Intranasal pediatric parainfluenza virus-vectored SARS-CoV-2 vaccine is protective in monkeys.

Pediatric SARS-CoV-2 vaccines are needed that elicit immunity directly in the airways as well as systemically. Building on pediatric parainfluenza virus vaccines in clinical development, we generated a live-attenuated parainfluenza-virus-vectored vaccine candidate expressing SARS-CoV-2 prefusion-stabilized spike (S) protein (B/HPIV3/S-6P) and evaluated its immunogenicity and protective efficacy in rhesus macaques. A single intranasal/intratracheal dose of B/HPIV3/S-6P induced strong S-specific airway mucosal immunoglobulin A (IgA) and IgG responses. High levels of S-specific antibodies were also induced in serum, which efficiently neutralized SARS-CoV-2 variants of concern of alpha, beta, and delta lineages, while their ability to neutralize Omicron sub-lineages was lower. Furthermore, B/HPIV3/S-6P induced robust systemic and pulmonary S-specific CD4+ and CD8+ T cell responses, including tissue-resident memory cells in the lungs. Following challenge, SARS-CoV-2 replication was undetectable in airways and lung tissues of immunized macaques. B/HPIV3/S-6P will be evaluated clinically as pediatric intranasal SARS-CoV-2/parainfluenza virus type 3 vaccine.

Systematic Discovery of Short Linear Motifs Decodes Calcineurin Phosphatase Signaling.

Short linear motifs (SLiMs) drive dynamic protein-protein interactions essential for signaling, but sequence degeneracy and low binding affinities make them difficult to identify. We harnessed unbiased systematic approaches for SLiM discovery to elucidate the regulatory network of calcineurin (CN)/PP2B, the Ca2+-activated phosphatase that recognizes LxVP and PxIxIT motifs. In vitro proteome-wide detection of CN-binding peptides, in vivo SLiM-dependent proximity labeling, and in silico modeling of motif determinants uncovered unanticipated CN interactors, including NOTCH1, which we establish as a CN substrate. Unexpectedly, CN shows SLiM-dependent proximity to centrosomal and nuclear pore complex (NPC) proteins-structures where Ca2+ signaling is largely uncharacterized. CN dephosphorylates human and yeast NPC proteins and promotes accumulation of a nuclear transport reporter, suggesting conserved NPC regulation by CN. The CN network assembled here provides a resource to investigate Ca2+ and CN signaling and demonstrates synergy between experimental and computational methods, establishing a blueprint for examining SLiM-based networks.

Human parainfluenza virus 3 vaccine candidates attenuated by codon-pair deoptimization are immunogenic and protective in hamsters.

Human parainfluenza virus type 3 (HPIV3) is a major pediatric respiratory pathogen lacking available vaccines or antiviral drugs. We generated live-attenuated HPIV3 vaccine candidates by codon-pair deoptimization (CPD). HPIV3 open reading frames (ORFs) encoding the nucleoprotein (N), phosphoprotein (P), matrix (M), fusion (F), hemagglutinin-neuraminidase (HN), and polymerase (L) were modified singly or in combination to generate 12 viruses designated Min-N, Min-P, Min-M, Min-FHN, Min-L, Min-NP, Min-NPM, Min-NPL, Min-PM, Min-PFHN, Min-MFHN, and Min-PMFHN. CPD of N or L severely reduced growth in vitro and was not further evaluated. CPD of P or M was associated with increased and decreased interferon (IFN) response in vitro, respectively, but had little effect on virus replication. In Vero cells, CPD of F and HN delayed virus replication, but final titers were comparable to wild-type (wt) HPIV3. In human lung epithelial A549 cells, CPD F and HN induced a stronger IFN response, viral titers were reduced 100-fold, and the expression of F and HN proteins was significantly reduced without affecting N or P or the relative packaging of proteins into virions. Following intranasal infection in hamsters, replication in the nasal turbinates and lungs tended to be the most reduced for viruses bearing CPD F and HN, with maximum reductions of approximately 10-fold. Despite decreased in vivo replication (and lower expression of CPD F and HN in vitro), all viruses induced titers of serum HPIV3-neutralizing antibodies similar to wt and provided complete protection against HPIV3 challenge. In summary, CPD of HPIV3 yielded promising vaccine candidates suitable for further development.

Intranasal respiratory syncytial virus vaccine attenuated by codon-pair deoptimization of seven open reading frames is genetically stable and elicits mucosal and systemic immunity and protection against challenge virus replication in hamsters.

Respiratory syncytial virus (RSV) is the most important viral agent of severe pediatric respiratory illness worldwide, but there is no approved pediatric vaccine. Here, we describe the development of the live-attenuated RSV vaccine candidate Min AL as well as engineered derivatives. Min AL was attenuated by codon-pair deoptimization (CPD) of seven of the 11 RSV open reading frames (ORFs) (NS1, NS2, N, P, M, SH and L; 2,073 silent nucleotide substitutions in total). Min AL replicated efficiently in vitro at the permissive temperature of 32°C but was highly temperature sensitive (shut-off temperature of 36°C). When serially passaged at increasing temperatures, Min AL retained greater temperature sensitivity compared to previous candidates with fewer CPD ORFs. However, whole-genome deep-sequencing of passaged Min AL revealed mutations throughout its genome, most commonly missense mutations in the polymerase cofactor P and anti-termination transcription factor M2-1 (the latter was not CPD). Reintroduction of selected mutations into Min AL partially rescued its replication in vitro at temperatures up to 40°C, confirming their compensatory effect. These mutations restored the accumulation of positive-sense RNAs to wild-type (wt) RSV levels, suggesting increased activity by the viral transcriptase, whereas viral protein expression, RNA replication, and virus production were only partly rescued. In hamsters, Min AL and derivatives remained highly restricted in replication in the upper and lower airways, but induced serum IgG and IgA responses to the prefusion form of F (pre F) that were comparable to those induced by wt RSV, as well as robust mucosal and systemic IgG and IgA responses against RSV G. Min AL and derivatives were fully protective against challenge virus replication. The derivatives had increased genetic stability compared to Min AL. Thus, Min AL and derivatives with selected mutations are stable, attenuated, yet highly-immunogenic RSV vaccine candidates that are available for further evaluation.

Blockade of GluN2B-containing NMDA receptors prevents potentiation and depression of responses during ocular dominance plasticity.

Monocular deprivation (MD) causes an initial decrease in synaptic responses to the deprived eye in juvenile mouse primary visual cortex (V1) through Hebbian long-term depression (LTD). This is followed by a homeostatic increase, which has been attributed to either synaptic scaling and to a slide threshold for Hebbian long-term potentiation (LTP) rather than scaling. We therefore asked in mice of all sexes whether the homeostatic increase during MD requires GluN2B-containing NMDA receptor activity, which is required to slide the plasticity threshold but not for synaptic scaling. Selective GluN2B blockade from 2-6d after monocular lid suture prevented the homeostatic increase in miniature excitatory postsynaptic current (mEPSC) amplitude in monocular V1 of acute slices and prevented the increase in visually evoked responses in binocular V1 in vivo. The decrease in mEPSC amplitude and visually evoked responses during the first 2d of MD also required GluN2B activity. Together, these results support the idea that GluN2B-containing NMDA receptors first play a role in LTD immediately following eye closure, and then promote homeostasis during prolonged MD by sliding the plasticity threshold in favor of LTP.Significance Statement Since first documented by Hubel and Wiesel, the changes in cortical ocular dominance induced by monocular deprivation (MD) have become a paradigmatic model to study experience-dependent plasticity. In juvenile rodents, brief MD induces a rapid reduction of cortical responses to the deprived eye followed by an enhanced response to the fellow eye. Although the initial response reduction is widely thought to involve NMDAR-dependent LTD, the processes underlying the late enhancement phase are still debatable. Two mechanisms have been proposed. The first is metaplasticity, in the form of a reduced induction threshold for NMDAR-dependent LTP following increased GluN2B-containing synaptic NMDARs. The second is an NMDAR-independent homeostatic synaptic scaling mechanism. Here, we show that blocking GluN2B-containing NMDARs is sufficient to prevent the late enhancement of non-deprived eye responses. Moreover, we found that GluN2B is also necessary for the initial depression of deprived eye responses. These findings not only give experimental support to the metaplasticity scenario for late cortical changes, but also underscore a crucial role for GluN2B in the entire ocular dominance plasticity process.

Helicobacter pylori Treatment and Gastric Cancer Risk After Endoscopic Resection of Dysplasia: A Nationwide Cohort Study.

BACKGROUND & AIMS: The study investigated the association between Helicobacter pylori treatment and the risk of gastric cancer after endoscopic resection of gastric dysplasia. METHODS: Patients who received endoscopic resection for gastric dysplasia between 2010 and 2020 from Korean nationwide insurance data were included. We verified the occurrence of new-onset gastric cancer and metachronous gastric neoplasm, which encompasses both cancer and dysplasia, >1 year after the index endoscopic resection. Newly diagnosed gastric cancer ≥3 years and ≥5 years was regarded as late-onset gastric cancer. A multivariable Cox regression model with H pylori treatment status as a time-dependent covariate was used to determine the risk of gastric cancer and metachronous gastric neoplasms. RESULTS: Gastric dysplasia in 69,722 patients was treated with endoscopy, and 49.5% were administered H pylori therapy. During the median 5.6 years of follow-up, gastric cancer developed in 2406 patients and metachronous gastric neoplasms developed in 3342 patients. Receiving H pylori therapy was closely related to lower gastric cancer risk (adjusted hazard ratio [aHR], 0.88; 95% confidence interval [CI], 0.80-0.96). H pylori treatment also significantly decreased metachronous gastric neoplasm development (aHR, 0.76; 95% CI, 0.70-0.82). Furthermore, H pylori therapy showed a prominent protective effect for late-onset gastric cancer development at ≥3 years (aHR, 0.84; 95% CI, 0.75-0.94) and ≥5 years (aHR, 0.80; 95% CI, 0.68-0.95). CONCLUSIONS: In this nationwide cohort, H pylori therapy after endoscopic resection of gastric dysplasia was associated with a reduced risk of gastric cancer and metachronous gastric neoplasm occurrence.

Periodontitis promotes bacterial extracellular vesicle-induced neuroinflammation in the brain and trigeminal ganglion.

Gram-negative bacteria derived extracellular vesicles (EVs), also known as outer membrane vesicles, have attracted significant attention due to their pathogenic roles in various inflammatory diseases. We recently demonstrated that EVs secreted by the periodontopathogen Aggregatibacter actinomycetemcomitans (Aa) can cross the blood-brain barrier (BBB) and that their extracellular RNA cargo can promote the secretion of proinflammatory cytokines, such as IL-6 and TNF-α, in the brain. To gain more insight into the relationship between periodontal disease (PD) and neuroinflammatory diseases, we investigated the effect of Aa EVs in a mouse model of ligature-induced PD. When EVs were administered through intragingival injection or EV-soaked gel, proinflammatory cytokines were strongly induced in the brains of PD mice. The use of TLR (Toll-like receptor)-reporter cell lines and MyD88 knockout mice confirmed that the increased release of cytokines was triggered by Aa EVs via TLR4 and TLR8 signaling pathways and their downstream MyD88 pathway. Furthermore, the injection of EVs through the epidermis and gingiva resulted in the direct retrograde transfer of Aa EVs from axon terminals to the cell bodies of trigeminal ganglion (TG) neurons and the subsequent activation of TG neurons. We also found that the Aa EVs changed the action potential of TG neurons. These findings suggest that EVs derived from periodontopathogens such as Aa might be involved in pathogenic pathways for neuroinflammatory diseases, neuropathic pain, and other systemic inflammatory symptoms as a comorbidity of periodontitis.

Live-attenuated pediatric parainfluenza vaccine expressing 6P-stabilized SARS-CoV-2 spike protein is protective against SARS-CoV-2 variants in hamsters.

The pediatric live-attenuated bovine/human parainfluenza virus type 3 (B/HPIV3)-vectored vaccine expressing the prefusion-stabilized SARS-CoV-2 spike (S) protein (B/HPIV3/S-2P) was previously evaluated in vitro and in hamsters. To improve its immunogenicity, we generated B/HPIV3/S-6P, expressing S further stabilized with 6 proline mutations (S-6P). Intranasal immunization of hamsters with B/HPIV3/S-6P reproducibly elicited significantly higher serum anti-S IgA/IgG titers than B/HPIV3/S-2P; hamster sera efficiently neutralized variants of concern (VoCs), including Omicron variants. B/HPIV3/S-2P and B/HPIV3/S-6P immunization protected hamsters against weight loss and lung inflammation following SARS-CoV-2 challenge with the vaccine-matched strain WA1/2020 or VoCs B.1.1.7/Alpha or B.1.351/Beta and induced near-sterilizing immunity. Three weeks post-challenge, B/HPIV3/S-2P- and B/HPIV3/S-6P-immunized hamsters exhibited a robust anamnestic serum antibody response with increased neutralizing potency to VoCs, including Omicron sublineages. B/HPIV3/S-6P primed for stronger anamnestic antibody responses after challenge with WA1/2020 than B/HPIV3/S-2P. B/HPIV3/S-6P will be evaluated as an intranasal vaccine to protect infants against both HPIV3 and SARS-CoV-2.

Pure laparoscopic donor hepatectomy: Experience of 556 cases at Seoul National University Hospital.

Pure laparoscopic donor hepatectomy (PLDH) has become a routine procedure at Seoul National University Hospital, and the pure laparoscopic method is now being applied to liver recipients as well. This study aimed to review the procedure and outcomes of PLDH to identify any areas that required improvement. Data from 556 donors who underwent PLDH between November 2015 and December 2021 and their recipients were retrospectively reviewed. Among these, 541 patients underwent pure laparoscopic donor right hepatectomy (PLDRH). The mean hospital stay of the donor was 7.2 days, and the rate of grade I, II, IIIa, and IIIb complications was 2.2%, 2.7%, 1.3%, and 0.9%, respectively, without any irreversible disabilities or mortalities. The most common early and late major complications in the recipient were intraabdominal bleeding (n = 47, 8.5%) and biliary problems (n = 198, 35.6%), respectively. Analysis of the PLDRH procedure showed that operative time, liver removal time, warm ischemic time, Δhemoglobin%, Δtotal bilirubin%, and postoperative hospital stay decreased significantly as the number of cases accumulated. In conclusion, the operative outcomes of PLDRH improved as the number of cases increased. However, continuous caution is needed because major complications still occur in donors and recipients even after hundreds of cases.

Combined liver-kidney transplantation in pediatric patients.

Combined liver-kidney transplantation (CLKT) is a surgical procedure that involves transplanting both liver and kidney organs. There are two types of CLKT: simultaneous liver-kidney transplantation (smLKT) and sequential LKT (sqLKT). CLKT accounts for a small percentage of liver transplantations (LTs), particularly in pediatric cases. Nevertheless, the procedure has demonstrated excellent outcomes, with high survival rates and lower rejection rates. The main indications for CLKT in pediatric patients differ somewhat from that in adults, in which end-stage kidney disease after LT is the major indication. In children, congenital diseases are common reason for performing CLKT; the examples of such diseases include autosomal recessive polycystic kidney disease with congenital hepatic fibrosis which equally affects both organs, and primary hyperoxaluria type 1, a primary liver disease leading kidney failure. The decision between smLKT or sqLKT depends on the dominant organ failure, the specific pathophysiology, and available organ sources. However, there remain significant surgical and societal challenges surrounding CLKT. Innovations in pharmacology and genetic engineering have decreased the necessity for CLKT in early-diagnosed cases without portal hypertension or kidney replacement therapy. Nonetheless, these advancements are not universally accessible. Therefore, decision-making algorithms should be crafted, considering region-specific organ allocation systems and prevailing medical environments.

All-or-none disconnection of pyramidal inputs onto parvalbumin-positive interneurons gates ocular dominance plasticity.

Disinhibition is an obligatory initial step in the remodeling of cortical circuits by sensory experience. Our investigation on disinhibitory mechanisms in the classical model of ocular dominance plasticity uncovered an unexpected form of experience-dependent circuit plasticity. In the layer 2/3 of mouse visual cortex, monocular deprivation triggers a complete, "all-or-none," elimination of connections from pyramidal cells onto nearby parvalbumin-positive interneurons (Pyr→PV). This binary form of circuit plasticity is unique, as it is transient, local, and discrete. It lasts only 1 d, and it does not manifest as widespread changes in synaptic strength; rather, only about half of local connections are lost, and the remaining ones are not affected in strength. Mechanistically, the deprivation-induced loss of Pyr→PV is contingent on a reduction of the protein neuropentraxin2. Functionally, the loss of Pyr→PV is absolutely necessary for ocular dominance plasticity, a canonical model of deprivation-induced model of cortical remodeling. We surmise, therefore, that this all-or-none loss of local Pyr→PV circuitry gates experience-dependent cortical plasticity.

A single intranasal dose of a live-attenuated parainfluenza virus-vectored SARS-CoV-2 vaccine is protective in hamsters.

Single-dose vaccines with the ability to restrict SARS-CoV-2 replication in the respiratory tract are needed for all age groups, aiding efforts toward control of COVID-19. We developed a live intranasal vector vaccine for infants and children against COVID-19 based on replication-competent chimeric bovine/human parainfluenza virus type 3 (B/HPIV3) that express the native (S) or prefusion-stabilized (S-2P) SARS-CoV-2 S spike protein, the major protective and neutralization antigen of SARS-CoV-2. B/HPIV3/S and B/HPIV3/S-2P replicated as efficiently as B/HPIV3 in vitro and stably expressed SARS-CoV-2 S. Prefusion stabilization increased S expression by B/HPIV3 in vitro. In hamsters, a single intranasal dose of B/HPIV3/S-2P induced significantly higher titers compared to B/HPIV3/S of serum SARS-CoV-2-neutralizing antibodies (12-fold higher), serum IgA and IgG to SARS-CoV-2 S protein (5-fold and 13-fold), and IgG to the receptor binding domain (10-fold). Antibodies exhibited broad neutralizing activity against SARS-CoV-2 of lineages A, B.1.1.7, and B.1.351. Four weeks after immunization, hamsters were challenged intranasally with 104.5 50% tissue-culture infectious-dose (TCID50) of SARS-CoV-2. In B/HPIV3 empty vector-immunized hamsters, SARS-CoV-2 replicated to mean titers of 106.6 TCID50/g in lungs and 107 TCID50/g in nasal tissues and induced moderate weight loss. In B/HPIV3/S-immunized hamsters, SARS-CoV-2 challenge virus was reduced 20-fold in nasal tissues and undetectable in lungs. In B/HPIV3/S-2P-immunized hamsters, infectious challenge virus was undetectable in nasal tissues and lungs; B/HPIV3/S and B/HPIV3/S-2P completely protected against weight loss after SARS-CoV-2 challenge. B/HPIV3/S-2P is a promising vaccine candidate to protect infants and young children against HPIV3 and SARS-CoV-2.

The Risk of Hypertension and Diabetes Mellitus According to Offspring's Birthweight in Women With Normal Body Mass Index: A Nationwide Population-Based Study.

BACKGROUND: Maladaptation to vascular, metabolic, and physiological changes during pregnancy can lead to fetal growth disorders. Moreover, adverse outcomes during pregnancy can further increase the risk of cardiovascular and metabolic diseases in mothers. Delivering a large-for-gestational-age (LGA) baby may indicate a pre-existing metabolic dysfunction, whereas delivering a small-for-gestational-age (SGA) baby may indicate a pre-existing vascular dysfunction. This study aims to assess the risk of hypertension (HTN) and diabetes mellitus (DM) in women with normal body mass index (BMI) scores who did not experience gestational DM or hypertensive disorders during pregnancy based on the offspring's birthweight. METHODS: This retrospective nationwide study included women with normal BMI scores who delivered a singleton baby after 37 weeks. Women with a history of DM or HTN before pregnancy and those with gestational DM or hypertensive disorders, were excluded from the study. We compared the risk of future maternal outcomes (HTN and DM) according to the offspring's birthweight. Multivariate analyses were performed to estimate the hazard ratio (HR) for the future risk of HTN or DM. RESULTS: A total of 64,037 women were included in the analysis. Of these, women who delivered very LGA babies (birthweight > 97th percentile) were at a higher risk of developing DM than those who delivered appropriate-for-gestational-age (AGA) babies (adjusted HR = 1.358 [1.068-1.727]), and women who delivered very SGA babies (birthweight < 3rd percentile) were at a higher risk of developing HTN than those who delivered AGA babies (adjusted HR = 1.431 [1.181-1.734]), even after adjusting for age, parity, gestational age at delivery, fetal sex, maternal BMI score, and a history of smoking. CONCLUSION: These findings provide a novel support for the use of the offspring's birthweight as a predictor of future maternal diseases such as HTN and DM.

The fate and prospects of stem cell therapy in the treatment of hypoxic-ischemic encephalopathy.

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of long-term neurological disability in neonates and adults. Despite emerging advances in supportive care, like the most effective approach, hypothermia, poor prognosis has still been present in current clinical treatment for HIE. Stem cell therapy has been adopted for treating cerebral ischemia in preclinical and clinical trials, displaying its promising therapeutic value. At present, reported treatments for stroke employed stem cells to replace the lost neurons and integrate them into the existing host circuitry, promoting the release of growth factors to support and stimulate endogenous repair processes and so on. In this review, a meaningful overview to numerous studies published up to now was presented by introducing the preclinical and clinical research status of stem cell therapy for cerebral ischemia and hypoxia, discussing potential therapeutic mechanisms of stem cell transplantation for curing HI-induced brain injury, summarizing a series of approaches for marking transplanted cells and existing imaging systems for stem cell labelling and in vivo tracking and expounding the endogenous regeneration capability of stem cells in the newborn brain when subjected to an HI insult. Additionally, it is promising to combine stem therapy with neuromodulation through specific regulation of neural circuits. The crucial neural circuits across different brain areas related to functional recovery are of great significance for the application of neuromodulation strategies after the occurrence of neonatal hypoxic-ischemic encephalopathy (NHIE).

Evaluation of a biotin-based surrogate virus neutralization test for detecting postvaccination antibodies against SARS-CoV-2 variants in sera.

A severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) surrogate virus neutralization test (sVNT) was used to determine the degree of inhibition of binding between human angiotensin converting enzyme 2 (hACE2) and the receptor binding domain (RBD) of spike protein by neutralizing antibodies in a biosafety level 2 facility. Here, to improve the sensitivity and specificity of the commercial sVNT, we developed a new biotin based sVNT using biotinylated RBD and HRP conjugated streptavidin instead of HRP conjugated RBD for direct detection in an ELISA assay that strongly correlated to the FDA approved cPass sVNT commercial kit (R2 = 0.8521) and pseudo virus neutralization test (R2 = 0.9006) (pVNT). The biotin based sVNT was evaluated in 535 postvaccination serum samples corresponding to second and third boosts of AZD1222 and BNT162b2 vaccines of the wild type strain. We confirmed that the neutralizing antibodies against SARS-CoV-2 variants in second vaccination sera decreased after a median of 141.5 days. Furthermore, vaccination sera from BNT162b2-BNT162b2 vaccines maintained neutralizing antibodies for longer than those of AZD1222 only vaccination. In addition, both vaccines maintained high neutralizing antibodies in third vaccination sera against Omicron BA.2 after a median of 27 days, but neutralizing antibodies significantly decreased after a median of 141.5 days. Along with the cPass sVNT commercial kit, biotin based sVNTs may also be suitable for specifically detecting neutralizing antibodies against multiple SARS-CoV-2 variants; however, to initially monitor the neutralizing antibodies in vaccinated sera using high throughput screening, conventional PRNT could be replaced by sVNT to circumvent the inconvenience of a long test time.

Initial outcome of external biliary drainage in living donor liver transplantation with pure laparoscopic donor hepatectomy.

Biliary complications after living donor liver transplantation (LDLT) are the most common and intractable complications due to both surgical and nonsurgical factors. External biliary drainage (EBD), a surgical option to prevent biliary complications, has recently been adopted in the era of pure laparoscopic donor right hepatectomy, which may result in increased bile duct problems in the recipients. This study retrospectively reviewed the patients who underwent LDLT with duct-to-duct anastomosis between July 2017 and October 2020 to analyze the initial outcomes of EBD and to compare the incidence of biliary complications in adult LDLT recipients who underwent duct-to-duct anastomosis with or without EBD. Only patients who underwent pure laparoscopic donor hepatectomy were included in this study. The patients were divided into 2 groups according to the application of EBD. The median follow-up period was 28.5 months. The overall incidence of Clavien-Dindo grade IIIa biliary complications was 35.0% (n=14) in the EBD group and 50.7% (n=76) in the non-EBD group ( p = 0.08). The incidence of biliary leakage was 0% in the EBD group and 15.3% in the non-EBD group ( p = 0.01). The EBD-related complication rate, that is, involving retraction, accidental removal, and dislocation, was 40.0%. EBD implementation is effective in preventing biliary leakage after LDLT with a graft procured using the pure laparoscopic donor right hepatectomy method with duct-to-duct biliary anastomosis. However, efforts should be made to prevent EBD-related complications. Further studies are needed to establish appropriate selection criteria for EBD.

Anatomical classification and clinical outcomes of biliary strictures in living donor liver transplantation using right liver grafts.

This study aimed to classify the anatomical types of biliary strictures, including intrahepatic biliary stricture (IHBS), after living donor liver transplantations (LDLTs) using right liver grafts and evaluate their prognosis. Among 692 adult patients who underwent right liver LDLT, 198 recipients with biliary strictures (28.6%) were retrospectively reviewed. Based on data obtained during the first cholangiography, the patients' biliary strictures were classified into the following three types according to the levels and number of branches involved: Types 1 (anastomosis), 2 (second-order branch [a, one; b, two or more; c, extended to the third-order branch]), and 3 (whole graft [a, multifocal strictures; b, diffuse necrosis]). IHBS was defined as a nonanastomotic stricture. Among the 198 recipients with biliary strictures, the IHBS incidence rates were 38.4% ( n = 76). The most common type of IHBS was 2c ( n = 43, 56.6%), whereas Type 3 ( n = 10, 13.2%) was uncommon. The intervention frequency per year significantly differed among the types (Type 1, 2.3; Type 2a, 2.3; Type 2b, 2.8; Type 2c, 4.3; and Type 3, 7.2; p < 0.001). The intervention-free period for more than 1 year, which was as follows, also differed among the types: Type 1, 84.4%; Type 2a, 87.5%; Type 2b, 86.7%; Type 2c, 72.1%; and Type 3, 50.0% ( p = 0.048). The graft survival rates of Type 3 (80.0%) were significantly lower than those of the other types ( p = 0.001). IHBSs are relatively common in right liver LDLTs. Although Type 3 IHBSs are rare, they require more intensive care and are associated with poorer graft survival rates than anastomosis strictures and Type 2 IHBS.

Early experiences with developing techniques for pure laparoscopic explant hepatectomy in living donor liver transplantation.

In recent years, laparoscopic techniques for liver resection or living donor hepatectomy have become common surgical methods. However, reports on laparoscopic surgeries for recipients are lacking. Our center has launched the minimally invasive living donor liver transplantation (LDLT) program in March 2020, which is led by two surgeons who are experienced in laparoscopic surgeries. Recently, we reported our first successful pure laparoscopic recipient explant hepatectomy and the first laparoscopic explant hepatectomy and robotic-assisted graft implantation. In this article, we introduce a series of minimally invasive surgical cases that were conducted by a single experienced surgeon to share our early experiences leading to our recent successes. We included 10 cases performed from June 2020 to May 2021 in our initial attempt at laparoscopic explant hepatectomy, graft implantation using midline incision, and robotic-assisted graft implantation surgery. The first four cases required open conversion during the liver mobilization process because of bleeding. The next two cases required open conversion to facilitate portal vein and hepatic artery division. We successfully performed pure laparoscopic explant hepatectomy in the last four cases. For the last case, we attempted to perform graft implantation using a robotic system, but bleeding required open conversion. All patients recovered without any significant acute postoperative problems and were discharged within 2 weeks. All 10 patients were followed up at outpatient clinics, and only one of the 10 patients had a late complication of LDLT. This study has shown that the minimally invasive approach in LDLT may be conducted safely without significant complications if it is performed by highly experienced surgeons working in high-volume centers.

Redo hepatic artery reconstruction for thrombosis without retransplantation in 1355 adult living donor liver transplantations.

Hepatic artery thrombosis (HAT) after liver transplantation is associated with a marked increase in morbidity, leading to graft and patient loss. We evaluated the outcomes of adult living donor liver transplantation patients with HAT under an aggressive surgical intervention. A total of 1355 recipients underwent adult living donor liver transplantation at the Seoul National University Hospital. Surgical redo reconstruction for HAT was performed in all cases except in those with graft hepatic artery injury and late detection of HAT. Postoperative HAT developed in 33 cases (2.4%) at a median time of 3.5 days. Thirty patients (90.9%) underwent redo-arterial reconstruction. The survival rates in patients with HAT were similar to the rates in those without HAT (72.7% vs. 83.8%, p = 0.115). Although graft survival rates were lower in patients with HAT (84.8%) than in those without HAT (98.0%) ( p < 0.001), the graft survival rate was comparable (92.0% vs. 98.0%, p = 0.124) in the 25 patients with successful revascularization. Biliary complication rates were higher in patients with HAT (54.5%) than in those without HAT (32.0%) ( p = 0.008). In conclusion, the successful redo reconstruction under careful selection criteria saved the graft without retransplantation in 96.0% of the cases. Surgical revascularization should be preferentially considered for the management of HAT in adult living donor liver transplantation.

Pure laparoscopic donor right hepatectomy in patients over 50 years old: Why age should not be a barrier.

INTRODUCTION: Given the global aging population, the average age of liver donors is increasing. This study aimed to evaluate the surgical outcomes of grafts from pure laparoscopic donor right hepatectomy (PLDRH) in liver donors aged > 50 years. METHODS: The medical records of liver donors were retrospectively reviewed. The donors underwent conventional donor right hepatectomy (CDRH) from January 2011 to May 2019 or PLDRH from March 2016 to May 2019. We divided the donors into three groups: PLDRH donors aged ≥50 (n = 26; Group 1) and aged < 50 (n = 257; Group 2), and CDRH donors aged ≥50 years (n = 66; Group 3). RESULTS: Operation time (p < .01) and hospital stay (p < .01) were significantly lower in Group 1 than in Group 3. Other postoperative outcomes of donors including graft anatomical variation, graft weight, graft-to-recipient weight ratio, and hepatic steatosis were similar among the three groups. Although no postoperative complications occurred in Groups 1 and 3, they were detected in 17 cases (6.6%) in Group 2. No postoperative complications were detected among the recipients. CONCLUSIONS: PLDRH was feasible and safe in donors aged over 50 years, with outcomes similar to those for donors aged <50 years. PLDRH should not be avoided solely based on the donor's age ≥50 years.