A dual role of miR-22 in rhabdomyolysis-induced acute kidney injury

AIM

In acute kidney injury (AKI), regions of the kidney are hypoxic. However, for reasons yet unknown, adaptation to hypoxia through hypoxia-inducible factor (HIF) is limited. Here, we studied miR-22, a potential HIF repressor, in normal kidneys, as well as in rhabdomyolysis-induced AKI, a condition where miR-22 is up-regulated.

METHODS

AKI in mice was provoked by IM injection of glycerol. Tissue homogenates were processed to determine the levels of candidate RNAs and proteins, as well as global gene expression profiles. Reporter assays quantified in vitro miR-22 activity and its modulation by mimic or inhibitor molecules, under normoxia or hypoxia (1% O₂ ) respectively. In vivo, anti-miR-22 molecules were applied to normal mice or prior to induction of AKI. Renal outcome was assessed by measuring plasma creatinine, plasma urea and the levels of the injury markers Kim-1 and Ngal.

RESULTS

Renal miR-22 is inducible by hypoxia and represses hypoxia-inducible factor (HIF). Specific inhibition of miR-22 regulates 1913 gene transcripts in kidneys controls and 3386 in AKI, many of which are involved in development or carcinogenesis. Specific inhibition of miR-22 up-regulates tissue protective HIF target genes, yet renal function and injury markers are unchanged or worsened.

CONCLUSIONS

miR-22 is a HIF repressor constitutively expressed in the adult kidney and up-regulated in AKI. Specific inhibition of miR-22 is efficient in vivo and profoundly affects renal gene expression in health and disease, including up-regulation of HIF. However, the net effect on rhabdomyolysis-induced AKI outcome is neutral or even negative.

Cyclosporine A induces endothelin-converting enzyme-1: Studies in vivo and in vitro

AIM

Cyclosporine A (CsA) induces renal vasoconstriction and hypoxia and enhances the expression of endothelin-1 (ET-1) pro-hormone (pre-pro-ET-1), plausibly leading to a feed-forward loop of renal vasoconstriction, hypoxia and enhanced synthesis of the potent vasoconstrictor ET-1. Endothelin-converting enzyme (ECE)-1 cleaves big endothelin to generate endothelin (ET)-1 and is upregulated by hypoxia via hypoxia-inducible factor (HIF). We hypothesized that in addition to the direct induction of ET-1 synthesis, CsA might also intensify renal ECE-1 expression, thus contributing to enhanced ET-1 synthesis following CsA.

METHODS

CsA was administered to Sprague Dawley rats (120 mg/kg/SC) for 4 days, and renal HIF and ECE-1 expression were assessed with Western blots and immunostaining. Human umbilical vein endothelial cells (HUVEC) and proximal tubular cell line (HK-2) were subjected to CsA, and ECE-1 induction was evaluated using real-time mRNA PCR and Western blots.

RESULTS

Cyclosporine A intensified renal parenchymal ECE-1 expression in the rat kidney, particularly in distal nephron segments, along with renal hypoxia (detected by pimonidazole adducts) and HIF expression, in line with our recent observations showing episodic hypoxia in mice subjected to CsA. Furthermore, in cultured normoxic HUVEC and HK-2 cells, CsA dose-dependently induced both pre-pro-ET-1 and ECE-1 mRNA and protein expression, with enhanced ET-1 generation.

CONCLUSION

CsA induces ECE-1 via both hypoxic and non-hypoxic pathways. ECE-1 may contribute to increased renal ET-1 generation following CsA, participating in a feed-forward loop of renal parenchymal hypoxia and ET synthesis.

Myoglobin facilitates angiotensin II-induced constriction of renal afferent arterioles

Vasoconstriction plays an important role in the development of acute kidney injury in rhabdomyolysis. We hypothesized that myoglobin enhances the angiotensin II (ANG II) response in afferent arterioles by increasing superoxide and reducing nitric oxide (NO) bioavailability. Afferent arterioles of C57Bl6 mice were isolated perfused, and vasoreactivity was analyzed using video microscopy. NO bioavailability, superoxide concentration in the vessel wall, and changes in cytosolic calcium were measured using fluorescence techniques. Myoglobin treatment (10−5 M) did not change the basal arteriolar diameter during a 20-min period compared with control conditions. NG-nitro-l-arginine methyl ester (l-NAME, 10−4 M) and l-NAME + myoglobin reduced diameters to 94.7 and 97.9% of the initial diameter, respectively. Myoglobin or l-NAME enhanced the ANG II-induced constriction of arterioles compared with control (36.6 and 34.2%, respectively, vs. 65.9%). Norepinephrine responses were not influenced by myoglobin. Combined application of myoglobin and l-NAME further facilitated the ANG II response (7.0%). Myoglobin or l-NAME decreased the NO-related fluorescence in arterioles similarly. Myoglobin enhanced the superoxide-related fluorescence, and tempol prevented this enhancement. Tempol also partly prevented the myoglobin effect on the ANG II response. Myoglobin increased the fura 2 fluorescence ratio (cytosolic calcium) during ANG II application (10−12 to 10−6 M). The results suggest that the enhanced afferent arteriolar reactivity to ANG II is mainly due to a myoglobin-induced increase in superoxide and associated reduction in the NO bioavailability. Signaling pathways for the augmented ANG II response include enhanced cytosolic calcium transients. In conclusion, myoglobin may contribute to the afferent arteriolar vasoconstriction in this rhabdomyolysis model.

Cyclosporin a induces renal episodic hypoxia

AIM

Cyclosporin A (CsA) causes renal toxicity. The underlying mechanisms are incompletely understood, but may involve renal hypoxia and hypoxia-inducible factors (Hifs). We sought for hypoxia and Hif in mouse kidneys with CsA-induced toxicity, assessed their time course, Hif-mediated responses and the impact of interventional Hif upregulation.

METHODS

Mice received CsA or its solvent cremophore for up to 6 weeks. Low salt diet (Na⁺ ↓) was given in combination with CsA to enhance toxicity. We assessed fine morphology, renal function, blood oxygen level-dependent magnetic resonance imaging under room air and following changes in breathing gas composition which correlate with vascular reactivity, pimonidazole adducts (which indicate O₂ tensions below 10 mmHg), Hif-α proteins, as well as expression of Hif target genes. Stable Hif upregulation was achieved by inducible, Pax8-rtTA-based knockout of von Hippel-Lindau protein (Vhl-KO), which is crucial for Hif-α degradation.

RESULTS

Cyclosporin A transiently increased renal deoxyhaemoglobin (R2*). Augmented vascular reactivity was observed at 2 h, but decreased at 24 h after CsA treatment. Na⁺ ↓/CsA provoked chronic renal failure with tubular degeneration and interstitial fibrosis. Nephron segments at risk for injury accumulated pimonidazole adducts, as well as Hif-α proteins. Remarkably, Hif target gene expression remained unchanged, while factor-inhibiting Hif (Fih) was enhanced. Na⁺ ↓/CsA/Vhl-KO aggravated morpho-functional outcome of chronic renal CsA toxicity.

CONCLUSIONS

Cyclosporin A provokes episodic hypoxia in nephron segments most susceptible to chronic CsA toxicity. Fih is upregulated and likely blocks further Hif activity. Continuous tubular Hif upregulation via Vhl-KO worsens the outcome of chronic CsA-induced renal toxicity.

Adaptive response to hypoxia and remote ischaemia pre-conditioning: a new hypoxia-inducible factors era in clinical medicine

Transient ischaemia leads to tolerance to subsequent protracted ischaemia. This 'ischaemia pre-conditioning' results from the induction of numerous protective genes, involved in cell metabolism, proliferation and survival, in antioxidant capacity, angiogenesis, vascular tone and erythropoiesis. Hypoxia-inducible factors (HIF) play a pivotal role in this transcriptional adaptive response. HIF prolyl hydroxylases (PHDs), serving as oxygen sensors, control HIFα degradation. HIF-mediated ischaemic pre-conditioning can be achieved with the administration of PHD inhibitors, with the attenuation of organ injury under various hypoxic and toxic insults. Clinical trials are currently under way, evaluating PHD inhibitors as inducers of erythropoietin. Once their safety is established, their potential use might be further tested in clinical trials in various forms of acute ischaemic and toxic organ damage. Repeated transient limb ischaemia was also found to attenuate ischaemic injury in remote organs. This 'remote ischaemic pre-conditioning' phenomenon (RIP) has been extensively studied recently in small clinical trials, preceding, or in parallel with an abrupt insult, such as myocardial infarction, cardiac surgery or radiocontrast administration. Initial results are promising, suggesting organ protection. Large-scale multi-centre studies are currently under way, evaluating the protective potential of RIP in cardiac surgery, in the management of myocardial infarction and in organ transplantation. The mechanisms of organ protection provided by RIP are poorly understood, but HIF seemingly play a role as well. Thus, Inhibition of HIF degradation with PHD inhibitors, as well as RIP (in part through HIF), might develop into novel clinical interventions in organ protection in the near future.

Chronic activation of vasopressin V2 receptor signalling lowers renal medullary oxygen levels in rats

AIM

In the present study, we aimed to elucidate the effects of chronic vasopressin administration on renal medullary oxygen levels.

METHODS

Adult Sprague Dawley or vasopressin-deficient Brattleboro rats were treated with the vasopressin V2 receptor agonist, desmopressin (5 ng/h; 3d), or its vehicle via osmotic minipumps. Immunostaining for pimonidazole and the transcription factor HIF-1α (hypoxia-inducible factor-1α) were used to identify hypoxic areas. Activation of HIF-target gene expression following desmopressin treatment was studied by microarray analysis.

RESULTS

Pimonidazole staining was detected in the outer and inner medulla of desmopressin-treated rats, whereas staining in control animals was weak or absent. HIF-1α immunostaining demonstrated nuclear accumulation in the papilla of desmopressin-treated animals, whereas no staining was observed in the controls. Gene expression analysis revealed significant enrichment of HIF-target genes in the group of desmopressin-regulated gene products (P = 2.6*10(-21) ). Regulated products included insulin-like growth factor binding proteins 1 and 3, angiopoietin 2, fibronectin, cathepsin D, hexokinase 2 and cyclooxygenase 2.

CONCLUSION

Our results demonstrate that an activation of the renal urine concentrating mechanism by desmopressin causes renal medullary hypoxia and an upregulation of hypoxia-inducible gene expression.

Action of hypoxia-inducible factor in liver and kidney from mice with Pax8-rtTA-based deletion of von Hippel-Lindau protein

AIM

Von Hippel-Lindau protein (VHL) provides the degradation of hypoxia-inducible factor (HIF). Tetracycline-induced, Pax8-rtTA-based knockout of VHL (VHL-KO) affects all renal tubules and periportal hepatocytes and leads to sustained upregulation of HIF. Here, we study the phenotype of VHL-KO in both organs, the time course of changes, and long-term morpho-functional outcome.

METHODS

Mice with doxycycline-induced VHL-KO and controls (CON) were followed for up to 9 months. Systemic and tissue parameters were evaluated using clinical chemistry, histology, immunohistochemistry, RT-PCR and in situ hybridisation.

RESULTS

At day 3 following VHL-KO, substantial abundance of HIF-1α and -2α was detected in the nuclei of hepatocytes and renal tubular epithelia. Hypoxia, induced by bleeding anaemia, did not further augment HIF signal. Erythropoietin mRNA was detectable in hepatocytes but not in the kidney. Vascular endothelial growth factor mRNA was upregulated in kidney but not in liver. At day 7 following VHL-KO, the renal capillary density was enhanced, reaching its maximum at day 14. Blood haemoglobin increased constantly up to day 28 (23.3 vs. 15.8 g dL(-1) , VHL-KO vs. CON). Thereafter, it was kept within the normal range by weekly blood collections. Pathological changes were absent from kidney and liver 9 months after VHL-KO.

CONCLUSIONS

Inducible, Pax8-rtTA-based deletion of VHL leads to organ-specific expression of epithelial HIF and erythropoietin in liver and kidney without causing pathological changes. Uniform, maximal and sustained HIF activation along the renal tubule may serve to study the potential benefits of hypoxia adaptation in experimental renal injury.

Affective disturbances modulate the neural processing of visceral pain stimuli in irritable bowel syndrome: an fMRI study

OBJECTIVE

To address the role of anxiety and depression symptoms in altered pain processing in irritable bowel syndrome (IBS).

DESIGN

In this functional magnetic resonance imaging study, the blood oxygen level-dependent (BOLD) response to rectal distensions delivered at previously determined individual discomfort thresholds was assessed.

PATIENTS

15 female patients with irritable bowel syndrome (IBS) and with normal rectal pain thresholds, and 12 healthy women.

MEASURES

The correlation of anxiety and depression symptoms, measured with the Hospital Anxiety and Depression Scale (HADS), with subjective pain ratings and the BOLD response during distension-induced brain activation were analysed within IBS. Group differences in pain-induced brain activation with and without controlling for HADS scores were evaluated.

RESULTS

Patients with IBS experienced significantly more pain and discomfort upon rectal distensions in the scanner, despite unaltered rectal sensory thresholds. Anxiety and depression scores were associated with these subjective stimulus ratings, but not with rectal sensory thresholds. Anxiety symptoms in IBS were significantly associated with pain-induced activation of the anterior midcingulate cortex and pregenual anterior cingulate cortex. Depression scores correlated with activation of the prefrontal cortex (PFC) and cerebellar areas within IBS. Group comparisons with the two-sample t test revealed significant activation in the IBS versus controls contrast in the anterior insular cortex and PFC. Inclusion of anxiety and depression scores, respectively, as confounding variables led to a loss of significant group differences.

CONCLUSIONS

Altered central processing of visceral stimuli in IBS is at least in part mediated by symptoms of anxiety and depression, which may modulate the affective-motivational aspects of the pain response.

Effects of psychological stress on the cerebral processing of visceral stimuli in healthy women

The aim of the study was to analyse effects of psychological stress on the neural processing of visceral stimuli in healthy women. The brain functional magnetic resonance imaging blood oxygen level-dependent response to non-painful and painful rectal distensions was recorded from 14 healthy women during acute psychological stress and a control condition. Acute stress was induced with a modified public speaking stress paradigm. State anxiety was assessed with the State-Trait-Anxiety Inventory; chronic stress was measured with the Perceived Stress Questionnaire. During non-painful distensions, activation was observed in the right posterior insular cortex (IC) and right S1. Painful stimuli revealed activation of the bilateral anterior IC, right S1, and right pregenual anterior cingulate cortex. Chronic stress score was correlated with activation of the bilateral amygdala, right posterior IC (post-IC), left periaqueductal grey (PAG), and right dorsal posterior cingulate gyrus (dPCC) during non-painful stimulation, and with activation of the right post-IC, right PAG, left thalamus (THA), and right dPCC during painful distensions. During acute stress, state anxiety was significantly higher and the acute stress - control contrast revealed activation of the right dPCC, left THA and right S1 during painful stimulation. This is the first study to demonstrate effects of acute stress on cerebral activation patterns during visceral pain in healthy women. Together with our finding that chronic stress was correlated wit the neural response to visceral stimuli, these results provide a framework for further studies addressing the role of chronic stress and emotional disturbances in the pathophysiology of visceral hyperalgesia.

Development of Kaposi's sarcoma under sirolimus-based immunosuppression and successful treatment with imiquimod

Kaposi's sarcoma (KS) is a vascular neoplasm typically observed in the immunocompromised patient populations, such as acquired immunodeficiency syndrome or transplant patients. KS can appear simultaneously at multiple sites as red to purple, maculo-papular or nodular cutaneous lesions sometimes showing a visceral extension. Sirolimus, an immunosuppressive agent with potent antitumor activity, has been effective in combating post-transplant KS. However, an aggressive regimen of immunosuppression for therapy of severe acute rejection episodes may abolish the antitumor effects of sirolimus. The following is a description of KS development under immunosuppressive therapy with sirolimus, and the successful treatment of KS lesions utilizing the topical application of imiquimod 5% cream, an immune response modifier.

Adaptation to hypoxia in the diabetic rat kidney

Hypoxia of the kidney in diabetes could predispose it to develop acute and chronic renal failure. To examine the relationship between renal hypoxia and renal failure, we measured hypoxia (as a pimonidazole adducts), hypoxia-inducible factors (HIFs), and a hypoxia target gene heme oxygenase-1. The studies were performed in rats with streptozotocin (STZ)-induced diabetes, Cohen diabetes sensitive rats, and during short-term artificial hyperglycemia in rats induced by intravenous glucose and octreotide. STZ-treated rats received insulin, the superoxide dismutase mimetic tempol, or contrast medium. Radiocontrast media causes hypoxia and HIF induction. Hypoxia, HIFs, and heme oxygenase were undetectable in controls, but transiently activated in STZ-treated and the Cohen diabetes sensitive rats. Different patterns of HIFs and pimonidazole were observed between the three models. Insulin abolished pimonidazole and HIF induction, whereas tempol lead to increased HIFs and heme oxygenase induction at similar levels of pimonidazole. When compared with control rats, STZ-treated rats exhibited more intense and protracted renal pimonidazole, with augmented hypoxia inducible factor production and reduced GFR following contrast media. Our data suggest that both regional hypoxia and hypoxia adaptation transiently occur in early stages of experimental diabetes, largely dependent on hyperglycemia or after contrast media. Tempol may augment the HIF response in diabetes.

Heightened expression of the cytotoxicity receptor NKG2D correlates with acute and chronic nephropathy after kidney transplantation

The activating cytotoxicity receptor NKG2D binds to stress-regulated molecules encoded by the major histocompatibility complex class I chain-related (MIC) and UL-16-binding protein (ULBP)/retinoic acid early transcript (RAET) gene family. To assess whether acute allograft rejection leads to an induction of these inducible ligands and their receptor NKG2D, we examined the mRNA profiles in kidney transplant biopsies. Expression levels were correlated with the incidence of acute rejection (aRx) episodes and chronic allograft nephropathy (CAN) proven by histology. Whereas MICA, ULBP1/3 and RAET1-E did not display heightened gene expression, elevated levels of NKG2D mRNA could be associated with aRx (p < 0.001). Immunohistology of kidney biopsies diagnosed with aRx revealed NKG2D+ cells in tubulointerstitial areas positive for CD8+ cells. Most importantly, elevated levels of NKG2D mRNA were associated with restricted long-term graft function assessed by the glomerular filtration rate at 6, 12 and 18 months posttransplantation. Induced NKG2D mRNA expression was still observable in biopsies diagnosed with CAN (p < 0.001), demonstrating a higher sensitivity and specificity compared to CD3, granzyme B and granulysin mRNA measurement. Significant elevated levels of NKG2D mRNA could be further detected in urine sediment prior to aRx, suggesting this receptor as a new candidate marker for the diagnosis of acute and chronic allograft rejection.

Hypoxia-inducible factors and tubular cell survival in isolated perfused kidneys

Adaptation to hypoxic environment is conferred through hypoxia-inducible transcription factors (HIFs). We have previously shown that the HIF system is transiently activated in vivo in radiocontrast-induced acute renal failure, associated with profound hypoxia in the renal medulla. Medullary thick ascending limbs (mTALs), the most affected nephron segments in this model, were virtually unable to mount an adaptive HIF response. Here, we study correlations between oxygenation, HIF activation, and cell viability in a related ex vivo model, the isolated perfused rat kidney (IPK). In IPKs perfused with cell-free oxygenated medium, severe medullary hypoxic damage developed, affecting 42+/-9% of mTALs in the mid-inner stripe. HIF-1alpha tubular immunostaining was noted with a zonal and tubular pattern largely similar to our findings in vivo: in 34+/-3% of collecting ducts (CDs) within the mid-inner stripe and extensively in the papillary tip, whereas mTALs were all HIF-negative. In IPKs supplemented with RBCs (improved oxygen supply), mTAL damage was totally prevented and CDs' HIF expression was attenuated (22+/-4%). By contrast, although measures designed to reduce medullary hypoxia by decreasing tubular reabsorptive activity (furosemide, ouabain, or high-albumin-non-filtering system) reduced mTAL damage, all paradoxically resulted in increased HIF expression in CDs (51+/-4%), and 17+/-3% of mTALs became immunostained as well. Our data confirm that CDs and mTALs have markedly different HIF responses, which correlate with their viability under hypoxic stress. mTALs transcriptional adaptation occurs within a narrow hypoxic range, and it appears that workload reduction can shift mTALs into this window of opportunity for HIF activation and survival.

Expression of hypoxia-inducible transcription factors in developing human and rat kidneys

Early kidney development is associated with the coordinated branching of the renal tubular and vascular system and hypoxia has been proposed to be a major regulatory factor in this process. Under low oxygen levels, the hypoxia-inducible transcription factor (HIF) regulates the expression of genes involved in angiogenesis, erythropoiesis and glycolysis. To investigate the role of HIF in kidney development, we analyzed the temporal and spatial expression of the oxygen regulated HIF-1alpha and -2alpha subunits at different stages of rat and human kidney development. Using double-staining procedures, localization of the HIF target geneproducts vascular endothelial growth factor (VEGF) and endoglin was studied in relation to HIFalpha. In both species, we found marked nuclear expression of HIF-1alpha in medullary and cortical collecting ducts and in glomerular cells. In contrast, HIF-2alpha was expressed in interstitial and peritubular cells podocytes of the more mature glomeruli. After completion of glomerulogenesis and nephrogenesis, HIF-1alpha and -2alpha were no longer detectable. The HIF-target gene VEGF colocalized with HIF-1alpha protein in glomeruli and medullary collecting ducts. HIF-2alpha colocalized with the endothelium-associated angiogenic factor, endoglin. Both HIFalpha isoforms are activated in the developing kidney in a cell-specific and temporally controlled manner, indicating a regulatory role of oxygen tension in nephrogenesis. HIF-1alpha seems to be primarily involved in tubulogenesis and HIF-2alpha in renal vasculogenesis. Both isoforms are found in glomerulogenesis, potentially having synergistic effects.

HLA type-independent method to monitor polyoma BK virus-specific CD4 and CD8 T-cell immunity

(Re)activation of quiescent viral diseases is a major problem in immunosuppressed transplant patients. Polyoma BK virus-associated nephropathy (PVAN) caused by active polyoma BK virus (BKV) infection became a main reason for graft loss in kidney transplantation. After diagnosis, most transplant centers react by reducing immunosuppression (IS) to allow the immune system to control the infection. However, the impact of reduced IS on BKV immunity is not well researched. Here we present an HLA type-independent method to monitor BKV-specific T-cell immunity. Applying our method, viral protein 1-specific CD4+ and CD8+ T-cell responses were detected in patients with serum BKV-DNA levels >250 000 copies/mL. In addition, specific T-cell responses were also found in allograft-infiltrating cells. The method can be used to assess the impact of decreased immunosuppression on BKV immunity and to clarify the role of specific T cells in the pathogenesis of PVAN. We strongly recommend its implementation in future clinical studies.

Proven Strategies to Reduce Cardiovascular Mortality in Hemodialysis Patients

BACKGROUND

In hemodialysis patients, left ventricular hypertrophy (LVH) correlates with mortality. The reason for LVH in uremics is multifactorial. The primary objective of our study was to investigate the effects of a multi-interventional treatment strategy on LVH.

METHODS

In 230 ambulatory patients, including patients with coronary artery disease, diabetes, diastolic and systolic dysfunction, we continued optimized cardiac therapy (beta-blockers, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers) with full anemia correction by intravenous epoetin-beta. The dose of epoetin-beta for maintaining target hemoglobin (Hb) was 68 +/- 23 IU/kg/week. Serial echocardiograms were recorded every 3-6 months. The mean observation period was 4.8 +/- 1.2 years.

RESULTS

Mean Hb at baseline was 11.2 +/- 2.0 versus 14.1 +/- 1.4 g/dl (p < 0.001) at study end. There was a significant reduction in left ventricular mass index (LVMI: 159 +/- 50.4 vs. 130.2 +/- 42.7 g/m(2); p < 0.001). In a subgroup of 2/3 of the patients, LVMI returned to normal (169 +/- 33 vs. 114 +/- 14 g/m2; p < 0.001).

CONCLUSION

Baseline LVMI (p < 0.001), Hb increase (p < 0.03), and triple cardiac therapy (p < 0.03) were significant and independent prognostic factors for a reduction in LVMI. The annual cardiovascular mortality was 5%. Even anemia correction from 12 to 14 g/dl results in further (p < 0.001) regression of LVMI.

Induction of pre-transplant Epstein-Barr virus (EBV) infection by donor blood transfusion in EBV-seronegative recipients may reduce risk of post-transplant lymphoproliferative disease in adolescent renal transplant patients: report of two cases

BACKGROUND

Post-transplant lymphoproliferative disease (PTLD) is a life-threatening complication following organ transplantation. The greatest risk is seen in Epstein-Barr virus (EBV)-seronegative patients receiving allografts from EBV-seropositive donors. We demonstrate a new approach of pre-transplant prophylaxis of EBV-related PTLD, suggesting that, prior to living-related renal transplantation, blood transfusion from an EBV-seropositive donor to an EBV-seronegative recipient could induce primary EBV infection in the recipient, developing EBV immunity and decreasing risk of PTLD.

METHODS

Recipients underwent weekly donor-specific blood transfusion (3 x 100 mL) before transplantation. EBV-mRNA expression, viral load, serological tests, and clinical signs of EBV infection were assessed following blood transfusion.

RESULTS

We explored a new approach in 2 young EBV-seronegative renal allograft recipients. Both patients developed primary EBV infection following blood transfusion before transplantation and showed symptom-free seroconversion post-transplantation without persistent EBV activation. There were no signs of PTLD during 5-year follow-up.

CONCLUSIONS

A new effective and inexpensive approach is suggested for development of EBV immunity and probably for prophylaxis of EBV-associated PTLD.

Pilot study to evaluate a water displacement technique to compare effects of diuretics and ACE inhibitors to alleviate lower extremity edema due to dihydropyridine calcium antagonists

Combination therapy is required in many patients to achieve goal blood pressure (BP). Calcium antagonists are highly effective antihypertensive drugs in a broad range of demographic groups. Yet, higher doses are associated with an increased frequency of lower extremity edema. The purpose of our open label, single-center clinical trial was to evaluate the use of concomitant pharmacologic therapies to attenuate the lower extremity edema associated with dihydropyridine calcium antagonists therapy using a water displacement technique. Forty-seven patients received 5 mg/day of oral amlodipine for a period of 6 weeks after a 4-week wash-out off of all antihypertensive medications to establish baseline BP. They were then randomized to receive either an additional 5 mg of amlodipine, 25 mg of hydrochlorothiazide (HCTZ), or 20 mg of benazepril for an additional 6 weeks. Blood pressure determinations and water displacement measurements were obtained at the end of the 4-week placebo wash-out period, after 6 weeks of 5 mg/day of oral amlodipine therapy, and after an additional 6 weeks of 5 mg of amlodipine and randomized drug therapy. Adjusted BP reductions (based on pretreatment BP) were -6.8/-3.8 mm Hg for the 10-mg amlodipine group, -9.9/-8.2 mm Hg for the amlodipine (5 mg)/HCTZ (25 mg) group, and -26.2/-16.4 mm Hg for the amlodipine (5 mg)/benazepril (20 mg) group (P < .0167, group 3 v group 1 diastolic BP, which was statistically significant by the improved Bonferroni method). Seventeen of the 47 patients developed at least a 10% increase in lower extremity edema water displacement in response to 5 mg/day of oral amlodipine therapy (36.2%). Adding 5 mg of amlodipine to a baseline of 5 mg of amlodipine resulted in no net change in lower extremity edema (+58.0 mL,+ 0.6% change, n=5). Adding 25 mg of HCTZ reduced lower extremity edema by a mean of 136.3 mL (-11.1% change, n=4). Benazepril reduced water displacement by 204.4 mL (-14.3% change, n=8). Our pilot study indicates that adding an angiotensin converting enzyme inhibitor to a dihydropyridine calcium channel blocker is the most effective way to not only reduce systolic and diastolic BP but also attenuate lower extremity edema. Due to the inherent daily variability of lower extremity edema, power calculations indicate many patients (n=702, 356 in each group) would be needed to compare the antiedema efficacy of the angiotensin converting enzyme inhibitor and the thiazide diuretic.

Massive elevation of procalcitonin plasma levels in the absence of infection in kidney transplant patients treated with pan-T-cell antibodies

OBJECTIVE

To determine the value of procalcitonin (PCT) monitoring in transplant patients receiving pan-T-cell antibody therapy.

DESIGN

Retrospective clinical study.

SETTING

A collaborative study between the Institute of Medical Immunology, the Department of Nephrology and Internal Intensive Care, both Charite, Humboldt University Berlin, and the Department of Laboratory Medicine, Friedrichshain Hospital, Berlin, Germany.

PATIENTS AND INTERVENTIONS

Thirty-one patients were included in the study: 8 kidney transplant patients with acute rejection episodes, 5 receiving OKT3 monoclonal antibody therapy, 3 receiving steroid bolus therapy; 21 patients undergoing renal transplantation, 11 receiving ATG perioperatively, 10 without ATG administration; 2 patients undergoing renal transplantation and receiving anti-IL-2R mAb.

MEASUREMENTS AND RESULTS

Procalcitonin (PCT) and tumor necrosis factor (TNF) alpha plasma levels were measured in infection-free transplant patients treated with the pan-T-cell antibodies ATG or OKT3. We found PCT plasma concentrations up to 600 ng/ml (reference < 0.5 ng/ ml), which are comparable to those seen in severe sepsis. Increases in TNF-alpha plasma levels preceded the rises in PCT. After peaking on day 1 of therapy the PCT plasma concentrations returned to normal values independently of further antibody administration. In contrast, steroid bolus therapy or anti-interleukin 2 receptor mAb administration did not increase plasma PCT or TNF-alpha levels.

CONCLUSIONS

PCT monitoring for evaluating infectious complications in kidney transplant patients must be very careful during pan-T-cell antibody therapy.

CSF SNAP-25 in schizophrenia and bipolar illness. A pilot study

Research efforts to identify and understand the pathophysiology of schizophrenia and bipolar illness are limited by the inability to study neuronal tissue of living patients. An alternative to sampling brain tissue from living patients is to measure neuronal proteins found in cerebral spinal fluid. One such candidate protein is synaptosomal-associated protein 25kDa. Our hypothesis is that the level of this protein in cerebral spinal fluid may be a marker of neuronal pathology. Cerebral spinal fluid from headache, schizophrenic, bipolar, and control subjects was used to measure the SNAP-25 level by quantitative dot blotting. Schizophrenic subjects had significantly elevated levels of SNAP-25 as compared to headache and control subjects. However, there was no significant difference between the bipolar group and schizophrenic or control groups. This study reports on a potentially useful clinical marker in schizophrenia, and the presence of elevated cerebral spinal fluid SNAP-25 may indicate alterations in neuronal functioning.

Measuring synaptosomal associated protein-25 kDa in human cerebral spinal fluid

Changes in the quantity and distribution of neuronal proteins have been reported in psychiatric and neurological illnesses. The majority of this work has been performed in post-mortem samples and the results are difficult to apply to clinical care. The objective of this study is to develop a methodology that can identify trace amounts of brain proteins in cerebral spinal fluid (CSF). Human cerebral spinal fluid was processed to remove albumin and immunoglobulins. CSF samples were analyzed on Western blots using a monoclonal antibody against SNAP-25. These samples were compared to SNAP-25 immunoprecipitated from CSF, rat and human brain homogenates. The monoclonal antibody Mab 331 identified a single band of 25 kDa in all samples. These results demonstrate that the presynaptic protein SNAP-25 can be identified and measured in CSF.

Transforming growth factor-beta 1 differentially regulates proliferation, morphology, and extracellular matrix expression by three neural crest-derived neuroblastoma cell lines

We reported previously (S. L. Rogers, P. J. Gegick, S. M. Alexander, and P. G. McGuire, Dev. Biol. 151, 191-203, 1992) that transforming growth factor-beta 1 (TGF beta 1) inhibited proliferation, up-regulated fibronectin synthesis, and suppressed melanogenesis in a population of quail neural crest cells in vitro. Here, we report that cell lines derived from the parent SK-N-SH neuroblastoma line (R. A. Ross, B. A. Spengler, and J. L. Biedler, J. Natl. Cancer Inst. 71, 741-747, 1983) respond differentially to TGF beta 1, and their responses provide further insights into the actions of this growth factor on neural crest subpopulations. The SH-EP cell line exhibits primarily nonneuronal traits and responded to TGF beta 1 with increased thymidine uptake after 6 days of culture, increased expression of fibronectin mRNA and protein, and decreased laminin synthesis. Many SH-EP cells also acquired a dramatically elongated morphology, reminiscent of Schwann cells in culture. Thymidine uptake by the neuronal SY5Y cell line was not substantially altered. Neither fibronectin mRNA nor protein was detectable in either TGF beta 1-treated or untreated cultures, although laminin synthesis was upregulated by the growth factor. In TGF beta 1-treated cultures of the intermediate SH-IN cell line, which has been reported to display both neuronal and nonneuronal characteristics, there was marked flattening of many cells, a steady decrease in thymidine uptake, and increased expression of both fibronectin and laminin. The observed responses of SH-IN cells mimic those observed in primary neural crest cultures and appear to represent similar differentiation toward a mesenchymal phenotype. These results substantiate the idea that closely related but diverging neural crest-derived cell types respond selectively to TGF beta 1 and demonstrate that these SK-N-SH-derived cell lines will be useful in experimental approaches that will allow us to infer mechanisms underlying regulation of neural crest differentiation.

[Pharmacodynamics and clinical adverse effects of mivacurium. The effect of oral premedication with H1/H2 antagonists]

Duration of neuromuscular block may be prolonged by H1/H2 antagonists. This study was designed to determine the influence of H1/H2 antagonist treatment on onset, duration and recovery after mivacurium chloride (MIV), a new nondepolarizing neuromuscular blocking agent with a relatively short duration of action, which is metabolized by human plasma cholinesterase (PChE). METHODS. After approval from the hospital ethical committee and written informed consent, 48 ASA I-II patients of either sex (ages 18-65 years, weight 45-100 kg) were included in this double blind study and randomly allocated to four groups of 12 each: group A, 0.105 mg/kg MIV (1.5 x ED95) and H1/H2 antagonist; group B, 0.105 mg/kg MIV and placebo; group C, 0.21 mg/kg MIV (3 x ED95) and H1/H2 antagonist; Group D 0.21 mg/kg MIV and placebo. Premedication consisted of 2 mg lormetazepam p.o., 300 mg ranitidine and 0.1 mg/kg dimetindene, or placebo p.o. Anaesthesia was induced with thiopentone (5-7 mg/kg) and maintained with N2O/O2 at a 65/35 ratio, enflurane (0.8-1.5%) and supplements of fentanyl. The ulnar nerve was stimulated with supramaximal 2 Hz train-of-four (TOF) every 10 s. Neuromuscular twitch response was recorded with EMG. Onset time (time from end of injection to maximal or total block), maximal block (%), T125 (time from end of injection to 25% recovery) were recorded after each dose, and recovery index (T1 from 25% to 75% recovery) and TOF70 (time from end of injection to TOF ratio of 70%), after the last dose. RESULTS. The four groups did not differ with respect to age, weight or height. There was no difference in the pharmacodynamics of mivacurium between the groups receiving H1/H2 antagonists and those receiving placebo. Following 1.5 x ED95 the onset was at 3.7 +/- 1.2 (H1/H2) and 3.8 +/- 0.9 min (placebo), respectively. Clinical duration (T125) was 13.1 +/- 3.4 and 12.8 +/- 3.4 min. 3 x ED95 led to a significant faster onset and longer duration (P < or = 0.05). Onset was at 1.9 +/- 0.7 (H1/H2) and 2.1 +/- 0.5 min (placebo), respectively, and clinical duration 19.1 +/- 6.1 and 19.3 +/- 3.8 min. Duration of repetitive doses (10.1 +/- 5.3 min), recovery index (6.8 +/- 2.9 min) and interval from last dose to spontaneous recovery (22.4 +/- 7.0 min) did not differ between groups. Three patients in group D (placebo and 0.21 mg/kg MIV) had haemodynamic changes of over 20% from baseline. Flush and erythema were significantly less pronounced after H1/H2 premedication than after placebo (4 vs 12 pts). CONCLUSIONS. Our results suggest that time of onset and clinical duration of effects of MIV are not altered by dimetindene and ranitidine. The duration depends more heavily on the dose of MIV. The recovery of neuromuscular function, once it has begun, is prolonged neither by MIV nor by H1/H2 antagonists. As MIV is mainly broken down by PChE, it is evident that its duration of action is more prolonged by atypical PChE activity than by interaction with other drugs. Oral H1/H2 premedication may diminish haemodynamic side-effects and clinical signs of histamine release.

Gowning on a postpartum ward fails to decrease colonization in the newborn infant

We conducted a randomized study to evaluate the effect of gowning by visitors and hospital personnel on a postpartum ward on nose and umbilical colonization and disease in healthy newborn infants. Cultures were obtained in infants assigned to the gowning and nongowning groups within 6 hours of birth from the anterior part of the nares and the base of the umbilicus and at the time of discharge from the nursery. There were 102 infants in the gowning group and 100 infants in the nongowning group. No significant differences were noted between the two groups with respect to sex, length of stay, mode of delivery, weight, or status of nursery admission culture results. The use of gowns on a postpartum ward failed to decrease nose or umbilical colonization when compared with infants in the nongowning group. Seventy (68.6%) of 102 infants in the gowning group and 65 (65%) of 100 infants in the nongowning group had negative umbilical cord cultures on admission to the nursery that became positive at discharge. On follow-up, no differences were noted between the two groups with respect to their health. Only one infant in each group had an infection develop in the first 4 weeks of life. We conclude that the routine use of cover gowns on postpartum units in healthy full-term infants is ineffective and costly. It may discourage health care providers from examining patients and providing care.