Influence of rabeprazole and lansoprazole on the pharmacokinetics of tacrolimus in relation to CYP2C19, CYP3A5 and MDR1 polymorphisms in renal transplant recipients

The objective of this study was to evaluate whether genetic polymorphisms of CYP2C19, CYP3A5 and MDR1 significantly impact the interaction between tacrolimus and rabeprazole or lansoprazole. Seventy-three recipients were randomly assigned after renal transplantation to receive repeated doses of tacrolimus for 28 days with a regimen of either 20 mg of rabeprazole or 30 mg of lansoprazole. Blood concentrations of tacrolimus were measured by microparticle enzyme immunoassay. The mean daily dose and the dose-adjusted area under the plasma concentration-time curves from 0 to 12 h (AUC(0-12)) of tacrolimus coadministered with rabeprazole or lansoprazole were the lowest and highest, respectively, in CYP2C19 poor metabolizers (PMs) having the CYP3A5*3/*3 genotype (0.084 and 0.112 mg/kg/day and 1.269 and 1.033 ng.h/ml/mg/kg, respectively). On the other hand, the mean dose-adjusted AUC(0-12) of tacrolimus coadministered with rabeprazole or lansoprazole were the highest in CYP2C19 PMs having the MDR13435CC+CT genotype, but not significantly.The present study indicates that there are significant interactions between tacrolimus and rabeprazole or lansoprazole in CYP2C19 PM renal transplant recipients bearing the CYP3A5*3/*3 genotypes. For recipients having these genetic polymorphisms, lower dosages of tacrolimus are required to achieve the target therapeutic index.     

Pyridoxamine reduces methylglyoxal and markers of glycation and endothelial dysfunction,but does not improve insulin sensitivity or vascular function in abdominally obese individuals: A randomized double-blind placebo-controlled trial

Aim

To investigate the effects of pyridoxamine (PM), a B6 vitamer and dicarbonyl scavenger, on glycation and a large panel of metabolic and vascular measurements in a randomized double-blind placebo-controlled trial in abdominally obese individuals.

Materials and methods

Individuals (54% female; mean age 50 years; mean body mass index 32 kg/m²) were randomized to an 8-week intervention with either placebo (n = 36), 25 mg PM (n = 36) or 200 mg PM (n = 36). We assessed insulin sensitivity, β-cell function, insulin-mediated microvascular recruitment, skin microvascular function, flow-mediated dilation, and plasma inflammation and endothelial function markers. PM metabolites, dicarbonyls and advanced glycation endproducts (AGEs) were measured using ultra-performance liquid chromatography tandem mass spectrometry. Treatment effects were evaluated by one-way ANCOVA.

Results

In the high PM dose group, we found a reduction of plasma methylglyoxal (MGO) and protein-bound Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1), as compared to placebo. We found a reduction of the endothelial dysfunction marker soluble vascular cell adhesion molecule-1 (sVCAM-1) in the low and high PM dose group and of soluble intercellular adhesion molecule-1 (sICAM-1) in the high PM dose, as compared to placebo. We found no treatment effects on insulin sensitivity, vascular function or other functional outcome measurements.

Conclusions

This study shows that PM is metabolically active and reduces MGO, AGEs, sVCAM-1 and sICAM-1, but does not affect insulin sensitivity and vascular function in abdominally obese individuals. The reduction in adhesion markers is promising because these are important in the pathogenesis of endothelial damage and atherosclerosis.     

Influence of formalin fixation duration on RNA quality and quantity from formalin-fixed paraffin-embedded hepatocellular carcinoma tissues

Analyzing RNA samples from formalin-fixed paraffin-embedded (FFPE) tissues is essential for precision medicine. We investigated RNA quantity and quality from FFPE tumor tissues fixed in formalin for various times and compared sequencing metrics from next-generation sequencing (NGS). Hepatocellular carcinoma (HCC) tissues were fixed in 10% neutral buffered formalin (1–240 h) and FFPE blocks were prepared. Total RNA was extracted, and the quantity and quality were assessed using the NanoDrop, Qubit and Bioanalyzer. After preparing sequencing libraries, NGS was performed on the Oncomine Dx Multi-CDx system. Total RNA yields of all samples met the threshold required for NGS, but longer fixation times resulted in decreased total RNA and long RNA fragment (>200 nt) yields. NGS analysis showed fewer sequencing reads of internal control genes from RNA with longer fixation times. RNA extracted from FFPE blocks stored for 500 days had reduced RNA yield and quality compared with RNA obtained from FFPE blocks prepared immediately. In conclusion, short and over-fixation should be avoided because of their negative impact on sequencing quality. Fixation process should be finished promptly within recommended guidelines (6–72 h) for cancer patients.     

Diabody-based recombinant formats of humanized IgG-like bispecific antibody with effective retargeting of lymphocytes to tumor cells

Recently, recombinant antibodies have been dissected into antigen-binding regions and rebuilt into multivalent high-avidity formats. These new structural designs are expected to improve in vivo pharmacokinetics and efficacy in clinical use. Here, we designed effective recombinant bispecific antibody (BsAb) formats based on hEx3, a humanized bispecific diabody with epidermal growth factor receptor and CD3 retargeting. The bispecific and bivalent IgG-like antibodies engineered from hEx3 (or its single-chain form, hEx3-scDb) and the human Fc region showed stronger binding to each target cell than did monovalent diabody formats, and their affinity was identical to that of the corresponding parent IgG. The bivalent effect of the constructed IgG-like BsAbs resulted in cell cytotoxicity 10 times that of monovalent diabodies, and further, the fusion of Fc portion contributed intense cytotoxicity in peripheral blood mononuclear cells by the induction of the antibody-dependent cellular cytotoxicity. The growth-inhibition effects of IgG-like BsAbs were superior to those of the approved therapeutic antibody cetuximab, which recognizes the same epidermal growth factor receptor antigen, even when peripheral blood mononuclear cells were used as effector cells. We thus demonstrated a critical improvement in the effect of hEx3 by the bottom-up construction of IgG-like BsAbs; in adoptive immunotherapy, monotherapy without supplemental molecules may be able to induce antibody-dependent cellular cytotoxicity.     

Topology and patch-clamp analysis of the sodium channel in relationship to the anti-lipid a antibody in campylobacteriosis

An infecting strain VLA2/18 of Campylobacter jejuni was obtained from an individual with campylobacteriosis and used to prepare chicken sera by experimental infection to investigate the role of serum anti-ganglioside antibodies in Guillain-Barré syndrome. Both sera of the patient and chicken contained anti-ganglioside antibodies and anti-Lipid A (anti-Kdo2-Lipid A) antibodies directed against the lipid A portion of the bacterial lipooligosaccharide. The anti-Kdo2-Lipid A activities inhibited voltage-gated Na (Nav) channel of NSC-34 cells in culture. We hypothesized that anti-Kdo2-Lipid A antibody acts on the functional inhibition of Nav1.4. To test this possibility, a rabbit peptide antibody (anti-Nav1.4 pAb) against a 19-mer peptide (KELKDNHILNHVGLTDGPR) on the alpha subunit of Nav1.4 was produced. Anti-Nav1.4 pAb was cross-reactive to Kdo2-Lipid A. Anti-Kdo2-lipid A antibody activity in the chicken serum was tested for the Na(+) current inhibition in NSC-34 cells in combination with mu-Conotoxin and tetrodotoxin. Contrary to our expectations, the anti-Kdo2-Lipid A antibody activity was extended to Nav channels other than Nav1.4. By overlapping structural analysis, it was found that there might be multiple peptide epitopes containing certain dipeptides showing a structural similarity with v-Lipid A. Thus, our study suggests the possibility that there are multiple epitopic peptides on the extracellular domains of Nav1.1 to 1.9, and some of them may represent target sites for anti-Kdo2-Lipid A antibody, to induce neurophysiological changes in GBS by disrupting the normal function of the Nav channels.     

Effects of ion channel blockers on basal hippocampal monoamine levels in freely moving diabetic and non-diabetic rats

This study characterized the ion channel activities in the hippocampus of diabetic rats by monitoring the levels of monoamines. Extracellular levels of serotonin and dopamine were measured in the hippocampus of awake, freely moving streptozotocin-induced diabetic rats, spontaneously diabetic rats, and non-diabetic rats, using in vivo microdialysis. Sodium, calcium, and potassium ion channel blockers were used to assess the ion channel activities. The results suggest that there are no abnormalities in the ion channels of diabetic brain, but the reduced levels of monoamines could be due to any problems of reuptake, release, and rate of breakdown of these molecules.