Endomyocardial, intralymphocyte, and whole blood concentrations of ciclosporin A in heart transplant recipients

BACKGROUND: In the early phases following heart transplantation a main challenge is to reduce the impact of acute rejections. Previous studies indicate that intracellular ciclosporin A (CsA) concentration may be a sensitive acute rejection marker in renal transplant recipients. The aims of this study were to evaluate the relationships between CsA concentrations at different target sites as potential therapeutic drug monitoring (TDM) tools in heart transplant recipients. METHODS: Ten heart transplant recipients (8 men, 2 women) on CsA-based immunosuppression were enrolled in this prospective single-center pilot study. Blood samples were obtained once to twice weekly up to 12 weeks post-transplant. One of the routine biopsies was allocated to this study at each sampling time. Whole blood, intralymphocyte, and endomyocardial CsA concentrations were determined with validated HPLC-MS/MS-methods. Mann–Whitney U test was used when evaluating parameters between the two groups of patients. To correlate whole blood, intralymphocyte, and endomyocardial CsA concentrations linear regression analysis was used. RESULTS: Three patients experienced mild rejections. In the study period, the mean (range) intralymphocyte CsA trough concentrations were 10.1 (1.5 to 39) and 8.1 (1.3 to 25) ng/10(6) cells in the rejection and no-rejection group, respectively (P=0.21). Corresponding whole blood CsA concentrations were 316 (153 to 564) and 301 (152 to 513) ng/mL (P=0.33). There were no correlations between whole blood, intralymphocyte, or endomyocardial concentrations of CsA (P >0.11). CONCLUSIONS: The study did not support an association between decreasing intralymphocyte CsA concentrations and acute rejections. Further, there were no association between blood concentrations and concentrations at sites of action, potentially challenging TDM in these patients

Pharmacokinetics and pharmacodynamics of continuous infusion of cefepime in cystic fibrosis patients, and stability of cefepime during simulated continuous infusion administration

Time above minimal inhibitory concentration (MIC) (T>MIC) is the PK/PD parameter that best correlates with bacterial killing for cefepime. Cefepime CI provides an efficient method of achieving T>MIC throughout the dosing interval. The purpose of this study was to determine whether cefepime exhibits sufficient stability and antibacterial activity to be given by 24-hour CI using portable infusion pumps. In addition, assess the PK and PD of CI versus intermittent infusion of cefepime in cystic fibrosis patients administered during an acute pulmonary exacerbation. The stability of cefepime in 5% dextrose distilled water (D5W) solutions was determined for a simulated CI using a portable infusion pump (Microject 30, Sorensen Medical) worn over a period of 24-36 hours. The temperatures in the bags were measured every ½ hour. In addition the stability at different storage conditions was tested, major degradation products identified and the antibacterial activity of degraded solution was measured. In this study, we also compared the PK and PD of traditional dosing (50mg/kg iv every 8 hour) versus CI of cefepime (100mg/kg/24hour), using standard two-stage PK modeling with ADAPT II software. The PD outcomes evaluated included sputum bacterial density, sputum interleukin-8 (IL-8) concentration and improvement in forced expiratory volume within 1 second (FEV1). In-vitro experiments revealed that cefepime stability at 24 hours following CI was 94.3±1.0%. The mean infusion bag temperature was 22.6±°1.5°C. Cefepime is stable for 15 days in a refrigerator and 10 hours at 37°C. The degradation includes cleavage of the R2 side chain and opening of the β-lactam ring. Antibacterial activity appeared to correlate with intact cefepime remaining in solution (r2>0.74, p<0.001). The Arrhenius plot showed that the average temperature in the bag should not exceed 29.1°C in order to maintain 90% stability at 24 hours. The PK analysis showed that a two-compartment model best describes cefepime observed serum concentration. The two-compartment PK parameters were calculated with MAP-Bayesian algorithm and were found to be total clearance of 2.5mL/min/kg, distribution clearance of 1.9mL/min/kg, distribution half-life of 0.53 hours, and elimination half-life of 2.8 hours. The sample size in this study was too small to be able to make any significant distinction between PD outcomes in the patients receiving CI versus those receiving intermittent dosing. It was possible to observe a trend, being that patients with T>MIC 100% of the time had a greater decline in bacterial density, and a higher decline in the inflammatory marker IL-8. These results demonstrated that the stability of cefepime supports CI. A cold pack is necessary if the average temperature in the drug solution exceeds 29°C. Solutions of cefepime should be stored in a refrigerator if not used right away, and in a freezer if not used within 5 days. The PD results showed an indication of better clinical outcome with CI administration, however more patients are needed to show statistical significance

Betraktninger om middelalderens Vágar basert på undervannsarkeologiske kilder

Vágar er først nevnt i det skriftlige kildematerialet som stedsnavn på slutten av 900-tallet, samt i sagatekstene med henvisning til viktige hendelser på stedet fra tidlig 1000-tall (Bjørgo 1982). Både skriftlige og arkeologiske kilder formidler med tydelighet at Vágar framsto som en sentral kjøpstad i Nord-Norge på 1200-tallet, men overgangen fra det som må ha vært et naturhavnområde og et sesongbasert fiskevær til en helårs havnebebyggelse med urban struktur er fortsatt dårlig belyst. Det er imidlertid klart at endringen har direkte tilknytning til kommersialisering av vinterfiske og økt produksjon av tørrfisk i Lofoten på 1100-tallet. Denne kommersialiseringen er igjen koblet til en ekspanderende tørrfiskhandel med Europa (Perdikaris 1998, 1999). Markedsgrunnlaget for tørrfisk ble delvis generert og ekspanderte som følge av religionsskiftet i Europa, der pålegget om faste medførte økt etterspørsel etter fisk. I tillegg var fremveksten av byer, markeder og handelsorganisasjoner viktige faktorer som bidro til ekspansjonen (Urbańczyk 1992). Tørrfiskhandelen skapte altså et økonomisk grunnlag, samtidig utgjorde Vágar-området et helt nettverk av gode naturhavner, alle med en sentral beliggenhet nær et av Nord-Atlanterens betydeligste fiskefelt for vårgytende torsk. Dette er faktorer som muliggjorde framveksten av en sentral kjøpstad her på 1200-tallet. Tørrfiskproduksjonen var imidlertid sesongpreget og både antall innbyggere og nivået av økonomisk aktivitet i Vágar var sannsynligvis gjenspeilet i denne årlige syklusen. Fast helårsbosetning er tydelig dokumentert i det arkeologiske funnmaterialet fra 1200-tallet samtidig med sesongbosetning tilknyttet vinterfiske (Bertelsen 2009: 205)

Urinary proteomic shotgun approach for identification of potential acute rejection biomarkers in renal transplant recipients

Background Acute rejection (AR) episodes in renal transplant recipients are suspected when plasma creatinine is elevated and other potential causes out ruled. Graft biopsies are however needed for definite diagnosis. Non-invasive AR-biomarkers is an unmet clinical need. The urinary proteome is an interesting source in the search for such a biomarker in this population. Methods In this proof of principle study, serial urine samples in the early post transplant phase from 6 patients with biopsy verified acute rejections and 6 age-matched controls without clinical signs of rejection were analyzed by shotgun proteomics. Results Eleven proteins fulfilled predefined criteria for regulation in association with AR. They presented detectable regulation already several days before clinical suspicion of AR (increased plasma creatinine). The regulated proteins could be grouped by their biological function; proteins related to growth and proteins related to immune response. Growth-related proteins (IGFBP7, Vasorin, EGF and Galectin-3-binding protein) were significantly up-regulated in association with AR (P = 0.03) while proteins related to immune response (MASP2, C3, CD59, Ceruloplasmin, PiGR and CD74) tended to be up-regulated ( P = 0.13). Conclusion The use of shotgun proteomics provides a robust and sensitive method for identification of potentially predictive urinary biomarkers of AR. Further validation of the current findings is needed to establish their potential clinical role with regards to clinical AR diagnosis. Trial registration ClinicalTrials.gov number NCT0013900

The concentration of cyclosporine metabolites is significantly lower in kidney transplant recipients with diabetes mellitus

Background: Diabetes mellitus is prevalent among kidney transplant recipients. The activity of drug metabolizing enzymes or transporters may be altered by diabetes leading to changes in the concentration of parent drug or metabolites. This study was aimed to characterize the effect of diabetes on the concentration of cyclosporine (CsA) and metabolites. Methods: Concentration-time profiles of CsA and metabolites (AM1, AM9, AM4N, AM1c, AM19, and AM1c9) were characterized over a 12-hour dosing interval in 10 nondiabetic and 7 diabetic stable kidney transplant recipients. All patients were male, had nonfunctional CYP3A5*3 genotype, and were on combination therapy with ketoconazole. Results: The average daily dose (±SD) of CsA was 65 ± 21 and 68 ± 35 mg in nondiabetic and diabetic subjects, respectively (P = 0.550). Cyclosporine metabolites that involved amino acid 1 (AM1, AM19, AM1c) exhibited significantly lower dose-normalized values of area under the concentration-time curve in patients with diabetes. Moreover, during the postabsorption phase (≥3 hours after dose), metabolite-parent concentration ratios for all metabolites, except AM4N, was significantly lower in diabetic patients. The pharmacokinetic parameters of ketoconazole were similar between the 2 groups thus excluding inconsistent ketoconazole exposure as a source of altered CsA metabolism. Conclusions: This study indicates that diabetes mellitus significantly affects the concentration of CsA metabolites. Because CsA is eliminated as metabolites via the biliary route, the decrease in the blood concentration of CsA metabolites during postabsorption phase would probably reflect lower hepatic cytochrome P450 3A4 enzyme activity. However, other mechanisms including altered expression of transporters may also play a role. Results of cyclosporine therapeutic drug monitoring in diabetic patients must be interpreted with caution when nonspecific assays are used. Copyright © 2012 by LippincottWilliams & Wilkins

Declining intracellular T-lymphocyte concentration of cyclosporine A precedes acute rejection in kidney transplant recipients

BACKGROUND. We investigated cyclosporine A (CsA) concentrations at the site of action, inside T-lymphocytes, to evaluate its applicability as a new supplementary therapeutic drug monitoring method after renal transplantation. METHOD. In this prospective single-center study, 20 kidney transplant recipients, mean age 54 (range 21-74) years, on CsA-based immunosuppression were included within 2 weeks posttransplant and followed for 3 months. Nine patients also had one full 12-hour pharmacokinetic profile performed. T-lymphocytes were isolated from 7 ml whole blood using Prepacyte and intracellular CsA concentrations were determined using a validated liquid chromatography double mass spectrometry method. RESULTS. Seven patients (35%) experienced acute rejections (all biopsy verified) during the first three months posttransplantation. Intracellular CsA concentrations tended to decline 1 week prior to acute rejection and the decrease was significant (-27.1±14.6%, P=0.014) three days before the rejection episodes were recognized clinically. In addition, the intracellular CsA area under the curve 0-12 measured during stable phase was 182% higher in the rejection-free patients (P=0.004). There was no difference between patients experiencing rejection and the rejection-free patients with respect to CsA C2-levels, dose (mg/kg), human leukocyte antigen mismatch, donor age, recipient age, or ABCB1 genotyping. CONCLUSION. Intracellular CsA T-lymphocyte concentrations declined significantly 3 days prior to a rejection episode and there was a general lower intracellular exposure of CsA in recipients experiencing rejection. Intracellular measurement of CsA therefore seems to have a potential to further improve individualization of therapeutic drug monitoring. Larger studies are needed to elucidate the role for intracellular T-lymphocyte measurements in ordinary clinical care, for both CsA and other immunosuppressive drugs. © 2008 Lippincott Williams & Wilkins, Inc