High prevalence of previously unknown heart failure and left ventricular dysfunction in patients with type 2 diabetes.

AIMS/HYPOTHESIS: The aim of this study was to assess the prevalence of (unknown) heart failure and left ventricular dysfunction in older patients with type 2 diabetes. METHODS: In total, 605 patients aged 60 years or over with type 2 diabetes in the south west of the Netherlands participated in this cross-sectional study (response rate 48.7%), including 24 with a cardiologist-confirmed diagnosis of heart failure. Between February 2009 and March 2010, the patients without known heart failure underwent a standardised diagnostic work-up, including medical history, physical examination, ECG and echocardiography. An expert panel used the criteria of the European Society of Cardiology to diagnose heart failure. RESULTS: Of the 581 patients studied, 161 (27.7%; 95% CI 24.1%, 31.4%) were found to have previously unknown heart failure: 28 (4.8%; 95% CI 3.1%, 6.6%) with reduced ejection fraction, and 133 (22.9%; 95% CI 19.5%, 26.3%) with preserved ejection fraction. The prevalence of heart failure increased steeply with age. Heart failure with preserved ejection fraction was more common in women. Left ventricular dysfunction was diagnosed in 150 patients (25.8%; 95% CI 22.3%, 29.4%); 146 (25.1%; 95% CI 21.6%, 28.7%) had diastolic dysfunction. CONCLUSIONS/INTERPRETATION: This is the first epidemiological study that provides exact prevalence estimates of (previously unknown) heart failure and left ventricular dysfunction in a representative sample of patients with type 2 diabetes. Previously unknown heart failure and left ventricular dysfunction are highly prevalent. Physicians should pay special attention to 'unmasking' these patients.

An improved system for the control of dissolved oxygen in freshwater aquaria.

A system for the removal and control of dissolved oxygen (DO) from freshwater was designed and constructed with aquarium-type fish studies in mind. Degassed water was obtained using a partial vacuum of -14 psi, and DO regulated at an aquarium scale using electronically controlled aeration with timed partial water renewal. The degassing system was capable of producing water with approximately 1.7 mg L(-1) DO within 10 min of operation, and 0.55 mg L(-1) after 2h. The control system was capable of maintaining DO levels of ca 0.8 mg L(-1) over 48 h in the absence of aeration and further capable of precisely controlling DO levels as low as 1.16+/-0.002 mg L(-1) (mean+/-SEM) with aeration over a 48 h period.

Androgenic effects of a Canadian bleached kraft pulp and paper effluent as assessed using threespine stickleback (Gasterosteus aculeatus).

The presence of unidentified estrogens and androgens in effluents from pulp and paper mills is well documented. However, their role in effluent effects on fish reproduction remains unclear. The objective of this study was to investigate the hypothesis that reproductive impacts of a modern pulp mill effluent are mediated by androgens and/or estrogens in the effluent. Male and female threespine stickleback were exposed to biologically treated Canadian bleached kraft mill effluent under flow-through conditions in the laboratory at 0, 1, 10 and 100% (v/v) dilutions. After 7 and 21 d of exposure, steroidogenesis was assessed using in vitro incubations of gonadal tissue in both males and females. mRNA expression of the estrogen-regulated gene vitellogenin, and the androgen-responsive gene spiggin were assessed using quantitative RT-PCR in the livers of male and posterior kidneys of female stickleback, respectively. Hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity was assessed in both sexes. Effluent extracts were examined for estrogenic and androgenic bioactivity using receptor binding bioassays, and were screened for pulp and paper related extractives and steroidal androgens using GC-MS. This effluent up-regulated spiggin mRNA in the kidney of female stickleback at 10% and 100% (v/v) effluent at 21 d, but not at 7 d of exposure. This change at the mRNA expression of the gene was associated with an increase in cell height in kidney proximal tubule epithelial cells at 100% effluent after both 7 and 21 d. Liver vitellogenin mRNA in male stickleback was not induced at either 7 or 21 d. EROD was induced at 10 and 100% after 21 d of exposure in both sexes, but not after 7 d of exposure. Despite evidence of exposure to androgens, there was no reduction in steroidogenic capacity at any effluent dilution. Effluent extracts were capable of eliciting the displacement of androgens and estrogens from receptors, but androgenic potency was 4-fold greater. A screen of more than 30 androgenic androstane steroids showed no detections. Hence, the androgenic constituents in this particular effluent remain unknown.

Prostaglandins E1 and E2 stimulate the proliferation of pulmonary artery smooth muscle cells.

Prostaglandins E1 and E2 are thought to be inhibitors of the growth of systemic vascular smooth muscle cells (SMC). However, their effect on the proliferation of SMC from the pulmonary artery (PA) has not been described and was the subject of this investigation. Cultures of bovine PA SMC were exposed to PGE1 and PGE2 under various conditions and their growth was assessed. PGE1 and PGE2 did not inhibit the growth of PA SMC in 10% fetal calf serum (FCS), but instead caused a dose dependent (10 ng - 1 microgram/ml) increase in [3H]-thymidine incorporation when added to cultures containing 0.5% FCS; the highest doses resulted in 95% and 75% increases in [3H]-thymidine uptake at 24 hours with PGE1 and PGE2 respectively. This was accompanied by a modest increase in actual cell numbers (e.g., 20% with 1 microgram/ml PGE1). Furthermore, PGE1 could mimic insulin-like growth factor (IGF-1) by potentiating the stimulation of SMC growth by fibroblast growth factor, suggesting that PGE1 may act as a progression factor in the growth cycle of these cells. There was, however, no effect of PGE1 on the proliferation of bovine aortic SMC. We conclude that, contrary to most reported effects on systemic SMC, PGE1 and PGE2 do not inhibit the proliferation of PA SMC but rather stimulate it.

Endothelin 1: mitogenic activity on pulmonary artery smooth muscle cells and release from hypoxic endothelial cells.

Endothelin, a recently described vasoconstrictor, has been shown to be a mitogen for vascular smooth muscle cells from systemic arteries and might play a role in pulmonary vascular remodeling produced by chronic exposure to hypoxia. We examined the effects of endothelin on proliferation of pulmonary artery smooth muscle cells and the effects of hypoxia and normoxia on the synthesis and secretion of endothelin by endothelial cells. Our results indicate that endothelin significantly increased the incorporation of [3H]thymidine by porcine pulmonary artery smooth muscle cells (122 +/- 4% to 168 +/- 13% of controls, with concentrations of endothelin from 1 to 1000 ng/ml). When tested on bovine pulmonary artery smooth muscle cells, endothelin increased [3H]thymidine incorporation over controls by approximately 140%; cell counts were increased by 107 +/- 4% and 122 +/- 7% at doses of 100 ng/ml and 1000 ng/ml, respectively. The secretion of endothelin by porcine endothelial cells was not affected by hypoxia (3520 +/- 138 pg/ml/10(6) cells in hypoxia vs 3770 +/- 326 pg/ml/10(6) cells in normoxia). Transforming growth factor-beta 1 stimulated the release by normoxic, and to a lesser degree by hypoxic, porcine endothelial cells of endothelin (4716 +/- 43 pg/ml/10(6) cells vs 4074 +/- 106 pg/ml/10(6) cells). Taken together, our results indicate that endothelin is weakly mitogenic for pulmonary artery smooth muscle cells, but may not significantly contribute to the remodeling seen in hypoxic pulmonary hypertension.

Inhibition of pulmonary artery smooth muscle cell growth by hypoxanthine, xanthine, and uric acid.

We have previously reported that medium conditioned by hypoxic pulmonary artery endothelial cells (ECCM) contains a factor of small molecular weight that inhibits the growth of pulmonary artery smooth muscle cells (SMC). We postulated that this factor might be a breakdown product of ATP and, therefore, measured the levels of hypoxanthine/xanthine (HX/X) and uric acid (UA) in ECCM and cell lysates from endothelial cells (EC) exposed to hypoxia and normoxia. Although hypoxic and normoxic cell lysates contained no UA and an equal amount of HX/X (2.9 +/- 0.3 and 2.9 +/- 0.5 microM, respectively), there was a 5-fold increase in the amount of HX/X present in hypoxic compared with normoxic ECCM (3.4 +/- 0.3 versus 0.6 +/- 0.4 microM, respectively; P less than 0.001) but no difference in UA levels (5 +/- 2 versus 5 +/- 1 microM, respectively). In separate experiments, we examined the effects of exogenous HX, X, and UA (doses ranging from 0.1 to 100 microM) on the proliferation of pulmonary and aortic SMC and pulmonary artery EC. Our results indicate that HX, X, and UA inhibit the proliferation of SMC in a dose-dependent manner without causing injury to the cells. The proliferation of EC, on the other hand, was not affected by UA and was significantly inhibited by HX and X only at doses of 100 microM. In conclusion, we have found that significant amounts of HX/X accumulate in hypoxic ECCM and that HX, X, and UA inhibit the proliferation of SMC. The relevance of these findings to conditions where hypoxia prevails is discussed.