Sticking together: independent evolution of biofilm formation in different species of staphylococci has occurred multiple times via different pathways.

BACKGROUND: Staphylococci cause a wide range of infections, including implant-associated infections which are difficult to treat due to the presence of biofilms. Whilst some proteins involved in biofilm formation are known, the differences in biofilm production between staphylococcal species remains understudied. Currently biofilm formation by Staphylococcus aureus is better understood than other members of the genus as more research has focused on this species. RESULTS: We assembled a panel of 385 non-aureus Staphylococcus isolates of 19 species from a combination of clinical sources and reference strains. We used a high-throughput crystal violet assay to assess the biofilm forming ability of all strains and assign distinct biofilm formation categories. We compared the prevalence of Pfam domains between the categories and used machine learning to identify amino acid 20-mers linked to biofilm formation. This identified some domains within proteins already linked to biofilm formation and important domains not previously linked to biofilm formation in staphylococci. RT-qPCR confirmed the expression of selected genes predicted to encode important domains within biofilms in Staphylococcus epidermidis. The prevalence and distribution of biofilm associated domains showed a link to phylogeny, suggesting different Staphylococcus species have independently evolved different mechanisms of biofilm production. CONCLUSIONS: This work has identified different routes to biofilm formation in diverse species of Staphylococcus and suggests independent evolution of biofilm has occurred multiple times across the genus. Understanding the mechanisms of biofilm formation in any given species is likely to require detailed study of relevant strains and the ability to generalise across the genus may be limited.

Characterisation of neonatal Staphylococcus capitis NRCS-A isolates compared with non NRCS-A Staphylococcus capitis from neonates and adults.

Staphylococcus capitis is a frequent cause of late-onset sepsis in neonates admitted to Neonatal Intensive Care Units (NICU). One clone of S. capitis, NRCS-A has been isolated from NICUs globally although the reasons for the global success of this clone are not well understood.We analysed a collection of S. capitis colonising babies admitted to two NICUs, one in the UK and one in Germany as well as corresponding pathological clinical isolates. Genome analysis identified a population structure of three groups; non-NRCS-A isolates, NRCS-A isolates, and a group of 'proto NRCS-A' - isolates closely related to NRCS-A but not associated with neonatal infection. All bloodstream isolates belonged to the NRCS-A group and were indistinguishable from strains carried on the skin or in the gut. NRCS-A isolates showed increased tolerance to chlorhexidine and antibiotics relative to the other S. capitis as well as enhanced ability to grow at higher pH values. Analysis of the pangenome of 138 isolates identified characteristic nsr and tarJ genes in both the NRCS-A and proto groups. A CRISPR-cas system was only seen in NRCS-A isolates which also showed enrichment of genes for metal acquisition and transport.We found evidence for transmission of S. capitis NRCS-A within NICU, with related isolates shared between babies and multiple acquisitions by some babies. Our data show NRCS-A strains commonly colonise uninfected babies in NICU representing a potential reservoir for potential infection. This work provides more evidence that adaptation to survive in the gut and on skin facilitates spread of NRCS-A, and that metal acquisition and tolerance may be important to the biology of NRCS-A. Understanding how NRCS-A survives in NICUs can help develop infection control procedures against this clone.

Industrial Halal hunted-game and feral animals' meat production.

Hunted wild game meat (HGM) is growing in popularity and attracting a premium among consumers. This has led to the emergence of supply chains for industrially produced HGM in many countries. With the growing demand for Halal meat and the disposable income of its consumers around the globe, meat and game industries in countries rich in wild game and feral animals would be encouraged to consider supplying Halal hunted game meat (HHGM) to Halal consumers around the world. Meeting the Halal requirements for industrial HHGM is easy given the already existing supply chains for HGM in many producing countries. What is needed by the Game and Meat Industries in these countries to comply with the Halal requirements in terms of the hunted animal and the hunter, the hunt location, modes and methods, the handling and processing of hunted carcases and the hunted animal welfare and sustainability in the industrial production of HHGM, is the subject of this review.

Preliminary evaluation of a rapid lateral flow calprotectin test for the diagnosis of prosthetic joint infection.

AIMS: This pilot study tested the performance of a rapid assay for diagnosing prosthetic joint infection (PJI), which measures synovial fluid calprotectin from total hip and knee revision patients. METHODS: A convenience series of 69 synovial fluid samples from revision patients at the Norfolk and Norwich University Hospital were collected intraoperatively (52 hips, 17 knees) and frozen. Synovial fluid calprotectin was measured retrospectively using a new commercially available lateral flow assay for PJI diagnosis (Lyfstone AS) and compared to International Consensus Meeting (ICM) 2018 criteria and clinical case review (ICM-CR) gold standards. RESULTS: According to ICM, 24 patients were defined as PJI positive and the remaining 45 were negative. The overall accuracy of the lateral flow test compared to ICM was 75.36% (52/69, 95% CI 63.51% to 84.95%), sensitivity and specificity were 75.00% (18/24, 95% CI 53.29% to 90.23%) and 75.56% (34/45, 95% CI 60.46% to 87.12%), respectively, positive predictive value (PPV) was 62.07% (18/29, 95% CI 48.23% to 74.19%) and negative predictive value (NPV) was 85.00% (34/40, 95% CI 73.54% to 92.04%), and area under the receiver operating characteristic (ROC) curve (AUC) was 0.78 (95% CI 0.66 to 0.87). Patient data from discordant cases were reviewed by the clinical team to develop the ICM-CR gold standard. The lateral flow test performance improved significantly when compared to ICM-CR, with accuracy increasing to 82.61% (57/69, 95% CI 71.59% to 90.68%), sensitivity increasing to 94.74% (18/19, 95% CI 73.97% to 99.87%), NPV increasing to 97.50% (39/40, 95% CI 85.20% to 99.62%), and AUC increasing to 0.91 (95% CI 0.81 to 0.96). Test performance was better in knees (100.00% accurate (17/17, 95% CI 80.49% to 100.00%)) compared to hips (76.92% accurate (40/52, 95% CI 63.16% to 87.47%)). CONCLUSION: This study demonstrates that the calprotectin lateral flow assay could be an effective diagnostic test for PJI, however additional prospective studies testing fresh samples are required.Cite this article: Bone Joint Res. 2020;9(5):202-210.

Age-dependent regulation of renal vasopressin V(1A) and V2 receptors in rats with genetic hypertension: implications for the treatment of hypertension.

The role of arginine vasopressin (AVP) as a hypertensive hormone remains controversial. We have previously reported that intervention with a V(1A) receptor antagonist in 6-week-old prehypertensive spontaneously hypertensive rats (SHR) for 4 weeks attenuated the subsequent development of hypertension in adult SHR. This study assessed the age-dependent regulation of plasma AVP levels and kidney V(1A) and V2 receptor expression during the development of hypertension in SHR and in normotensive Sprague Dawley rats. Systolic blood pressure (SBP), plasma AVP, and plasma renin activity (PRA) and kidney V(1A) and V2 receptor expression were assessed. SHR were studied at three ages: prehypertensive (6 weeks), developed hypertension (10 weeks), and established hypertension (16 weeks). SBP increased with age in SHR (P < .01) and both plasma AVP (P < .01) and PRA (P < .05) were increased in 10-week-old SHR. Renal medulla V(1A) receptor gene expression decreased in 10-week and 16-week-old SHR (P < .01), with a reduction in V(1A) receptor protein in the inner medulla of 16-week-old SHR (P < .05) compared with young SHR. There was no change in V2 receptor expression during the development of hypertension. In normotensive rats, plasma AVP, PRA, and kidney V(1A) and V2 receptor expression were unchanged over time. These data suggest that in SHR, activation of plasma AVP and the renal V(1A) receptor occurs during developing hypertension, with downregulation when hypertension is established. The use of V(1A) receptor antagonists in prehypertension may provide a unique opportunity for the prevention of hypertension in high-risk individuals.

Combination renin-angiotensin system blockade and angiotensin-converting enzyme 2 in experimental myocardial infarction: implications for future therapeutic directions.

The RAS (renin-angiotensin system) is activated after MI (myocardial infarction), and RAS blockade with ACEis [ACE (angiotensin-converting enzyme) inhibitors] or ARBs (angiotensin receptor blockers) slows but does not completely prevent progression to heart failure. Cardiac ACE is increased after MI and leads to the formation of the vasoconstrictor AngII (angiotensin II). The enzyme ACE2 is also activated after MI and degrades AngII to generate the vasodilator Ang-(1-7) [angiotensin-(1-7)]. Overexpression of ACE2 offers cardioprotective effects in experimental MI, but there is conflicting evidence as to whether the benefits of ACEis and ARBs are mediated through increasing ACE2 after MI. In the present study, we assessed the effect of an ACEi and ARB, alone and in combination, on cardiac ACE2 in a rat MI model. MI rats received vehicle, ACEi (ramipril; 1 mg/kg of body weight), ARB (valsartan; 10 mg/kg of body weight) or combination (ramipril at 1 mg/kg of body weight and valsartan at 10 mg/kg of body weight) orally for 28 days. Sham-operated rats were also studied and received vehicle alone. MI increased LV (left ventricular) mass (P<0.0001), impaired cardiac contractility (P<0.05) and activated cardiac ACE2 with increased gene (P<0.05) and protein expression (viable myocardium, P<0.05; border zone, P<0.001; infarct, P<0.05). Ramipril and valsartan improved remodelling (P<0.05), with no additional effect of dual therapy. Although ramipril inhibited ACE, and valsartan blocked the angiotensin receptor, neither treatment alone nor in combination augmented cardiac ACE2 expression. These results suggest that the cardioprotective effects of ramipril and valsartan are not mediated through up-regulation of cardiac ACE2. Strategies that do augment ACE2 after MI may be a useful addition to standard RAS blockade after MI.

Angiotensin-(1-7) infusion is associated with increased blood pressure and adverse cardiac remodelling in rats with subtotal nephrectomy.

ACE (angiotensin-converting enzyme) 2 is expressed in the heart and kidney and metabolizes Ang (angiotensin) II to Ang-(1-7) a peptide that acts via the Ang-(1-7) or mas receptor. The aim of the present study was to assess the effect of Ang-(1-7) on blood pressure and cardiac remodelling in a rat model of renal mass ablation. Male SD (Sprague-Dawley) rats underwent STNx (subtotal nephrectomy) and were treated for 10 days with vehicle, the ACE inhibitor ramipril (oral 1 mg·kg(-1) of body weight·day(-1)) or Ang-(1-7) (subcutaneous 24 µg·kg(-1) of body weight·h(-1)) (all n = 15 per group). A control group (n = 10) of sham-operated rats were also studied. STNx rats were hypertensive (P<0.01) with renal impairment (P<0.001), cardiac hypertrophy (P<0.001) and fibrosis (P<0.05), and increased cardiac ACE (P<0.001) and ACE2 activity (P<0.05). Ramipril reduced blood pressure (P<0.01), improved cardiac hypertrophy (P<0.001) and inhibited cardiac ACE (P<0.001). By contrast, Ang-(1-7) infusion in STNx was associated with further increases in blood pressure (P<0.05), cardiac hypertrophy (P<0.05) and fibrosis (P<0.01). Ang-(1-7) infusion also increased cardiac ACE activity (P<0.001) and reduced cardiac ACE2 activity (P<0.05) compared with STNx-vehicle rats. Our results add to the increasing evidence that Ang-(1-7) may have deleterious cardiovascular effects in kidney failure and highlight the need for further in vivo studies of the ACE2/Ang-(1-7)/mas receptor axis in kidney disease.

ACE inhibition reduces infarction in normotensive but not hypertensive rats: correlation with cortical ACE activity.

Angiotensin-converting enzyme (ACE) inhibition can reduce stroke risk by up to 43% in humans and reduce the associated disability, and hence understanding the mechanism of improvement is important. In animals and humans, these effects may be independent of the blood pressure-lowering effects of ACE inhibition. Normotensive (Wistar-Kyoto (WKY)) and hypertensive (spontaneously hypertensive rat (SHR)) animals were treated with the ACE inhibitors ramipril or lisinopril for 7 or 42 days before 2 hours of transient middle cerebral artery occlusion (MCAo). Blood pressure, serum ACE, and blood glucose levels were measured and stroke infarct volume was recorded 24 hours after stroke. Despite greater reductions in blood pressure, infarct size was not improved by ACE inhibition in hypertensive animals. Short-term ACE inhibition produced only a modest reduction in blood pressure, but WKY rats showed marked reductions in infarct volume. Long-term ACE inhibition had additional reductions in blood pressure; however, infarct volumes in WKY rats did not improve further but worsened. WKY rats differed from SHR in having marked cortical ACE activity that was highly sensitive to ACE inhibition. The beneficial effects of ACE inhibition on infarct volume in normotensive rats do not correlate with changes in blood pressure. However, WKY rats have ACE inhibitor-sensitive cortical ACE activity that is lacking in the SHR.

Reduction in renal ACE2 expression in subtotal nephrectomy in rats is ameliorated with ACE inhibition.

Alterations within the RAS (renin-angiotensin system) are pivotal for the development of renal disease. ACE2 (angiotensin-converting enzyme 2) is expressed in the kidney and converts the vasoconstrictor AngII (angiotensin II) into Ang-(1-7), a peptide with vasodilatory and anti-fibrotic actions. Although the expression of ACE2 in the diabetic kidney has been well studied, little is known about its expression in non-diabetic renal disease. In the present study, we assessed ACE2 in rats with acute kidney injury induced by STNx (subtotal nephrectomy). STNx and Control rats received vehicle or ramipril (1 mg. kg (-1) of body weight . day (-1), and renal ACE, ACE2 and mas receptor gene and protein expression were measured 10 days later. STNx rats were characterized by polyuria, proteinuria, hypertension and elevated plasma ACE2 activity (all P<0.01) and plasma Ang-(1-7) (P<0.05) compared with Control rats. There was increased cortical ACE binding and medullary mas receptor expression (P<0.05), but reduced cortical and medullary ACE2 activity in the remnant kidney (P<0.05 and P<0.001 respectively) compared with Control rats. In STNx rats, ramipril reduced blood pressure (P<0.01), polyuria (P<0.05)and plasma ACE2 (P<0.01), increased plasma Ang-(1-7) (P<0.001), and inhibited renal ACE(P<0.001). Ramipril increased both cortical and medullary ACE2 activity (P<0.01), but reduced medullary mas receptor expression (P<0.05). In conclusion, our results show that ACE2 activity is reduced in kidney injury and that ACE inhibition produced beneficial effects in association with increased renal ACE2 activity. As ACE2 both degrades AngII and generates the vasodilator Ang-(1-7), a decrease in renal ACE2 activity, as observed in the present study, has the potential to contribute to the progression of kidney disease.

Early undernutrition leads to long-lasting reductions in body weight and adiposity whereas increased intake increases cardiac fibrosis in male rats.

Previous studies suggest that both overfeeding and undernutrition during development increase the risk of obesity and hypertension in adulthood. In this study, we examined both short- (24 d) and long- (16 wk) term effects of early postnatal over- and underfeeding in rats on body weight, body composition, plasma hormones, adiposity markers, and hypothalamic neuropeptide Y content. Cardiovascular changes were also examined by measuring blood pressure and cardiac fibrosis. Rats raised in litters of 3, 12, or 18 pups per mother were used to model early onset overfeeding, control, and underfeeding, respectively. At 24 d of age, pups raised in small litters (SL) were 10% heavier than pups from normal litters, accompanied by increased organ mass and fat mass, elevated plasma leptin, corticosterone, and uncoupling protein-1 mRNA in brown adipose tissue. On the other hand, pups raised in large litters were 17% lighter with no significant changes in plasma leptin. Overfeeding during the first 3 wk of life led to increased plasma leptin concentration in adulthood, whereas underfed rats remained significantly lighter throughout the study, with no evidence of catch-up growth. Rats raised in SL were more susceptible to developing cardiac fibrosis with a 22% increase in collagen deposition compared with control rats at 16 wk of age (P < 0.05). This was independent of any changes in blood pressure. This study demonstrates that nutritional changes early in postnatal development can have long-lasting effects on body weight, adiposity, and some mediators involved in energy homeostasis and can also lead to structural changes in the heart in adulthood. This highlights the importance of identifying potential early life risk factors involved in the modulation of childhood nutrition.

ACE2 and diabetic complications.

Angiotensin converting enzyme (ACE) is a key enzyme in the renin angiotensin system (RAS) and converts angiotensin (Ang) I to the vasoconstrictor Ang II, which is thought to be responsible for most of the physiological and pathophysiological effects of the RAS. This classical view of the RAS was challenged with the discovery of the enzyme, ACE2 which both degrades Ang II and leads to formation of the vasodilatory and anti-proliferative peptide, Ang 1-7. Activation of the RAS is a major contributor to diabetic complications, and blockade of the vasoconstrictor and hypertrophic actions of Ang II, slows but does not prevent the progression of such complications. The identification of ACE2 in the heart and kidney adds further complexity to the RAS, provides the rationale to explore the role of this enzyme in pathophysiological states, including the microvascular and macrovascular complications of diabetes. It is believed that ACE2 acts in a counter-regulatory manner to ACE to modulate the balance between vasoconstrictors and vasodilators within the heart and kidney, and may thus play a significant role in the pathophysiology of cardiac and renal disease. Relatively little is known about ACE2 in diabetes, and this review will explore and discuss the data that is currently available. The discovery of ACE2 presents a novel opportunity to develop drugs that specifically influence ACE2 activity and/or expression, and it is possible that such compounds may have considerable clinical value in the prevention and treatment of the complications of diabetes.

Upregulation of hepatic angiotensin-converting enzyme 2 (ACE2) and angiotensin-(1-7) levels in experimental biliary fibrosis.

BACKGROUND/AIMS: Angiotensin-converting enzyme 2 (ACE2), its product, angiotensin-(1-7) and its receptor, Mas, may moderate the adverse effects of angiotensin II in liver disease. We examined the expression of these novel components of the renin angiotensin system (RAS) and the production and vasoactive effects of angiotensin-(1-7) in the bile duct ligated (BDL) rat. METHODS: BDL or sham-operated rats were sacrificed at 1, 2, 3 and 4 weeks. Tissue and blood were collected for gene expression, enzyme activity and peptide measurements. In situ perfused livers were used to assess angiotensin peptide production and their effects on portal resistance. RESULTS: Hepatic ACE2 gene and activity (P<0.0005), plasma angiotensin-(1-7) (P<0.0005) and Mas receptor expression (P<0.01) were increased following BDL compared to shams. Perfusion experiments confirmed that BDL livers produced increased angiotensin-(1-7) (P<0.05) from angiotensin II and this was augmented (P<0.01) by ACE inhibition. Whilst angiotensin II increased vasoconstriction in cirrhotic livers, angiotensin-(1-7) had no effect on portal resistance. CONCLUSIONS: RAS activation in chronic liver injury is associated with upregulation of ACE2, Mas and hepatic conversion of angiotensin II to angiotensin-(1-7) leading to increased circulating angiotensin-(1-7). These results support the presence of an ACE2-angiotensin-(1-7)-Mas axis in liver injury which may counteract the effects of angiotensin II.

Connective tissue growth factor and cardiac fibrosis after myocardial infarction.

The temporal and spatial expression of transforming growth factor (TGF)-beta(1) and connective tissue growth factor (CTGF) was assessed in the left ventricle of a myocardial infarction (MI) model of injury with and without angiotensin-converting enzyme (ACE) inhibition. Coronary artery ligated rats were killed 1, 3, 7, 28, and 180 days after MI. TGF-beta(1), CTGF, and procollagen alpha1(I) mRNA were localized by in situ hybridization, and TGF-beta(1) and CTGF protein levels by immunohistochemistry. Collagen protein was measured using picrosirius red staining. In a separate group, rats were treated for 6 months with an ACE inhibitor. There were temporal and regional differences in the expression of TGF-beta(1), CTGF, and collagen after MI. Procollagen alpha1(I) mRNA expression increased in the border zone and scar peaking 1 week after MI, whereas collagen protein increased in all areas of the heart over the 180 days. Expression of TGF-beta(1) mRNA and protein showed major increases in the border zone and scar peaking 1 week after MI. The major increases in CTGF mRNA and protein occurred in the viable myocardium at 180 days after MI. Long-term ACE inhibition reduced left ventricular mass and decreased fibrosis in the viable myocardium, but had no effect on cardiac TGF-beta(1) or CTGF. TGF-beta(1) is involved in the initial, acute phase of inflammation and repair after MI, whereas CTGF is involved in the ongoing fibrosis of the heart. The antifibrotic benefits of captopril are not mediated through a reduction in CTGF.

Myocardial infarction increases ACE2 expression in rat and humans.

AIMS: Angiotensin converting enzyme (ACE) 2 catalyses the cleavage of angiotensin (Ang) I to Ang 1-9 and of Ang II to Ang 1-7. ACE2 deficiency impairs cardiac contractility and upregulates hypoxia-induced genes, suggesting a link with myocardial ischaemia. We studied the expression of ACE2 after myocardial infarction (MI) in the rat as well as in human failing hearts. METHODS AND RESULTS: Rats were killed at days 1, 3, and 28 after MI, or treated for 4 weeks with the ACE inhibitor ramipril (1 mg/kg). Cardiac gene and protein expression of ACE and ACE2 were assessed by quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry/activity assays/in vitro autoradiography, respectively. Both ACE (P = 0.022) and ACE2 (P = 0.015) mRNA increased in the border/infarct area compared with the viable area at day 3 after MI. By day 28, increases in ACE (P = 0.005) and ACE2 (P = 0.006) mRNA were also seen in the viable myocardium of MI rats compared with myocardium of control rats. ACE2 protein localized to macrophages, vascular endothelium, smooth muscle, and myocytes. Ramipril attenuated cardiac hypertrophy and inhibited cardiac ACE. In contrast, ramipril had no effect on cardiac ACE2 mRNA, which remained elevated in all areas of the MI rat heart. Immunoreactivity of both ACE and ACE2 increased in failing human hearts. CONCLUSION: The increase in ACE2 after MI suggests that it plays an important role in the negative modulation of the renin angiotensin system in the generation and degradation of angiotensin peptides after cardiac injury.

Upregulation of cardiac insulin-like growth factor-I receptor by ACE inhibition after myocardial infarction: potential role in remodeling.

This study evaluated the effects of angiotensin-converting enzyme (ACE) inhibition after myocardial infarction (MI) on cardiac remodeling and gene expression and localization of components (ligands, receptors, and binding proteins) of the cardiac insulin-like growth factor (IGF) system. After ligation of the coronary artery, rats were randomized to vehicle or ACE inhibitor (Captopril, 50 mg/kg/day) for 4 weeks. Blood pressure, cardiac remodeling, and components of the IGF system were localized in the heart using in situ hybridization (ISH) and immunohistochemistry (IHC). The average infarct size was 42%. There were regional differences in the expression of the IGF system after MI, with increased IGF-I mRNA abundance in the border (24-fold) and infarct (12-fold) and increased IGF-binding protein (IGFBP)-3 mRNA in all areas of the failing left ventricle (threefold). Captopril reduced blood pressure, attenuated cardiac remodeling, and caused a threefold increase in IGF-I receptor mRNA and protein in infarct, border zone, and viable myocardium (p<0.01). Captopril had no effect on IGF-I mRNA but further increased IGFBP-3 mRNA and protein in the border zone, (p<0.05). The changes in the cardiac IGF system following MI are highly localized, persist for at least 4 weeks, and can be modulated by ACE inhibition. These data suggest that the benefits of ACE inhibitors in attenuation of cardiac remodeling may be mediated in part through increased expression of the IGF-I receptor sensitizing the myocardium to the positive effects of endogenous IGF-I.

Differential tissue and enzyme inhibitory effects of the vasopeptidase inhibitor omapatrilat in the rat.

Vasopeptidase inhibitors simultaneously inhibit angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). The present study characterized the tissue distributions of ACE and NEP, and assessed the effects of the vasopeptidase inhibitor omapatrilat on ACE and NEP in rat tissues. In vivo ACE and NEP inhibition was studied by in vitro autoradiography and using the ACE inhibitor radioligand (125)I-MK351A and the NEP inhibitor radioligand (125)I-RB104 in rats that received oral omapatrilat (40 mg x day(-1) x kg(-1)) for 3 days. In vitro autoradiography was used to examine the distribution of ACE and NEP in the kidney, aorta, heart, adrenal gland, lung, intestine, liver, spleen and brain, and to assess enzyme inhibition after oral omapatrilat. Omapatrilat inhibited plasma ACE and increased plasma renin activity (P <0.01). Tissue ACE was inhibited by 70-95% (P <0.01), except in the brain, where ACE was not inhibited. NEP was inhibited by 87% in the kidney and by 20-40% in atria, aorta, adrenal gland, lung, liver and intestine; it was not inhibited in the brain, the ventricle or the spleen. Omapatrilat is a potent vasopeptidase inhibitor that significantly inhibits tissue ACE and NEP, with the degree of inhibition varying according to the enzyme and the tissue under assessment. The degree and site of tissue enzyme inhibition by vasopeptidase inhibitors may be relevant to end-organ protection as well as to the side-effect profiles of these agents.

A breaker of advanced glycation end products attenuates diabetes-induced myocardial structural changes.

The formation of advanced glycation end products (AGEs) on extracellular matrix components leads to accelerated increases in collagen cross linking that contributes to myocardial stiffness in diabetes. This study determined the effect of the crosslink breaker, ALT-711 on diabetes-induced cardiac disease. Streptozotocin diabetes was induced in Sprague-Dawley rats for 32 weeks. Treatment with ALT-711 (10 mg/kg) was initiated at week 16. Diabetic hearts were characterized by increased left ventricular (LV) mass and brain natriuretic peptide (BNP) expression, decreased LV collagen solubility, and increased collagen III gene and protein expression. Diabetic hearts had significant increases in AGEs and increased expression of the AGE receptors, RAGE and AGE-R3, in association with increases in gene and protein expression of connective tissue growth factor (CTGF). ALT-711 treatment restored LV collagen solubility and cardiac BNP in association with reduced cardiac AGE levels and abrogated the increase in RAGE, AGE-R3, CTGF, and collagen III expression. The present study suggests that AGEs play a central role in many of the alterations observed in the diabetic heart and that cleavage of preformed AGE crosslinks with ALT-711 leads to attenuation of diabetes-associated cardiac abnormalities in rats. This provides a potential new therapeutic approach for cardiovascular disease in human diabetes.