Does hydration status influence kidney volume in autosomal dominant polycystic kidney disease?

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive kidney disease where the size of the kidneys is correlated to the stage of kidney failure. Total kidney volume (TKV) is used as a prognostic marker to determine disease stage, progression, and possible effect of treatment. It has been shown that water restriction is associated with reduced kidney volume in healthy subjects. The aim of this study was to evaluate the relationship between TKV and hydration status in ADPKD patients. 40 ADPKD patients with chronic kidney disease stage 1 - 3 were randomized to either 3 hours of water restriction (n = 21) or 1 hour of water loading (n = 19; intake: 20 mL/kg). The patients had a mean age of 38 years (19 - 73) and mean plasma creatinine level of 91 (54 - 178) µmol/L. Magnetic resonance imaging of the kidneys was performed before and after intervention, and TKV was measured using the ellipsoid formula. Water restriction resulted in an insignificant 0.67% increase in TKV (median: 1.48, interquartile range (IQR): 6.1, range: -1. - 4.5). Water loading resulted in an insignificant 2.67% increase in TKV (median: 3.18, IQR: 11.4, range: -3.6 - 7.8). Interestingly, a 7.09% increase in right-kidney volume was found after water loading (median: 5.58, IQR: 9.4 range: 1.9 - 11.3, p < 0.05), whereas the left-kidney volume showed an insignificant decrease of 0.18% after water loading (median: -1.65, IQR: 18.0, range: -12.5 - 5.5). We found in ADPKD patients that neither short-term water restriction nor acute water loading had significant effects, suggesting that the use of TKV for disease staging is independent of hydration level in these patients.

Increasing incidence and improved survival in ANCA-associated vasculitis-a Danish nationwide study.

BACKGROUND: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) carries a high risk of morbidity and mortality, with outcomes modified by treatment and an incidence that may be increasing. We examined temporal changes in incidence and mortality during 2000-15 using nationwide healthcare registries. METHODS: Patients with incident AAV were identified using International Classification of Diseases Version 10 (ICD10) codes and grouped according to inclusion year (Period 1: 2000-04, Period 2: 2005-09, Period 3: 2010-15). Log link cumulative incidence regression adjusted for age, sex, renal function, cardiovascular disease, diabetes, hypertension and advanced disease severity were used to model survival. RESULTS: We identified 1631 patients (52% male), corresponding to an incidence of 18.5 persons/million/year (Period 1: 15.1, Period 2: 18.5, Period 3: 21.4). The slope of incident serologic ANCA testing was steeper than that of AAV (P = 0.002). Mean [standard deviation (SD)] age was 60.2 (16.7) years and mean (SD) follow-up was 6.8 (4.7) years. A total of 571 (35%) patients died (5-year mortality of 22.1%), with an absolute risk ratio (ARR) for Periods 2 and 3 compared with Period 1 of 0.80 [confidence interval (CI) 0.65-0.98, P = 0.031] and 0.39 (CI 0.31-0.50, P < 0.001). About 274 patients developed end-stage renal disease (ESRD) [16.8% (Period 1: 23.3%, Period 2: 17.6%, Period 3: 12.5%)], with ARR decreasing over time: Period 2 0.61 (CI 0.42-0.87, P = 0.007) and Period 3 0.57 (CI 0.39-0.83, P = 0.003). The overall risk of death associated with ESRD or chronic kidney disease was 1.74 (CI 1.29-2.37, P < 0.001) and 1.58 (CI 1.21-2.07, P < 0.001). CONCLUSIONS: Incidence of ANCA testing and AAV diagnosis increased over the test period. Falls over time in mortality and ESRD risk may relate to earlier diagnosis and changes in treatment practice.

Effect of increased potassium intake on the renin-angiotensin-aldosterone system and subcutaneous resistance arteries: a randomized crossover study.

BACKGROUND: Increased potassium intake lowers blood pressure (BP) in hypertensive patients. The underlying mechanism is not fully understood but must be complex because increased potassium intake elevates circulating concentrations of the BP-raising hormone aldosterone. METHODS: In a randomized placebo-controlled crossover study in 25 normotensive men, we investigated the effect of 4 weeks of potassium supplement (90 mmol/day) compared with 4 weeks of placebo on the renin-angiotensin-aldosterone system (RAAS), urine composition and 24-h ambulatory BP. Vascular function was also assessed through wire myograph experiments on subcutaneous resistance arteries from gluteal fat biopsies. RESULTS: Higher potassium intake increased urinary potassium excretion (144.7 ± 28.7 versus 67.5 ± 25.5 mmol/24-h; P < 0.0001) and plasma concentrations of potassium (4.3 ± 0.2 versus 4.0 ± 0.2 mmol/L; P = 0.0002), renin {mean 16 [95% confidence interval (CI) 12-23] versus 11 [5-16] mIU/L; P = 0.0047}, angiotensin II [mean 10.0 (95% CI 6.2-13.0) versus 6.1 (4.0-10.0) pmol/L; P = 0.0025] and aldosterone [mean 440 (95% CI 336-521) versus 237 (173-386) pmol/L; P < 0.0001]. Despite RAAS activation, systolic BP (117.6 ± 5.8 versus 118.2 ± 5.2 mmHg; P = 0.48) and diastolic BP (70.8 ± 6.2 versus 70.8 ± 6.3 mmHg; P = 0.97) were unchanged. In the wire myograph experiments, higher potassium intake did not affect endothelial function as assessed by acetylcholine [logarithmically transformed half maximal effective concentration (pEC50): 7.66 ± 0.95 versus 7.59 ± 0.85; P = 0.86] and substance P (pEC50: 8.42 ± 0.77 versus 8.41 ± 0.89; P = 0.97) or vascular smooth muscle cell reactivity as assessed by angiotensin II (pEC50: 9.01 ± 0.86 versus 9.02 ± 0.59; P = 0.93) and sodium nitroprusside (pEC50: 7.85 ± 1.07 versus 8.25 ± 1.32; P = 0.25) but attenuated the vasodilatory response of retigabine (pEC50: 7.47 ± 1.16 versus 8.14 ± 0.90; P = 0.0084), an activator of Kv7 channels. CONCLUSIONS: Four weeks of increased potassium intake activates the RAAS in normotensive men without changing BP and this is not explained by improved vasodilatory responses ex vivo.

Intravenous pulse methylprednisolone for induction of remission in severe ANCA associated Vasculitis: a multi-center retrospective cohort study.

BACKGROUND: Intravenous pulse methylprednisolone (MP) is commonly included in the management of severe ANCA associated vasculitis (AAV) despite limited evidence of benefit. We aimed to evaluate outcomes in patients who had, or had not received MP, along with standard therapy for remission induction in severe AAV. METHODS: We retrospectively studied 114 consecutive patients from five centres in Europe and the United States with a new diagnosis of severe AAV (creatinine > 500 µmol/L or dialysis dependency) and that received standard therapy (plasma exchange, cyclophosphamide and high-dose oral corticosteroids) for remission induction with or without pulse MP between 2000 and 2013. We evaluated survival, renal recovery, relapses, and adverse events over the first 12 months. RESULTS: Fifty-two patients received pulse MP in addition to standard therapy compared to 62 patients that did not. There was no difference in survival, renal recovery or relapses. Treatment with MP associated with higher risk of infection during the first 3 months (hazard ratio (HR) 2.7, 95%CI [1.4-5.3], p = 0.004) and higher incidence of diabetes (HR 6.33 [1.94-20.63], p = 0.002), after adjustment for confounding factors. CONCLUSIONS: The results of this study suggest that addition of pulse intravenous MP to standard therapy for remission induction in severe AAV may not confer clinical benefit and may be associated with more episodes of infection and higher incidence of diabetes.

Elevated potassium levels in patients with chronic kidney disease: occurrence, risk factors and clinical outcomes-a Danish population-based cohort study.

Background: Data on the true burden of hyperkalemia (HK) in patients with chronic kidney disease (CKD) in a real-world setting are scarce. Methods: The incidence rate of HK [first blood test with an elevated blood potassium level level >5.0 mmol/L] in primary or hospital care was assessed in a population-based cohort of all newly diagnosed CKD patients [second estimated glomerular filtration rate (eGFR) measurement <60 mL/min/1.73 m2 or hospital diagnosis] in northern Denmark. Risk factors and clinical outcomes were compared for CKD patients with HK and matched CKD patients without HK. Results: Of 157 766 patients with CKD, 28% experienced HK, for an overall HK incidence rate of 70/1000 person-years. Among patients with Stage 3A, 3B, 4 or 5 CKD, 9, 18, 31 and 42%, respectively, experienced HK within the first year. Important HK risk factors included diabetes {prevalence ratio [PR] 1.74 [95% confidence interval (CI) 1.69-1.79]}, heart failure [PR 2.31 (95% CI 2.23-2.40)] and use of angiotensin-converting enzyme inhibitors [PR 1.45 (95% CI 1.42-1.48)], potassium supplements [PR 1.59 (95% CI 1.55-1.62)] or spironolactone [PR 2.53 (95% CI 2.44-2.63)]. In CKD patients who developed HK, 34% had any acute hospitalization 6 months before the HK event, increasing to 57% 6 months after HK [before-after risk ratio 1.72 (95% CI 1.69-1.74)]. The 6-month mortality following HK was 26%, versus 6% in matched non-HK patients. Compared with non-HK patients, 6-month hazard ratios for any acute hospitalization in HK patients were 2.11-fold higher, including hazard ratios of 2.07 for cardiac diagnoses, 2.29 for ventricular arrhythmias, 3.26 for cardiac arrest, 4.77 for intensive care and 4.85 for death. Conclusions: More than one in four CKD patients develops HK. Patients with severe CKD, diabetes, heart failure or use of spironolactone are at high risk. HK is associated with severe clinical outcomes.

The effect of spironolactone on calcineurin inhibitor induced nephrotoxicity: a multicenter randomized, double-blind, clinical trial (the SPIREN trial).

BACKGROUND: Calcineurin inhibitor induced nephrotoxicity contributes to late allograft failure in kidney transplant patients. Evidence points towards aldosterone to play a role in the development of fibrosis in multiple organs. Animal studies have indicated a beneficial effect of mineralocorticoid receptor antagonists preventing calcineurin inhibitor induced nephrotoxicity. Only few studies have explored this effect in humans. The objective of this study is to evaluate the effect of spironolactone on glomerular filtration rate and fibrosis in kidney transplant patients. METHOD: Prospective, double-blind, randomized, clinical trial including 170 prevalent kidney transplant patients. Patients are randomized to spironolactone 25-50 mg/day or placebo for three years. Primary outcome is glomerular filtration rate evaluated by chrome-EDTA clearance. Secondary outcomes are 24-h protein excretion, amount of interstitial fibrosis in renal allograft biopsies, and cardiovascular events. As an exploratory outcome, we aim to identify markers of fibrosis in blood and urine. DISCUSSION: Long term allograft survival remains a key issue in renal transplantation, partly due to calcineurin inhibitor induced nephrotoxicity. Evidence from animal- and small human studies indicate a beneficial effect of mineralocorticoid receptor antagonism on renal function and fibrosis. This study aims to test this hypothesis in a sufficiently powered randomized clinical trial. Results might influence the future management of long term allograft survival in renal transplantation. TRIAL REGISTRATION: ClinicalTrials.gov identifier (05/17/2012): NCT01602861 . EudraCT number (05/31/2011): 2011-002243-98.

Prognostic impact of carboxylesterase 1 gene variants in patients with congestive heart failure treated with angiotensin-converting enzyme inhibitors.

OBJECTIVE: Most angiotensin-converting enzyme inhibitors (ACEIs) are prodrugs activated by carboxylesterase 1 (CES1). We investigated the prognostic importance of CES1 gene (CES1) copy number variation and the rs3815583 single-nucleotide polymorphism in CES1 among ACEI-treated patients with congestive heart failure (CHF). METHODS: Danish patients with chronic CHF enrolled in the previously reported Echocardiography and Heart Outcome Study were categorized according to their CES1 variants and followed up for up to 10 years. Risk for cardiovascular death and all-cause death was modeled by Cox proportional hazard analyses. RESULTS: A total of 491 ACEI-treated patients were included in the analyses. After a mean follow-up of 5.5 years, we found no difference in the risk for cardiovascular death and all-cause death between patients having three [hazard ratios (HRs) 1.06 (95% confidence interval (CI) 0.77-1.45) and 1.16 (95% CI 0.88-1.52)] or four [HRs 0.88 (95% CI 0.39-2.01) and 1.37 (95% CI 0.74-2.54)] CES1 copies and those with two copies, respectively. Similarly, no difference in the risk for cardiovascular and all-cause death was found for patients heterozygous [HRs 0.91 (95% CI 0.70-1.19) and 0.88 (95% CI 0.69-1.12)] or homozygous [HRs 0.58 (95% CI 0.30-1.15) and 0.82 (95% CI 0.48-1.39)] for the rs3815583 minor allele versus patients homozygous for the major allele. The active promoter of CES1A2 and the rs71647871 single-nucleotide polymorphism minor allele were detected at very low frequencies. CONCLUSION: This study did not support the use of CES1 copy number variation or rs3815583 as a predictor of fatal outcomes in ACEI-treated patients with CHF.

Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in patients with abdominal aortic aneurysms: nation-wide cohort study.

OBJECTIVE: The renin-angiotensin system is thought to play a pivotal role in the pathogenesis of abdominal aortic aneurysms (AAAs). However, effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) on human AAAs remain unclear. We therefore examined whether treatment with ACEIs or ARBs influenced hard clinical end points in a nation-wide cohort of patients with AAA. APPROACH AND RESULTS: All patients diagnosed with AAA during the period 1995 to 2011 were identified from the Danish nation-wide registries. Subjects were divided according to ACEI and ARB treatment status and followed up for an average of 5 years. Study outcomes were evaluated by time-dependent Cox proportional hazard models. Of 9441 patients with AAA, 12.6% were treated with ACEIs and 5.0% received ARBs. Incidence rates of death from AAA per 100 patient-years were 3.7, 3.6, 4.0, and 4.7 for treatment with ACEIs or ARBs, ACEIs, ARBs, and no ACEI/ARB, respectively. Hazard ratios of death from AAA were 0.64 (95% confidence interval, 0.51-0.80; P<0.001) for patients receiving ACEIs and 0.65 (95% confidence interval, 0.48-0.88; P=0.006) for those receiving ARBs, respectively (P for difference=0.944). The risk of surgery for AAA was significantly reduced in patients receiving ACEIs (hazard ratio, 0.86 [95% confidence interval, 0.74-0.99]; P=0.040) but not in patients receiving ARBs (hazard ratio, 1.02 [95% confidence interval, 0.84-1.23]; P=0.867; P for difference=0.119). CONCLUSIONS: In this observational study, treatment with ACEIs or ARBs was associated with a comparable reduction in mortality but not in surgery for AAA among patients with AAA. Randomized controlled trials are warranted to confirm these findings.

Age- and time-dependent increases in incident anti-glomerular basement membrane disease: a nationwide cohort study.

Background: Epidemiologic assessments of anti-glomerular basement membrane (GBM) disease have been challenging due to its rare occurrence. We examined changes in the incidence and outcomes from 1998 to 2018 using nationwide healthcare registries. Methods: All patients with incident anti-GBM disease were identified using the International Classification of Diseases, 10th Revision code DM31.0A. Controls were matched 4:1 on birthyear and sex using exposure density sampling. Log link regression adjusted for time, age and sex was applied to model survival. Results: We identified 97 patients with incident anti-GBM disease, corresponding to an incidence of 0.91 cases/million/year [standard deviation (SD) 0.6]. The incidence increased over time [1998-2004: 0.50 (SD 0.2), 2005-2011: 0.80 (SD 0.4), 2012-2018: 1.4 (SD 0.5); P = .02] and with age [0.76 (SD 0.4), 1.5 (SD 1.04) and 4.9 (SD 2.6) for patients <45, 45-75 and >75 years]. The median age was 56 years (interquartile range 46) and 51.6% were female. Dialysis was required in 58.4%, 61.9% and 62.9% of patients at day 30, 180 and 360, respectively. The 1-year kidney survival probability was 0.38 (SD 0.05) and exhibited time-dependent changes [1998-2004: 0.47 (SD 0.13), 2005-2011: 0.16 (SD 0.07), 2012-2018: 0.46 (SD 0.07); P = .035]. The 5-year mortality was 26.8% and mortality remained stable over time (P = .228). The risk of death was greater than that of the matched background population {absolute risk ratio [ARR] 5.27 [confidence interval (CI) 2.45-11.3], P < .001}, however, it was comparable to that of patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) requiring renal dialysis at presentation [ARR 0.82 (CI 0.48-1.41), P = .50]. Conclusion: The incidence of anti-GBM disease increased over time, possibly related to temporal demographic changes. Mortality remained high and was comparable with an age- and sex-matched cohort of dialysis-dependent AAV patients.

Effect of Increased Potassium Intake on Adrenal Cortical and Cardiovascular Responses to Angiotensin II: A Randomized Crossover Study.

Background Increased potassium intake lowers blood pressure in patients with hypertension, but increased potassium intake also elevates plasma concentrations of the blood pressure-raising hormone aldosterone. Besides its well-described renal effects, aldosterone is also believed to have vascular effects, acting through mineralocorticoid receptors present in endothelial and vascular smooth muscle cells, although mineralocorticoid receptors-independent actions are also thought to be involved. Methods and Results To gain further insight into the effect of increased potassium intake and potassium-stimulated hyperaldosteronism on the human cardiovascular system, we conducted a randomized placebo-controlled double-blind crossover study in 25 healthy normotensive men, where 4 weeks treatment with a potassium supplement (90 mmol/day) was compared with 4 weeks on placebo. At the end of each treatment period, we measured potassium and aldosterone in plasma and performed an angiotensin II (AngII) infusion experiment, during which we assessed the aldosterone response in plasma. Hemodynamics were also monitored during the AngII infusion using ECG, impedance cardiography, finger plethysmography (blood pressure-monitoring), and Doppler ultrasound. The study showed that higher potassium intake increased plasma potassium (mean±SD, 4.3±0.2 versus 4.0±0.2 mmol/L; P=0.0002) and aldosterone (median [interquartile range], 440 [336-521] versus 237 [173-386] pmol/L; P<0.0001), and based on a linear mixed model for repeated measurements, increased potassium intake potentiated AngII-stimulated aldosterone secretion (P=0.0020). In contrast, the hemodynamic responses (blood pressure, total peripheral resistance, cardiac output, and renal artery blood flow) to AngII were similar after potassium and placebo. Conclusions Increased potassium intake potentiates AngII-stimulated aldosterone secretion without affecting systemic cardiovascular hemodynamics in healthy normotensive men. Registration EudraCT Number: 2013-004460-66; URL: https://www.ClinicalTrials.gov; Unique identifier: NCT02380157.

Severely Disseminated Kaposi Sarcoma after ABO-Incompatible Kidney Transplantation Treated Successfully with Paclitaxel and Gemcitabine Combined with Hemodialysis.

Kaposi Sarcoma (KS) is driven by human herpes virus 8 causing vascular proliferation which is induced by loss of immune function most often due to HIV or immunosuppressants. KS occurs with increased incidence in kidney transplant recipients, but rarely is disseminated. We report a 64-year-old male who developed severely disseminated KS 5 months after ABO-incompatible kidney-transplantation. No guidelines for chemotherapy exist in this case and reduced kidney function and impaired immune system complicates the use of systemic chemotherapy in kidney transplant recipients. A combination of paclitaxel and gemcitabine followed by two days of hemodialysis treatment was chosen since paclitaxel can be given in full dose independently of kidney function and gemcitabine is metabolised to 2',2'-difluorodeoxyuridine which is found to be highly dialysable. The present treatment was well tolerated by the patient with one episode of leukopenia and elevated alanine transaminase during treatment which resolved. There were no serious adverse events and the patient obtained a complete remission verified by Positron Emission Tomography CT after ending chemotherapy and at one-year follow up.

Temporal Regulation of Glomerular and Cortical Tubulointerstitial Genes Involved in the Development of Nephrotoxic Serum Nephritis.

BACKGROUND/AIMS: Murine nephrotoxic nephritis (NTN) is a well-established model resembling chronic kidney disease. Investigating gene expression patterns separately in the glomerular and cortical tubulointerstitial structure could provide new knowledge about structure-specific changes in expression of genes in the NTN model. METHODS: Glomerular, cortical tubulointerstitial and whole kidney tissues from mice subjected to nephrotoxic serum (NTS) or phosphate buffered saline (PBS) were collected on day 7, 21 and 42 using laser microdissection (LMD). Total RNA was extracted and subjected to nCounter NanoString. Histology, immunohistochemistry, in situ hybridization and/or quantitative real time PCR (qRT PCR) were performed to confirm regulation of selected genes. RESULTS: LMD provided detailed information about genes that were regulated differently between structures over time. Some of the fibrotic and inflammatory genes (Col1a1, Col3a1 and Ccl2) were upregulated in both structures, whereas other genes such as Spp1 and Grem1 were differentially regulated suggesting spatial pathogenic mechanisms in the kidney. Downregulation of cortical tubulointerstitium genes involved in iron metabolism was detected along with iron accumulation. CONCLUSION: This study demonstrates several regulated genes in pathways important for the pathogenesis of the NTN model and that LMD identifies structure-specific changes in gene expression during disease development. Furthermore, this study shows the benefits of isolating glomeruli and cortical tubulointerstitium in order to identify gene regulation.

Elevated Potassium Levels in Patients With Congestive Heart Failure: Occurrence, Risk Factors, and Clinical Outcomes: A Danish Population-Based Cohort Study.

BACKGROUND: Data on the true burden of hyperkalemia in patients with heart failure (HF) in a real-world setting are limited. METHODS AND RESULTS: Incidence rates of hyperkalemia (first blood test with a potassium level >5.0 mmol/L) in primary or hospital care were assessed in a population-based cohort of patients with incident HF diagnoses in northern Denmark from 2000 to 2012. Risk factors and clinical outcomes were compared in patients with HF with versus without hyperkalemia. Of 31 649 patients with HF, 39% experienced hyperkalemia (mean follow-up, 2.2 years). Risks of experiencing a second, third, or fourth event were 43%, 54%, and 60%, respectively. Among patients with HF with stage 3A, 3B, 4, or 5 kidney dysfunction, 26%, 35%, 44%, and 48% experienced hyperkalemia within the first year. Important hyperkalemia risk factors included chronic kidney disease (prevalence ratio, 1.46; 95% confidence interval [CI], 1.43-1.49), diabetes mellitus (prevalence ratio, 1.38; 95% CI, 1.32-1.45), and spironolactone use (prevalence ratio, 1.48; 95% CI, 1.42-1.54). In patients with HF who developed hyperkalemia, 53% had any acute-care hospitalization 6 months before the hyperkalemia event, increasing to 74% 6 months after hyperkalemia (before-after risk ratio, 1.41; 95% CI, 1.38-1.44). Compared with matched patients with HF without hyperkalemia, adjusted 6-month hazard ratios in patients with hyperkalemia were 2.75-fold (95% CI, 2.65-2.85) higher for acute-care hospitalization and 3.39-fold (95% CI, 3.19-3.61) higher for death. CONCLUSIONS: Almost 4 in 10 patients with HF develop hyperkalemia, and many patients have recurrent hyperkalemia episodes. Hyperkalemia risk is strongly associated with degree of reduced kidney function and use of spironolactone. Hyperkalemia is associated with severe clinical outcomes and death in HF.

[Primary membranous nephropathy presenting as relapsing ascites].

Ascites is common in patients with liver cirrhosis. It may present as a clinical manifestation in nephrotic syndrome in adults, typically with heart- or liver disease together with other oedema. We describe a 64-year-old male patient - with no liver or heart disease - with relapsing ascites and no other oedema, who was surprisingly diagnosed with primary membranous nephropathy (MN), and the autoantibody anti-PLA2R was positive. Through immunotherapy the ascites disappeared. Anti-PLA2R and anti-TSHD7A can be used in the diagnosis (primary/secondary MN) and may play a role in the treatment and prognosis.

[Autosomal dominant polycystic kidney disease].

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disorder which causes end stage renal disease. In Denmark, estimated 5,000 patients are living with the disease. Most of the patients are in regular contact with physicians due to the progression of kidney failure causing hypertension as well as cyst infections, back pain, abdominal distension and other symptoms caused by the enlarged kidneys. In this article we describe the clinical presentation, the genetics, the pathophysiology and the current and future treatment modalities of the disease.

Correlations between calcineurin phosphatase inhibition and cyclosporine metabolites concentrations in kidney transplant recipients: implications for immunoassays.

Cyclosporine exhibits a wide spectrum of metabolites that vary considerably in the extent to which they interfere with the various parent drug monitoring immunoassays. There is no consensus regarding the clinical significance of metabolites. Cyclosporine exerts its immunosuppressive action by inhibiting the enzyme calcineurin phosphatase. Determination of the enzyme's activity is one of the most promising pharmacodynamic markers. It is unknown how calcineurin phosphatase inhibition correlates with various cyclosporine monitoring assays and what is the potential impact of metabolites in this perspective? The aim of the present study was to determine the concentration of cyclosporine (by means of three different assay methods) and the four most significant metabolites (AM1, AM4N, AM9, and AM1C) in relation to calcineurin phosphatase inhibition. Twelve randomly selected cyclosporine-treated renal transplant patients were included in the study. Blood samples were drawn before, 1, 2, 3, 4, 6, 8, and 12 hr after oral intake of cyclosporine. Parent drug and metabolites were determined by liquid chromatography/tandem mass spectrometry (LC/MSMS). Additionally, cyclosporine concentration was determined by the enzyme multiplied immunoassay technique (EMIT) and by the polyclonal fluorescence polarization immunoassay (pFPIA). Calcineurin phosphatase activity was measured by its ability to dephosphorylate a previously phosphorylated 19-amino acid peptide. We found that calcineurin phosphatase inhibition correlates strongly with parent cyclosporine metabolites concentrations determined by all three assay methods. Determination methods that took metabolites into consideration exhibit stronger correlations with calcineurin phosphatase inhibition (sum of cyclosporin plus metabolites r=-0.93, LC/MSMS; pFPIA r=-0.94, P

Pharmacodynamic Impact of Carboxylesterase 1 Gene Variants in Patients with Congestive Heart Failure Treated with Angiotensin-Converting Enzyme Inhibitors.

BACKGROUND: Variation in the carboxylesterase 1 gene (CES1) may contribute to the efficacy of ACEIs. Accordingly, we examined the impact of CES1 variants on plasma angiotensin II (ATII)/angiotensin I (ATI) ratio in patients with congestive heart failure (CHF) that underwent ACEI dose titrations. Five of these variants have previously been associated with drug response or increased CES1 expression, i.e., CES1 copy number variation, the variant of the duplicated CES1 gene with high transcriptional activity, rs71647871, rs2244613, and rs3815583. Additionally, nine variants, representatives of CES1Var, and three other CES1 variants were examined. METHODS: Patients with CHF, and clinical indication for ACEIs were categorized according to their CES1 genotype. Differences in mean plasma ATII/ATI ratios between genotype groups after ACEI dose titration, expressed as the least square mean (LSM) with 95% confidence intervals (CIs), were assessed by analysis of variance. RESULTS: A total of 200 patients were recruited and 127 patients (63.5%) completed the study. The mean duration of the CHF drug dose titration was 6.2 (SD 3.6) months. After ACEI dose titration, there was no difference in mean plasma ATII/ATI ratios between subjects with the investigated CES1 variants, and only one previously unexplored variation (rs2302722) qualified for further assessment. In the fully adjusted analysis of effects of rs2302722 on plasma ATII/ATI ratios, the difference in mean ATII/ATI ratio between the GG genotype and the minor allele carriers (GT and TT) was not significant, with a relative difference in LSMs of 0.67 (95% CI 0.43-1.07; P = 0.10). Results of analyses that only included enalapril-treated patients remained non-significant after Bonferroni correction for multiple parallel comparisons (difference in LSM 0.60 [95% CI 0.37-0.98], P = 0.045). CONCLUSION: These findings indicate that the included single variants of CES1 do not significantly influence plasma ATII/ATI ratios in CHF patients treated with ACEIs and are unlikely to be primary determinants of ACEI efficacy.

Comparison between 1alpha(OH)D3 and 1,25(OH)2D3 on the suppression of plasma PTH levels in uremic patients, evaluated by the 'whole' and 'intact' PTH assays.

BACKGROUND/AIMS: The aim was to evaluate the acute effects of intravenous 1alpha(OH)D3 and 1,25(OH)2D3 on (1) plasma parathyroid hormone (PTH) and Ca2+ levels in chronic uremic patients and (2) circulating large C-terminal PTH fragments as measured by the 'whole PTH' assay compared to two different 'intact PTH' assays. METHODS: 11 patients on chronic hemodialysis with plasma intact PTH >90 pg/ml were studied. At time zero 10 microg 1,25(OH)2D3 (Calcijex, Abbott, USA), or 10 microg 1alpha(OH)D3 (Etalpha, LEO, Denmark) or 10 ml of isotonic saline was injected as a bolus. Blood samples for analyses of plasma Ca2+ and plasma PTH were drawn at 0, 6, 12, 24, 48 and 72 h. The same patient was studied 3 times in a random fashion with an interval of 3 weeks. Further, 7 of the patients were studied after an injection of 6 microg 1,25(OH)2D3 intravenously. RESULTS: No significant changes in plasma Ca2+ and PTH were seen after administration of saline. Twenty-four hours after administration of 1,25(OH)2D3, plasma PTH decreased from a maximum level of PTHWHOLE 151 +/- 27 to a minimum of 58 +/- 13 pg/ml; from a maximum level of PTHTOTAL 247 +/- 40 to a minimum of 99 +/- 26 pg/ml and from a maximum level of PTHINTACT 205 +/- 29 to a minimum of 83 +/- 18 pg/ml (p < 0.001). Twenty-four hours after administration of 1alpha(OH)D3, plasma PTH levels decreased from a maximum level of PTHWHOLE 155 +/- 21 to a minimum of 116 +/- 15 pg/ml; from a maximum level of PTHTOTAL 265 +/- 33 to a minimum of 221 +/- 35 pg/ml and from a maximum level of PTHINTACT 222 +/- 26 to a minimum of 182 +/- 23 pg/ml (p < 0.05). Regardless of which of the three assays that was applied, the percentage suppression of PTH following administration of 1,25(OH)2D3 was approximately 60% and following administration of 1alpha(OH)D3 approximately 20%. Significant correlations were demonstrated between the Whole and the intact PTH assays, and as expected between the 2 intact assays ('Whole'/'Intact', r = 0.92, p < 0.0001, 'Whole'/'Total', r = 0.94, p < 0.0001, 'Intact'/'Total', r = 0.97, p < 0.0001) with no influence of the two vitamin D analogs administered. Plasma Ca2+ remained stable after administration of saline. After 24 h, no increase in plasma Ca2+ was observed after administration of 1alpha(OH)D3 or after administration of 6 microg 1,25(OH)2D3, while plasma Ca2+ after administration of 10 microg 1,25(OH)2D3 increased to 1.31 +/- 0.03 mmol/l (p < 0.008). After 72 h, 1alpha(OH)D3 increased plasma Ca2+ to 1.22 +/- 0.02 mmol/l (p < 0.05) and 10 microg 1,25(OH)2D3 to 1.27 +/- 0.03 mmol/l. Plasma phosphate was within the normal range before administration of saline (1.24 +/- 0.13 mmol/l), 1,25(OH)2D3 (1.28 +/- 0.12 mmol/l) and 1alpha(OH)D3 (1.46 +/- 0.21 mmol/l). Plasma phosphate increased significantly after 24, 48 and 72 h to a maximum of 2.06 +/- 0.27 mmol/l after administration of 1,25(OH)2D3 and a maximum of 1.94 +/- 0.31 mmol/l after administration of 1alpha(OH)D3. Plasma phosphate was significantly higher after 1,25(OH)2D3 than after 1alpha(OH)D3 at 48 (p = 0.016) and 72 h (p < 0.010). CONCLUSION: A single intravenous dose of both 10 microg 1,25(OH)2D3 and 1alpha(OH)D3 significantly suppressed plasma PTH. The acute suppressive effect of 1,25(OH)2D3 was 3 times greater than that of 1alpha(OH)D3. The increase in plasma Ca2+ after intravenous administration of 10 microg of 1,25(OH)2D3 was, however, significantly greater than that of 10 microg of 1alpha(OH)D3 (p < 0.005). The PTH response to acute administration of 10 microg of the two vitamin D analogs was in principle the same, when measured by the three different assays and resulted in a parallel shift of the PTH response curves. Thus, circulating levels of large C-terminal PTH fragments were not influenced by differences in plasma Ca2+ or by the vitamin D analog given.