Combination of everolimus with calcineurin inhibitor medication resulted in post-transplant haemolytic uraemic syndrome in lung transplant recipients--a case series.

BACKGROUND: Post-transplant haemolytic uraemic syndrome (HUS) is a rare but serious disease with a high mortality rate, when left untreated. Immunosuppressive drugs like calcineurin inhibitors as well as mammalian target of rapamycin inhibitors have been reported as causative agents for post-transplant HUS. METHODS: A retrospective observational study was performed in lung transplant recipients, who took part in an interventional study, in two centres. Haemoglobin, platelets, creatinine and lactate dehydrogenase levels were monitored during routine follow-up and patients with deteriorating kidney function were screened for post-transplant HUS. All cases of post-transplant HUS were identified by clinical and laboratory findings. Outcome was recorded until 6 months after diagnosis. RESULTS: A total of 2188 visits in 512 lung transplant recipients (outpatients) were analysed. Out of those, 126 patients took part in an interventional study. In this study, 67 were switched to everolimus in combination with calcineurin inhibitors 4 weeks after transplantation, 59 patients remained on standard immunosuppression (calcineurin inhibitors, mycophenolate mofetil and prednisolone). Five cases of post-transplant HUS were identified in the everolimus group. None of the patients had evidence of gastrointestinal infection or preexisting renal disease. Post-transplant HUS was treated with therapeutic plasma exchange and methylprednisolone pulse therapy. Everolimus was discontinued in all five patients. This treatment regimen led to normalization of haemoglobin, platelets and improved renal function. Two patients developed end-stage renal failure and were maintained on haemodialysis. One patient died due to multiorgan failure. Improvement of renal function was seen in two patients. No further cases were recorded in patients without everolimus during the study period. CONCLUSIONS: Our data should raise the awareness of post-transplant HUS in lung transplant recipients. Post-transplant HUS is a rare disease, but it is a serious cause of acute renal failure in lung transplant recipients treated with a combination of everolimus and calcineurin inhibitors.

Molecular correlates of renal function in kidney transplant biopsies.

The molecular changes in the parenchyma that reflect disturbances in the function of kidney transplants are unknown. We studied the relationships among histopathology, gene expression, and renal function in 146 human kidney transplant biopsies performed for clinical indications. Impaired function (estimated GFR) correlated with tubular atrophy and fibrosis but not with inflammation or rejection. Functional deterioration before biopsy correlated with inflammation and tubulitis and was greater in cases of rejection. Microarray analysis revealed a correlation between impaired renal function and altered expression of sets of transcripts consistent with tissue injury but not with those consistent with cytotoxic T cell infiltration or IFN-gamma effects. Multivariate analysis of clinical variables, histologic lesions, and transcript sets confirmed that expression of injury-related transcript sets independently correlated with renal function. Analysis of individual genes confirmed that the transcripts with the greatest positive or negative correlations with renal function were those suggestive of response to injury and parenchymal dedifferentiation not inflammation. We defined new sets of genes based on individual transcripts that correlated with renal function, and these highly correlated with the previously developed injury sets and with atrophy and fibrosis. Thus, in biopsies performed for clinical reasons, functional disturbances are reflected in transcriptome changes representing tissue injury and dedifferentiation but not the inflammatory burden.

Lipoprotein lipase-facilitated uptake of LDL is mediated by the LDL receptor.

LPL mediates the uptake of lipoproteins into different cell types independent of its catalytic activity. The mechanism of this process and its physiological relevance are not clear. Taking into account the importance of the endothelial barrier for lipoprotein uptake, in vitro studies with primary aortic endothelial cells from wild-type and low density lipoprotein receptor (LDLR)-deficient (LDLR(-/-)) mice were performed. Addition of LPL almost doubled the uptake of LDL into wild-type cells. However, there was virtually no LPL-mediated change of LDL uptake into LDLR(-/-) cells. Upregulation of LDLR by lipoprotein-deficient serum/lovastatin in wild-type cells resulted in a 7-fold increase of LPL-mediated LDL uptake. Uptake of chylomicron remnants was not affected by LDLR expression. In proteoglycan-deficient cells, LPL did not increase the uptake of lipoproteins. The physiological relevance of this pathway was studied in mice that were both LDLR(-/-) and transgenic for catalytically inactive LPL in muscle. In the presence of LDLR, inactive LPL reduced LDL cholesterol significantly (13-24%). In the absence of LDLR, LDL cholesterol was not affected by transgenic LPL. Metabolic studies showed that in the presence of LDLR, LPL increased the muscular uptake of LDL by 77%. In the absence of LDLR, transgenic LPL did not augment LDL uptake. Chylomicron uptake was not affected by the LDLR genotype. We conclude that LPL-mediated cellular uptake of LDL, but not of chylomicrons, is dependent on the presence of both LDLR and proteoglycans.

Abstraction and natural language semantics.

According to the traditional view, a word prototypically denotes a class of objects sharing similar features, i.e. it results from an abstraction based on the detection of common properties in perceived entities. I explore here another idea: words result from abstraction of common premises in the rules governing our actions. I first argue that taking 'inference', instead of 'reference', as the basic issue in semantics does matter. I then discuss two phenomena that are, in my opinion, particularly difficult to analyse within the scope of traditional semantic theories: systematic polysemy and plurals. I conclude by a discussion of my approach, and by a summary of its main features.