Progesterone hydroxylation by cytochromes P450 2C and 3A enzymes in marmoset liver microsomes

1.?Common marmosets (Callithrix jacchus) are potentially useful nonhuman primate models for preclinical drug metabolism studies. However, the roles of marmoset cytochrome P450 (P450) isoforms in the oxidation of endobiotic progesterone have not been fully investigated. In this study, the roles of marmoset P450 isoforms in progesterone hydroxylation were extensively determined.

2.?The activities of liver microsomes from individual marmosets with respect to progesterone 21/17α- and 16α/6β-hydroxylation were significantly correlated with those for flurbiprofen 4-hydroxylation and midazolam 1′-hydroxylation, respectively, as similar correlations have been found in humans. Anti-P450 2?C and 3?A antibodies suppressed progesterone 21/17α- and 16α/6β-hydroxylation, respectively, in marmoset liver microsomes.

3.?Recombinant marmoset P450 2C58 and 2C19 catalyzed progesterone to form 21-hydroxyprogesterone and 16α-hydroxyprogesterone, respectively, as major products with high maximum velocity/K_m values of 0.53 and 0.089?mL/min/nmol, respectively. Recombinant marmoset P450 3A4/90 oxidized progesterone to form 6β-hydroxyprogesterone as a major product with homotropic cooperativity (>1 of Hill coefficients).

4.?These results indicate that the overall activities and roles of liver microsomal P450 enzymes in marmoset livers are similar to those in humans, especially for progesterone 21/17α- and 16α/6β-hydroxylation by marmoset P450 2?C and 3?A enzymes, respectively, suggesting important roles for these P450 enzymes in the metabolism of endobiotics in marmosets.     

Cerebral blood velocity and arterial pressure at the onset of exercise: potential influence of the cardiopulmonary baroreflex

Clinical Autonomic Research -     

Macrophage‐derived inflammatory cytokines regulate growth factors and pain‐related molecules in mice with intervertebral disc injury

Upregulation of inflammatory cytokines and various growth factors is a significant contributor to discogenic low back pain. The aim of this study was to investigate possible regulation of pain‐related molecules by macrophages and the role of macrophage‐derived molecules in injured intervertebral disc (IVD)s. C57BL/6J mice were used in this study. We characterized the expression profiles of genes for tumor necrosis factor (TNF)‐alpha, interleukin (IL)‐1beta, nerve growth factor (NGF), and vascular endothelial growth factor (VEGF) in both intact and injured IVDs. We examined whether macrophage depletion, induced by systemic injection of clodronate‐laden liposomes, affected the expression of these molecules in injured IVDs. The effect of TNF‐alpha on cultured F4/80‐CD11b‐cells in injured IVDs was investigated. Expression of TNF‐alpha and IL‐1beta was significantly increased in injured IVDs, but decreased by macrophage depletion. Expression of NGF and VEGF was also significantly increased, but by contrast was not decreased by macrophage depletion. TNF‐alpha treatment of F4/80‐cells from injured IVDs upregulated NGF, VEGF, cyclooxygenase (COX)‐2, and microsomal prostaglandin E synthase‐1 (mPGES1). IVD injury upregulated inflammatory cytokines and various growth factors. Macrophages in the injured IVDs produced inflammatory cytokines, but not growth factors. Macrophage‐derived inflammatory cytokines regulate growth factors and pain‐related molecules. These findings demonstrate further complexity in the pathogenesis of discogenic pain. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2274–2279, 2018.

     

Sagittal alignment of the lower extremity while standing in Japanese male

There is little information available regarding the sagittal mechanical axis of the lower extremity of normal subjects under weight-bearing conditions. The purpose of this study was to determine the sagittal alignment of the lower extremity under such conditions. Anteroposterior and lateral radiographs were taken of the 20 lower extremities of 10 healthy male Japanese volunteers (mean age, 27 years) while standing. The coronal mechanical axis passed through 33.9% medial to the proximal tibial articulating surface. The sagittal mechanical axis passed through 38.0% anterior to the distal femoral condyle and 27.9% anterior to the proximal tibial articulating surface, and also passed 5.2 mm anterior to the intercondylar notch. Our study therefore showed that the coronal and sagittal mechanical axes of the lower extremity do not always pass through the center of the knee. This has important implications for alignment in surgery of lower extremities such as total knee arthroplasty and osteotomy. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.     

Endothelins reciprocally regulate VEGF‐A and angiopoietin‐1 production in cultured rat astrocytes: Implications on astrocytic proliferation

Vascular endothelial growth factors (VEGFs) and angiopoietins (ANGs) are involved in pathophysiological responses in damaged nerve tissues. Astrocytes produce VEGFs and ANGs upon brain ischemia and traumatic injury. To clarify the extracellular signals regulating VEGF and ANG production, effects of endothelins (ETs), a family of endothelium‐derived peptides, were examined in cultured rat astrocytes. ET‐1 (100 nM) and Ala^1,3,11,15‐ET‐1 (100 nM), an ET_B receptor agonist, increased VEGF‐A mRNA levels in cultured astrocytes, while ANG‐1 mRNA was decreased by ETs. ET‐1 did not affect astrocytic VEGF‐B, placental growth factor (PLGF), and ANG‐2 mRNA levels. The effects of ET‐1 on VEGF‐A and ANG‐1 mRNAs were inhibited by BQ788, an ET_B antagonist. Release of VEGF‐A proteins from cultured astrocytes was increased by ET‐1. In contrast, ET‐1 reduced release of astrocytic ANG‐1. Exogenous ET‐1 (100 nM) and VEGF₁₆₅ (100 ng/mL), an isopeptide of VEGF‐A, stimulated bromodeoxyuridine (BrdU) incorporation into cultured astrocytes. Treatment with ET‐1 and VEGF₁₆₅ increased the numbers of cyclin D1‐positive astrocytes. Exogenous ANG‐1 (250 ng/mL) did not stimulate the BrdU incorporation. Increases in BrdU incorporation by ET‐1 and VEGF₁₆₅ were not affected by ANG‐1. In 60–70% confluent cultures, SU4312 (10 μM), a VEGF receptor tyrosine kinase inhibitor, partially reduced the effects of ET‐1 on BrdU incorporation and cyclin D1 expression. ET‐induced BrdU incorporation and cyclin D1 expression were reduced by a neutralizing antibody against VEGF‐A. Our findings suggest that ET‐1 is a factor regulating astrocytic VEGF‐A and ANG‐1, and that increased VEGF‐A production potentiates ET‐induced astrocytic proliferation by an autocrine mechanism. © 2012 Wiley Periodicals, Inc.