L-Carnitine Combined with Leucine Supplementation Does Not Improve the Effectiveness of Progressive Resistance Training in Healthy Aged Women.

OBJECTIVES: To evaluate the effect of L-carnitine (LC) in combination with leucine supplementation on muscle strength and muscle hypertrophy in aged women participating in a resistance exercise training (RET) program. DESIGN/SETTING/PARTICIPANTS: Thirty-seven out of sixty (38.3% dropout) healthy women aged 60-75 years (mean 67.6 ± 0.7 years) completed the intervention in one of three groups. One of the supplemented groups received 1 g of L-carnitine-L-tartrate in combination with 3 g of L-leucine per day (LC+L group; n = 12), and the second supplemented group received 4 g of L-leucine per day (L group; n = 13). The control group (CON group; n = 12) received no supplementation. INTERVENTION: All three groups completed the same RET protocol involving exercise sessions twice per week for 24 weeks. MEASUREMENTS: Before and after the experiment, participants performed isometric and isokinetic muscle strength testing on the Biodex dynamometer. The cross-sectional areas of the major knee extensors and total thigh muscles were assessed using magnetic resonance imaging. Fasting serum levels of insulin-like growth factor-1 (IGF-1), myostatin and decorin, and plasma levels of total carnitine (TC) and trimethylamine-N-oxide (TMAO) levels were measured. RESULTS: The 24-week RET significantly increased muscle strength and muscle volume, but the group and time interactions were not significant for the muscle variables analyzed. Plasma total carnitine increased only in the LC+L group (p = 0.009). LC supplementation also caused a significant increase in plasma TMAO, which was higher after the intervention in the LC+L group than in the L (p < 0.001), and CON (p = 0.005) groups. The intervention did not change plasma TMAO concentration in the L (p = 0.959) and CON (p = 0.866) groups. After the intervention serum decorin level was higher than before in both supplemented groups combined (p = 0.012), still not significantly different to post intervention CON (p = 0.231). No changes in serum IGF-1 and myostatin concentrations and no links between the changes in blood markers and muscle function or muscle volume were observed. CONCLUSIONS: LC combined with leucine or leucine alone does not appear to improve the effectiveness of RET.

Glaucoma patients have an increased level of trimethylamine, a toxic product of gut bacteria, in the aqueous humor: a pilot study.

PURPOSE: Animal studies suggest that gut bacteria metabolites are involved in regulation of intraocular pressure or development of glaucoma. However, clinical data are lacking. Here, we wanted to compare level of trimethylamine (TMA), an uremic toxin produced by gut bacteria, along with betaine and trimethylamine N-oxide (TMAO), a substrate and a product of its metabolism, in the aqueous humor and in plasma of patients with glaucoma and their controls. METHODS: Twenty patients were selected for cataract phacoemulsification, and 20 patients selected for phacotrabeculectomy were enrolled in the study. Patients were matched with controls on systemic diseases and estimated glomerular filtration rate. Blood samples were collected in the preoperative suite, whereas aqueous humor samples were collected as the first step of both procedures. Subsequently, level of betaine, TMA and TMAO was analyzed by means of chromatography. RESULTS: In the aqueous humor, level of TMA, but not betaine or TMAO, was significantly higher in the phacotrabeculectomy group than in the phacoemulsification group. Plasma level of betaine, TMA and TMAO was similar between groups. In both groups, level of betaine and TMA, but not TMAO, was significantly higher in plasma than in the aqueous humor. CONCLUSION: TMA, but not TMAO or betaine level, is increased in the aqueous humor of patients with glaucoma. TMA might play a role in pathogenesis of glaucoma; however, prospective studies are needed to confirm our findings.

Evaluation of the Relationship Between Concentrations of Tacrolimus Metabolites, 13-O-Demethyl Tacrolimus and 15-O-Demethyl Tacrolimus, and Clinical and Biochemical Parameters in Kidney Transplant Recipients.

BACKGROUND: Tacrolimus (Tac), an essential component of immunosuppressive therapy after solid-organ transplantation, has a narrow therapeutic index and requires therapeutic drug monitoring. Monitoring of Tac predose blood concentrations seems to be not always sufficient to avoid adverse effects. The aim of the study was to evaluate the levels of main Tac metabolites, 13-O-demethyl tacrolimus (13-DMT), 31-O-demethyl tacrolimus (31-DMT), and 15-O-demethyl tacrolimus (15-DMT), in kidney transplant recipients and to link them to clinical and biochemical parameters. METHODS: In 63 kidney transplant patients, concentrations of 13-DMT, 31-DMT, and 15-DMT were quantified using liquid chromatography combined with tandem mass spectrometry (LC/MS/MS). RESULTS: None of the patients had detectable 31-DMT blood levels. There was a positive correlation between 13-DMT/Tac and alanine aminotransferase (ALAT) (r = 0.29, P = .046) and a negative correlation between 13-DMT/Tac and hemoglobin (r = -0.33, P = .008). Tac level did not correlate with ALAT nor with hemoglobin. There was no relationship between 13-DMT/Tac or 15-DMT/Tac and other biochemical or hematologic parameters or data, such as age, body mass index, arterial pressure, or time posttransplant. We observed significantly higher Tac concentrations in patients with hypercholesterolemia or hypertriglyceridemia compared with those without these comorbidities (6.45 ± 2.32 vs 5.16 ± 2.12 ng/mL, P = .043; 6.60 ± 2.30 vs 5.34 ± 2.20 ng/mL, P = .033, respectively). CONCLUSION: Our data may reflect 13-DMT accumulation in liver dysfunction and higher Tac clearance in anemia. However, these results may suggest that 13-DMT/Tac ratio is a marker of myelotoxicity and hepatotoxicity. Further studies should be carried out to determine whether monitoring of 13-DMT could be beneficial in minimizing the adverse effects.

Cardiovascular Disease in Kidney Transplantation and Its Association With Blood Concentrations of Cyclosporine and Cyclosporine Metabolites.

Cyclosporine A (CsA) is the first calcineurin inhibitor used as immunosuppressive agent. Its administration is associated with multiple adverse effects including cardiovascular diseases (CVDs), but their mechanisms have not been fully elucidated. Cyclosporine metabolites are not well studied in this context. This study was aimed at analysis of the incidence of CVDs and their association with concentrations of cyclosporine and its metabolites. Sixty patients after kidney transplantation (KTX) taking an immunosuppressive regimen including CsA participated in the study. There were 22 women (36.67%) and 38 men (63.33%), mean age 51.73 years, mean 109.38 months after KTX. We observed a correlation between mean diastolic blood pressure and concentrations of metabolite to parent drug ratios of AM1-CsA/CsA (r = 0.35, P = .006), dihydroxy-CsA/CsA (r = 0.42, P = .001), trihydroxy-CsA/CsA (r = 0.42; P = .003) and desmethyl-carboxy-CsA/CsA (r = 0.65, P = .003). There were no significant associations of other CsA metabolites' parameters with CVDs (coronary disease, hypertension, stroke, arrhythmia, diabetes mellitus, obesity). Study results suggest that blood pressure increases associated with CsA therapy could be caused by CsA metabolites that influence mainly diastolic blood pressure levels. A lack of such differences in relation with other CVDs may suggest that more complex mechanisms are involved in the development of cardiovascular injury and disease after kidney transplantation.

Tacrolimus Metabolite M-III May Have Nephrotoxic and Myelotoxic Effects and Increase the Incidence of Infections in Kidney Transplant Recipients.

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.

Hydroxylated, Hydroxymethylated, Dihydroxylated, and Trihydroxylated Cyclosporine Metabolites Can Be Nephrotoxic in Kidney Transplant Recipients.

BACKGROUND: Cyclosporine (CsA) is an immunosuppressive agent whose use is associated with adverse effects, including nephrotoxicity. There are reports indicating that some CsA metabolites may contribute to these effects. This study was aimed at evaluation of CsA metabolites and correlating them with kidney function. METHODS: In 62 kidney transplant recipients (41.9% women; overall mean age, 48.44 ± 11.75 years), concentrations of CsA and 4 groups of metabolites were assessed: hydroxylated (HCsA), hydroxymethylated (HMCsA), dihydroxylated (DHCsA), and trihydroxylated (THCsA). The results were normalized with the use of the metabolite-to-parent drug ratio, and results were linked with estimated glomerular filtration rate (eGFR) at 3 months before (-3M), point zero (0M), and after 3 (+3M) and 12 (+12M) months. RESULTS: Multivariate analysis demonstrated the negative influence of eGFR -3M on HMCsA/CsA (ß = -0.266; P < .05) and the negative influence of HCsA/CsA, HMCsA/CsA, DHCsA/CsA, and THCsA/CsA on eGFR +3M (ß = -0.339, ß = 0.396, ß = -0.314, and ß = -0.321, respectively; P < .005) and eGFR +12M (ß = -0.363, ß = -0.316, ß = -0.267, and ß = -0.312, respectively; P < .05). We did not detect such influence of CsA concentrations on eGFR +3M and +12M. The THCsA/CsA receiver operating characteristic cutoff value for prediction of improvement of kidney function at +12M was 0.143. CONCLUSIONS: Our results suggest that impaired function of the transplanted kidney affects the accumulation of HMCsA. It is possible that the increased metabolite (HCsA, HMCsA, DHCsA, and THCsA) to cyclosporine ratio could influence or could be a marker of cyclosporine nephrotoxicity. In this context, the most promising marker seems to be THCsA/CsA ratio, but its real significance requires further studies to determine.

Determination of Concentrations of Azathioprine Metabolites 6-Thioguanine and 6-Methylmercaptopurine in Whole Blood With the Use of Liquid Chromatography Combined With Mass Spectrometry.

BACKGROUND: 6-Mercaptopurine (6-MP) and its prodrug azathioprine (AZA) are used in many autoimmune diseases and after solid-organ transplantation. Their properties are mediated by active metabolites, 6-thioguanine nucleotides (6-TGN), and 6-methylmercaptopurine (6-MMP). The most common adverse effects are myelo- and hepato-toxicity. The aim of the study was quantification of 6-TG and 6-MMP, with the use of liquid chromatography combined with tandem mass spectrometry (LC/MS/MS) in solid-organ transplant recipients. METHODS: In 33 patients, kidney transplant recipient (n = 25) and liver transplant recipient (n = 8) intra-erythrocyte concentrations of 6-TG and 6-MMP were measured with the use of LC/MS/MS. RESULTS: The mean concentration of 6-TG was 205.35 ± 157.62 pmol/8 × 10(8) red blood cells (RBC); median concentration of 6-MMP was 1064.1 (35.78-11,552.9) pmol/8 × 10(8) RBC. There were no correlations between 6-TG levels and peripheral blood parameters (white blood cell count, WBC; hemoglobin, Hb concentration; PLT, blood platelet count) or alanine aminotransferase activity (AlAT) activity. Relationships between 6-MMP concentrations and peripheral blood parameters (WBC, Hb, PLT) or AlAT activity have not been found. Subgroups with leukopenia, anemia, thrombocytopenia, and liver dysfunction did not differ in concentrations of 6-TG or 6-MMP. We have observed a negative correlation between daily azathioprine dose and WBC count (r = -0.37, P = .04). CONCLUSIONS: Relationships between concentrations of azathioprine metabolites and myelotoxicity or hepatotoxicity have not been confirmed. Further studies on larger groups of patients would be helpful in a more accurate understanding of the impact of azathioprine metabolites on parameters of bone marrow and liver function.