Tacrolimus EP Impurity I

Blood specimens from twenty-six renal transplant recipients treated with cyclosporine (CsA) were collected at weekly intervals, two months after transplantation. Specimens were grouped according to their CsA concentrations. Group I consisted of ten specimens with CsA concentration of >400 ng/ml; group II consisted of ten specimens with CsA concentrations ranging from 120-300 ng/ml; and group III consisted of six specimens with CsA concentrations of < 100 ng/ml. In addition, specimens from five renal transplant patients who, instead of CsA, received the immunosuppressant FK506 (group IV), and from six healty individuals were included. Plasma low-density lipoproteins (LDL) were isolated and their susceptibility to oxidation was studied by continuously monitoring the formation of conjugated dienes during copper ion-mediated oxidation. Patients with higher blood concentrations of CsA (groups I and II) had significantly higher oxidizability of LDL, as indicated by the shorter time required to start the oxidation (lag phase). The oxidizability of samples with low concentration of CsA (group III) was not significantly different from that of FK506-treated patients or healthy individuals. There was a negative correlation (r = -0702, P < 0.01) between oxidizability (lag phase) and CsA concentration in LDL. No correlation between blood CsA and plasma cholesterol or triglyceride concentration was evident during a three-month period postoperatively. Similarly, no correlation between the degree of oxidizability and plasma cholesterol or triglycerides was found at the time of the experiment. These findings suggest a prooxidant effect of CsA to plasma LDL, and may indicate that CsA is an important risk factor in the accelerated atherosclerosis of renal transplant recipients.

Intestinal transplantation is the only curative form of treatment for fulminant short bowel syndrome. Results have been hampered by frequent rejection episodes as well as technical and infectious complications. We report the first case of complete small bowel transplantation performed at our institution. A 37-year-old male patient suffered from massive gut infarction due to a superior mesenteric artery embolus from a thrombus in the descending aorta resulting from hereditary protein S and C deficiency. The primary surgery resulted in a duodenocolostomy requiring total parenteral nutrition. The course was further complicated by multiple central line infections and pre-renal kidney failure induced by dehydration. After 17 months, we performed a cadaveric small bowel transplant using systemic venous drainage. The ileum was anastomosed end-to-end to the recipient ascending colon. The proximal jejunum was used to create a jejunostomy, with an end-to-side duodenojejunostomy. Immunosuppression consisted of a single-administration of antithymocyte globulin (ATG), tacrolimus, mycophenolate mofetil (MMF), and methylprednisolone given enterally from day 1. Biopsies of the upper jejunum showed no signs of rejection. The graft was monitored via capsule video endoscopy after 9 weeks and appeared normal. The patient was discharged on day 35, completely on an enteral diet and gaining weight with a good quality of life. Oral valganciclovir was given for the cytomegalovirus prophylaxis infection (donor-positive, recipient-negative constellation), with no clinical or serologic signs of infection. The early course after small bowel transplantation using a quadruple regimen was clinically successful. The use of video-capsules allows for noninvasive visual monitoring of bowel segments that cannot be reached endoscopically.

Background:Tacrolimus (Tac) is one of the most commonly used immunosuppressive drugs after solid organ transplantation. Eight Tac metabolites have been described, but their clinical importance remains unclear. The aim of this study was quantification of the 2 major Tac metabolites, 13-O-demethyl (M-I) and 15-O-demethyl (M-III), in kidney transplant recipients and to link them with parameters of kidney and liver function, peripheral blood cell counts, and infection incidence.Methods:In 81 kidney transplant recipients, concentrations of Tac, M-I, and M-III were measured with the use of liquid chromatography combined with tandem mass spectrometry (LC-MS-MS).Results:There was a negative correlation between M-III levels and estimated glomerular filtration rate (eGFR; r = -0.244; P < .05). Also, a negative correlation between M-III concentrations and red blood cell count (RBC) was found (r = -0.349; P < .05). Neither concentrations of Tac nor of M-I correlated with eGFR or RBC. M-I, M-III, and Tac were not related to alanine aminotransferase activity. Significantly higher Tac and M-III concentrations in the group with all types of infections in comparison with the group without infections were observed (6.95 ± 2.09 ng/mL vs 5.73 ± 2.43 ng/mL [P = .03] and 0.27 ± 0.17 ng/mL vs 0.20 ± 0.11 ng/mL [P = .04], respectively).Conclusions:The results suggest that higher concentrations of M-III may have a nephrotoxic or myelotoxic effect and result in higher incidence of infections. Further studies are needed to confirm if monitoring of M-III could minimalize adverse effects such as nephrotoxicity or infections.

To compare the effect of tacrolimus (FK506) and cyclosporine (CsA) on plasma lipoproteins in renal transplant recipients receiving maintainance therapy, the following prospective study was undertaken. Blood from nineteen recipients on tacrolimus (FK group) and from twenty-one on CsA (CsA group) was collected at baseline, 3-, 6-, and 10-month intervals. Plasma lipids, lipoproteins and oxidation properties of lipoproteins were determined. Plasma total cholesterol, low density lipoprotein (LDL) cholesterol, and apolipoprotein B (apoB) were substantially increased in both groups, although only the CsA group showed significant differences at all time intervals and at the baseline. High density lipoprotein cholesterol, triglycerides, and apolipoprotein A varied in both groups at time intervals from the baseline, but not significantly. The susceptibility to oxidation of LDL isolated from the FK group at all times was uninfluenced by the tacrolimus treatment, and values were comparable to those obtained from LDL isolated from healthy individuals. A significantly higher susceptibility to oxidation as indicated by the shorter time required to start the formation of conjugated dienes was observed in LDL isolated from the CsA group at 3 and at 6 months of therapy. Tacrolimus-treated patients appear to have less hyperlipidemic and have LDL less susceptible to oxidation than patients treated with CsA.