The Florey turns 50

The origins of the Howard Florey Laboratories of Experimental Physiology, Department of Physiology, The University of Melbourne, are tied to the ground‐breaking clinical work of Derek A Denton in 1947 and to the investigations of the initial scientific team into the control of salt and water balance in health and disease over the period 1947–1963 were Professor RD Wright, Drs JR Goding, IR McDonald, John P Coghlan, E Marelyn Wintour and John R Blair‐West. An Act of Parliament in 1971 by the Victorian State Government formally established the Institute named after Howard Florey, the Australian Nobel Prize winner who isolated penicillin. The Howard Florey Laboratories/Institute quickly became an international leader in the scientific areas of the physiological control of body fluids and electrolyte balance, especially sodium regulation and the regulation of the secretion of aldosterone, the adrenal salt‐retaining hormone; the micro measurement of hormones, in particular steroids and peptides; instinctive ingestive behaviour; fetal fluid regulation; hybridization histochemistry, and the hormone relaxin. Subsequently, the senior staff included, inter alia, Bruce Scoggins, Richard Weisinger, John McDougall, Brian Oldfield, Michael McKinley, Robin McAllen, Hugh Niall, Geoff Tregear and Felix Beck. During the 1990s, an explosion occurred in neuroscience and, in 1997, the Board made the strategic decision to change the focus of the Institute to brain disorders. From 1997 to 2007, Fred Mendelsohn steered the Florey to become one of Australia's premier brain research institutes and, under the current director (the eminent clinician and neuroscientist Geoffrey Donnan), this reputation has been further enhanced.     

Mineralocorticoid-stimulating activity of adipose tissue

Obesity is strongly associated with arterial hypertension. A positive correlation between obesity and plasma aldosterone levels has been observed by different investigators, suggesting that an abnormal secretion of aldosterone in obesity contributes to the development of arterial hypertension in obese subjects. The mechanisms proposed to explain this abnormal aldosterone production mainly involve the adipose renin-angiotensin system, an indirect effect of increased fatty acids, and direct adrenal stimulation by adipocyte secretory products. Indeed, adipose mineralocorticoid-stimulating activity was recently observed in isolated human adipocytes, suggesting a hitherto unknown direct involvement of adipose tissue in the regulation of blood pressure in obesity.     

安体舒通对左旋硝基精氨酸甲酯（L-NAME）／高盐致高血压大鼠肾内小动脉重塑的影响

目的　评价醛固酮拮抗剂安体舒通能否预防左旋 -硝基 -精氨酸甲酯 (L NAME) /高盐高血压大鼠肾内小动脉重塑发生以及该作用在不同剂量安体舒通组是否存在差异。方法　 30只Spague Dawley大鼠随机分为 4组 :1)对照 (C)组 :自来水灌胃及饮用自来水 ;2 )NO合酶抑制剂 (L)组 :L NAME灌胃 饮用 1%盐水 ;3)小剂量安体舒通 (S)组 :L NAME 安体舒通 2 0mg/kg·d灌胃 饮用 1%盐水 ;4 )大剂量安体舒通 (B)组 :L -NAME 安体舒通 10 0mg/kg·d灌胃 饮用 1%盐水。 8周后应用病理学方法测定肾内小动脉血管重塑指标。结果　各组大鼠血压差异显著 (F =19.799,P <0 0 0 1)。C组血压明显低于L、S、B组 (P <0 0 1) ,B组显著低于L、S组 (P <0 0 5 ) ,而L、S组之间差异不显著 (P >0 0 5 )。各组大鼠肾内小动脉腔径 (F =6 .314 ,P =0 0 0 3)、中层厚度 (F =11.36 3,P <0 0 0 1)、腔面积 (F =4 5 92 ,P =0 0 12 )、中层 /腔径比值 (F =2 2 5 4 4 ,P <0 0 0 1)以及中层纤维化比例 (F =18 72 9,P =0 0 0 0 )显示明显的差异。表现为L组腔径、腔面积明显小于C、S、B组 ,而中层厚度 ,中层 /腔径比值以及中层纤维化比例明显大于C、S、B组 ,而C、S、B三组间上述指标无差异。血清钾、钠、肌酐水平以及血浆醛固酮水平组间     

Differences in composition of sweat induced by thermal exposure and by running exercise

To determine the differences in sweat composition between sweat induced by thermal stress alone and that induced by physical exercise, seven young healthy men first sat in a hot room and then performed running exercise. A 20-minute stay in a climate chamber at 40 degrees C resulted in a 5% reduction in body weight. The same body weight loss was induced by running exercise. Both sodium and chloride concentrations were much lower in the sweat induced by thermal exposure than that induced by the running exercise (p less than 0.01), while urea nitrogen and creatinine concentrations were significantly higher after thermal exposure than after the running exercise (p less than 0.01). Potassium concentrations did not differ significantly with either procedure. These findings suggest that sweat composition varies with the kind of induction and that more salt seems to be lost through exercise-induced sweating than by just sitting in a hot environment.     

Effects of long‐term transdermal hormone replacement therapy on the renin–angiotensin– aldosterone system,plasma bradykinin levels and blood pressure in normotensive postmenopausal women

Aim: This study was designed to investigate the effects of 24‐month long‐term transdermal hormone replacement therapy (HRT) on the circulating levels of components of the renin–angiotensin–aldosterone system (RAAS) and bradykinin, blood pressure (BP) and lipid profile in normotensive postmenopausal women (PMW). Methods: Twenty‐two normotensive PMW were randomized to receive transdermal HRT (continuous 17‐β estradiol patch at 36 µg/day plus cyclic oral medroxyprogesterone acetate 2.5 mg/day for 12 days/month) (n = 12) or control (n = 10). The plasma renin activity (PRA), serum angiotensin‐converting enzyme (ACE) activity, plasma angiotensin (Ang) I, Ang II, aldosterone, bradykinin, and BP were measured before, and 12 and 24 months after, the start of the HRT. Results: In the HRT group, the diastolic BP and mean BP were significantly decreased at 12 and 24 months (both P < 0.05) after the start of therapy, however, no significant change of the systolic BP was noted during the study period. No changes in the RAAS components or lipid profile were noted in either group. The plasma bradykinin levels were significantly reduced at 12 (P < 0.05) and 24 months (P < 0.01), while no changes were observed in the control group. Conclusion: More than 12 months of long‐term transdermal HRT kept diastolic BP, mean BP and plasma bradykinin levels decreased in normotensive PMW, without influencing any of the components of the RAAS. This therapy may allow optimal blood pressure control and prevent elevation of the cardiovascular risk.     

Proteinuric renal disease in type 2 diabetes—Is remission of proteinuria associated with improved mortality and morbidity?

Aims

Patients with type 2 diabetes and macroalbuminuria are at high risk for end stage renal disease (ESRD), cardiovascular disease and death, but remission of proteinuria may improve prognosis. We examine the effectiveness of currently recommended treatments on inducing remission of proteinuria, and on morbidity and mortality.

Methods

Observational study of 78 patients with type 2 diabetes (46 male) with mean age (SD) of 61.5 (11) years, with a urinary albumin/creatinine ratio (ACR) ≥ 50 mg/mmol. All were treated with agents blocking the renin–angiotensin system. Follow-up was from recognition of ACR ≥ 50 mg/mmol until death or March 2011 (median 6 years). Remission of proteinuria was defined as ≥70% reduction from peak ACR, sustained for ≥1 year.

Results

Only 22 of 78 patients (28%) achieved remission of proteinuria. Thirty-six (46%) had at least one major event (death, dialysis or cardiovascular). Remission of proteinuria was associated with lower incidence of ESRD/death (9% vs 36%; p = 0.02) but cardiovascular events were not reduced (32% vs 30%). A third of patients had no retinopathy when albuminuria was first recognised, suggesting that non-diabetic renal pathologies were prominent. There was a significant interaction between the severity of diabetic retinopathy and remission of proteinuria on the risk of ESRD/death (p = 0.0003).

Conclusions

Remission of proteinuria was achieved in only a third of patients despite efforts to achieve blood pressure targets <130/80 mmHg. Failure to attain remission of proteinuria was associated with increased risk of ESRD or death, a risk compounded by the presence of severe diabetic retinopathy.     

Glutamate receptors and the regulation of steroidogenesis in the human adrenal gland: The metabotropic pathway

Background

l-glutamate is a major excitatory neurotransmitter in the mammalian brain. Glutamate receptors have been reported in the rat adrenal cortex and in human aldosterone-producing adenomas (APA). However, details regarding the expression levels and functions of these receptors in human adrenocortical tissues remain unknown.

Methods

The mRNA levels of glutamate receptors were evaluated by qPCR in: 12 normal adrenal cortex (NAC), 11 APA, and 12 cortisol-producing adenoma (CPA) tissues. Protein localization was evaluated by immunohistochemistry for 15 NAC, 5 idiopathic hyperaldosteronism cases, 15 APA and 15 CPA. H295R cells were treated with angiotensin-II or forskolin alone or combined with the GRM2/3 agonist LY354740.

Results

The level of GRM3 mRNA was higher in APA than in CPA (P = 0.0086) or NAC (P = 0.0022). GRM1, IGLUR2, and IGLUR3 were also detected in adrenocortical tissues. When added to angiotensin-II/forskolin treatments, LY354740 decreased aldosterone and cortisol production in H295R cells.

Conclusions

GRM3 is considered to regulate steroidogenesis in adrenocortical tissues.     

洛伐他汀对醛固酮诱导鼠心肌成纤维细胞增殖及其 iNOS-NO 系统活性的调控作用

目的：探讨洛伐他汀对醛固酮诱导心肌成纤维细胞（ CFs）增殖及诱导型一氧化氮合酶-一氧化氮（ iN-OS-NO）系统活性的调控作用。方法用胰酶消化法分离、培养新生SD大鼠CFs,采用MTT比色法、硝酸还原酶法、分光光度法和半定量RT-PCR技术,观察不同浓度洛伐他汀对CFs增殖、NO含量、iNOS活性和iNOS mRNA表达的影响。结果洛伐他汀（1×10-8～1×10-5 mol/L）能剂量依赖性抑制醛固酮诱导CFs的增殖,升高CFs的NO含量、iNOS活性及增加iNOS mRNA的表达（P均＜0．05）,甲羟戊酸（1×10-3 mol/L）、法尼酯焦磷酸（5μmol/L）可完全逆转洛伐他汀的上调作用。洛伐他汀干预下醛固酮诱导CFs的NO生成量与iNOS活性、iNOS活性与iNOS mRNA表达均呈正相关（r分别为0．826、0．752,P均＜0．01）;CFs增殖数目与NO含量呈负相关（r＝-0．908,P＜0．01）。结论洛伐他汀可上调醛固酮诱导CFs的iNOS-NO系统活性,抑制CFs增殖,并呈剂量依赖性,其作用机制可能与甲羟戊酸途径调节有关。     

The role of galectin‐3 in heart failure and cardiovascular disease

Galectin‐3, a β‐galactoside‐binding lectin, is a new important player in the progression of heart failure (HF) and is also linked to poor outcome in patients with cardiovascular disease. Genetic or pharmacological inhibition of galectin‐3 slows down the progression of myocardial inflammation, reduces collagen production, attenuates cardiac remodelling, and ameliorates cardiac function. In this review, we summarize recent progress in research on galectin‐3 as a regulatory molecule involved in cardiovascular fibrosis in HF and its potential role in the diagnosis, risk assessment and treatment of cardiovascular diseases.     

Effects of canrenone in patients with metabolic syndrome

Background: Metabolic syndrome is becoming a common disease due to a rise in obesity rates among adults.

Objectives: The aim was to evaluate the effects of canrenone compared to placebo on metabolic and inflammatory parameters in patients affected by metabolic syndrome.

A total of 145 patients were treated with placebo or canrenone, 50 mg/day, for 3 months and then 50 mg b.i.d. till the end of the study.

Blood pressure, body weight, body mass index, fasting plasma glucose (FPG), fasting plasma insulin, HOMA-IR, lipid profile, plasma aldosterone, brain natriuretic peptide, high-sensitivity C-reactive protein (Hs-CRP), tumor necrosis factor-α (TNF-α) and M value were evaluated.

Results: A decrease of blood pressure was observed in canrenone group compared to baseline; moreover, systolic blood pressure value recorded after 6 months of canrenone therapy was lower than the one recorded with placebo. Canrenone gave a significant decrease of FPI and HOMA index, and an increase of M value both compared to baseline and to placebo. Canrenone also decreased triglycerides and FPG was not observed with placebo. Canrenone also decreased plasma aldosterone, Hs-CRP and TNF-α compared to baseline and to placebo.

Conclusion: Canrenone seems to be effective in reducing some factors involved in metabolic syndrome and in improving insulin-resistance and the inflammatory state observed in these patients.