Seung Kee Min

Moderate-to-severe early-onset hyperuricaemia: a prognostic marker of long-term kidney transplant outcome

BACKGROUND Hyperuricaemia commonly occurs in renal transplant recipients (RTRs), but the effects of post-transplant hyperuricaemia on kidney transplant outcome have not been clearly established. This work was designed to explore the impact of hyperuricaemia on renal transplant outcome. METHODS The authors examined this issue by analysing the clinical outcome of 281 RTRs. Hyperuricaemia (defined as UA > 7.0 mg/dl in men and >6.0 mg/dl in women for at least two consecutive tests, n = 121) was classified as early onset (within 1 year of transplant, n = 90) or late onset (n = 31). Graft function was estimated using the MDRD Study Equation 7 (eGFR(MDRD)). RESULTS As late-onset hyperuricaemia was found to be induced by a progressive decline in the graft function (P < 0.01), data from early-onset hyperuricaemic recipients were used. Early-onset moderate-to-severe hyperuricaemia (defined as UA >or= 8.0 mg/dl) was found to be a significant risk factor for chronic allograft nephropathy (P = 0.035) and a poorer graft survival (P = 0.026) by multivariate analysis, whereas mild hyperuricaemia was not. The impact of moderate-to-severe hyperuricaemia on renal transplant survival was dependent on the duration of exposure. Likewise, the detrimental effect of early-onset hyperuricaemia on the graft function was dependent on UA levels and exposure time. After control of the baseline graft function by analysis of only recipients with a good graft function at 1 year post-transplantation (eGFR(MDRD) > 60 ml/min), moderate-to-severe early-onset hyperuricaemia was also found to be a marker of long-term graft dysfunction and failure. CONCLUSION Moderate-to-severe early-onset hyperuri- caemia may be a prognostic marker of the long-term graft outcome in RTRs, which needs further investigation.

Cold ischemic time is critical in outcomes of expanded criteria donor renal transplantation

The outcomes of expanded criteria donor (ECD) kidneys have been reported to be inferior compared with standard criteria donor (SCD) kidneys. However, the graft survival rate of ECD is not so inferior to SCD in Korea. The purposes of this study were to compare the outcomes of ECD kidneys with SCD kidneys and identify the influencing factors. We retrospectively studied 143 deceased donor transplants from August 2006 to June 2010. The patients were divided into SCD (n = 117) and ECD (n = 26) by UNOS criteria. The one‐ and three‐yr graft survival rates of SCD and ECD (99.1% and 94.4% vs. 100% and 92.9%, respectively, p = 0.15) were not significantly different between groups. The mean cold ischemic time (CIT) was 3.8 ± 2.2 h. When compared the outcome of ECD kidneys with data reported by Organ Procurement and Transplantation Network and the Scientific Registry of Transplant Recipients (OPTN/SRTR) (one‐ and three‐yr graft survival rate: 86.7% and 73.2%), the graft survival rate of our center was superior. In OPTN/SRTR data, transplant with CIT shorter than 11 h was only 20%. The outcomes of ECD grafts are outstanding and comparable with SCD grafts in our center, and the only distinguishing factor is markedly short CIT. Finishing the allocation before organ recovery and immediate operations after recovery could shorten the CIT.

Effects of external wrapping and increased blood flow on atrophy of the baboon iliac artery

OBJECTIVE Increased blood flow causes neointimal atrophy, whereas relief of wall tension with an external wrap causes arterial medial atrophy. To study the effects of blood flow and wall tension separately and together, we applied tight or loose wraps on high-flow or normal-flow iliac arteries in baboons. METHOD Baboon external iliac arteries were wrapped with loose-fitting and tight-fitting expanded polytetrafluoroethylene (ePTFE), leaving part unwrapped. A downstream arteriovenous fistula was constructed on one side to increase blood flow approximately twofold. The arteries were perfusion-fixed with 10% formalin after 4 (n = 5) and 28 days (n = 5). RESULTS At 4 days, compared with the unwrapped artery, the loosely and tightly wrapped normal-flow artery showed significant medial atrophy (23% and 30%, respectively; P < .05). The tightly wrapped artery showed a loss of cells (27%; P = .02) but no change in cell density. At 28 days, the medial cross-sectional area was decreased by the tight wrap and loose wrap under normal (45% and 28%, respectively; P < .05) and high (43% and 29%, respectively; P < .05) flow. High flow did not alter the effect of wrapping nor did it affect the unwrapped medial area. At 28 days, the normal and high flow tightly wrapped media showed an insignificant loss of cells but had increased cell density (47% and 30%, respectively; P < .05), suggesting preferential loss of extracellular matrix. Decorin was expressed at the late time only in the tightly wrapped normal and high-flow media and was associated with tight packing of the collagen, as detected by picrosirius red staining. CONCLUSION Loose-fitting and tight-fitting ePTFE wraps induced an inflammatory foreign body response that caused medial atrophy with loss of cells and extracellular matrix; the tight wrap was more effective. High blood flow did not prevent or augment medial atrophy. CLINICAL RELEVANCE Research in arterial restenosis has focused on the biologic mechanisms and pharmacologic approaches to the prevention of intimal hyperplasia. An alternative therapeutic approach might be to induce atrophy of established intimal hyperplasia. We have previously reported that high blood flow induces neointimal regression in expanded polytetrafluoroethylene grafts in baboons. Here we provide another model of vascular atrophy induced by external wrapping. The similarity between baboons and humans in their vascular systems and individual genetic heterogeneity makes these experiments of great relevance. Up- or down-regulated genes common to both models might be key regulators of vascular atrophy and therefore suitable therapeutic targets for pharmacologic treatment of established lesions.

Expression of cell cycle regulators during smooth muscle cell proliferation after balloon catheter injury of rat artery.

Intimal hyperplasia is defined as the abnormal migration and proliferation of vascular smooth muscle cells (VSMCs) with deposition of extracellular matrix. However, the cell cycle regulatory mechanisms of injury-induced VSMC proliferation are largely unknown. To examine the expression kinetics of cell cycle regulatory factors which is known to be worked positively or negatively, we used rat balloon injury model. Marked induction of proliferating cell nuclear antigen (PCNA), G1/S cyclin-dependent kinase (cdk2), and its regulatory subunit (cyclin E) occurred between 1 and 3 days after balloon arterial injury, and this was sustained for up to 7 days and then declined. However, the induction of the negative regulators, p21 and p27, occurred between 3 and 5 days of injury, peaked after 7 and 14 days and was then sustained. VSMC proliferation after balloon catheter injury of the rat iliac artery is associated with coordinated expression of positive (cdk2, cyclin E and PCNA) and negative (p21, p27) regulators. Cell cycle regulators such as cdk2, cyclin E, p21, p27 may be suitable targets for the control of intimal hyperplasia.

A link between smooth muscle cell death and extracellular matrix degradation during vascular atrophy

OBJECTIVE High blood flow induces neointimal atrophy in polytetrafluoroethylene (PTFE) aortoiliac grafts and a tight external PTFE wrap of the iliac artery induces medial atrophy. In both nonhuman primate models, atrophy with loss of smooth muscle cells and extracellular matrix (ECM) begins at ≤4 days. We hypothesized that matrix loss would be linked to cell death, but the factors and mechanisms involved are not known. The purpose of this study was to determine commonly regulated genes in these two models, which we hypothesized would be a small set of genes that might be key regulators of vascular atrophy. METHODS DNA microarray analysis (Sentrix Human Ref 8; Illumina, San Diego, Calif; ∼23,000 genes) was performed on arterial tissue from the wrap model (n = 9) and graft neointima from the graft model (n = 5) 1 day after wrapping or the switch to high flow, respectively. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was also performed. Expression of this vascular atrophy gene set was also studied after Fas ligand-induced cell death in cultured smooth muscle cells and organ cultured arteries. RESULTS Microarray analysis showed 15 genes were regulated in the same direction in both atrophy models: 9 upregulated and 6 downregulated. Seven of nine upregulated genes were confirmed by qRT-PCR in both models. Upregulated genes included the ECM-degrading enzymes ADAMTS4, tissue plasminogen activator (PLAT), and hyaluronidase 2; possible growth regulatory factors, including chromosome 8 open reading frame 4 and leucine-rich repeat family containing 8; a differentiation regulatory factor (musculoskeletal embryonic nuclear protein 1); a dead cell removal factor (ficolin 3); and a prostaglandin transporter (solute carrier organic anion transporter family member 2A1). Five downregulated genes were confirmed but only in one or the other model. Of the seven upregulated genes, ADAMTS4, PLAT, hyaluronidase 2, solute carrier organic anion transporter family member 2A1, leucine-rich repeat family containing 8, and chromosome 8 open reading frame 4 were also upregulated in vitro in cultured smooth muscle cells or cultured iliac artery by treatment with FasL, which causes cell death. However, blockade of caspase activity with Z-VAD inhibited FasL-mediated cell death, but not gene induction. CONCLUSION Seven gene products were upregulated in two distinctly different in vivo nonhuman primate vascular atrophy models. Induction of cell death by FasL in vitro induced six of these genes, including the ECM-degrading factors ADAMTS4, hyaluronidase 2, and PLAT, suggesting a mechanism by which the program of tissue atrophy coordinately removes extracellular matrix as cells die. These genes may be key regulators of vascular atrophy.

Infected Aortic Aneurysm caused by Mycobacterium bovis after Intravesical Bacillus Calmette-Guérin Treatment for Bladder Cancer

A 70-year-old man presented with lower back pain and cyanotic changes in his left lower extremity. He was diagnosed with infected aortic aneurysm and infectious spondylitis. He had received intravesical Bacillus Calmette-Guérin (BCG) therapy up to 1 month before the onset of symptoms. The aneurysm was excised and an aorto-biiliac interposition graft was performed. Mycobacterium tuberculosis complex was cultured in the surgical specimens. Real-time polymerase chain reaction (PCR) targeting the senX3-regX3 region, and multiplex PCR using dual-priming oligonucleotide primers targeting the RD1 gene, revealed that the organism isolated was Mycobacterium bovis BCG. The patient took anti-tuberculosis medication for 1 year, and there was no evidence of recurrence at 18 months follow-up.

Delayed Presentation of Endovenous Heat-Induced Thrombosis Treated by Thrombolysis and Subsequent Open Thrombectomy

Although endovenous heat-induced thrombosis (EHIT) is frequently reported after endovenous laser ablation (EVLA), the incidence and timing of occurrence of EHIT are not fully understood. We present a case of EHIT successfully treated with a combination of surgical and endovascular treatments. A 57-year-old woman, two months post bilateral EVLA, presented with a swollen leg. Deep vein thrombosis was diagnosed by Doppler ultrasonography and computerized tomographic venography. We treated the patient with catheter-directed thrombolysis with urokinase after insertion of an inferior vena cava filter. After thrombolytic treatment, we performed surgical venous thrombectomy, due to the presence of a large thrombus in the femoral vein. During the operation, we found organized old thrombus at the great saphenous vein which connected to the deep femoral vein. From these findings, we confirmed the presence of EHIT despite a long time having passed after EVLA. The patient was placed on anticoagulation therapy with oral rivaroxaban for three months.

Early Experiences of Laparoscopic Aortofemoral Bypass in Korea–report from a Single Center

Although endovascular approach can be widely applied to occlusive aortoiliac segment, aortofemoral bypass (AFB) continues to offer superior long term patency. In an effort to reduce the morbidity of AFB, LAFB (laparoscopic AFB) has been developed. We report our initial experiences to determine the feasibility and safety. From September 2005 to May 2008, LAFB was performed in 12 patients. A transabdominal retrocolic approach with pneumoperitoneum or direct approach was preferred. LAFB consisted of aortic dissection, vascular control with or without intracorporeal anastomosis. Last two cases were performed using da Vinci system for secure proximal anastomosis as an end to side fashion. Laparoscopic procedures were successfully performed in 11 patients. One patient underwent open conversion due to small bowel injury and bleeding. Mean operating time and aortic clamping time was 446 minutes and 87.5 minutes. The time to return of bowel function was about 2.1 days (2.1 ± 1.2). Compartment syndrome was developed in one patient at immediate postoperatively. During this study period, operating time was shown in decreasing tendency. Although LAFB is challenging procedure with steep learning curve, it is feasible technique and appears to ease patients postoperative course.