Structure-activity relationships of new N-acylanthranilic acid derivatives as plasminogen activator inhibitor-1 inhibitors.

Novel anthranilic acid derivatives having substituted N-acyl side chains were designed and synthesized for evaluation as plasminogen activator inhibitor-1 (PAI-1) inhibitors. Compounds with a 4-diphenylmethyl-1-piperazinyl moiety on the acyl side chains in general exhibited potent in vitro PAI-1 inhibitory activity and good pharmacokinetic profiles after oral administration in rats. Compound 16f (TM5275) was identified as a promising candidate for further pharmacological evaluation.

Body weight control by a high-carbohydrate/low-fat diet slows the progression of diabetic kidney damage in an obese, hypertensive, type 2 diabetic rat model.

Obesity is one of several factors implicated in the genesis of diabetic nephropathy (DN). Obese, hypertensive, type 2 diabetic rats SHR/NDmcr-cp were given, for 12 weeks, either a normal, middle-carbohydrate/middle-fat diet (MC/MF group) or a high-carbohydrate/low-fat diet (HC/LF group). Daily caloric intake was the same in both groups.

Structure-activity relationships of new 2-acylamino-3-thiophenecarboxylic acid dimers as plasminogen activator inhibitor-1 inhibitors.

Small molecule inhibitors of plasminogen activator inhibitor (PAI)-1 have been reported to date but their clinical effects still remain unknown. The present study was undertaken to investigate the structure-activity relationships (SAR) of newly synthesized 2-acylamino-3-thiophenecarboxylic acid dimers based upon a core structure of TM5001 (1) and TM5007 (2) that we have previously identified as orally effective PAI-1 inhibitors. In general, compounds possessing bulky or/and hydrophobic substituents (e.

A novel inhibitor of plasminogen activator inhibitor-1 provides antithrombotic benefits devoid of bleeding effect in nonhuman primates.

Inhibition of plasminogen activator inhibitor (PAI)-1 is useful to treat several disorders including thrombosis. An inhibitor of PAI-1 (TM5275) was newly identified by an extensive study of structure-activity relationship based on a lead compound (TM5007) which was obtained through virtual screening by docking simulations. Its antithrombotic efficacy and adverse effects were tested in vivo in rats and nonhuman primates (cynomolgus monkey).

Very high doses of valsartan provide renoprotection independently of blood pressure in a type 2 diabetic nephropathy rat model.

Aim: Angiotensin II type 1 receptor blockers (ARB) retard the progression of hypertensive diabetic kidney disease. Clinical evidence suggests that the dose of ARB required to correct hypertension is suboptimal for renoprotection evaluated by proteinuria. No systematic, prospective study has yet evaluated separately the effect of increasing doses of ARB on blood pressure and proteinuria.

A novel Sartan derivative with very low angiotensin II type 1 receptor affinity protects the kidney in type 2 diabetic rats.

Background: Antihypertensive angiotensin II receptor blockers (ARBs) protect the kidney, at least in part, independently of blood pressure lowering. Still, the extent to which blood pressure lowering is related to renoprotection remains unclear.

Methods And Results: 139 newly synthesized ARB-derivatives were assayed for inhibition of advanced glycation (AGEs).

The role of megsin, a serine protease inhibitor, in diabetic mesangial matrix accumulation.

In diabetic nephropathy decreased activities of matrix metalloproteinase (MMP)-2, MMP-9 and plasmin contribute to mesangial matrix accumulation. Megsin, a novel member of the serine protease inhibitor superfamily, is predominantly expressed in mesangial cells and is up-regulated in diabetic nephropathy and its overexpression spontaneously induces progressive mesangial expansion in mice. High-glucose stimulated megsin mRNA expression in an in vivo model of type II diabetic nephropathy as well as in vitro in cultured mesangial cells.

Inhibition of advanced glycation end products: an implicit goal in clinical medicine for the treatment of diabetic nephropathy?

Several factors have been incriminated in the genesis of diabetic nephropathy. To elucidate their interplay, we have used a hypertensive, obese, diabetic rat model with nephropathy (SHR/NDmcr-cp) that mimics human type 2 diabetes. This model is characterized by hypertension, obesity with the metabolic syndrome, diabetes with insulin resistance, and intrarenal advanced glycation end product (AGE) accumulation.

Reduction of albuminuria by angiotensin receptor blocker beyond blood pressure lowering: evaluation in megsin/receptor for advanced glycation end products/inducible nitric oxide synthase triple transgenic diabetic nephropathy mouse model.

Aim: Antihypertensive agents inhibiting the renin-angiotensin system (RAS), such as angiotensin II type 1 receptor blockers (ARB), are now part of the standard treatment of patients with diabetic nephropathy, regardless of the presence of systemic hypertension. Whether ARB achieve better renoprotection than other RAS-independent antihypertensive drugs has been an issue of controversy. Several lines of large clinical studies provided better renoprotection of ARB.

Inhibition of plasminogen activator inhibitor-1: its mechanism and effectiveness on coagulation and fibrosis.

Objective: Serine protease inhibitors (serpin) play a central role in various pathological processes including coagulation, fibrinolysis, malignancy, and inflammation. Inhibition of serpins may prove therapeutic. As yet, however, only very few small molecule serpin inhibitors have been reported.

A novel inhibitor of advanced glycation and endoplasmic reticulum stress reduces infarct volume in rat focal cerebral ischemia.

We have developed a novel, non-toxic inhibitor of advanced glycation and oxidative stress, TM2002, devoid of effect on blood pressure. In transient focal ischemia, TM2002 significantly decreased infarct volume compared with vehicle (79.5+/-18.

Cobalt ameliorates renal injury in an obese, hypertensive type 2 diabetes rat model.

Background: Chronic renal hypoxia is suspected to play a pathogenic role in the genesis of diabetic nephropathy (DN). Cobalt enhances the activity of the hypoxia-inducible factor (HIF), a key factor in the defence against hypoxia. Its long-term effect on DN is evaluated.

A novel class of prolyl hydroxylase inhibitors induces angiogenesis and exerts organ protection against ischemia.

Objective: Hypoxia inducible factor (HIF) plays a pivotal role in the adaptation to ischemic conditions. Its activity is modulated by an oxygen-dependent hydroxylation of proline residues by prolyl hydroxylases (PHD).

Methods And Results: We discovered 2 unique compounds (TM6008 and TM6089), which inhibited PHD and stabilized HIF activity in vitro.

A novel class of advanced glycation inhibitors ameliorates renal and cardiovascular damage in experimental rat models.

Background: The reno- and cardiovascular-protective effects of angiotensin II receptor blockers (ARBs), have been ascribed, at least in part, to their ability to inhibit the formation of advanced glycation end products (AGEs), independently of their effect on blood pressure. They act through decreased oxidative stress, unlike previously reported AGE inhibitors which entrap reactive carbonyl (RCOs) precursors of AGEs. The hypotensive effects of ARBs', however, may limit their use.

Establishment of a sandwich ELISA for human megsin, a kidney-specific serine protease inhibitor.

Background: We previously identified a novel serine protease inhibitor (serpin), megsin, which is predominantly expressed in the kidney. Megsin expression is up-regulated in human and experimental renal diseases associated with mesangial proliferation and expansion, suggesting that urinary megsin may be a novel diagnostic marker for some renal diseases.

Methods: We established a specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) for megsin and measured urinary megsin of patients with various renal diseases.

Carbonyl stress reduction in peritoneal dialysis fluid: development of a novel high-affinity adsorption bead.

Objective: Heat sterilization of glucose peritoneal dialysis (PD) fluid generates reactive carbonyl compounds (RCOs), which have been implicated in the formation of advanced glycation end products (AGEs) on peritoneal proteins, with an attendant deterioration of peritoneal permeability in PD patients. To reduce their levels in PD fluid, we had previously devised beads coupled with RCO-trapping agents. The hazards linked to the diffusion of RCO-trapping compounds in the systemic circulation are avoided.

Renoprotective properties of angiotensin receptor blockers beyond blood pressure lowering.

Clinical studies have demonstrated that some antihypertensive agents provide renoprotection independent of BP lowering. Recent in vitro and in vivo studies evaluated the mechanisms involved in this protection. First, the in vitro effects of several angiotensin II type 1 receptor blockers (ARB), calcium channel blockers (CCB), and beta blockers (BB) on various mediators were compared: Formation of pentosidine (an advanced glycation end product), hydroxyl radical-induced formation of o-tyrosine, and transition metals-induced oxidation of ascorbic acid (the Fenton reaction).

In a type 2 diabetic nephropathy rat model, the improvement of obesity by a low calorie diet reduces oxidative/carbonyl stress and prevents diabetic nephropathy.

Background: The present study has been undertaken to unravel the critical factors involved in the progression of diabetic nephropathy (DN).

Methods: A unique type 2 diabetic rat model with a wide range of metabolic derangements and hypertension has been utilized, the spontaneously hypertensive/NIH-corpulent rat SHR/NDmcr-cp(cp/cp). It develops histologically evident glomerular injury and tubulointerstitial damage, including mesangial activation, podocyte injury, and inflammatory cell infiltration in the tubulointerstitium.

Pyridoxamine improves functional, structural, and biochemical alterations of peritoneal membranes in uremic peritoneal dialysis rats.

Background: We previously suggested that biochemical alterations of peritoneal membrane associated with long-term peritoneal dialysis might be, at least in part, accounted for by reactive carbonyl compounds overload originating both from uremic circulation and heat sterilization of glucose peritoneal dialysis fluid. In the present study, we utilized a uremic rat model on peritoneal dialysis and evaluated the protective effects of pyridoxamine, a recently developed inhibitor of advanced glycation end product (AGE), on structural, functional, and biochemical alterations of peritoneal membrane.

Methods: Uremic rats were generated by subtotal nephrectomy, some of which were undergone peritoneal dialysis with dialysate and/or given intraperitoneal pyridoxamine.

From molecular footprints of disease to new therapeutic interventions in diabetic nephropathy.

Proteins are particularly attractive targets for product analysis, which is used to understand pathology. Protein modifications, such as advanced glycation end products (AGEs), serve as footprints of biochemical processes and also help in the search for novel agents that efficiently inhibit protein damage. Interestingly, several medical agents that are used clinically interfere with oxidative protein damage through different mechanisms characteristic of their chemical structures.

Novel serpinopathy in rat kidney and pancreas induced by overexpression of megsin.

The intracellular polymerization of abnormal serine protease inhibitors (serpins) results in liver or neuronal cell abnormalities recently identified as "serpinopathies." It was demonstrated in transgenic rats that overexpression of megsin, a recently discovered serpin located in the kidney, produces renal and pancreatic lesions characteristic of serpinopathies. Megsin expression is elevated in a variety of organs, including kidney and pancreas.

Ultrapure dialysate decreases plasma pentosidine, a marker of "carbonyl stress".

Background: Advanced glycation end products (AGEs) and their reactive carbonyl precursors accumulate in renal failure ("carbonyl stress"). Carbonyl stress derives from a broad derangement in the nonenzymatic biochemistry of both carbohydrates and lipids. We tested the influence of dialysate quality on plasma level of pentosidine, an AGE moiety taken as a surrogate marker of carbonyl stress, in hemodialysis patients.

Affinity adsorption of glucose degradation products improves the biocompatibility of conventional peritoneal dialysis fluid.

Background: Reactive carbonyl compounds (RCOs) present in peritoneal dialysis (PD) fluid have been incriminated in the progressive deterioration of the peritoneal membrane in long-term PD patients. They are initially present in fresh conventional heat-sterilized glucose PD fluid and are supplemented during dwell time by the diffusion of blood RCOs within the peritoneal cavity. In the present study, RCO entrapping agents were immobilized on affinity beads to adsorb RCOs both in fresh PD fluid and in PD effluent.

Specificity of a heme-assimilating system of Vibrio vulnificus to synthetic heme compounds.

Vibrio vulnificus strain L-180, a clinical isolate, can obtain iron from a synthetic heme, iron-tetra(4-sulfonatophenyl)porphyrin (Fe-TPPS), as well as from a natural heme, protoheme. This assimilation of iron bound to TPPS was demonstrated to be a common property of V. vulnificus by testing a total of 27 strains isolated from both clinical and environmental sources.

Overexpression of the serpin megsin induces progressive mesangial cell proliferation and expansion.

Mesangial cells maintain normal glomerular function by mediating ECM remodeling and immune complex disposal. We have recently identified megsin, a novel member of the serine protease inhibitor (serpin) superfamily predominantly expressed in the mesangium. While our previous studies suggested a role for megsin in the pathogenesis of human glomerular diseases, its exact biological significance remained unknown.