Noninvasive graft monitoring using donor-derived cell-free DNA in Japanese liver transplantation

AIM

To evaluate the use of donor-derived cell-free DNA (dd-cfDNA) in diagnosing graft injuries in Japanese liver transplantation (LTx), including family-related living donors.

METHODS

A total of 321 samples from 10 newly operated LTx recipients were collected to monitor the early dynamics of dd-cfDNA levels after LTx. Fifty-five samples from 55 recipients were collected during protocol biopsies (PB), whereas 36 samples from 27 recipients were collected during event biopsies, consisting of 11 biopsy-proven acute rejection (AR), 20 acute dysfunctions without rejection (ADWR), and 5 chronic rejections. The levels of dd-cfDNA were quantified using a next-generation sequencer based on single nucleotide polymorphisms.

RESULTS

The dd-cfDNA levels were elevated significantly after LTx, followed by a rapid decline to the baseline in patients without graft injury within 30 days post-LTx. The dd-cfDNA levels were significantly higher in the 11 samples obtained during AR than those obtained during PB (p < 0.0001), which decreased promptly after treatment. The receiver operator characteristic curve analysis of diagnostic ability yielded areas under the curve of 0.975 and 0.897 for AR (rejection activity index [RAI] ≥3) versus PB and versus non-AR (ADWR + PB). The dd-cfDNA levels during AR were elevated earlier and correlated more strongly with the RAI (r = 0.740) than aspartate aminotransferase/alanine aminotransferase. The dd-cfDNA levels were neither associated with graft fibrosis based on histology nor the status of donor-specific antibodies in PB samples.

CONCLUSIONS

Donor-derived cell-free DNA serves as a sensitive biomarker for detecting graft injuries in LTx. Further large-scale cohort studies are warranted to optimize its use in differentiating various post-LTx etiologies.

All That Glitters in cfDNA Analysis Is Not Gold or Its Utility Is Completely Established Due to Graft Damage: A Critical Review in the Field of Transplantation

In kidney transplantation, a biopsy is currently the gold standard for monitoring the transplanted organ. However, this is far from an ideal screening method given its invasive nature and the discomfort it can cause the patient. Large-scale studies in renal transplantation show that approximately 1% of biopsies generate major complications, with a risk of macroscopic hematuria greater than 3.5%. It would not be until 2011 that a method to detect donor-derived cell-free DNA (dd-cfDNA) employing digital PCR was devised based on analyzing the differences in SNPs between the donor and recipient. In addition, since the initial validation studies were carried out at the specific moments in which rejection was suspected, there is still not a good understanding of how dd-cfDNA levels naturally evolve post-transplant. In addition, various factors, both in the recipient and the donor, can influence dd-cfDNA levels and cause increases in the levels of dd-cfDNA themselves without suspicion of rejection. All that glitters in this technology is not gold; therefore, in this article, we discuss the current state of clinical studies, the benefits, and disadvantages.

Ascending aortic graft penetration by fractured sternal wire: A word of caution

The fractured sternal wire is a relatively common postoperative finding after sternotomy. However, fractured wires have the potential of surrounding organ injury, which can be fatal. Here, we describe the successful surgical treatment of ascending aortic penetration by fractured sternal wire.

Higher levels of allograft injury in black patients early after heart transplantation

Black patients suffer higher rates of antibody-mediated rejection and have worse long-term graft survival after heart transplantation. Donor-derived cell free DNA (ddcfDNA) is released into the blood following allograft injury. This study analyzed %ddcfDNA in 63 heart transplant recipients categorized by Black and non-Black race, during the first 200 days after transplant. Immediately after transplant, %ddcfDNA was higher for Black patients (mean [SE]: 8.3% [1.3%] vs 3.2% [1.2%], p = 0.001). In the first week post-transplant, the rate of decay in %ddcfDNA was similar (0.7% [0.68] vs 0.7% [0.11], p = 0.78), and values declined in both groups to a comparable plateau at 7 days post-transplant (0.46% [0.03] vs 0.45% [0.04], p = 0.78). The proportion of Black patients experiencing AMR was higher than non-Black patients (21% vs 9% [hazard ratio of 2.61 [95% confidence interval: 0.651-10.43], p = 0.18). Black patients were more likely to receive a race mismatched organ than non-Black patients (69% vs 35%, p = 0.01), which may explain the higher levels of early allograft injury.

Cell-Free DNA to Detect Heart Allograft Acute Rejection

BACKGROUND

After heart transplantation, endomyocardial biopsy (EMBx) is used to monitor for acute rejection (AR). Unfortunately, EMBx is invasive, and its conventional histological interpretation has limitations. This is a validation study to assess the performance of a sensitive blood biomarker-percent donor-derived cell-free DNA (%ddcfDNA)-for detection of AR in cardiac transplant recipients.

METHODS

This multicenter, prospective cohort study recruited heart transplant subjects and collected plasma samples contemporaneously with EMBx for %ddcfDNA measurement by shotgun sequencing. Histopathology data were collected to define AR, its 2 phenotypes (acute cellular rejection [ACR] and antibody-mediated rejection [AMR]), and controls without rejection. The primary analysis was to compare %ddcfDNA levels (median and interquartile range [IQR]) for AR, AMR, and ACR with controls and to determine %ddcfDNA test characteristics using receiver-operator characteristics analysis.

RESULTS

The study included 171 subjects with median posttransplant follow-up of 17.7 months (IQR, 12.1-23.6), with 1392 EMBx, and 1834 %ddcfDNA measures available for analysis. Median %ddcfDNA levels decayed after surgery to 0.13% (IQR, 0.03%-0.21%) by 28 days. Also, %ddcfDNA increased again with AR compared with control values (0.38% [IQR, 0.31-0.83%], versus 0.03% [IQR, 0.01-0.14%]; P<0.001). The rise was detected 0.5 and 3.2 months before histopathologic diagnosis of ACR and AMR. The area under the receiver operator characteristic curve for AR was 0.92. A 0.25%ddcfDNA threshold had a negative predictive value for AR of 99% and would have safely eliminated 81% of EMBx. In addition, %ddcfDNA showed distinctive characteristics comparing AMR with ACR, including 5-fold higher levels (AMR ≥2, 1.68% [IQR, 0.49-2.79%] versus ACR grade ≥2R, 0.34% [IQR, 0.28-0.72%]), higher area under the receiver operator characteristic curve (0.95 versus 0.85), higher guanosine-cytosine content, and higher percentage of short ddcfDNA fragments.

CONCLUSIONS

We found that %ddcfDNA detected AR with a high area under the receiver operator characteristic curve and negative predictive value. Monitoring with ddcfDNA demonstrated excellent performance characteristics for both ACR and AMR and led to earlier detection than the EMBx-based monitoring. This study supports the use of %ddcfDNA to monitor for AR in patients with heart transplant and paves the way for a clinical utility study. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070.

Monoacylglycerol Acyltransferase 1 Knockdown Exacerbates Hepatic Ischemia/Reperfusion Injury in Mice With Hepatic Steatosis

Nonalcoholic fatty liver disease (NAFLD) is becoming the most common indication for liver transplantation. The growing prevalence of NAFLD not only increases the demand for liver transplantation, but it also limits the supply of available organs because steatosis predisposes grafts to ischemia/reperfusion injury (IRI) and many steatotic grafts are discarded. We have shown that monoacylglycerol acyltransferase (MGAT) 1, an enzyme that converts monoacylglycerol to diacylglycerol, is highly induced in animal models and patients with NAFLD and is an important mediator in NAFLD-related insulin resistance. Herein, we sought to determine whether Mogat1 (the gene encoding MGAT1) knockdown in mice with hepatic steatosis would reduce liver injury and improve liver regeneration following experimental IRI. Antisense oligonucleotides (ASO) were used to knockdown the expression of Mogat1 in a mouse model of NAFLD. Mice then underwent surgery to induce IRI. We found that Mogat1 knockdown reduced hepatic triacylglycerol accumulation, but it unexpectedly exacerbated liver injury and mortality following experimental ischemia/reperfusion surgery in mice on a high-fat diet. The increased liver injury was associated with robust effects on the hepatic transcriptome following IRI including enhanced expression of proinflammatory cytokines and chemokines and suppression of enzymes involved in intermediary metabolism. These transcriptional changes were accompanied by increased signs of oxidative stress and an impaired regenerative response. We have shown that Mogat1 knockdown in a mouse model of NAFLD exacerbates IRI and inflammation and prolongs injury resolution, suggesting that Mogat1 may be necessary for liver regeneration following IRI and that targeting this metabolic enzyme will not be an effective treatment to reduce steatosis-associated graft dysfunction or failure.

Graft injury and re-transplantation in liver transplant patients with COVID-19

This article discusses the current scene of liver transplantation (LT) in light of the impact of COVID-19, with particular emphasis on the possibility of graft injury and re-transplantation in LT patients infected with SARS-CoV-2. A major concern is whether such patients experience a more severe form of disease which may lead to a higher risk of acute, irreversible liver injury. If this is serious, it may necessitate re-transplantation. This article aims to raise awareness in this relatively under-researched domain. More studies are required to evaluate this issue since it has strong implications in healthcare resource allocation and clinical decision-making. Several potential research directions are proposed, including the possibility of prolonging bridging therapy for non-urgent LT cases: patients with hepatocellular carcinoma; and whether hepatoprotective agents play a role in liver-sparing during SARS-CoV-2 infection. There is also substantial discussion of the relevance of lung injury in LT patients with COVID-19 since it is not uncommon regarding the high expression of ACE2 receptors in the lungs, and that lung injury remains the major cause of death in patients with chronic liver disease.

Determining the incidence of needle-related complications in hemodialysis access: We need a better system

INTRODUCTION

Hemodialysis access complications are common. We hypothesize that many of these complications can be traced back to needle-related injury from routine cannulation practices or inadvertent cannulation injuries. We set out to compare the rates of hemodialysis access complications under prior and current diagnosis coding systems, determine the incidence of needle-related complications for hemodialysis access, and describe the association of needle-related complications and resulting interventions.

METHODS

Arteriovenous graft and arteriovenous fistula placements occurring in the first 6 months of 2014 and 2016 were identified in the United States Renal Data System Medicare claims data. Placements were followed until end of hemodialysis access life or end of the calendar year. Diagnoses and resulting interventions occurring during placement life were identified and mapped to needle-related complication terms.

RESULTS

Almost 30,000 placements for 27,000 patients were followed in each year, with 67% of all accesses placed being arteriovenous fistula and 33% arteriovenous graft. In both years, 75% of arteriovenous fistulae and arteriovenous grafts required one or more interventions. Stenosis and thrombosis were the most common complications diagnosed and treated (41% and 16%, respectively); however, potential needle-related complications accounted for 6% of this dataset.

DISCUSSION

International Classification of Diseases, 9th Revision, was inadequate for determining the incidence of specific hemodialysis access complications or needle-related complications. International Classification of Diseases, 10th Revision, introduced several more hemodialysis access diagnoses but is still subject to coding confusion and catch-all coding for a variety of common and otherwise well-defined complications, suggesting that the true incidence of needle-related complications is buried in the non-specific diagnosis codes. These findings mark the clear need for an improved diagnosis coding system that consistently represents all common hemodialysis access complications.

Use of a novel immediate access dialysis graft designed to prevent needle-related complications: A first-in-man case report

Currently, there is no vascular access that possesses all ideal qualities for hemodialysis access, but attributes particularly lacking include: ease of identification (cannulation zone), ease of access, resistance to stenosis, durable to repetitive cannulation, resistance to infection, resistance to acute needle-related injuries, and instant hemostasis. The overall value of these attributes could be appreciated in the reduction of complications (patient burden and suffering, which can also result in increased healthcare costs), and improved safety and durability. In this case report, we present a novel hemodialysis access graft that has the potential to provide the following benefits: it is designed to be self-sealing and immediately usable post implant, easy to identify, easy to access, has more durable cannulation zones, and protects from needle-related injuries. This case report describes the first-in-man use of this novel graft technology to replace a giant, thrombotic, and difficult-to-access arteriovenous fistula to provide the patient with a potentially safer and more durable access that does not require placement of a bridging dialysis catheter. This single-patient experience suggests that implantation and function of this novel graft as a hemodialysis access is feasible in a human subject with end-stage renal disease, and it suggests that the novel properties (i.e. immediate use, easy identification, easy use, cannulation zone durability, and protection from needle-related injuries) of this graft seem to function as intended.

Risk of Secondary ACL Injury in Adolescents Prescribed Functional Bracing After ACL Reconstruction

Background:

There is a high incidence of a secondary anterior cruciate ligament (ACL) injury in unbraced adolescent athletes. Little is known about the effect of functional bracing with regard to the risk of secondary ACL injuries among adolescents.

Hypothesis:

Our primary hypothesis was that adolescents would have a high rate of secondary ACL injury even with brace use. A secondary hypothesis was that the reinjury rate with brace use would be lower than that of a historical control group of unbraced patients.

Study Design:

Case series; Level of evidence, 4.

Methods:

A group of 219 patients (age <20 years at surgery) who underwent ACL reconstruction and were prescribed postoperative functional bracing during cutting and pivoting sports for 2 years after surgery completed a survey regarding reinjury to either knee. Rates of knee injuries following ACL reconstruction were calculated and compared with those reported in a similar unbraced cohort. The effect of demographic and anatomic factors on risk of secondary ACL injuries was also investigated.

Results:

The overall follow-up rate was 65% (142/219) at a mean 5.6 years after surgery. In the braced cohort, the overall graft retear rate was 10%, with the highest retear rates observed in male patients 17 years of age and younger (18%). The overall contralateral ACL injury and combined (graft or contralateral ACL) secondary injury rates were 13% and 23%, respectively, with female patients younger than 18 years having the highest contralateral and combined injury rates (17% and 26%, respectively). Younger age (odds ratio [OR], 0.70; P = .021), family history of ACL injury (OR, 2.81; P = .015), and higher lateral tibial slope (OR, 1.25; P = .016) were associated with increased risk of secondary knee injury in the braced cohort. Compared with the unbraced cohort, the braced cohort had a lower overall graft retear rate (P = .028), a lower graft retear rate in patients younger than 18 years (P = .012), lower early graft retear rate (within the first year after surgery) (P = .011), and lower early graft retear rate in subjects younger than 18 years (P = .003).

Conclusion:

Postoperative use of functional bracing can result in reduced risk of graft retear and no change in contralateral injury rates. Clinicians may want to consider the use of postoperative functional bracing in adolescent patients.

An immediate access dialysis graft designed to prevent needle-related complications: Results from the initial pre-clinical studies

INTRODUCTION

No technology has been specifically developed with the intent to reduce needle-related vascular access injuries; a significant source of complications and abandonment. We present the initial pre-clinical study results of a novel, self-sealing, immediate cannulation dialysis graft that aims to prevent needle-related complications; to promote safe, reliable needle access; to reduce catheter use; and could facilitate home hemodialyisis.

METHODS

The innovative graft design consists of two cannulation chambers with self-sealing properties and materials that prevent side and back wall needle puncture. Study and control grafts (expanded polytetrafluoroethylene) were implanted in one pig and 10 sheep in two studies over the course of 1 year. First cannulation occurred immediately post implant for all study grafts. Post-cannulation time to hemostasis, hematoma and seroma formation, infection, and patency were recorded.

RESULTS

The two studies account for nearly 60 weeks (average 6.4 weeks/graft) of study graft follow-up. In the ovine study, average study graft time to hemostasis was 27.3 s (standard deviation = 26.3, range = 0-120), and the control averaged 177.2 s (standard deviation = 113.4, range = 60-600), p < 0.0001. Secondary patency was 75% and 67% for the study and control grafts, respectively. Neither study nor control groups experienced seroma, graft infections, or deaths.

DISCUSSION

All novel grafts in the studies were implanted successfully and functioned as intended. There were no complications related to tunneling of the study graft and the chamber prevented back/side wall needle injury. This novel technology may help to mitigate these needle-related complications, while allowing for early/immediate cannulation which could also reduce catheter contact time.

Application of graft-derived cell-free DNA in ornithine transcarbamylase deficiency patient after living donor liver transplantation: Two case reports

RATIONALE

Graft-derived-cell-free DNA (Gcf-DNA) in plasma was a promising biomarker to monitor graft-rejection after liver transplantation. However, little is known about the application of Gcf-DNA in living-donor-liver-transplantation (LDLT).

PATIENTS CONCERN

In this study, 2 patients diagnosed with Ornithine Transcarbamylase Deficiency (OTCD) were enrolled and indicated for LDLT.

DIAGNOSES

Two patients were genetically diagnosed with OTCD, and they suffered from recurrent and uncontrollable hyper-ammonemia and failed in accepting the normalized OTCD treatments, such as decreasing dietary nitrogen intake and increasing waste-nitrogen excretion.

INTERVENTIONS

LDLT was performed in the 2 patients uneventfully, and we collected circulating cell-free DNA from plasma in specific postoperative time points (day 1, day 7, day 14, day 30, day 60). Since both of the recipients were sex-mismatch with the donors, we measured Gcf-DNA through the Y-chromosome method and compared it with the routine liver function.

OUTCOMES

The result showed that Gcf-DNA had the similar discrimination of graft injury trend while compared to routine liver function. The follow-up showed these 2 patients' status is stable.

LESSONS

Applying Gcf-DNA to monitor graft injury in LDLT is promising, but still long term follow-up and more samples are needed for validation.

The impact of diet-induced hepatic steatosis in a murine model of hepatic ischemia/reperfusion injury

The prevalence of obesity-associated nonalcoholic fatty liver disease has significantly increased over the past decade, and end-stage liver disease secondary to nonalcoholic steatohepatitis has become 1 of the most common indications for liver transplantation. This both increases the demand for organs and decreases the availability of donor livers deemed suitable for transplantation. Although in the past many steatotic livers were discarded due to concerns over enhanced susceptibility to ischemia/reperfusion injury (IRI) and organ failure, the discrepancy between supply and demand has resulted in increasing use of expanded criteria donor organs including steatotic livers. However, it remains controversial whether steatotic livers can be safely used for transplantation and how best to improve the performance of steatotic grafts. We aimed to evaluate the impact of diet-induced hepatic steatosis in a murine model of IRI. Using a diet of high trans-fat, fructose, and cholesterol (HTF-C) and a diet high in saturated fats, sucrose, and cholesterol (Western diet), we were able to establish models of mixed macrovesicular and microvesicular steatosis (HTF-C) and microvesicular steatosis (Western). We found that the presence of hepatic steatosis, whether it is predominantly macrovesicular or microvesicular, significantly worsens IRI as measured by plasma alanine aminotransferase levels and inflammatory cytokine concentration, and histological evaluation for necrosis. Additionally, we report on a novel finding in which hepatic IRI in the setting of steatosis results in the induction of the necroptosis factors, receptor interacting protein kinase (RIPK) 3, RIPK1, and mixed-lineage kinase domain-like. These data lay the groundwork for additional experimentation to test potential therapeutic approaches to limit IRI in steatotic livers by using a genetically tractable system. Liver Transplantation 24 908-921 2018 AASLD.

Anterior Cruciate Ligament Injury, Reconstruction, and the Optimization of Outcome

Anterior cruciate ligament reconstruction (ACLR) provides an established surgical intervention to control pathological tibiofemoral translational and rotational movement. ACLR is a safe and reproducible intervention, but there remains an underlying rate of failure to return to preinjury sporting activity levels. Postoperative pathological laxity and graft reinjury remain concerns. Previously, unrecognized meniscal lesions, disruption of the lateral capsule, and extracapsular structures offer potential avenues to treat and to therefore improve kinematic outcome and functional results, following reconstruction. Addressing laterally based injuries may also improve the durability of intraarticular ACLR. Improving the anterior cruciate ligament (ACL) graft replication of the normal ACL attachment points on the femur and the tibia, using either double bundle or anatomical single bundle techniques, improves kinematics, which may benefit outcome and functionality, following reconstruction.

Interferon-gamma inducible protein 10 (IP10) induced cisplatin resistance of HCC after liver transplantation through ER stress signaling pathway

Tumor recurrence remains an obstacle after liver surgery, especially in living donor liver transplantation (LDLT) for patients with hepatocellular carcinoma (HCC). The acute-phase liver graft injury might potentially induce poor response to chemotherapy in recurrent HCC after liver transplantation. We here intended to explore the mechanism and to identify a therapeutic target to overcome such chemoresistance. The associations among graft injury, overexpression of IP10 and multidrug resistant genes were investigated in a rat liver transplantation model, and further validated in clinical cohort. The role of IP10 on HCC cell proliferation and tumor growth under chemotherapy was studied both in vitro and in vivo. The underlying mechanism was revealed by detecting the activation of endoplasmic reticulum (ER) stress signaling pathways. Moreover, the effect of IP10 neutralizing antibody sensitizing cisplatin treatment was further explored. In rat liver transplantation model, significant up-regulation of IP10 associated with multidrug resistant genes was found in small-for-size liver graft. Clinically, high expression of circulating IP10 was significant correlated with tumor recurrence in HCC patients underwent LDLT. Overexpression of IP10 promoted HCC cell proliferation and tumor growth under cisplatin treatment by activation of ATF6/Grp78 signaling. IP10 neutralizing antibody sensitized cisplatin treatment in nude mice. The overexpression of IP10, which induced by liver graft injury, may lead to cisplatin resistance via ATF6/Grp78 ER stress signaling pathway. IP10 neutralizing antibody could be a potential adjuvant therapy to sensitize cisplatin treatment.

The impact of surveillance and rapid reduction in immunosuppression to control BK virus-related graft injury in kidney transplantation

We prospectively screened 609 consecutive kidney (538) and kidney-pancreas (71) transplant recipients for BK viremia over a 4-year interval using polymerase chain reaction viral load detection and protocol kidney biopsies. We found that BK viremia is common at our center: total cases 26.7%, cases during first year 21.3% (mean 4 months), and recipients with ≥ 10 000 copies/ml 12.3%. We found few predictive clinical or demographic risk factors for any BK viremia or viral loads ≥ 10,000 copies/ml, other than prior treatment of biopsy confirmed acute rejection and/or higher immunosuppressive blood levels of tacrolimus (P = 0.001) or mycophenolate mofetil (P = 0.007). Viral loads at diagnosis (<10 000 copies/ml) demonstrated little impact on graft function or survival. However, rising copy numbers demand early reductions in immunosuppressive drug doses of at least 30-50%. Viral loads >185 000 copies/ml at diagnosis were predictive of BK virus-associated nephropathy (BKVAN; OR: 113.25, 95% CI: 17.22-744.6, P < 0.001). Surveillance for BK viremia and rapid reduction of immunosuppression limited the incidence of BKVAN to 1.3%. The addition of leflunomide or ciprofloxacin to immunosuppressive dose reduction did not result in greater rates of viral clearance. These data support the role of early surveillance for BK viremia to limit the impact on transplant outcome, although the most effective schedule for screening awaits further investigation.