Ammonul and arginine to heterozygous carrier females of OTCD during labor.

METHODS USED

Two heterozygote OTCD mothers carrying male fetuses with a prenatal diagnosis of OTCD received intravenous Ammonul, arginine and dextrose-containing fluids shortly before birth. Maintenance Ammonul and arginine infusions and high-caloric enteral nutrition were started immediately after birth. Ammonul metabolites were measured in umbilical cord blood and the blood of the newborn immediately after delivery. Serial ammonia and biochemical analyses were performed following delivery.

SUMMARY OF RESULTS

Therapeutic concentrations of Ammonul metabolites were detected in umbilical cord and neonatal blood samples. Plasma ammonia and glutamine levels in the postnatal period were within the normal range. Peak ammonia levels in the first 24-48h were 53mcmol/l and 62mcmol/l respectively. The boys did not experience neurological sequelae secondary to hyperammonemia and received liver transplantation at ages 3months and 5months. The patients show normal development at ages 7 and 3years.

CONCLUSION

Prenatal treatment of mothers who harbor severe OTCD mutations and carry affected male fetuses with intravenous Ammonul and arginine, followed by immediate institution of maintenance infusions after delivery, results in therapeutic levels of benzoate and phenylacetate in the newborn at delivery and, in conjunction with high-caloric enteral nutrition, prevents acute hyperammonemia and neurological decompensation. Following initial medical management, early liver transplantation may improve developmental outcome.

Fatal Emmonsia sp. Infection and Fungemia after Orthotopic Liver Transplantation

We report a fatal case of disseminated Emmonsia sp. infection in a 55-year-old man who received an orthotopic liver transplant. The patient had pneumonia and fungemia, and multisystem organ failure developed. As human habitats and the number of immunocompromised patients increase, physicians must be aware of this emerging fungal infection.

Stereotactic body radiotherapy for pediatric hepatocellular carcinoma with central biliary obstruction

Here, we present the case of a pediatric patient with newly diagnosed hepatocellular carcinoma causing central biliary obstruction and persistently elevated bilirubin of 3.0-4.3 mg/dl despite placement of bilateral internal-external biliary drains. The tumor was not resectable, and the patient was not a candidate for liver transplant due to nodal disease, for chemotherapy due to hyperbilirubinemia, or for local therapies aside from stereotactic body radiotherapy (SBRT). In this report, we discuss the successful use of SBRT in the management of this patient, and its role in allowing the patient to become a candidate for additional therapies.

Perioperative management of pediatric en-bloc combined heart-liver transplants: a case series review

BACKGROUND

Combined heart and liver transplantation (CHLT) in the pediatric population involves a complex group of patients, many of whom have palliated congenital heart disease (CHD) involving single ventricle physiology.

OBJECTIVE

The purpose of this study was to describe the perioperative management of pediatric patients undergoing CHLT at a single institution and to identify management strategies that may be used to optimize perioperative care.

METHODS

We did a retrospective database review of all patients receiving CHLT at a children's hospital between 2006 and 2014. Information collected included preoperative characteristics, intraoperative management, blood transfusions, and postoperative morbidity and mortality.

RESULTS

Five pediatric CHLTs were performed over an 8-year period. All patients had a history of complex CHD with multiple sternotomies, three of whom had failing Fontan physiology. Patient age ranged from 7 to 23 years and weight from 29.5 to 68.5 kg. All CHLTs were performed using an en-bloc technique where both the donor heart and liver were implanted together on cardiopulmonary bypass (CPB). The median operating room time was 14.25 h, median CPB time was 3.58 h, and median donor ischemia time was 4.13 h. Patients separated from CPB on dopamine, epinephrine, and milrinone infusions and two required inhaled nitric oxide. All patients received a massive intraoperative blood transfusion post CPB with amounts ranging from one to three times the patient's estimated blood volume. The patient who required the most transfusions was in decompensated heart and liver failure preoperatively. Four of the five patients received an antifibrinolytic agent as well as a procoagulant (prothrombin complex concentrate or recombinant activated Factor VII) to assist with hemostasis. There were no 30-day thromboembolic events detected. Postoperatively the median length of mechanical ventilation, ICU stay and stay to hospital discharge was 4, 8, and 37 days, respectively. All patients are alive and free from allograft rejection at this time.

CONCLUSION

Combined heart and liver transplantation in the pediatric population involves a complex group of patients with unique perioperative challenges. Successful management starts with thorough preoperative planning and communication and involves strategies to deal with massive intraoperative hemorrhage and coagulopathy in addition to protecting and supporting the transplanted heart and liver and meticulous surgical technique. An integrated multidisciplinary team approach is the cornerstone for successful outcomes.

Effect of Liver Transplant on Long-term Disease-Free Survival in Children With Hepatoblastoma and Hepatocellular Cancer

INTRODUCTION

Hepatoblastoma (HBL) and hepatocellular cancer (HCC) are the most common primary hepatic malignant neoplasms in childhood. Given the rarity of these childhood tumors and their propensity to present at advanced stages, updated long-term data are needed.

OBJECTIVE

To determine the efficacy of liver transplant in children with HBL or HCC.

DESIGN, PARTICIPANTS, AND SETTING

This single-institution retrospective medical record review and analysis spanned from January 1, 1997, through September 17, 2014, at Stanford University School of Medicine. A total of 40 patients younger than 18 years underwent liver transplant for treatment of HBL (n = 30) or HCC (n = 10) during the study period, with follow-up until September 17, 2014. Patients who underwent transplant for HCC included those with tumors that were greater in size than what is proposed by the Milan (a single tumor measuring ≤5 cm or ≤3 nodules measuring ≤3 cm) and University of California, San Francisco (single tumor measuring ≤6.5 cm or ≤3 nodules measuring ≤4.5 cm and a total diameter of ≤8 cm), criteria.

MAIN OUTCOMES AND MEASURES

Disease-free and overall patient survival and graft survival.

RESULTS

Using a Kaplan-Meier survival analysis, 1-, 5-, and 10-year disease-free survival after liver transplant was 93%, 82%, and 82%, respectively, for 30 patients with HBL and 90%, 78%, and 78%, respectively, for 10 patients with HCC. Risk factors associated with HBL recurrence after transplant included having pretreatment extent of disease stage IV lesions and a longer waiting list time and being older at the time of the transplant. Recurrence was found in 2 of 7 patients with HBL and pretransplant metastases, which were not found to be an independent risk factor for recurrence. Patients with HCC larger than the proposed Milan and University of California, San Francisco, criteria experienced good 5-year disease-free (82%) and overall (78%) survival after transplant. Being older at the time of transplant (18 vs 11 years; P = .04) and the presence of metastatic disease (1 patient vs none; P = .05) were associated with HCC tumor recurrence.

CONCLUSIONS AND RELEVANCE

Liver transplant combined with chemotherapy is an excellent treatment that provides long-term disease-free survival in children diagnosed with advanced HBL and HCC. Early addition to a waiting list and aggressive multimodal therapy provide excellent results. Transplant should still be considered in children with HCC larger than the Milan and University of California, San Francisco, criteria.

Cysteamine in renal transplantation: A report of two patients with nephropathic cystinosis and the successful re-initiation of cysteamine therapy during the immediate post-transplant period

Nephropathic cystinosis is a rare disorder causing the accumulation of intracellular cystine crystals in tissues. The damage to the proximal tubules of the kidneys results in Fanconi syndrome, and patients with cystinosis experience the progression of chronic kidney disease, resulting in the need for kidney transplantation. Treatment of cystinosis with cysteamine has proven to be effective; however, it has many gastrointestinal side effects that are concerning for transplant specialists during the immediate post-transplant period. Transplant specialists routinely discontinue cysteamine therapy for up to six weeks to ensure proper immunosuppressant absorption. This practice is worrisome because it communicates the acceptability of lapses of cysteamine treatment to patients. It may be better to re-initiate cysteamine therapy shortly after transplantation while the patient is followed more closely by the transplant team. This report presents two pediatric patients with nephropathic cystinosis who successfully restarted cysteamine therapy in the immediate post-transplant period without issue in regard to immunosuppression absorption or gastrointestinal side effects. These cases challenge current practice of discontinuing cysteamine therapy during kidney transplantation, and immediate re-initiation of cysteamine therapy in cystinosis patients post-transplant should be considered.

Arterial flow regulator enables transplantation and growth of human fetal kidneys in rats

Here we introduce a novel method of transplanting human fetal kidneys into adult rats. To overcome the technical challenges of fetal-to-adult organ transplantation, we devised an arterial flow regulator (AFR), consisting of a volume adjustable saline-filled cuff, which enables low-pressure human fetal kidneys to be transplanted into high-pressure adult rat hosts. By incrementally withdrawing saline from the AFR over time, blood flow entering the human fetal kidney was gradually increased until full blood flow was restored 30 days after transplantation. Human fetal kidneys were shown to dramatically increase in size and function. Moreover, rats which had all native renal mass removed 30 days after successful transplantation of the human fetal kidney were shown to have a mean survival time of 122 days compared to 3 days for control rats that underwent bilateral nephrectomy without a prior human fetal kidney transplant. These in vivo human fetal kidney models may serve as powerful platforms for drug testing and discovery.

Treatment of methylmalonic acidemia by liver or combined liver-kidney transplantation

OBJECTIVE

To assess biochemical, surgical, and long-term outcomes of liver (LT) or liver-kidney transplantation (LKT) for severe, early-onset methylmalonic acidemia/acid (MMA).

STUDY DESIGN

A retrospective chart review (December 1997 to May 2012) of patients with MMA who underwent LT or LKT at Lucile Packard Children's Hospital at Stanford.

RESULTS

Fourteen patients underwent LT (n = 6) or LKT (n = 8) at mean age 8.2 years (range 0.8-20.7). Eleven (79%) were diagnosed during the neonatal period, including 6 by newborn screening. All underwent deceased donor transplantation; 12 (86%) received a whole liver graft. Postoperative survival was 100%. At a mean follow-up of 3.25 ± 4.2 years, patient survival was 100%, liver allograft survival 93%, and kidney allograft survival 100%. One patient underwent liver re-transplantation because of hepatic artery thrombosis. After transplantation, there were no episodes of hyperammonemia, acidosis, or metabolic decompensation. The mean serum MMA at the time of transplantation was 1648 ± 1492 μmol/L (normal <0.3, range 99-4420). By 3 days, post-transplantation levels fell on average by 87% (mean 210 ± 154 μmol/L), and at 4 months, they were 83% below pre-transplantation levels (mean 305 ± 108 μmol/L). Developmental delay was present in 12 patients (86%) before transplantation. All patients maintained neurodevelopmental abilities or exhibited improvements in motor skills, learning abilities, and social functioning.

CONCLUSIONS

LT or LKT for MMA eradicates episodes of hyperammonemia, results in excellent long-term survival, and suggests stabilization of neurocognitive development. Long-term follow-up is underway to evaluate whether patients who undergo early LT need kidney transplantation later in life.

Immune cell function assay does not identify biopsy-proven pediatric renal allograft rejection or infection

Management of pediatric renal transplant patients involves multifactorial monitoring modalities to ensure allograft survival and prevent opportunistic infection secondary to immunosuppression. An ICFA, which utilizes CD4 T-cell production of ATP to assess immune system status, has been used to monitor transplant recipients and predict susceptibility of patients to rejection or infection. However, the validity of this assay to reflect immune status remains unanswered. In a two-yr retrospective study that included 31 pediatric renal transplant recipients, 42 patient blood samples were analyzed for immune cell function levels, creatinine, WBC (white blood cell) count, immunosuppressive drug levels, and viremia, concurrent with renal biopsy. T-cell ATP production as assessed by ICFA levels did not correlate with allograft rejection or with the presence or absence of viremia. ICFA levels did not correlate with serum creatinine or immunosuppressive drug levels, but did correlate with WBC count. The ICFA is unreliable in its ability to reflect immune system status in pediatric renal transplantation. Further investigation is necessary to develop methods that will accurately predict susceptibility of pediatric renal transplant recipients to allograft rejection and infection.

Improved survival outcomes in patients with non-alcoholic steatohepatitis and alcoholic liver disease following liver transplantation: an analysis of 2002-2012 United Network for Organ Sharing data

There is an increasing trend of patients with hepatocellular carcinoma (HCC) and non-alcoholic fatty liver disease undergoing liver transplantation in the US. Our study utilized data from the 2002 to 2012 United Network for Organ Sharing registry to evaluate model for end-stage liver disease era trends in US liver transplantations focused on patients with non-alcoholic steatohepatitis (NASH), hepatitis C (HCV), alcoholic liver disease (ALD), and HCC. Survival outcomes were stratified by liver disease etiology and compared across time periods using Kaplan-Meier and Cox proportional hazards models. Patients with NASH were more likely to be women, had higher body mass index (BMI), and had higher prevalence of diabetes and cardiac disease. However, overall long-term survival was significantly higher in patients with NASH and ALD (p < 0.001). Compared to HCV, patients with NASH had significantly higher post-transplantation survival (HR 0.69, 95% CI 0.63-0.77), and lower risk of graft failure (HR 0.76, 95% CI 0.69-0.83). Despite having higher BMI and higher prevalence of diabetes and cardiac disease, patients with NASH had better post-liver transplantation survival compared to patients with HCV or HCC. Patients with ALD also had superior survival outcomes. However, these survival differences were limited to patients without HCC that underwent liver transplantation.

Primary surgical resection versus liver transplantation for transplant-eligible hepatocellular carcinoma patients

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of mortality worldwide. Existing studies comparing outcomes after liver transplantation (LT) versus surgical resection among transplant-eligible patients are conflicting.

AIM

The purpose of this study was to compare long-term survival between consecutive transplant-eligible HCC patients treated with resection versus LT.

METHODS

The present retrospective matched case cohort study compares long-term survival outcomes between consecutive transplant-eligible HCC patients treated with resection versus LT using intention-to-treat (ITT) and as-treated models. Resection patients were matched to LT patients by age, sex, and etiology of HCC in a 1:2 ratio.

RESULTS

The study included 171 patients (57 resection and 114 LT). Resection patients had greater post-treatment tumor recurrence (43.9 vs. 12.9 %, p < 0.001) compared to LT patients. In the as-treated model of the pre-model for end stage liver disease (MELD) era, LT patients had significantly better 5-year survival compared to resection patients (100 vs. 69.5 %, p = 0.04), but no difference was seen in the ITT model. In the multivariate Cox proportional hazards model, inclusive of age, sex, ethnicity, tumor stage, and MELD era (pre-MELD vs. post-MELD), treatment with resection was an independent predictor of poorer survival (HR 2.72; 95 % CI, 1.08-6.86).

CONCLUSION

Transplant-eligible HCC patients who received LT had significantly better survival than those treated with resection, suggesting that patients who can successfully remain on LT listing and actually undergo LT have better outcomes.

Liver transplantation for urea cycle disorders in pediatric patients: a single-center experience

LT has emerged as a surgical treatment for UCDs. We hypothesize that LT can be safely and broadly utilized in the pediatric population to effectively prevent hyperammonemic crises and potentially improve neurocognitive outcomes. To determine the long-term outcomes of LT for UCDs, charts of children with UCD who underwent LT were retrospectively reviewed at an academic institution between July 2001 and May 2012. A total of 23 patients with UCD underwent LT at a mean age of 3.4 yr. Fifteen (65%) patients received a whole-liver graft, seven patients (30%) received a reduced-size graft, and one patient received a living donor graft. Mean five-yr patient survival was 100%, and allograft survival was 96%. Mean peak blood ammonia (NH(3) ) at presentation was 772 μmol/L (median 500, range 178-2969, normal <30-50). After transplantation, there were no episodes of hyperammonemia. Eleven patients were diagnosed with some degree of developmental delay before transplantation, which remained stable or improved after transplantation. Patients without developmental delay before transplantation maintained their cognitive abilities at long-term follow-up. LT was associated with the eradication of hyperammonemia, removal of dietary restrictions, and potentially improved neurocognitive development. Long-term follow-up is underway to evaluate whether LT at an early age (<1 yr) will attain improved neurodevelopmental outcomes.

Rituximab treatment for recurrence of nephrotic syndrome in a pediatric patient after renal transplantation for congenital nephrotic syndrome of Finnish type

Congenital nephrotic syndrome (CNS) of the Finnish type due to mutation in the NPHS-1 gene results in massive proteinuria due to structural abnormality in the glomerular slit diaphragm, and is usually refractory to immunosuppressive therapy. Patients eventually require bilateral nephrectomy and renal replacement therapy, with transplantation being the ultimate goal. Post-transplant recurrence of nephrotic syndrome occurs in about 25% of children and is thought to be immune-mediated secondary to antibodies formed against the nephrin protein in renal allograft. Conventional therapy with calcineurin inhibitors (CNI), cyclophosphamide and corticosteroids with or without plasmapheresis often fails to achieve remission resulting in graft loss in 12-16%. There is limited experience with use of rituximab (RTX) in pediatric organ transplant recipients. We report the first case of post-transplant recurrence of nephrotic syndrome in a 4-yr-old child with CNS due to NPHS-1 mutation in whom CNI, corticosteroid and cyclophosphamide therapy was unsuccessful, but who achieved remission after depletion of B cells with RTX, associated with a decrease in the level of anti-nephrin antibodies. The child remains in remission 5 yr following treatment. Our experience suggests that activated B cells may play a pivotal role in the recurrence of nephrosis after renal transplantation in children with CNS.

Pediatric combined heart-liver transplantation performed en bloc: a single-center experience

Pediatric CHLT is rarely performed in transplant centers and even fewer are performed en bloc. In the hands of an experienced surgeon with the appropriate patient selection, CHLT performed en bloc may have several operative and immunologic benefits, thereby resulting in improved outcomes for the transplant recipient. A single-institutional, retrospective review from 1/1/06 to 12/31/10 was conducted. Three pediatric patients with end-stage heart and liver disease who were considered low immunologic risk were included. All were managed by the same surgeon with a herein-described CHLT donor and recipient operation. Data were collected on patient and graft survival, rejection episodes, infectious complications, operative time, intraoperative transfusion requirements, and immunosuppression regimens. One-yr patient and graft survival rates were 100%. No patients experienced antibody-mediated or cell-mediated rejection. No patients had postoperative infections, and all patients were free of opportunistic infections at one-yr post-transplant. All patients were maintained safely on steroid-free immunosuppression. There were no intraoperative complications. In pediatric end-stage heart and liver disease patients with low immunologic risk, it is reasonable to proceed with en bloc CHLT so long as there is an experienced surgeon to perform the case. This offers operative and immunologic advantages to the recipient while maintaining equivalent, if not improved, recipient and graft outcomes.