Graft loss and the antiphospholipid syndrome following liver transplantation

Background/Aims: The antiphospholipid syndrome is characterised by arterial and venous thromboses affecting small and large vessels, together with the presence of lupus anticoagulant and anticardiolipin antibodies.Methods: We report two cases of the antiphospholipid syndrome following liver transplantation which resulted in hepatic vessel thrombosis and subsequent graft loss, and we discuss the value of anticoagulation in prevention of further thrombotic episodes. Identification of these cases prompted a retrospective analysis for the presence of IgG anticardiolipin antibody, the most useful laboratory marker of vascular thrombosis in the antiphospholipid syndrome. Serum taken at 2 to 4 weeks following transplantation (when thrombotic events might be anticipated) was analysed further in 132 patients undergoing liver transplantation.Results: Hepatic vessel thrombosis occurred in (16%) post transplantation. Anticardiolipin IgG was present in (8.8%) recipients who developed a hepatic vessel thrombosis following liver transplantation, compared to (6.3%) (p=0.59) in whom transplantation was not complicated by hepatic vessel thrombosis.Conclusions: The presence of IgG anticardiolipin antibody was uncommon in recipients following liver transplantation and was not associated with an increased risk of hepatic vessel thrombosis. In contrast, the antiphospholipid syndrome which is rare may result in hepatic artery occlusion and graft loss, and so prompt recognition of the clinical syndrome is critical. Although screening for the antibody is not warranted in liver transplant recipients, it is important to be aware of the syndrome as optimal management of such cases may prevent graft loss.     

Exome sequencing in developmental eye disease leads to identification of causal variants in GJA8, CRYGC,PAX6 and CYP1B1

Developmental eye diseases, including cataract/microcornea, Peters anomaly and coloboma/microphthalmia/anophthalmia, are caused by mutations encoding many different signalling and structural proteins in the developing eye. All modes of Mendelian inheritance occur and many are sporadic cases, so provision of accurate recurrence risk information for families and affected individuals is highly challenging. Extreme genetic heterogeneity renders testing for all known disease genes clinically unavailable with traditional methods. We used whole-exome sequencing in 11 unrelated developmental eye disease patients, as it provides a strategy for assessment of multiple disease genes simultaneously. We identified five causative variants in four patients in four different disease genes, GJA8, CRYGC, PAX6 and CYP1B1. This detection rate (36%) is high for a group of patients where clinical testing is frequently not undertaken due to lack of availability and cost. The results affected clinical management in all cases. These variants were detected in the cataract/microcornea and Peters anomaly patients. In two patients with coloboma/microphthalmia, variants in ABCB6 and GDF3 were identified with incomplete penetrance, highlighting the complex inheritance pattern associated with this phenotype. In the coloboma/microphthalmia patients, four other variants were identified in CYP1B1, and CYP1B1 emerged as a candidate gene to be considered as a modifier in coloboma/microphthalmia.     

Transcranial Magnetic Stimulation: Use of Motor Evoked Potentials in the Evaluation of Surgically Induced Spinal Cord Ischemia

Abstract

We evaluated transcranial magnetic stimulation producing motor evoked potentials (TMS MEP) as a method to detect spinal cord ischemia during surgery for thoracoabdominal aneurysms. Four groups of swine were subjected to different types of surgically-induced ischemia. TMS MEP and neurological function were assessed at baseline, immediately after the ischemic insult and after four hours of reperfusion/post-ligation. Cross-clamping of the aorta in groups A & B resulted in the disappearance and subsequent reappearance of TMS MEP with significantly prolonged latencies in most animals and variable neurological function. Ligation of intercostal arteries produced no changes in TMS MEP or neurological function (group C). However, after ligation of intercostal and lumbar arteries, group D demonstrated no reappearance of TMS MEP and severe neurological deficits. TMS MEP can provide rapid detection of global spinal cord ischemia and can also predict local devascularization injury. (J Spinal Cord Med 1997; 20:395-401)     

Breast milk transmission of flaviviruses in the context of Zika virus: A systematic review

Background

Since the Zika virus epidemic in the Americas began in 2015, Zika virus transmission has occurred throughout the Americas. However, limited information exists regarding possible risks of transmission of Zika virus and other flaviviruses through breast feeding and human milk. We conducted a systematic review of the evidence regarding flaviviruses detection in and transmission through milk, specifically regarding Zika virus, Japanese encephalitis virus, tick‐borne encephalitis virus, Powassan virus, West Nile virus, dengue virus, and yellow fever virus.

Methods

Medline, Embase, Global Health, CINAHL , Cochrane Library, Scopus, Popline, Virtual Health Library, and WorldCat were searched through June 2017. Two authors independently screened potential studies for inclusion and extracted data. Human and nonhuman (animal) studies describing: 1) confirmed or suspected cases of mother‐to‐child transmission through milk; or 2) the presence of flavivirus genomic material in milk.

Results

Seventeen studies were included, four animal models and thirteen observational studies. Dengue virus, West Nile virus, and Zika virus viral ribonucleic acid was detected in human milk, including infectious Zika virus and dengue virus viral particles. Human breast‐feeding transmission was confirmed for only yellow fever virus. There was evidence of milk‐related transmission of dengue virus, Powassan virus, and West Nile virus in animal studies.

Conclusions

Because the health advantages of breast feeding are considered greater than the potential risk of transmission, the World Health Organization recommends that mothers with possible or confirmed Zika virus infection or exposure continue to breast feed. This review did not identify any data that might alter this recommendation.

     

A novel fluorometric assay for aldo-keto reductase 1C3 predicts metabolic activation of the nitrogen mustard prodrug PR-104A in human leukaemia cells

Aldo-keto reductase 1C3 (AKR1C3, EC 1.1.1.188) metabolises steroid hormones, prostaglandins and xenobiotics, and activates the dinitrobenzamide mustard prodrug PR-104A by reducing it to hydroxylamine PR-104H. Here, we describe a functional assay for AKR1C3 in cells using the fluorogenic probe coumberone (a substrate for all AKR1C isoforms) in conjunction with a specific inhibitor of AKR1C3, the morpholylurea SN34037. We use this assay to evaluate AKR1C3 activity and PR-104A sensitivity in human leukaemia cells. SN34037-sensitive reduction of coumberone to fluorescent coumberol correlated with AKR1C3 protein expression by immunoblotting in a panel of seven diverse human leukaemia cell lines, and with SN34037-sensitive reduction of PR-104A to PR-104H. SN34037 inhibited aerobic cytotoxicity of PR-104A in high-AKR1C3 TF1 erythroleukaemia cells, but not in low-AKR1C3 Nalm6 pre-B cell acute lymphocytic leukaemia (B-ALL) cells, although variation in PR-104H sensitivity confounded the relationship between AKR1C3 activity and PR-104A sensitivity across the cell line panel. AKR1C3 mRNA expression showed wide variation between leukaemia patients, with consistently higher levels in T-ALL than B-ALL. In short term cultures from patient-derived paediatric ALL xenografts, PR-104A was more potent in T-ALL than B-ALL lines, and PR-104A cytotoxicity was significantly inhibited by SN34037 in T-ALL but not B-ALL. Overall, the results demonstrate that SN34037-sensitive coumberone reduction provides a rapid and specific assay for AKR1C3 activity in cells, with potential utility for identifying PR-104A-responsive leukaemias. However, variations in PR-104H sensitivity indicate the need for additional biomarkers for patient stratification.