Relationship between plasma mid-regional pro-adrenomedullin level and resistance to antihypertensive therapy in stable kidney transplant recipients

We investigated the relationship between plasma mid-regional pro-adrenomedullin (MR-proADM)-like immunoreactive substance (IS) level and clinical characteristics associated with renal failure or resistance to antihypertensive therapy in stable kidney transplant recipients. Forty-six Japanese kidney transplant recipients who underwent transplantation more than 90 days prior to the study were included. To evaluate resistance to antihypertensive therapy, we calculated the treatment intensity score of the antihypertensive drugs in each recipient. Morning blood samples were collected and plasma MR-proADM-IS levels were measured using an enzyme immunoassay. A significant correlation was observed between plasma MR-proADM-IS level with creatinine clearance or treatment intensity score. Multiple regression analysis identified plasma MR-proADM level and body mass index as significant independent factors associated with treatment intensity score. Plasma MR-proADM level may be a useful biomarker indicating the degree of resistance to antihypertensive therapy.

Significant increase in plasma 4β-hydroxycholesterol concentration in patients after kidney transplantation

Several previous studies have shown that renal failure decreases not only renal elimination but also metabolic clearance of drugs, particularly those metabolized by CYP3A. However, whether recovery of renal function results in recovery of hepatic CYP3A activity remains unknown. In this study, we evaluated the effect of renal function on CYP3A activity after kidney transplantation in patients with end-stage renal disease (ESRD) by measuring the change in CYP3A activity using plasma concentration of 4β-hydroxycholesterol as a biomarker. The study enrolled 13 patients with ESRD who underwent the first kidney allograft transplantation. Morning blood samples were collected before and 3, 7, 10, 14, 21, 30, 60, 90, 120, 150 and 180 days after kidney transplantation. Plasma concentration of 4β-hydroxycholesterol was measured using GC-MS. Compared with before kidney transplantation, creatinine clearance increased significantly from day 3 after kidney transplantation and stabilized thereafter. Plasma concentration of 4β-hydroxycholesterol was elevated significantly on days 90 and 180 after kidney transplantation. In conclusion, this study suggests the recovery of CYP3A activity with improvement in renal function after kidney transplantation in patients with ESRD.

Association of sustained high plasma trough concentration of voriconazole with the incidence of hepatotoxicity

BACKGROUND

Therapeutic drug monitoring (TDM) of voriconazole is important to optimize efficacy and to minimize toxicity and intolerance. In this study, we evaluated the effect of sustained high plasma trough concentration of voriconazole on the incidence of hepatotoxicity in hospitalized Japanese patients.

METHODS

Thirty-nine patients were divided into 3 groups according to trough concentrations in two consecutive TDMs: <4 μg/ml in the first TDM (group A, n=25), >4 μg/ml in the first and <4 μg/ml in the second TDM (group B, n=8), and >4 μg/ml in both first and second TDMs (group C, n=6).

RESULTS

Incidences of hepatotoxicity in groups A, B and C were 16.0, 25.0 and 83.3%, and significant differences were observed between groups A and C and groups B and C. Multiple logistic regression analysis identified the classification into groups A, B and C as an independent variable of hepatotoxicity.

CONCLUSIONS

These results suggest that sustained high trough concentration of voriconazole may increase the risk of hepatotoxicity, and decreasing trough concentration to <4 μg/ml by dose adjustment after the initial TDM may reduce the incidence of hepatotoxicity in patients treated with voriconazole.

Significant decrease in plasma midregional proadrenomedullin level in patients with end-stage renal disease after living kidney transplantation

Impaired renal function has been suggested to significantly impact plasma midregional proADM (MR-proADM) level. The aim of this study was to assess whether improvement of renal function after living kidney transplantation has an impact on plasma MR-proADM-like immunoreactive substance (IS) level. Eleven patients with end-stage renal disease (ESRD) who were scheduled to undergo the first living kidney allograft transplantation were enrolled. Plasma MR-proADM-IS levels were measured before and 3, 7, 10, 14, 21, 30, 60 and 90 days after kidney transplantation. Plasma MR-proADM-IS level decreased significantly from day 3 after kidney transplantation compared to before kidney transplantation. A significant negative correlation was observed between creatinine clearance and plasma MR-proADM-IS level from before to 90 days after kidney transplantation (rs=-0.70, p<0.0001). These results suggest that recovery of kidney function after kidney transplantation may lead to decrease in plasma MR-proADM level in patients with ESRD, and that plasma MR-proADM level may depend largely on renal function.

Dipeptidyl peptidase-4 inhibitors and angioedema: a class effect?

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to be generally well tolerated. However, angioedema has been reported as one of the rare adverse events of these drugs.

CASE REPORT

We report a case in which angioedema induced by vildagliptin disappeared after changing to another DPP-4 inhibitor, alogliptin.

DISCUSSION

Our case suggests that there is a difference in the risk of angioedema among DPP-4 inhibitors. To clarify this possibility, further investigation on the risk of angioedema among DPP-4 inhibitors is warranted.

Collective excitation of an electric dipole on a molecular dimer in an organic dimer-Mott insulator

The terahertz response in 10-100 cm(-1) was investigated in an organic dimer-Mott (DM) insulator κ-(ET)(2)Cu(2)(CN)(3) that exhibits a relaxorlike dielectric anomaly. An ~30 cm(-1) band in the optical conductivity was attributable to collective excitation of the fluctuating intradimer electric dipoles that are formed by an electron correlation. We succeeded in observing photoinduced enhancement of this ~30 cm(-1) band, reflecting the growth of the electric dipole cluster in the DM phase. Such optical responses in κ-(ET)(2)Cu(2)(CN)(3) reflect an instability near the boundary between the DM-ferroelectric charge ordered phases.

Switching to an L/N-type calcium channel blocker shows renoprotective effects in patients with chronic kidney disease: the Kyoto Cilnidipine Study

OBJECTIVE

This open-label, randomized controlled trial investigated the effects of cilnidipine, an L/N-type calcium channel blocker (CCB), in patients with chronic kidney disease (CKD).

METHODS

Sixty patients with CKD and well-controlled hypertension being treated with a renin- angiotensin system (RAS) inhibitor and an L-type CCB (L-CCB) were randomly assigned either to switch from the L-CCB to cilnidipine after a 4-week observation period or to continue with L-CCB treatment. Blood pressure, heart rate and renal function were monitored for 12 months. Data were available for analysis from 50 patients: 24 from the cilnidipine group and 26 from the L-CCB group.

RESULTS

Blood pressure was well controlled in both groups. After 12 months, proteinuria and heart rate were significantly decreased in the cilnidipine group, but proteinuria increased and heart rate remained unchanged in the L-CCB group. There was a significant positive correlation between the percentage changes in proteinuria and heart rate.

CONCLUSIONS

Cilnidipine has antihypertensive effects equivalent to those of L-CCBs. In patients with CKD, proteinuria can be decreased by switching from an L-CCB to cilnidipine, thereby improving renal function.

The role of serum adiponectin levels in women with polycystic ovarian syndrome

PURPOSE OF INVESTIGATION

The aim of this study was to measure serum adiponectin concentrations in women with polycystic ovarian syndrome (PCOS) and to assess possible correlations between adiponectin and the hormonal or metabolic parameters of this syndrome.

MATERIALS AND METHODS

Serum adiponectin levels were evaluated in 20 women with PCOS and 22 women without PCOS whose age and body mass index (BMI) matched the patients. The levels of fasting blood glucose, fasting insulin, gonadotropin, and sex steroid hormones were evaluated in both groups. The homeostasis model assessment (HOMA) score was also calculated. The serum adiponectin levels were assayed by enzyme-linked immunoabsorbent assay (ELISA).

RESULTS

Serum adiponectin levels were significantly lower in obese women than in normal-weight women, and they were also significantly lower in PCOS patients with HOMA scores greater than 1.7 compared with those with HOMA scores lower than 1.7. When the subjects were divided in two groups based on serum adiponectin levels (> 40 microg/ml, < 40 microg/ml), 65% of patients with PCOS were included in the lower adiponectin group (p < 0.05). In addition, gonadotropin levels were increased, dependent on the adiponectin levels in women with PCOS.

CONCLUSION

Adiponectin is regarded as a possible link between adiposity and insulin resistance (IR). From this data, the secretions of gonadotropin are implicated in the levels of adiponectin in women with PCOS. It is suggested that adiponectin may play an important role in the pathogenesis of PCOS.

Development and clinical application of an enzyme immunoassay for the determination of midregional proadrenomedullin

Adrenomedullin (ADM) is a 52-amino acid peptide with a variety of physiologic functions such as immunomodulating activity, direct bactericidal activity, maintenance of renal homeostasis, and vasodilatory activity. Midregional proADM (MR-proADM) is derived from a larger 185-amino acid precursor peptide, prepro-adrenomedulin (preproADM), by posttranslational processing. It is suggested to be co-synthesized with ADM in equimolar amounts and has the advantages over ADM in having a longer half-life, no bioactivity, and no binding to protein. Therefore, MR-proADM serves as a surrogate for ADM secretion. In this study, we attempted to develop an enzyme immunoassay (EIA) for quantifying MR-proADM-like immunoreactive substance (IS), which is applicable for monitoring plasma MR-proADM levels. By using β-d-galactosidase-labeled preproADM(83-94) as a marker antigen, anti-rabbit IgG-coated immunoplate as a bound/free separator, and 4-methylumbelliferyl-β-d-galactopyranoside as a fluorogenic substrate, a sensitive and specific EIA was developed for the quantification of MR-proADM-IS in human plasma. The lower limit of quantification was 0.032 pmol/well, and the steep competitive inhibition EIA calibration curve obtained was linear between 0.16 and 10 nmol/L. By using human plasma samples containing 0.2 and 2.0 nmol/L of MR-proADM, the interassay coefficients of variation (reproducibility) were 10.78% and 8.83%, respectively, and intraassay coefficients were 3.91% and 7.81%. Plasma MR-proADM-IS level was significantly higher in patients with chronic renal failure (1.39 ± 0.50 nmol/L) compared with healthy subjects (0.19 ± 0.07 nmol/L). These results suggest that our EIA may be useful to evaluate plasma MR-proADM levels as a biomarker in various clinical settings.

Is peak concentration needed in therapeutic drug monitoring of vancomycin? A pharmacokinetic-pharmacodynamic analysis in patients with methicillin-resistant staphylococcus aureus pneumonia

BACKGROUND

We analyzed the pharmacokinetic-pharmacodynamic relationship of vancomycin to determine the drug exposure parameters that correlate with the efficacy and nephrotoxicity of vancomycin in patients with methicillin-resistant Staphylococcus aureus pneumonia and evaluated the need to use peak concentration in therapeutic drug monitoring (TDM).

METHODS

Serum drug concentrations of 31 hospitalized patients treated with vancomycin for methicillin-resistant S. aureus pneumonia were collected.

RESULTS

Significant differences in trough concentration (Cmin)/minimum inhibitory concentration (MIC) and area under the serum concentration-time curve (AUC0-24)/MIC were observed between the response and non-response groups. Significant differences in Cmin and AUC0-24 were observed between the nephrotoxicity and non-nephrotoxicity groups. Receiver operating characteristic curves revealed high predictive values of Cmin/MIC and AUC0-24/MIC for efficacy and of Cmin and AUC0-24 for safety of vancomycin.

CONCLUSIONS

These results suggest little need to use peak concentration in vancomycin TDM because Cmin/MIC and Cmin are sufficient to predict the efficacy and safety of vancomycin.

Regional quantification of muscarinic acetylcholine receptors and β-adrenoceptors in human airways

BACKGROUND AND PURPOSE Muscarinic acetylcholine receptors (mAChRs) and β-adrenoceptors in the airways and lungs are clinically important in chronic obstructive pulmonary disease (COPD) and asthma. However, the quantitative and qualitative estimation of these receptors by radioligand binding approaches in human airways has not yet been reported because of tissue limitations. EXPERIMENTAL APPROACH The regional distribution and relative proportion of mAChR and β-adrenoceptor subtypes were evaluated in human bronchus and lung parenchyma by a tissue segment binding method with [(3)H]-N-methylscopolamine ([(3)H]-NMS) for mAChRs and [(3)H]-CGP-12,177 for β-adrenoceptors. Functional responses to carbachol and isoprenaline were also analysed in the bronchus. KEY RESULTS The M(3) subtype predominantly occurred in the bronchus, but the density decreased from the segmental to subsegmental bronchus, and was absent in lung parenchyma. On the other hand, the M(1) subtype occurred in the lung only, and the M(2) subtype was distributed ubiquitously in the bronchus and lungs. β(2)-adrenoceptors were increased along the airways, and their densities in the subsegmental bronchus and lung parenchyma were approximately twofold higher than those of mAChRs in the same region. β(1)-adrenoceptors were also detected in lung parenchyma but not in the bronchus. The muscarinic contractions and adrenoceptor relaxations in both bronchial regions were mediated through M(3)-mAChRs and β(2)-adrenoceptors, respectively. CONCLUSIONS AND IMPLICATIONS From the present radioligand binding approach with intact tissue segments, we constructed a distribution map of mAChRs and β-adrenoceptors in human bronchus and lung parenchyma for the first time, providing important evidence for future pharmacotherapy and new drug development for respiratory disorders.

Correlation between plasma ammonia level and serum trough concentration of free valproic acid in patients with epilepsy

Therapeutic drug monitoring of valproic acid (VPA) is essential to prevent toxicity, but the correlation between plasma ammonia level and serum VPA concentration remains unclear. We examined the correlation of plasma ammonia level with VPA dose and serum trough concentrations of total and free VPA in Japanese patients with epilepsy. Thirty-eight data sets from 19 Japanese patients with epilepsy were analyzed. The relations of VPA dose and serum total and free VPA concentrations with plasma ammonia level, and the breakpoints of VPA parameters predicting hyperammonemia (plasma ammonia higher than 60 µmol/L) were analyzed. A significant positive correlation was observed between plasma ammonia level and VPA dose (r(s)=0.56, p=0.00062), serum trough total VPA concentration (r(s)=0.55, p=0.00086) and serum trough free VPA concentration (r(s)=0.58, p=0.00041). The breakpoints predicting hyperammonemia were VPA dose of 30.4 mg/kg, serum trough total VPA concentration of 90.9 µg/mL, and serum trough free VPA concentration of 8.65 µg/mL, with impurity reductions at 1.35, 1.35 and 2.02, respectively. These findings suggest that serum trough concentration of free VPA is the most reliable predictor for hyperammonemia, and that the risk of developing hyperammonemia may increase in patients with serum trough free VPA concentrations higher than 8.65 µg/mL.

Effect of pilocarpine on substance P and calcitonin gene-related peptide releases correlate with salivary secretion in human saliva and plasma

WHAT IS KNOWN AND OBJECTIVE

Pilocarpine, a muscarinic receptor agonist, has been used for the treatment of dry mouth. Salivary glands are supplied with nerve fibres that contain neuropeptides, such as substance P, calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP), which are important modulators of salivation. It is known that measurement of salivary and plasma levels of neuropeptides is useful for assessing the dose-pharmacological effect relationship of drugs. The relationship between the action of pilocarpine and neuropeptides in humans has not been studied. Moreover, studies evaluate the usefulness of drug salivary levels in the pharmacological evaluation of drugs are scarce. The aim of this study was to examine the effects of pilocarpine on the levels of substance P-, CGRP- and VIP-like immunoreactive substances (IS) in saliva and plasma taken in healthy humans.

METHODS

Five healthy male subjects participated in this study. Pilocarpine tablet (10 mg) or placebo tablet was orally administered with 100 mL of water. Each subject was administered placebo and drug with an interval of 4 weeks in between. Saliva was sampled before and at 20, 40, 60, 90, 120, 180 and 240 min after administration of the test substances. Venous blood samples (10 mL) were also taken from a forearm vein at each time interval. The samples were then enzyme immunoassayed using a highly sensitive system for substance P-, CGRP- and VIP-IS. The amount of saliva was measured by the Saxon test.

RESULTS

A single oral administration of pilocarpine increased the release of salivary substance P-IS (the area under the concentration-time curve: AUC(0→240 min)) compared with the placebo. Pilocarpine also significantly increased the release of salivary CGRP-IS (AUC(0→240 min)). Pilocarpine significantly increased the release of plasma CGRP-IS. The salivary volume correlated with the salivary level of substance P and CGRP-IS (r = 0·84, P < 0·05 and r = 0·59, P < 0·05, respectively). AUC(0→240 min) for substance P-IS in saliva correlated with that for plasma (r = 0·78, P < 0·05).

WHAT IS NEW AND CONCLUSION

Pilocarpine increases the release of salivary substance P and CGRP-IS. This suggests that one mechanism by which pilocarpine improves dry mouth is by local stimulation of neuropeptidergic nerves. Moreover, saliva levels of substance P showed good correlation with the plasma levels. The substance P levels in saliva and plasma may be good indicators of the effects of drugs used in dry mouth/xerostomic patients.

E-cadherin and c-met expression as a prognostic factor in gastric cancer

E-cadherin has an important role in the cell-cell adhesion and is known as an invasion suppressor gene. The c-met, which is a receptor of hepatocyte growth factor receptor, is involved in the proliferative and motile activity in cancer cells. The invasive and metastatic capacities of gastric cancer were studied from the immunohistochemically examined expression of MET and E-cadherin. Among 127 primary gastric cancers, 47 (34%) tumors were found to have preserved E-cadherin expression and the other 84 tumors showed reduced E-cadherin expression. MET expression was found in 55 (43%) tumors. A strong correlation was found between reduced E-cadherin expression and a larger tumor, positive serosal invasion, lymph node metastases or poor prognosis. Tumors with MET expression have the tendencies to invade deeply, to metastasize in more remote lymph nodes or peritoneum and to run a poor prognosis. MET over-expression and reduced E-cadherin expression were strongly associated with lymph node metastasis, peritoneal dissemination and poor prognosis. This group of patients with simultaneously abnormal expressions of these genes had a sixfold relative risk of death, as compared with patients with tumors showing MET negative or preserved E-cadherin expression. These results indicate that immunohistochemical combined analyses of MET and E-cadherin expression may be a powerful tool for the evaluation of invasive capacity and the prognosis of gastric cancer patients.

Acceleration of diabetes development in CXC chemokine receptor 3 (CXCR3)-deficient NOD mice

AIMS/HYPOTHESIS

The aim of this study was to understand the role of CXC chemokine receptor 3 (CXCR3), a T-helper 1(Th1) type chemokine receptor, in the pathogenesis of type 1 diabetes.

METHODS

We observed the incidence of diabetes in Cxcr3 homozygous knockout mice. We compared the expression pattern of various cytokines and chemokines and the frequency of FOXP3(+) cells in the pancreas and pancreatic lymph nodes from Cxcr3 ( -/- ) NOD mice and wild-type NOD mice. In addition, we observed the migration ability of CXCR3(+)CD4(+) cells to pancreatic islets upon adoptive transfer. Finally, we examined whether Cxcr3 (+) regulatory T cells (Tregs) actually suppressed the onset of diabetes in vivo.

RESULTS

Cxcr3 ( -/- ) NOD mice developed spontaneous diabetes earlier than did wild-type NOD mice. In Cxcr3 ( -/- ) NOD mice, Tregs were more frequent in pancreatic lymph nodes and less frequent in pancreatic islets than in wild-type NOD mice. While transferred CXCR3(-)CD4(+) cells from wild-type NOD mice did not infiltrate pancreatic islets of NOD-severe combined immunodeficiency (SCID) mice, CXCR3(+)CD4(+) cells from the same mice migrated into the recipient islets and contained Forkhead box P3 (FOXP3) upon adoptive transfer. Moreover, CD4(+)CD25(+) cells from wild-type NOD mice suppressed and delayed the onset of diabetes compared with those from Cxcr3 ( -/- ) NOD mice in a cyclophosphamide-induced diabetes model system.

CONCLUSIONS/INTERPRETATION

The mechanism of accelerated diabetes onset in Cxcr3 ( -/- ) NOD mice was considered to be due to the lack of hybrid Tregs (CXCR3(+)FOXP3(+)CD4(+) cells), which could effectively migrate into and regulate Th1 inflammation in local lesions under Cxcr3 knockout conditions.