Long-term treatment with empagliflozin, a novel, potent and selective SGLT-2 inhibitor, improves glycaemic control and features of metabolic syndrome in diabetic rats.

Empagliflozin is a potent, selective sodium glucose co-transporter-2 inhibitor that is in development for the treatment of type 2 diabetes. This series of studies was conducted to assess the in vivo pharmacological effects of single or multiple doses of empagliflozin in Zucker diabetic fatty rats. Single doses of empagliflozin resulted in dose-dependent increases in urinary glucose excretion and reductions in blood glucose levels. After multiple doses (5 weeks), fasting blood glucose levels were reduced by 26 and 39% with 1 and 3 mg/kg empagliflozin, respectively, relative to vehicle. After 5 weeks, HbA1c levels were reduced (from a baseline of 7.9%) by 0.3 and 1.1% with 1 and 3 mg/kg empagliflozin, respectively, versus an increase of 1.1% with vehicle. Hyperinsulinaemic-euglycaemic clamp indicated improved insulin sensitivity with empagliflozin after multiple doses versus vehicle. These findings support the development of empagliflozin for the treatment of type 2 diabetes.

Empagliflozin, a novel selective sodium glucose cotransporter-2 (SGLT-2) inhibitor: characterisation and comparison with other SGLT-2 inhibitors.

AIMS: Empagliflozin is a selective sodium glucose cotransporter-2 (SGLT-2) inhibitor in clinical development for the treatment of type 2 diabetes mellitus. This study assessed pharmacological properties of empagliflozin in vitro and pharmacokinetic properties in vivo and compared its potency and selectivity with other SGLT-2 inhibitors. METHODS: [(14)C]-alpha-methyl glucopyranoside (AMG) uptake experiments were performed with stable cell lines over-expressing human (h) SGLT-1, 2 and 4. Two new cell lines over-expressing hSGLT-5 and hSGLT-6 were established and [(14)C]-mannose and [(14)C]-myo-inositol uptake assays developed. Binding kinetics were analysed using a radioligand binding assay with [(3)H]-labelled empagliflozin and HEK293-hSGLT-2 cell membranes. Acute in vivo assessment of pharmacokinetics was performed with normoglycaemic beagle dogs and Zucker diabetic fatty (ZDF) rats. RESULTS: Empagliflozin has an IC(50) of 3.1 nM for hSGLT-2. Its binding to SGLT-2 is competitive with glucose (half-life approximately 1 h). Compared with other SGLT-2 inhibitors, empagliflozin has a high degree of selectivity over SGLT-1, 4, 5 and 6. Species differences in SGLT-1 selectivity were identified. Empagliflozin pharmacokinetics in ZDF rats were characterised by moderate total plasma clearance (CL) and bioavailability (BA), while in beagle dogs CL was low and BA was high. CONCLUSIONS: Empagliflozin is a potent and competitive SGLT-2 inhibitor with an excellent selectivity profile and the highest selectivity window of the tested SGLT-2 inhibitors over hSGLT-1. Empagliflozin represents an innovative therapeutic approach to treat diabetes.

[MR tomographic measurement of the diastolic relaxation of the hypertrophied left ventricle with the single-slice-multiphase technic]. / MR-tomographische Messung der diastolischen Relaxation hypertrophierter linker Ventrikel mit Single-slice-multi-phase-Technik.

In order to assess diastolic ventricular function in hypertensive patients, a single-slice multiphase sequence was used in order to measure contraction and early diastolic relaxation. There was no difference in the contraction velocity between hypertensives and normals (Vsys. n.r. = 56.1 +/- 13.8% LVDV/s vs. 51.7 +/- 8.6% LVEDV/s, stat, n. sign.). Early diastolic relaxation velocity in hypertensives was reduced as compared with the control group (Vdiast. 1n.r. = 37.9 +/- 13.1% LVEDV/s vs. 47.1 +/- 9.6% LVEDV/s, p < 0.05). There was no linear relation between abnormal relaxation and the extent of myocardial hypertrophy. Hypertensives with myocardial hypertrophy frequently had reduced early diastolic relaxation velocity. Regression analysis for estimating left ventricular volumes derived from single-slice measurements were confirmed by additional multislice measurements. The calculated LVEDV correlated at r = 0.956 with multi-slice measurements and tended to show lower values (LVEDV n.r. = 104.6 +/- 30.8 ml vs. LVEDV = 102.1 +/- 28.8 ml, r = 0.956, p < 0.05). The LVESV was overestimated by the multi-slice technique, the calculated regression volume averaged 23% lower, realistic values (LVESV n.r. = 28.5 +/- 15.3 ml vs. LVESV = 37.1 +/- 15.6 ml, r = 0.887, p < 0.001).

[An unusual case of ureter ligation after abdominal hysterectomy]. / Sonderfall einer Ureterligatur nach abdomineller Hysterektomie.

Iatrogenic ureteral lesion is a severe complication in gynecological surgery. We present a case in which the obstruction led to fornix rupture, urine extravasation and urinary ascites. The problematic diagnostic pathway is emphasized.

BIBW2992, an irreversible EGFR/HER2 inhibitor highly effective in preclinical lung cancer models.

Genetic alterations in the kinase domain of the epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) patients are associated with sensitivity to treatment with small molecule tyrosine kinase inhibitors. Although first-generation reversible, ATP-competitive inhibitors showed encouraging clinical responses in lung adenocarcinoma tumors harboring such EGFR mutations, almost all patients developed resistance to these inhibitors over time. Such resistance to first-generation EGFR inhibitors was frequently linked to an acquired T790M point mutation in the kinase domain of EGFR, or upregulation of signaling pathways downstream of HER3. Overcoming these mechanisms of resistance, as well as primary resistance to reversible EGFR inhibitors driven by a subset of EGFR mutations, will be necessary for development of an effective targeted therapy regimen. Here, we show that BIBW2992, an anilino-quinazoline designed to irreversibly bind EGFR and HER2, potently suppresses the kinase activity of wild-type and activated EGFR and HER2 mutants, including erlotinib-resistant isoforms. Consistent with this activity, BIBW2992 suppresses transformation in isogenic cell-based assays, inhibits survival of cancer cell lines and induces tumor regression in xenograft and transgenic lung cancer models, with superior activity over erlotinib. These findings encourage further testing of BIBW2992 in lung cancer patients harboring EGFR or HER2 oncogenes.

Profound and sustained inhibition of platelet aggregation by Fradafiban, a nonpeptide platelet glycoprotein IIb/IIIa antagonist, and its orally active prodrug, Lefradafiban, in men.

BACKGROUND: Clinical trials have demonstrated that platelet glycoprotein (GP) IIb/IIIa antagonists effectively prevent acute thrombotic events. Orally active GP IIb/IIIa antagonists are essential to evaluate the clinical benefit of long-term treatment. We therefore investigated platelet inhibition by the GP IIb/IIIa antagonist Fradafiban (BIBU 52; Fradafiban is the recommended INN of BIBU 52) and its orally administered prodrug, Lefradafiban (BIBU 104; Lefradafiban is the recommended INN of BIBU 104) in healthy subjects. METHODS AND RESULTS: The activity and plasma levels of Fradafiban and Lefradafiban were evaluated in double-blind, placebo-controlled studies in 130 healthy male subjects. One to 15 mg Fradafiban continuously infused over 30 minutes reversibly inhibited platelet aggregation in platelet-rich plasma ex vivo in response to 20 micromol/L ADP (5 mg, 100% inhibition at 27 minutes after administration) and to both 1.0 (5 mg, 100%) and 10 microg/mL (15 mg, 97+/-3%) collagen. Single oral doses of Lefradafiban inhibited ADP-induced aggregation by 59+/-14% (50 mg [mean+/-SD]; n=8), 90+/-12% (100 mg), and 99+/-2% (150 mg) 8 hours after administration. Correlations between activity and Fradafiban plasma levels were identical after Fradafiban and Lefradafiban treatment. After day 1, oral TID Lefradafiban treatment for 7 days inhibited aggregation by > or = 31+/-9.6% (25 mg TID; n=8), 53+/-12% (50 mg; n=7), and 88+/-6.6% (75 mg; n=8) just before the next dose. A similar correlation between the activity and Fradafiban plasma levels was observed at days 1, 2, and 7. CONCLUSIONS: Oral administration of Lefradafiban maintains the potent platelet GP IIb/IIIa antagonism of Fradafiban during treatment of healthy subjects for 1 week without signs of loss of the antiplatelet activity.

Reduced secretion of proinflammatory cytokines of monosodium urate crystal-stimulated monocytes in chronic renal failure: an explanation for infrequent gout episodes in chronic renal failure patients?

BACKGROUND: In gouty arthritis, monosodium urate (MSU) crystals interact with monocytes and neutrophils to produce inflammatory reactions associated with acute synovitis. In patients with end-stage renal disease (ESRD), gouty arthritis is a rare condition despite often severe hyperuricaemia. We wondered whether differences in the secretion of proinflammatory cytokines by MSU crystal-stimulated monocytes might be one explanation for the low incidence of gouty arthritis in patients with ESRD compared with healthy controls. METHODS: Thirteen patients with ESRD on intermittent haemodialysis treatment, six patients with chronic renal failure not yet on dialysis, and 15 age- and sex-matched healthy controls were examined. Monocytes, purified from peripheral blood mononuclear cells (PBMC) by immunomagnetic bead separation, were incubated for 18 h in the presence of MSU crystals, Escherichia coli lipopolysaccharide (LPS) or medium alone. The supernatants were studied for the presence of interleukin (IL)-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) using cytokine-specific enzyme-linked immunosorbent assays. RESULTS: Monocytes from patients with ESRD produced significantly lower amounts of IL-1beta, IL-6 and TNF-alpha after stimulation with MSU crystals or LPS than did monocytes from healthy subjects. Cytokine production was not significantly different between ESRD patients on haemodialysis and chronic renal failure patients not yet on dialysis. Artificial MSU crystals were stronger stimuli than tophus-derived 'natural' MSU crystals. CONCLUSION: We demonstrate that monocyte-associated immunosuppression in ESRD leads to reduced secretion of proinflammatory cytokines in response to stimuli such as MSU crystals. This may be one of the factors preventing many ESRD patients from the manifestation of acute gout despite often severe hyperuricaemia.

Antagonism of the GPIIb/IIIa receptor with the nonpeptidic molecule BIBU52: inhibition of platelet aggregation in vitro and antithrombotic efficacy in vivo.

The glycoprotein (GP) IIb/IIIa (the alphallb beta3 integrin) found on platelets binds fibrinogen or von Willebrand factor when the platelet is activated, thereby mediating the aggregation of platelets. Blockade of the GPIIb/IIIa should prevent platelet aggregation independent of the substance or substances responsible for activating the platelets. This comprehensive inhibition of platelet aggregation is thought to be an effective therapeutic approach to various clinical thromboembolic syndromes. This study investigated the platelet inhibition provided by blocking GPIIb/IIIa by using a new nonpeptidic molecule, BIBU52, in both in vitro and in vivo models. BIBU52 competes with [125I]fibrinogen for binding sites on human platelets in a Ca2+ and pH-dependent manner with a 50% inhibitory concentration (IC50) of 35 +/- 12 nM. BIBU52 inhibited the aggregation of human platelets in platelet-rich plasma induced by collagen (1-2 microg/ml), adenosine diphosphate (ADP; 2.5 microM), and a thrombin receptor-activating peptide (TRAP; SFLLRNPNDKYEPF-NH2; 25 microM) with IC50 values of 82, 83, and 200 nM, respectively. The inhibition of platelet aggregation by BIBU52 was found to be highly species dependent. BIBU52 inhibited aggregation in plasma from rhesus and marmoset monkeys with an IC50 of 150 nM but was totally ineffective in rat plasma. The selectivity of BIBU52 for inhibiting GPIIb/IIIa in comparison with other adhesion molecules was investigated in a human endothelial cell adhesion assay. The adhesion of human endothelial cells to matrices of vitronectin, fibronectin, collagen I, or laminin was not affected by concentrations as high as 100 microM BIBU52; thus BIBU52 demonstrates a high selectivity for the human GPIIb/IIIa. The antithrombotic effect of BIBU52 in vivo was investigated in three animal models of recurrent arterial thrombus formation. In the guinea pig aorta, BIBU52 inhibited thrombus formation dose dependently, with lack of thrombus formation for 1 h after a bolus dose of 1.0 mg/kg i.v.. Both acetylsalicylic acid and dazoxiben were less effective in this model. In pigs with recurrent thrombus formation in the carotid artery, 1.0 mg/kg i.v. also inhibited thrombus formation. Heparin was not effective in the pig, and acetylsalicylic acid was only partially effective. In the pig, the dose of 1.0 mg/kg i.v. BIBU52 also was associated with a 70% inhibition of collagen-induced platelet aggregation ex vivo but with only a transient prolongation of sublingual bleeding time to a maximum of 2.5-fold and without other hemodynamic effects. In the marmoset monkey, a dose of 10 microg/kg i.v. could abolish recurrent arterial thrombosis. Hemodynamic effects of BIBU52 in anesthetized pigs were not detected in doses < or = 10 mg/kg. These data demonstrate that BIBU52 is a potent and selective antagonist of the human GPIIb/IIIa receptor and capable of substantial inhibition of platelet aggregation in vitro and ex vivo as well as inhibition of arterial thrombus formation in vivo in animal models of thrombosis.

[An association of arterial occlusive disease with cyclosporine therapy after kidney transplantation]. / Assoziation einer arteriellen Verschlusskrankheit mit Ciclosporin-Therapie nach Nierentransplantation.

Renal transplantation followed by immunosuppression with cyclosporine (whole-blood levels 200-300 micrograms/l) and methylprednisolone (4 mg daily) was performed in a 54-year-old man with chronic glomerulonephritis. Three years later rapidly progressive arterial obstructive disease (peripheral type) developed. Parenteral treatment with prostaglandins, calcium antagonists and nitrates, as well as a lumbar sympathectomy, was unsuccessful so that, in rapid succession, several amputations on upper and lower limbs became necessary. The disease progression was arrested only when azathioprine replaced cyclosporine. Raynaud's phenomenon, present at the time, also disappeared and analgesics were no longer required. Histological examination revealed severe Mönckeberg arteriosclerosis and thromboembolic occlusion of the affected vessels. The cyclosporine treatment, especially the hypercoagulability induced by it, and the Mönckeberg arteriosclerosis were thought to be significant factors in the pathogenesis of the rapidly progressive arterial disease. It is concluded that, in the presence of progressive arterial obstructive disease occurring under cyclosporine treatment, the replacement by other immunosuppressive agents should be considered.

[Baclofen intoxication in chronic hemodialysis and kidney transplantation]. / Baclofenintoxikation bei chronischer Hämodialyse und Nierentransplantation.

Fourteen days after renal transplantation, at first gave with good transplant function, a 36-year-old woman developed neurogenic dysfunction of bladder emptying. This was treated with baclofen, 5 mg three times daily by mouth. Between the 7th and 10th treatment day she progressively developed an organic psychotic syndrome and increasing respiratory paralysis after the onset of renal failure, associated with rejection of the transplanted kidney which required dialysis. Plasma concentration of baclofen was 565 ng/ml (therapeutic range 80-400 ng/ml). After discontinuing the drug and renewed haemodialysis the baclofen level rapidly fell and the symptoms receded. In a second case, a 57-year-old man on dialysis developed a thalamic pain syndrome after an intracerebral haemorrhage in the region of the basal ganglia. He was given four times 10 mg baclofen by mouth over 24 hours. 24 hours after the first dose he became deeply unconscious with respiratory failure. Plasma concentration of baclofen after the first haemodialysis period was 480 ng/ml. After 48 hours of artificial ventilation it was possible to extubate; a symptomatic transitory psychotic syndrome disappeared within 4 days. Both patients had pre-existing cerebral damage in addition to the chronic renal failure (in the first patient, meningoencephalitis 30 years previously with persisting focal lesions in the computed tomogram CT]; in the second one, residual lesions in the CT after intracerebral haemorrhage). It is emphasized that in patients who are in renal failure baclofen treatment should be undertaken cautiously: toxic signs can quickly develop especially if there is pre-existing cerebral damage.

A comparative cell-based high throughput screening strategy for the discovery of selective tyrosine kinase inhibitors with anticancer activity.

Growth factor receptor tyrosine kinases (RTK) have been implicated in tumor growth, metastasis and angiogenesis, and are thus considered promising targets for therapeutic intervention in malignant diseases. We present a novel drug discovery strategy to find inhibitors of RTKs based on comparative screening of compound libraries employing functional cellular assays. Cell lines stably expressing HER2 and the receptors for hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), insulin-like growth factor-I (IGF-I) and epidermal growth factor (EGF) have been established. All cell lines are based on FDC-P1, a murine myeloid progenitor cell line which allows a direct comparison of results obtained in primary screens. In addition, the same cell lines are suitable for compound optimization and for animal studies. Using this strategy we report the identification of promising lead candidates for further drug development which are highly selective, non-cytotoxic and cell permeable with potencies in the low micromolar range.