Roles of Bone Morphogenetic Protein-6 in Aldosterone Regulation by Adrenocortical Cells

Aldosterone production occurs in the adrenal cortex, and is regulated primarily by angiotensin II (Ang II), potassium and adrenocorticotropin (ACTH). In the presence of the aldosterone stimulators, steroidogenesis is further governed by local autocrine and/or paracrine factors in the adrenal cortex. We reported the presence of functional bone morphogenetic protein (BMP) system in the adrenal cortex and also demonstrated that BMP-6 increases Ang II-induced aldosterone production, which could be involved in the "aldosterone breakthrough" phenomenon. Aldosterone breakthrough is the phenomenon by which circulating aldosterone concentrations increase above pre-treatment levels after long-term therapy with ACE inhibitors or Ang II type 1 receptor antagonists (ARB). This phenomenon may lead to important clinical consequences since increased aldosterone in a high-salt state facilitates cardiovascular and renal damage in hypertensive patients. We found that long-term ARB treatment reverses the reduction of aldosterone synthesis by adrenocortical cells, thereby causing "cellular aldosterone breakthrough". The availability of BMP-6 in the adrenal cortex may be at least partly involved in the occurrence of cellular escape from aldosterone suppression under chronic treatment with ARB

Activities of bone morphogenetic proteins in prolactin regulation by somatostatin analogs in rat pituitary GH3 cells

Involvement of the pituitary BMP system in the modulation of prolactin (PRL) secretion regulated by somatostatin analogs, including octreotide (OCT) and pasireotide (SOM230), and a dopamine agonist, bromocriptine (BRC), was examined in GH3 cells. GH3 cells are rat pituitary somato-lactotrope tumor cells that express somatostatin receptors (SSTRs) and BMP system molecules including BMP-4 and -6. Treatment with BMP-4 and -6 increased PRL and cAMP secretion by GH3 cells. The BMP-4 effects were neutralized by adding a BMP-binding protein Noggin. These findings suggest the activity of endogenous BMPs in augmenting PRL secretion by GH3 cells. BRC and SOM230 reduced PRL secretion, but OCT failed to reduce the PRL level. In GH3 cells activated by forskolin, BRC suppressed forskolin-induced PRL secretion with reduction in cAMP levels. OCT did not affect forskolin-induced PRL level, while SOM230 reduced PRL secretion and PRL mRNA expression induced by forskolin. BMP-4 treatment enhanced the reducing effect of SOM230 on forskolin-induced PRL level while BMP-4 did not affect the effects of OCT or BRC. Noggin treatment had no significant effect on the BRC actions reducing PRL levels by GH3 cells. However, in the presence of Noggin, OCT elicited an inhibitory effect on forskolin-induced PRL secretion and PRL mRNA expression, whereas the SOM230 effect on PRL reduction was in turn impaired. It was further found that BMP-4 and -6 suppressed SSTR-2 but increased SSTR-5 mRNA expression of GH3 cells. These findings indicate that Noggin rescues SSTR-2 but downregulates SSTR-5 by neutralizing endogenous BMP actions, leading to an increase in OCT sensitivity and a decrease in SOM230 sensitivity of GH3 cells. In addition, BMP signaling was facilitated in GH3 cells treated with forskolin. Collectively, these findings suggest that BMPs elicit differential actions in the regulation of PRL release dependent on cellular cAMP-PKA activity. BMPs may play a key role in the modulation of SSTR sensitivity of somato-lactotrope cells in an autocrine/paracrine manner

Hematopoietic Stem Cell Transplantation in Children with Refractory Cytopenia of Childhood: Single-Center Experience Using High-Dose Cytarabine Containing Myeloablative and Aplastic Anemia Oriented Reduced-Intensity Conditioning Regimens

AbstractRefractory cytopenia of childhood (RCC) is the most common subtype of myelodysplastic syndrome in children, and the clinical course of RCC is heterogeneous. A certain proportion of RCC patients need allogeneic hematopoietic stem cell transplantation (HSCT); however, data on HSCT outcomes are not abundant, and the optimal intensity of a preparative conditioning regimen remains uncertain. In this study, we evaluated the outcomes of HSCT in 24 patients with RCC. Eleven patients received myeloablative conditioning (MAC) consisting of high-dose cytarabine, cyclophosphamide, and either total body irradiation (TBI) or busulfan. Nine patients (38%) received a reduced-intensity conditioning (RIC) regimen; of these, 7 received low-dose TBI and cyclophosphamide (200 mg/kg) with or without antithymocyte globulin or fludarabine, and 2 patients received low-dose TBI, fludarabine, and melphalan (140 mg/m2). The remaining 4 patients had disease progression before HSCT and received the MAC regimen. With a median follow-up of 91 months (range, 6 to 263), the probability of overall survival at 5 years was 81.1% (95% CI, 57.0 to 92.5). The 5-year overall survival for the 15 patients who received MAC was 73.3% (95% CI, 43.6 to 89.1), and all 9 patients with RIC are alive without any events. Further study is needed to evaluate the efficacy of RIC for children with RCC with an expectation for reduction of late effects such as growth retardation and infertility

Glutamate Snsor Using L-Glutamate Oxidase and Its Application for Sensing GOT/GPT Activity

L-Glutamate measurement and GOT/GPT assay was successful by H2O2 measurement using the L-glutamate oxidase with 4-aminoantipyrine / phenol method. But, in examination of oxigen electrode, immobilized L-glutamate oxidase at the cellulose to L-glutamate and GOT-GPT sensor, Lpglutamate measurement was used for the amperometric determination with non-fixed enzyme. On examination of electron mediator, response for L-glutamate was observed with each of the compounds ferricyane, ferrocene-COOH, ferrocene-MeOH, and benzoquinone. L-Glutamate was measured by carbon printed tip electrode the L-glutamate oxidase and ferricyane based on the principle of chronoamperometry. A linear calibration graph was obtained between 1mM and 30mM. These results suggest that L-glutamate oxidase is able to utilize to L-glutamate sensor, and that there is a strong possibility to put this sensor to sensing for GOT/GPT activity

Aldosterone breakthrough caused by chronic blockage of angiotensin II type 1 receptors in human adrenocortical cells: Possible involvement of bone morphogenetic protein-6 actions

Circulating aldosterone concentrations occasionally increase after initial suppression with angiotensin II (Ang II) converting enzyme inhibitors or Ang II type 1 receptor blockers (ARBs), a phenomenon referred to as aldosterone breakthrough. However, the underlying mechanism causing the aldosterone breakthrough remains unknown. Here we investigated whether aldosterone breakthrough occurs in human adrenocortical H295R cells in vitro. We recently reported that bone morphogenetic protein (BMP)-6, which is expressed in adrenocortical cells, enhances Ang II-but not potassium-induced aldosterone production in human adrenocortical cells. Accordingly, we examined the roles of BMP-6 in aldosterone breakthrough induced by long-term treatment with ARB. Ang II stimulated aldosterone production by adrenocortical cells. This Ang II stimulation was blocked by an ARB, candesartan. Interestingly, the candesartan effects on Ang II-induced aldosterone synthesis and CYP11B2 expression were attenuated in a course of candesartan treatment for 15 d. The impairment of candesartan effects on Ang II-induced aldosterone production was also observed in Ang II- or candesartanpretreated cells. Levels of Ang II type 1 receptor mRNA were not changed by chronic candesartan treatment. However, BMP-6 enhancement of Ang II- induced ERK1/2 signaling was resistant to candesartan. The BMP-6-induced Smad1, -5, and -8 phosphorylation, and BRE-Luc activity was augmented in the presence of Ang II and candesartan in the chronic phase. Chronic Ang II exposure decreased cellular expression levels of BMP-6 and its receptors activin receptor-like kinase-2 and activin type II receptor mRNAs. Cotreatment with candesartan reversed the inhibitory effects of Ang II on the expression levels of these mRNAs. The breakthrough phenomenon was attenuated by neutralization of endogenous BMP-6 and activin receptor-like kinase-2. Collectively, these data suggest that changes in BMP-6 availability and response may be involved in the occurrence of cellular escape from aldosterone suppression under chronic treatment with ARB.</p

肝右葉切除の一症例における術後血清胆汁酸の変動について

Postoperative serum bile acids in a patient with hepatectomy were determined by gas-liquid chromatography. The results showed that two high peaks of serum bile acid levels were found respectively on the 2nd and 7th postoperative day, although serum bile acid levels returned to normal after the 15th postoperative day. The high peaks were considered to be due to the escape of necrotic hepatic intracellular bile acids into systemic blood stream, poor uptake of bile acids by hepatocytes and reabsorption of bile acids leaked from the residual liver into the peritoneal cavity