Discovery and pharmacological characterization of SAR707 as novel and selective small molecule inhibitor of stearoyl-CoA desaturase (SCD1).

Stearoyl-CoA desaturase (SCD1) is linked to the pathogenesis of obesity, dyslipidemia and type 2 diabetes. It is the rate-limiting enzyme in the synthesis of monounsaturated 16:1 n-7 and 18:1 n-9 fatty acyl-CoAs and catalyzes an essential part of lipogenesis. Here, we describe the identification, in vitro properties and in vivo efficacy of a novel class of heterocyclic small molecule hexahydro-pyrrolopyrrole SCD1 inhibitors. SAR707, a compound representative for the series, was optimized to high in vitro potency, selectivity and favorable overall properties in enzymatic and cellular assays. In vivo, this compound reduced serum desaturation index, decreased body weight gain and improved lipid parameters and blood glucose levels of obese Zucker diabetic fatty rats treated for 4 weeks in a chronic study. In parallel, fissures of the eye lid, alopecia and inflammation of the skin were observed from day 11 on in all animals treated with the same metabolically active dose. In summary, we described in vitro and in vivo properties of a novel, potent and selective SCD1 inhibitor that improved body weight, blood glucose and triglycerides in an animal model of obesity, type 2 diabetes and dyslipidemia. However, the favorable in vivo properties of systemic SCD1 inhibition shown in our study were accompanied by dose-dependently occurring adverse target-related effects observed in skin. Thus, systemic SCD1 inhibition by small molecules might therefore not represent a feasible approach for the treatment of chronic metabolic diseases.

Vasopeptidase inhibition prevents target organ damage and improves survival in spontaneously hypertensive rats.

BACKGROUND: Vasopeptidase inhibition has been shown to be an effective antihypertensive principle but its long-term effects on hypertensive target organ damage are not known. We investigated the myocardial, vascular and renal effects of chronic vasopeptidase inhibition in arterial hypertension. METHODS AND RESULTS: One hundred and thirty-nine male spontaneously hypertensive rats aged 15 months were treated chronically with either the pure angiotensin-converting enzyme (ACE) inhibitor, ramipril (1 mg/kg/d in drinking water, n=46), or the vasopeptidase inhibitor AVE7688 (30 mg/kg/d in chow, n=46), or placebo (n=47) and followed up until they died. After six months, both ramipril and AVE7688 had markedly reduced plasma ACE activity, normalised blood pressure (BP), reduced left ventricular mass and improved systolic function to similar extents. Acetylcholine mediated relaxation of aortic rings was improved by both ramipril and AVE7688. There was substantial albuminuria in the placebo group (albumin-to-creatinine ratio 107+/-54 microg/mg), which was significantly reduced by ramipril to 57+/-34 microg/mg, and practically abolished in the AVE7688 group (22+/-12 microg/mg, p<0.05 vs. placebo and ramipril). Tubulo-interstitial damage (semi-quantitative score) was significantly reduced by AVE7688 and ramipril. Overall mortality was markedly reduced in the ramipril and AVE7688 groups (13% and 16% at six months, respectively), both p<0.05 vs. placebo (71%). CONCLUSIONS: Vasopeptidase inhibition effectively controls BP and reduces myocardial, vascular and renal target organ damage, resulting in a markedly prolonged survival. At similar degrees of plasma ACE inhibition, AVE7688 compared to ramipril offers superior protection against hypertensive kidney damage.

The hepatic transcriptome as a window on whole-body physiology and pathophysiology.

Transcriptomics can be a valuable aid to pathologists. The information derived from microarray studies may soon include the entire transcriptomes of most cell types, tissues and organs for the major species used for toxicology and human disease risk assessment. Gene expression changes observed in such studies relate to every aspect of normal physiology and pathophysiology. When interpreting such data, one is forced to look "far from the lamp post:' and in so doing, face one's ignorance of many areas of biology. The central role of the liver in toxicology, as well as in many aspects of whole-body physiology, makes the hepatic transcriptome an excellent place to start your studies. This article provides data that reveals the effects of fasting and circadian rhythm on the rat hepatic transcriptome, both of which need to be kept in mind when interpreting large-scale gene expression in the liver. Once you become comfortable with evaluating mRNA expression profiles and learn to correlate these data with your clinical and morphological observations, you may wonder why you did not start your studies of transcriptomics sooner. Additional study data can be viewed at the journal website at (www.toxpath.org). Two data files are provided in Excel format, which contain the control animal data from each of the studies referred to in the text,including normalized signal intensity data for each animal (n=5) in the 6-hour, 24-hour, and 5-day time points. These files are briefly described in the associated 'Readme' file, and the complete list of GenBank numbers and Affymetrix IDs are provided in a separate txt file. These files are available at http://taylorandfrancis.metapress.comlopenurl.asp?genre=journal&issn=0192-6233. Click on the issue link for 33(1), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through (www.toxpath.org).

Nephroprotection in Zucker diabetic fatty rats by vasopeptidase inhibition is partly bradykinin B2 receptor dependent.

1. Vasopeptidase inhibition (i.e., the simultaneous inhibition of both angiotensin-converting enzyme (ACE) and neutral endopeptidase) can ameliorate diabetic nephropathy. We investigated whether this nephroprotection is mediated by the bradykinin B2 receptor. 2. In all, 43 obese Zucker diabetic fatty (ZDF/Gmi-fa/fa) rats aged 21 weeks were separated into four groups and treated for 26 weeks with either placebo, the bradykinin B2 receptor antagonist icatibant (500 microg kg(-1) day(-1) s.c. infusion), the vasopeptidase inhibitor AVE7688 (45 mg kg(-1) day(-1) in chow), or AVE7688 plus icatibant. Nephropathy was assessed as albuminuria at age 31 and 39 weeks, and by histopathologic scoring at the end of the treatment period. 3. All animals had established diabetes mellitus (blood glucose >20 mmol l(-1)) and marked albuminuria at baseline. Blood glucose was not influenced by any treatment. Icatibant alone did not influence albuminuria (8.6+/-1.6 vs placebo 9.5+/-1.3 mg kg(-1) h(-1)). AVE7688 reduced albuminuria at week 31 markedly to 1.1+/-0.1 mg kg(-1) h(-1) and reduced glomerular and tubulo-interstitial kidney damage at week 47. In the AVE7688 plus icatibant group, proteinuria was significantly higher than in the AVE7688 only group (2.0+/-0.6 mg kg(-1) h(-1)), but still reduced compared to placebo. In addition, icatibant partly antagonized the tubulo-interstitial protection mediated by AVE7688. 4. We conclude that vasopeptidase inhibition provides nephroprotection in rats with type II diabetic nephropathy, which is partly mediated by bradykinin B2 receptor activation.

Vasopeptidase inhibition prevents nephropathy in Zucker diabetic fatty rats.

BACKGROUND: Blocking the renin-angiotensin system is an established therapeutic principle in diabetic nephropathy. We investigated whether inhibition of both neutral endopeptidase and ACE (vasopeptidase inhibition) can prevent functional and morphological features of nephropathy in the Zucker diabetic fatty (ZDF) rat, an animal model of type II diabetes. METHODS: Homozygous (fa/fa) ZDF rats (each n=15) aged 10 weeks were treated with placebo, ramipril (1 mg/kg/day in drinking water), or the vasopeptidase inhibitor AVE7688 (45 mg/kg/day in chow). Metabolic parameters and renal function (metabolic cages) were assessed at baseline (age 10 weeks), and at age 17, 27, and 37 weeks. Twenty heterozygous animals (fa/-) served as lean, nondiabetic controls. At age 37 weeks, the animals were sacrificed and the kidneys analyzed histopathologically. RESULTS: Overt diabetes mellitus (blood glucose >20 mmol/l) was established at age 17 weeks in all homozygous ZDF rats. In the placebo group, urinary protein excretion increased progressively from 8+/-1 (baseline) to 342+/-56 mg/kg/day (week 37) whereas diabetes and proteinuria were absent in the lean control group. Ramipril tended to reduce albuminuria and morphological damage (p=ns) but AVE7688 virtually prevented albuminuria (33+/-12 mg/kg/day, p<0.05 vs. ZDF placebo) and drastically reduced the incidence and severity of glomerulosclerosis and tubulointerstitial damage. CONCLUSIONS: In ZDF rats, development of diabetes mellitus is accompanied by functional and morphological kidney damage that resembles human diabetic nephropathy. Diabetic nephropathy can be prevented by chronic vasopeptidase inhibition.

Regulation of rat organic anion transporters in bile salt-induced cholestatic hepatitis: effect of ursodeoxycholate.

Hepatic uptake of organic anions, including bile salts, is mediated by members of the organic anion-transporting polypeptide (Oatp) family. In rat liver, Oatp1 (Slc21a1), Oatp2 (Slc21a5), and Oatp4 (Slca10) are expressed at the basolateral membrane of hepatocytes and may be differentially regulated under pathophysiologic conditions such as cholestasis. The aim of this study was to determine the effects of cholic acid (CA) and ursodeoxycholic acid (UDCA) on the expression of Oatp4 compared with Ntcp, Oatp1, and Oatp2. Wistar rats were fed with CA (0.5%) or both CA (0.5%) and UDCA (0.25%) for 3 weeks. Oatp expression was studied by Northern and Western blot analysis as well as immunofluorescence analysis. Transport function was compared measuring biliary secretion of (14)C-CA and (14)C-taurocholic acid (TCA). In CA-fed animals, biliary secretion of (14)C-CA and (14)C-TCA was markedly delayed over 40 minutes compared with controls. Accordingly, Oatp4 protein was significantly down-regulated in CA-fed animals together with Oatp1 and Ntcp. Cofeeding of CA plus UDCA prevented the impairment of (14)C-CA and (14)C-TCA secretion and the down-regulation of Oatp4. Oatp4 messenger RNA (mRNA) levels did not differ significantly between bile salt-fed groups, suggesting a posttranscriptional effect of CA on Oatp4 expression. In contrast to Oatp1 and Oatp4, Oatp2 protein expression was increased by CA feeding, indicating a differential regulation of Oatp transporters. In conclusion, we show that CA feeding may cause cholestasis associated with a posttranscriptional down-regulation of Oatp4. UDCA may prevent impairment of hepatic function by restoring hepatic transporter expression.