Published papers

The S2 alar-iliac screw (S2AIS) is commonly used for long spinal fusion as a rigid distal foundation in spinal deformity surgeries, and it is also used in percutaneous sacropelvic fixation for providing an in-line connection to the proximal spinal constructs without using offset connectors. Although the pelvic shape is different between males and females, reports on S2AIS trajectories according to gender have been scarce in the literature. In this paper, S2AIS trajectories are compared between males and females using pelvic three-dimensional computed tomography (3D-CT) in a normal Japanese population. After resetting the caudal angulation in CT-imaging plane manipulation, the angulation of S2AIS was more lateral in the axial plane and more horizontal in the coronal plane in females. Mean distances from the midline to starting points of S2AIS tended to be shorter in females, whereas mean distances from the midline to the posterior superior iliac spine was significantly longer in females. We also found that there were positive correlations between the patients’ height and the maximal lengths of S2AISs, and the patients’ height and minimal areas of S2AIS pathways. Our results are useful not only for conventional open spinal surgery, but also for minimally invasive spine surgery.

Animal experimental studies involving the Igaki-Tamai stent (ITS), a bioresorbable poly-l-lactic acid scaffold, in peripheral arteries are limited, and existing studies evaluated only short-term (3-month) outcomes. This study compared arterial responses associated with the ITS and bare metal stent (BMS) over 6 months using intravascular ultrasound (IVUS) analysis and evaluated feasibility in porcine iliac arteries. Four miniature pigs underwent stent implantation with the ITS in the right iliac artery and the BMS in the left iliac artery. Follow-up evaluations at 6, 12, and 24 weeks included angiographic and IVUS analyses to assess neointimal hyperplasia, percent area stenosis (%AS), and percent in-stent volume obstruction (%VO). Histological analysis was performed to evaluate tissue injury and inflammation scores. At 6 weeks, the neointimal area did not differ significantly between the ITS and BMS groups (8.49 ± 2.10 mm² vs 13.47 ± 6.67 mm², P =.205). However, the ITS group exhibited a significantly smaller neointimal area at 12 weeks (6.87 ± 1.15 mm² vs 20.65 ± 10.99 mm², P =.050) and 24 weeks (5.20 ± 0.85 mm² vs 22.32 ± 12.03 mm², P =.042). %AS and %VO were significantly lower in the ITS group at all follow-ups. The ITS group showed reduced tissue damage (injury score: 0.80 ± 0.430 vs 1.74 ± 0.908, P <.001) and inflammation (inflammation score: 1.25 ± 0.516 vs 1.67 ± 0.832, P <.001) compared with the BMS group. The ITS was associated with reduced vessel injury, lower inflammatory response, and favorable luminal remodeling over 6 months in healthy porcine iliac arteries.

Introduction: Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection. Methods: A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002 to 2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed. Results: One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%. The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (P = 0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; P = 0.01) as well as aortoenteric fistula (HR 1.9, P = 0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, P = 0.04), as well as those with American Society of Anesthesiologists classification less than 3 (HR 0.35, P = 0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs. 60 years, P = 0.01) and less likely to have patent repairs during follow up (59% vs. 32%, P = 0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs. 29%, P < 0.01) Conclusion: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material.

Background: In Japan’s deceased-donor liver transplantation (DDLT), a new allocation policy based on the Model for End-Stage Liver Disease (MELD) score, including the exceptional MELD system (Ex-MELD), which periodically assigns additional points to the basal MELD score, was implemented in May 2019. We assessed the current state of this system for adult candidates with chronic end-stage liver disease. Methods: Adult candidates (≥ 18 years) registered in the Japan Organ Transplant Network for DDLT as Status 2 cases (including chronic end-stage liver disease patients) between May 2019 and April 2023 were evaluated. We divided them into the MELD, Ex-MELD (major) [start 16 points, 2 points by 180 days], and Ex-MELD [hepatocellular carcinoma (HCC)] groups. Transplant probability and waitlist mortality rates were compared using competing risk analyses. The annual proportion of DDLT and the transition of median MELD at transplantation were also investigated. Results: There were 757 candidates in MELD,126 in Ex-MELD (major), and 99 in Ex-MELD (HCC) groups. The transplant probability rates were not significantly different (3-year transplant probability rate; MELD: 24.0% vs. Ex-MELD (major): 21.0% vs. Ex-MELD (HCC): 24.1%). The rate in the Ex-MELD (major) increased dramatically as the waiting period lengthened. The waitlist mortality rates in the Ex-MELD (major) group were significantly lower (3-year waitlist mortality rate; MELD: 50.5% vs. Ex-MELD (major): 25.0% vs. Ex-MELD (HCC): 57.0%). Although the proportion of Ex-MELD (major) increased yearly in the transplanted cases, the median MELD at transplantation did not change significantly. Conclusions: We clearly showed the current status of adult Status 2 candidates.

Background: It is unclear how early- and delayed-onset organ/space surgical site infections (SSIs) affect the long-term prognosis of patients with colorectal cancer, who are potential candidates for adjuvant chemotherapy. This study aimed to investigate the association between the timing of SSI onset and clinical outcome. Methods: This retrospective, multicenter cohort study evaluated patients who were diagnosed with high-risk stage II or III colorectal cancer and underwent elective surgery between 2010 and 2020. Five-year recurrence-free survival (RFS) was the primary endpoint and was compared between early SSI, delayed SSI (divided based on the median date of SSI onset), and non-SSI groups. Results: A total of 2,065 patients were included. Organ/space SSI was diagnosed in 91 patients (4.4%), with a median onset of 6 days after surgery. The early-onset SSI group had a higher proportion of patients with Clavien–Dindo grade ≥IIIb SSI than the delayed-onset SSI. Patients who received adjuvant chemotherapy (AC) had earlier organ/space SSI onset than those who did not. The adjusted hazard ratio of 5-year RFS in the delayed-onset SSI was 2.58 (95% confidence interval: 1.43–4.65; p = 0.002): higher than that in the early-onset SSI, with the non-SSI as the reference. Conclusions: Delayed-onset organ/space SSI worsened long-term prognosis compared to early-onset, and this may be due to delayed initiation of AC. Patients who are clinically suspected of having lymph node metastasis might need additional intervention to prevent delays in commencing AC due to the delayed SSI.

Aim: Using nationwide data collected over the past 20 years, we aimed to investigate deceased donor liver transplantation (DDLT) outcomes to develop a unique risk model that can be used to establish a standard for organ acceptance in Japan. Methods: Data were collected for 449 recipients aged ≥18 years who underwent DDLT between 1999 and 2019. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to develop an original risk score model for 1-year graft loss (termed the Japan Risk Index [JRI]). We developed risk indices according to recipient, donor, and surgery components (termed JRI-R, D, and S, respectively). The JRI was validated via a 5-fold cross-validation. We also compared DDLT outcomes and risk indices among Era1 (−2011), Era2 (−2015), and Era3 (−2019). Results: The 1-year graft survival rate was 89.5% and improved significantly, reaching 84.7%, 87.6%, and 93.9% in Era1, Era2, and Era3, respectively. The JRI was calculated as JRI-R (re-transplantation, Model for End-Stage Liver Disease score, medical condition in intensive care unit) × JRI-D (age, catecholamine index, maximum sodium, maximum total bilirubin) × JRI-S (total ischemic time) × 0.84. The risk model achieved a mean C-statistic value of 0.81 in the validation analysis. The risk index was significantly lower in Era3 than in Era2. Conclusion: Changes in the risk index over time indicated that avoiding risks contributed to the improved outcomes in Era3. The JRI is unique to adult DDLT in Japan and may be useful as a reference for organ acceptance in the future.

Background: Infectious complications after solid organ transplantation can be fatal, and early diagnosis and intervention are important. To the best of our knowledge, no study has examined the diagnostic utility of presepsin, a known accurate biomarker, for infectious complications after liver transplantation. This study aimed to evaluate the utility of presepsin for detecting infection and perioperative kinetics of presepsin after liver transplantation. Material/Methods: This single-institutional prospective, observational study included 13 patients who underwent living-donor or de-ceased-donor liver transplantation. Perioperative serum presepsin level was measured 6 times within a week to evaluate its association with infectious complications and compare it with procalcitonin and C-reactive protein levels and leukocyte count. Postoperatively, patients were followed up for 15 days for infectious complications. Results: Five of the 13 patients developed infectious complications after liver transplantation. The median time for infection diagnosis was 9 postoperative days (25th-75th percentile, 7-10). Presepsin levels on 5 and 7 postoperative days were significantly higher in patients with infection than in those without (P=0.019 and P=0.011, re-spectively). In receiver operating characteristic analysis, area under the curve values of presepsin on 5 and 7 postoperative days (0.881 and 0.905, respectively) were higher than those of other biomarkers. The optimal cut-off value of presepsin was 1361 pg/mL on postoperative day 5 and 1375 pg/mL on postoperative day 7. Conclusions: Although this study included a small number of patients, presepsin levels on postoperative days 5 and 7 may be useful indicators for infectious complications after liver transplantation.

Objective: This retrospective cohort study aimed to emulate the ADVANCE trial population and directly compare the Endurant and Excluder using propensity score matching. Methods: Patients were included if endovascular aneurysm repair was performed for abdominal aortic aneurysm using either Endurant or Excluder at 10 hospitals in Japan between January 2012 and July 2022. Cases were selected according to the modified ADVANCE trial inclusion and exclusion criteria. To minimize selection bias and simulate a randomized controlled trial setting, propensity score matching was performed using patient and anatomical characteristics. The primary outcome measure was the proportion of patients with sac regression ≥ 5 mm at 1 year. The secondary outcome measures were rates of freedom from late complications, T1aEL, sac enlargement ≥ 5 mm, and overall survival. Outcomes were first analyzed in patients within the instructions for use (IFU) and then in all matched patients including outside IFU patients. Results: After matching, the within-IFU group included 124 pairs and the total cohort of 266 pairs. The primary outcome measures for Endurant and Excluder were met in 38.9% and 36.6% (p = 0.74) in the within-IFU group and 33.5% and 35.0% (p = 0.74) in the total cohort, respectively. No significant differences were observed in any secondary outcome measures. However, T2EL and use of additional proximal cuff were significantly more frequent for Excluder in both the within-IFU and total cohort. Furthermore, T1b and T5ELs occurred significantly more for Endurant in the total cohort. Conclusion: There were no significant differences in all clinical outcome measures between Endurant and Excluder. Levels of evidence: Level IV, multicenter retrospective cohort study.

[Case 1] A 54-year-old female presented with severe liver damage. During diagnosis, contrast-enhanced CT enhanced the area of hypoattenuation on unenhanced CT in the arterial phase, after which the enhanced effect was prolonged to the equilibrium phase. Then, we started immunosuppressive therapy based on the results, including corticosteroid administration, and her hepatitis subsided. [Case 2] A 57-year-old female also presented with severe hepatitis. Contrast-enhanced CT findings were similar to those of Case 1. Since hepatic encephalo-pathy developed and worsened to degree IV, a brain-dead liver transplant was conducted on the 21st day. Nev-ertheless, histological diagnosis was challenging in both cases. Therefore, when unenhanced CT shows hetero-geneous hypoattenuation in the liver and contrast-enhanced CT shows a characteristic blood flow disorder, acute-onset autoimmune hepatitis and corticosteroid treatment should be considered, including in complex se-rological or histological case diagnoses.

Purpose: This study retrospectively evaluated the 12-month outcomes of the Zenith Alpha Abdominal Endovascular graft (Zenith Alpha AAA, Cook, Inc, Bloomington, Indiana), which was launched partially in Japan in March 2019, starting with 9 selected sites. Methods: A retrospective analysis was performed of all endovascular aneurysm repairs (EVAR) for abdominal aortic aneurysms using the Zenith Alpha AAA. Late complications were defined as any aneurysm-related events occurring >30 days after EVAR, including an aneurysm sac enlargement of >5 mm and any reinterventions performed. Endoleaks without sac enlargement or reinterventions were excluded from late complications. Results: During the study period, 79 EVARs using the Zenith Alpha AAA were performed. The mean age was 76.6±6.9 years old, 91.1% of patients were male, and the mean aneurysm diameter was 51.1±7.5 mm. Instructions for use violation was observed in 27 patients (34.2%), most frequently being a severely angulated proximal neck (>60°). There were 4 intraoperative complications, including 2 unintentional partial renal artery coverages caused by the premature anchoring of the exposed suprarenal stent barb to the aortic wall, which was a result of the design change of the top cap deletion. Since it was a partial coverage without flow impairment and since renal stenting was unsuccessful, it was left untreated and had no subsequent renal function impairment. During the mean follow-up of 444±123 days, 74 patients completed 12 months of follow-up. Freedom from late complications at 12 months was 90.8%, which included 2 limb occlusions (2.5%). Of 71 patients with a 12-month computed tomography scan, there was only 1 type 1a endoleak (1.3%), 1 sac enlargement of >5 mm (1.3%), and an aneurysm sac shrinkage of >5 mm was observed in 42.2% of patients. There was no type 3 endoleak during the follow-up. Conclusions: This study demonstrated that the new generation of low-profile Zenith Alpha AAA has satisfactory early clinical outcomes, comparable to those obtained with the conventional Zenith endovascular graft. Long-term follow-up is needed to determine whether these favorable outcomes persist.

Purpose: To evaluate the efficacy of the Active Seal technology employed in the AFX endovascular aortic aneurysm system (AFX), during endovascular aneurysm repair (EVAR) in patients with abdominal aortic aneurysms (AAAs) having a conical proximal neck. Materials and Methods: A retrospective analysis of the EVAR for AAA with a conical proximal neck using the AFX was performed at 17 Japanese hospitals between January 2016 and August 2020. The conical proximal neck was defined as a cone-shaped proximal neck, with more than 10% diameter increase within a 15 mm length at the proximal landing zone. All anatomical analyses were performed in the core laboratory, and cases with parallel walls within the proximal neck adequate for the landing zone were excluded from the study. Results: This study included 53 patients, but only 39 patients (mean age, 76.6 ± 6.7 years; 87.0% males; mean aneurysm diameter, 52.0 ± 8.0 mm) were analyzed after being characterized as having a pure conical neck by the core laboratory. The mean proximal neck diameters at the lower renal artery and proximal edge of the aneurysm were 20.0 ± 2.9 mm and 27.5 ± 4.9 mm, respectively. The mean proximal neck length was 21.5 ± 6.0 mm. Instructions for use violations other than the conical neck were observed in 15 patients (38.5%). The VELA cuff was used in all cases; however, additional proximal cuff was required in 9 more cases (23.1%). The Active Seal technology was able to significantly extend the proximal sealing zone from 21.5 ± 6.0 to 26.0 ± 12.2 mm (p =.047). Thirty-six patients completed the 12-month follow-up (one patient was lost to follow-up, and 2 patients died from causes unrelated to the aneurysm), and there were no type-1a and 3 endoleaks with only one reintervention (2.6%) related to type 1b endoleak in the 12-month period. Furthermore, there was no significant enlargement of the proximal neck diameter at 12 months (at 1 month: 20.6 ± 3.4 mm and at 12 months: 21.3 ± 3.8 mm; p =.420). Conclusion: The Active Seal technology of the AFX significantly extended the proximal seal zone and no type-1a endoleak and proximal neck dilation was observed in patients with conical proximal neck at 12 months.

Purpose: Recent reports of the Zenith Alpha abdominal endovascular graft (Zenith Alpha AAA, Cook, Inc., Bloomington, Indiana) have demonstrated an unexpectedly high incidence of limb graft occlusion (LGO). The purpose of this study was to prospectively evaluate the performance of the Zenith AAA in Japan, with a specific focus on LGO. Materials and methods: All endovascular aneurysm repairs (EVARs) for abdominal aortic aneurysms performed using the Zenith Alpha AAA from July 2020 to October 2021 in 23 Japanese hospitals were prospectively evaluated. All computed tomographic images were analyzed in the core laboratory. Late complications were defined as any aneurysm-related events occurring >30 days after EVAR, including aneurysm sac enlargement of >5 mm and any reinterventions performed. Endoleaks without sac enlargement or reintervention were excluded as late complications. Results: During the study period, 147 EVARs were performed using the Zenith Alpha AAA. The mean patient age was 76.5±7.7 years, 84.4% of patients were male, and the mean aneurysm diameter was 52.4±9.2 mm. Instruction-for-use violations were observed in 76 patients (51.7%), primarily associated with a severely angulated proximal neck (>60°). There were six intraoperative complications and 62 additional intraoperative treatments reported, most of which involved preemptive coil embolization of the inferior mesenteric artery (37 cases). Technical success, defined as the absence of type 1 or 3 endoleaks on final angiography, was achieved in 99.3% of patients. At 12 months, there was only one case of type 1/3 endoleak (0.8%) and one aneurysm sac enlargement exceeding 5 mm (0.8%); however, a high incidence of type 2 endoleaks was observed in 35.2% of patients, and aneurysm sac regression exceeding 5 mm was achieved in 30.1% of patients. Nine late complications were observed, and the rate of freedom from late complications at 12 months was 93.5%, encompassing four LGOs and one limb graft stenosis (3.4%). Conclusions: In contrast to recent reports, our Japanese multicenter prospective study demonstrated satisfactory early clinical results, including an acceptable LGO rate, for the low-profile Zenith Alpha AAA. Long-term follow-ups will be performed to confirm the persistence of these outcomes. Clinical Impact: This study prospectively evaluated the performance of 147 Zenith Alpha AAAs used for endovascular aneurysm repair with core-lab adjudication focusing especially on limb graft occlusion (LGO). At 12 months, aneurysm sac regression exceeding 5 mm was achieved in 30.1% of patients, and there was only one type 1/3 endoleak, one aneurysm sac enlargement (>5 mm), and nine late complications including five LGOs (3.4%), resulting in rate of freedom from late complications at 93.5%. Satisfactory early clinical results, including an acceptable rate of LGO can be achieved, particularly with cautious usage of the Zenith Alpha Spiral-Z Endovascular Leg.” 5mm), and nine late complications including five LGOs (3.4%), resulting in rate of freedom from late complications at 93.5%. Satisfactory early clinical results, including an acceptable rate of LGO can be achieved, particularly with cautious usage of the Zenith Alpha Spiral-Z Endovascular Leg.

Hepatic epithelioid hemangioendothelioma (HEHE), which is extremely rare, is considered to have a malignant grade between that of hepatic hemangioma and that of hepatic hemangiosarcoma; however, some cases progress so quickly that they present with portal hypertension. We report the case of a woman with findings similar to those of acute-onset autoimmune hepatitis (AIH) that was not diagnosed before liver transplantation. The patient presented with jaundice and ascites. A hematological examination revealed negative tumor markers, high IgG levels, and negative hepatitis virus markers. Computed tomography findings of the liver showed map-like signs characteristic of acute-onset AIH. Despite some response, immunosuppressive drugs such as prednisolone, cyclosporine, and mycophenolate mofetil did not improve liver failure, and she underwent liver transplantation after 200 days of treatment. The explanted liver exhibited white areas that extended in a map-like manner and were occupied by fibrous stroma. Tumors with WWTR1-CAMTA1 gene fusion were recognized and diagnosed as HEHE. Although a histological examination is essential, a percutaneous liver biopsy could not be performed preoperatively because of the presence of ascites. Furthermore, the rarity of the disease, similarity of imaging findings with non-neoplastic patterns, and serological findings made it difficult to differentiate this case from acute-onset autoimmune hepatitis.

Liver transplantation is often the only lifesaving option for acute liver failure (ALF); however, the predictors of short-term mortality (death within one year) after living donor liver transplantation (LDLT) for ALF have yet to be defined. We retrospectively collected patients ≥18 years old who underwent LDLT for ALF between 2010 and 2020 at 35 centers in Asia. Univariate and multivariate logistic regression analyses were conducted to identify the clinical variables related to short-term mortality and establish a novel scoring system. The Kaplan-Meier method was performed to explore the association between the score and overall survival. Of the 339 recipients, 46 (13.6%) died within 1 year after LDLT. Multivariate analyses revealed 4 independent risk factors for death: use of vasopressors or mechanical ventilation, the higher model for end-stage liver disease score, and a lower graft-to-recipient weight ratio. The internally validated c-statistic of the short-term mortality after transplant (SMT) score derived from these 4 variables was 0.80 (95% confidence interval: 0.74-0.87). The SMT score successfully stratified recipients into low-, intermediate-, and high-risk groups with 1-year overall survival rates of 96%, 80%, and 50%, respectively. In conclusion, our novel SMT score based on 4 predictors will guide ALF recipient and living donor selection.

Endovascular aneurysm repair (EVAR) is a widely accepted treatment for aortic pathologies owing to its minimally invasive nature. However, long-term complications, such as stent graft migration and infection, remain unresolved, primarily due to the persistent presence of synthetic materials and limited tissue integration. This pilot study evaluated the feasibility of a novel tissue-engineered stent graft (TESG) combining a bioresorbable poly-L-lactic acid (PLLA) stent with decellularized porcine veins. The veins were processed using a sodium dodecyl sulfate and the Triton X-100 decellularization protocol. Histological and ultrastructural analyses confirmed effective cell removal while preserving extracellular matrix components. Quantitative deoxyribonucleic acid (DNA) analysis showed a > 97% reduction in DNA content. The TESGs were assembled by suturing the decellularized veins into bioresorbable PLLA stents and implanted into porcine iliac arteries (n = 3). Commercially available prosthetic grafts were used as control implants to evaluate differences in tissue responses. Graft patency and morphology were assessed at implantation and on postoperative day 14 using angiography and intravascular ultrasonography. All TESGs remained patent, with no evidence of thrombosis or aneurysmal changes. Histological analysis revealed early endothelialization and smooth muscle cell infiltration within the TESG wall, in contrast to the prosthetic graft controls, which lacked comparable cellular integration. This study demonstrated the short-term feasibility and biological compatibility of a fully bioresorbable TESG. Although long-term outcomes remain to be established, these results support further development of TESG to reduce late complications through improved tissue integration and avoidance of permanent synthetic materials.

Mesenchymal stromal/stem cells (MSCs) have shown potential in the treatment of degenerative diseases, including ischemia/reperfusion injury (IRI), which occurs during organ transplantation and represents the main cause of post-transplant graft dysfunction. However, MSCs have heterogeneous characteristics, and studies of MSCs therapy have shown a variety of outcomes. To establish a new effective MSCs therapy, we developed an adipose-derived mesenchymal stromal/stem cell line (ASCL) and compared its therapeutic effects on primary adipose-derived MSCs (ASCs) using a hepatocyte co-culture model of hypoxia/reoxygenation in vitro and a rat model of hepatic IRI in vivo. The results showed that both ASCL and ASCs protect against hypoxia by improving hepatocyte viability, inhibiting reactive oxygen species release, and upregulating transforming growth factor-β in vitro. In vivo, ASCL or ASCs were infused into the spleen 24 h before the induction of rat hepatic IRI. The results showed that ASCL significantly improved the survival outcomes compared with the control (normal saline infusion) with the significantly decreased serum levels of liver enzymes and less damage to liver tissues compared with ASCs. Both ASCL and ASCs suppressed NOD-like receptor family pyrin domain-containing 3 inflammasome activation and subsequently reduced the release of activated IL-1β and IL-18, which is considered an important mechanism underlying ASCL and ASCs infusion in hepatic IRI. In addition, ASCL can promote the release of interleukin-1 receptor antagonist, which was previously reported as a key factor in hampering the inflammatory cascade during hepatic IRI. Our results suggest ASCL as a new candidate for hepatic IRI treatment due to its relatively homogeneous characteristics.

Background: Long-term placement of prophylactic drains may result in retrograde infections. Aim: To investigate the association between the timing of drain removal and clinical outcomes. Methods: This retrospective, single-centre cohort study evaluated 110 patients who underwent elective gastrointestinal or hepatopancreatobiliary surgery and developed subsequent organ/space surgical site infection (SSI) between 2016 and 2020. The difference between the culture-positive species of prophylactic drains and direct aspiration was evaluated; whether the prophylactic drains functioned effectively at the time of SSI diagnosis; and whether the empirical antibiotics administered before drainage were effective against all the detected bacteria. Finally, clinical outcomes were compared between early (i.e. cases wherein the prophylactic drain had already been removed or replaced at the time of SSI diagnosis) and late (removal after diagnosis) drain removal. Findings: The prophylactic drains functioned effectively in only 27 (25%) patients at the time of SSI diagnosis. Due to the results of direct aspiration cultures, 43% of patients required antibiotic escalation. The median time to drain removal or first replacement was seven postoperative days. The early removal group included 43 patients (39%). Compared with early removal, late removal resulted in a higher frequency of vancomycin use (7.0% vs 22.4%; P = 0.037). Conclusion: Prolonged prophylactic drain placement is associated with complicated infections requiring vancomycin; therefore, the drains should be removed as soon as possible. Additionally, obtaining the cultures of direct aspiration should be actively considered, as escalation of antimicrobial therapy is often performed based on culture results.