Involvement of the kallikrein-kinin system in the antihypertensive effect of the angiotensin converting enzyme inhibitors.

1. Studies were performed in normal subjects and in rats to assess the effect of angiotensin converting enzyme (ACE) inhibition on the kallikrein-kinin system. As ACE is identical to kininase II, one of the enzymes physiologically involved in bradykinin degradation, bradykinin may be expected to accumulate during ACE inhibition. 2. A competitive antagonist of bradykinin was used to explore in unanaesthetized rats the contribution of circulating bradykinin to blood pressure control under ACE inhibition. 3. No evidence was found for a role of this vasodilating peptide in the blood pressure lowering effect of acute ACE inhibition. 4. The plasma activity of carboxypeptidase N (= kininase I), another pathway of bradykinin degradation, remained intact during a 1 week course of treatment with an ACE inhibitor in normal subjects. This therefore indicates that bradykinin formed during ACE inhibition can still be metabolized.

DNA topology: feeling the pulse of a topoisomerase.

The action of individual type II DNA topoisomerases has been followed in real time by observing the elastic response of single DNA molecules to sequential strand passage events. Micromanipulation methods provide a complementary approach to biochemical studies for investigating the mechanism of DNA topoisomerases.

Effect of indomethacin on the renal response to angiotensin II receptor blockade in healthy subjects.

BACKGROUND: Non-steroidal anti-inflammatory drugs are known to promote sodium retention and to blunt the blood pressure lowering effects of several classes of antihypertensive agents including beta-blockers, diuretics and angiotensin converting enzyme (ACE) inhibitors. The purpose of the present study was to investigate the acute and sustained effects of indomethacin on the renal response to the angiotensin II receptor antagonist valsartan and to the ACE inhibitor enalapril. METHODS: Twenty normotensive subjects maintained on fixed sodium intake (100 mmol sodium/day) were randomized to receive for one week: valsartan 80 mg o.d., enalapril 20 mg o.d., valsartan 80 mg o.d. + indomethacin 50 mg bid and enalapril 20 mg o.d. + indomethacin 50 mg bid. This single-blind study was designed as a parallel (valsartan vs. enalapril) and cross-over trial (valsartan or enalapril vs. valsartan + indomethacin or enalapril + indomethacin). Renal hemodynamics and urinary electrolyte excretion were measured for six hours after the first and seventh administration of each treatment regimen. RESULTS: The results show that valsartan and enalapril have comparable renal effects characterized by no change in glomerular filtration rate and significant increases in renal plasma flow and sodium excretion. The valsartan- and enalapril-induced renal vasodilation is not significantly blunted by indomethacin. However, indomethacin similarly abolishes the natriuresis induced by the angiotensin II antagonist and the ACE inhibitor. CONCLUSIONS: This observation suggests that although angiotensin receptor antagonists do not affect prostaglandin metabolism, the administration of a non-steroidal anti-inflammatory drug blunts the natriuretic response to angiotensin receptor blockade.

Multicenter phase II trial of gefitinib first-line therapy followed by chemotherapy in advanced non-small-cell lung cancer (NSCLC): SAKK protocol 19/03.

BACKGROUND: Gefitinib is active in patients with pretreated non-small-cell lung cancer (NSCLC). We evaluated the activity and toxicity of gefitinib first-line treatment in advanced NSCLC followed by chemotherapy at disease progression. PATIENTS AND METHODS: In all, 63 patients with chemotherapy-naive stage IIIB/IV NSCLC received gefitinib 250 mg/day. At disease progression, gefitinib was replaced by cisplatin 80 mg/m(2) on day 1 and gemcitabine 1250 mg/m(2) on days 1, 8 for up to six 3-week cycles. Primary end point was the disease stabilization rate (DSR) after 12 weeks of gefitinib. RESULTS: After 12 weeks of gefitinib, the DSR was 24% and the response rate (RR) was 8%. Median time to progression (TtP) was 2.5 months and median overall survival (OS) 11.5 months. Never smokers (n = 9) had a DSR of 56% and a median OS of 20.2 months; patients with epidermal growth factor receptor (EGFR) mutation (n = 4) had a DSR of 75% and the median OS was not reached after the follow-up of 21.6 months. In all, 41 patients received chemotherapy with an overall RR of 34%, DSR of 71% and median TtP of 6.7 months. CONCLUSIONS: First-line gefitinib monotherapy led to a DSR of 24% at 12 weeks in an unselected patients population. Never smokers and patients with EGFR mutations tend to have a better outcome; hence, further trials in selected patients are warranted.

A multicenter phase II trial (SAKK 36/06) of single-agent everolimus (RAD001) in patients with relapsed or refractory mantle cell lymphoma.

BACKGROUND: Mantle cell lymphoma accounts for 6% of all B-cell lymphomas and is generally incurable. It is characterized by the translocation t(11;14) leading to cyclin D1 over-expression. Cyclin D1 is downstream of the mammalian target of rapamycin threonine kinase and can be effectively blocked by mammalian target of rapamycin inhibitors. We set out to examine the single agent activity of the orally available mammalian target of rapamycin inhibitor everolimus in a prospective, multicenter trial in patients with relapsed or refractory mantle cell lymphoma (NCT00516412). DESIGN AND METHODS: Eligible patients who had received a maximum of three prior lines of chemotherapy were given everolimus 10 mg for 28 days (one cycle) for a total of six cycles or until disease progression. The primary endpoint was the best objective response. Adverse reactions, progression-free survival and molecular response were secondary endpoints. RESULTS: Thirty-six patients (35 evaluable) were enrolled and treatment was generally well tolerated with Common Terminology Criteria grade ≥ 3 adverse events (>5%) including anemia (11%), thrombocytopenia (11%) and neutropenia (8%). The overall response rate was 20% (95% CI: 8-37%) with two complete remissions and five partial responses; 49% of the patients had stable disease. At a median follow-up of 6 months, the median progression-free survival was 5.5 months (95% CI: 2.8-8.2) overall and 17.0 (6.4-23.3) months for 18 patients who received six or more cycles of treatment. Three patients achieved a lasting complete molecular response, as assessed by polymerase chain reaction analysis of peripheral blood. CONCLUSIONS: Everolimus as a single agent is well tolerated and has anti-lymphoma activity in relapsed or refractory mantle cell lymphoma. Further studies of everolimus in combination with chemotherapy or as a single agent for maintenance treatment are warranted.

Histone deacetylase inhibitors impair antibacterial defenses of macrophages.

Histone deacetylases (HDACs) control gene expression by deacetylating histones and nonhistone proteins. HDAC inhibitors (HDACi) are powerful anticancer drugs that exert anti-inflammatory and immunomodulatory activities. We recently reported a proof-of-concept study demonstrating that HDACi increase susceptibility to bacterial infections in vivo. Yet, still little is known about the effects of HDACi on antimicrobial innate immune defenses. Here we show that HDACi belonging to different chemical classes inhibit at multiple levels the response of macrophages to bacterial infection. HDACi reduce the phagocytosis and the killing of Escherichia coli and Staphylococcus aureus by macrophages. In line with these findings, HDACi decrease the expression of phagocytic receptors and inhibit bacteria-induced production of reactive oxygen and nitrogen species by macrophages. Consistently, HDACi impair the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits and inducible nitric oxide synthase. These data indicate that HDACi have a strong impact on critical antimicrobial defense mechanisms in macrophages.

Complementary effects of adenosine and angiotensin II in hypoxemia-induced renal dysfunction in the rabbit.

The acute renal effects of hypoxemia and the ability of the co-administration of an angiotensin converting enzyme inhibitor (perindoprilat) and an adenosine receptor antagonist (theophylline) to prevent these effects were assessed in anesthetized and mechanically-ventilated rabbits. Renal blood flow (RBF) and glomerular filtration rate (GFR) were determined by the clearances of para-aminohippuric acid and inulin, respectively. Each animal acted as its own control. In 8 untreated rabbits, hypoxemia induced a significant drop in mean blood pressure (-12 +/- 2%), GFR (-16 +/- 3%) and RBF (-12 +/- 3%) with a concomitant increase in renal vascular resistance (RVR) (+ 18 +/- 5%), without changes in filtration fraction (FF) (-4 +/- 2%). These results suggest the occurrence of both pre- and postglomerular vasoconstriction during the hypoxemic stress. In 7 rabbits pretreated with intravenous perindoprilat (20 microg/kg), the hypoxemia-induced changes in RBF and RVR were prevented. FF decreased significantly (-18 +/- 2%), while the drop in GFR was partially blunted. These results could be explained by the inhibition of the angiotensin-mediated efferent vasoconstriction by perindoprilat. In 7 additional rabbits, co-administration of perindoprilat and theophylline (1 mg/kg) completely prevented the hypoxemia-induced changes in RBF (+ 11 +/- 3%) and GFR (+ 2 +/- 3%), while RVR decreased significantly (-14 +/- 3%). Since adenosine and angiotensin II were both shown to participate, at least in part, in the renal changes induced by hypoxemia, the beneficial effects of perindoprilat and theophylline in this model could be mediated by complementary actions of angiotensin II and adenosine on the renal vasculature.

An angiotensin II- and NF-kappaB-dependent mechanism increases connexin 43 in murine arteries targeted by renin-dependent hypertension.

AIMS: Connexins (Cxs) play a role in the contractility of the aorta wall. We investigated how connexins of the endothelial cells (ECs; Cx37, Cx40) and smooth muscle cells (SMCs; Cx43, Cx45) of the aorta change during renin-dependent and -independent hypertension. METHODS AND RESULTS: We subjected both wild-type (WT) mice and mice lacking Cx40 (Cx40(-/-)), to either a two-kidney, one-clip procedure or to N-nitro-l-arginine-methyl-ester treatment, which induce renin-dependent and -independent hypertension, respectively. All hypertensive mice featured a thickened aortic wall, increased levels of Cx37 and Cx45 in SMC, and of Cx40 in EC (except in Cx40(-/-) mice). Cx43 was up-regulated, with no effect on its S368 phosphorylation, only in the SMCs of renin-dependent models of hypertension. Blockade of the renin-angiotensin system of Cx40(-/-) mice normalized blood pressure and prevented both aortic thickening and Cx alterations. Ex vivo exposure of WT aortas, carotids, and mesenteric arteries to physiologically relevant levels of angiotensin II (AngII) increased the levels of Cx43, but not of other Cx. In the aortic SMC line of A7r5 cells, AngII activated kinase-dependent pathways and induced binding of the nuclear factor-kappa B (NF-kappaB) to the Cx43 gene promoter, increasing Cx43 expression. CONCLUSION: In both large and small arteries, hypertension differently regulates Cx expression in SMC and EC layers. Cx43 is selectively increased in renin-dependent hypertension via an AngII activation of the extracellular signal-regulated kinase and NF-kappaB pathways.

Experience with angiotensin II antagonists in hypertensive patients.

1. The availability of orally active specific angiotensin receptor antagonists (AT1 antagonists) has opened new therapeutic choices and provided probes to test the specific role of the renin-angiotensin system in the pathogenesis of cardiovascular disease. 2. The data available so far suggest that the antihypertensive efficacy of angiotensin receptor antagonists is comparable to that of angiotensin-converting enzyme (ACE) inhibitors. This provides further evidence that this latter class of drugs exerts its effect mainly through blockade of the renin-angiotensin enzymatic cascade. As expected, the association of a diuretic exerts an equally strong additive effect to the antihypertensive efficacy of both classes of drugs. 3. The most common side effect of ACE inhibitors, dry cough, does not occur with AT1 antagonists, which confirms the long-held view that this untoward effect of the ACE inhibitors is due to renin-angiotensin-independent mechanisms. 4. Long-term studies with morbidity/mortality outcome results are needed, before a definite position can be assigned to this newcomer in the orchestra of modern antihypertensive drugs. Notwithstanding, this new class of agents already represents an exciting new addition to our therapeutic armamentarium.

Cardiovascular hypertrophy: role of angiotensin II and bradykinin.

Angiotensin II can raise blood pressure rapidly by inducing direct vasoconstriction and by activating the sympathetic nervous system via central and peripheral mechanisms. In addition, this peptide may act as a growth factor to cause vascular and cardiac hypertrophy (CVH). The structural changes caused by hypertension can therefore be amplified by angiotensin II. Blockade of angiotensin II generation with angiotensin-converting enzyme (ACE) inhibitors appears to be particularly effective in preventing the development of cardiovascular hypertrophy. This beneficial effect might be related to some extent to local accumulation of bradykinin. ACE is one of the enzymes physiologically involved in bradykinin degradation. Treatment of hypertensive rats with a selective bradykinin antagonist can attenuate the blood pressure-lowering effect of ACE inhibition and render less effective the prevention of intimal thickening after endothelial removal from the rat carotid artery. Bradykinin is a vasodilator that acts by increasing the release of endothelium-derived factors such as nitric oxide and prostacyclin, which may have antiproliferative activity. However, blockade of the renin-angiotensin system with an angiotensin II subtype 1-receptor antagonist is also effective in preventing cardiac hypertrophy and neointimal proliferation after endothelial injury. Therefore, the exact contribution of bradykinin to the beneficial effects of ACE inhibition on cardiovascular hypertrophy remains to be further explored.

Angiotensin II antagonists.

Acute blockade of the renin-angiotensin system with the parenterally active angiotensin II antagonist saralasin has been shown to effectively lower blood pressure in a large fraction of patients with essential hypertension and to improve hemodynamics in some patients with congestive heart failure. It is now possible to antagonize chronically angiotensin II at its receptor using the non-peptide angiotensin II inhibitor losartan (DuP 753, MK 954). When administered by mouth, this compound induces a dose-dependent inhibition of the pressor response to exogenous angiotensin II. This effect is closely related to circulating levels of the active metabolite E3174. Preliminary studies performed in hypertensive patients suggest that losartan has a blood pressure lowering action equivalent to that of an ACE inhibitor. Whether this compound will compare favorably with ACE inhibitors requires however further investigation.

Melan-A/MART-1-specific CD4 T cells in melanoma patients: identification of new epitopes and ex vivo visualization of specific T cells by MHC class II tetramers.

Over the past decade, many efforts have been made to identify MHC class II-restricted epitopes from different tumor-associated Ags. Melan-A/MART-1(26-35) parental or Melan-A/MART-1(26-35(A27L)) analog epitopes have been widely used in melanoma immunotherapy to induce and boost CTL responses, but only one Th epitope is currently known (Melan-A51-73, DRB1*0401 restricted). In this study, we describe two novel Melan-A/MART-1-derived sequences recognized by CD4 T cells from melanoma patients. These epitopes can be mimicked by peptides Melan-A27-40 presented by HLA-DRB1*0101 and HLA-DRB1*0102 and Melan-A25-36 presented by HLA-DQB1*0602 and HLA-DRB1*0301. CD4 T cell clones specific for these epitopes recognize Melan-A/MART-1+ tumor cells and Melan-A/MART-1-transduced EBV-B cells and recognition is reduced by inhibitors of the MHC class II presentation pathway. This suggests that the epitopes are naturally processed and presented by EBV-B cells and melanoma cells. Moreover, Melan-A-specific Abs could be detected in the serum of patients with measurable CD4 T cell responses specific for Melan-A/MART-1. Interestingly, even the short Melan-A/MART-1(26-35(A27L)) peptide was recognized by CD4 T cells from HLA-DQ6+ and HLA-DR3+ melanoma patients. Using Melan-A/MART-1(25-36)/DQ6 tetramers, we could detect Ag-specific CD4 T cells directly ex vivo in circulating lymphocytes of a melanoma patient. Together, these results provide the basis for monitoring of naturally occurring and vaccine-induced Melan-A/MART-1-specific CD4 T cell responses, allowing precise and ex vivo characterization of responding T cells.

Parenteral anticoagulants in heart disease: Current status and perspectives (Section II). Position Paper of the ESC Working Group on Thrombosis - Task Force on Anticoagulants in Heart Disease.

Anticoagulants are a mainstay of cardiovascular therapy, and parenteral anticoagulants have widespread use in cardiology, especially in acute situations. Parenteral anticoagulants include unfractionated heparin, low-molecular-weight heparins, the synthetic pentasaccharides fondaparinux, idraparinux and idrabiotaparinux, and parenteral direct thrombin inhibitors. The several shortcomings of unfractionated heparin and of low-molecular-weight heparins have prompted the development of the other newer agents. Here we review the mechanisms of action, pharmacological properties and side effects of parenteral anticoagulants used in the management of coronary heart disease treated with or without percutaneous coronary interventions, cardioversion for atrial fibrillation, and prosthetic heart valves and valve repair. Using an evidence-based approach, we describe the results of completed clinical trials, highlight ongoing research with currently available agents, and recommend therapeutic options for specific heart diseases.

Temozolomide combined with bevacizumab in metastatic melanoma. A multicenter phase II trial (SAKK 50/07)

Background: Single agent DTIC is the standard therapy for metastatic melanoma (MM) with response rates of 5−20%. Temozolomide (Tem) as an oral drug has shown equal efficacy in phase III trials. Preclinical models have shown an inhibitory effect for bevacizumab (Bev) on the proliferation of melanoma cells as well as on sprouting endothelial cells. Therefore, a therapeutic approach that combines angiogenesis inhibitors with cytotoxic agents may provide clinical benefit in MM. Methods: Design: Multicenter phase II trial. Primary endpoint: Clinical benefit (CR, PR and SD) at 12 weeks; secondary endpoints: best overall response by RECIST, response duration, progression free survival, adverse events, survival after 6 months and overall survival. Sample size was calculated according to Simon's two stage optimal design (5% significance level and 80% power) with an overall sample size of 62 patients (pts) to test H0: 20% versus H1: 35% rate of clinical benefit. Response assessment was done every 6 weeks (3 cycles). Eligibility: Stage IV MM, ECOG PS 0−2, no prior treatment for metastatic disease. Treatment regimen: One cycle consisted of Tem at 150 mg/m2 days 1−7 po and Bev at 10 mg/kg day 1 over 30 min iv and was repeated every 2 weeks until progression or unacceptable toxicity. Results: Between January 2008 and April 2009, 62 pts (40 male/22 female) at a median age of 61 years (range 30−86) with stage IV (M1a:4, M1b:12, M1c:46) melanoma were enrolled in 9 centers. The first 50 pts, who received 415 cycles are included in this interim report. The overall response rate was 26% (CR: 1 pt, PR: 12 pts; PR not confirmed yet in 3 pts), and 44% (22 pts) had stable disease over 1.5−7.5 months (median: 3). Only 30% (15 pts) had disease progression at the first evaluation at week 6. The hematological grade 3/4 toxicities according to NCI CTAE 3.0 were thrombocytopenia 10% (5 pts), neutropenia 8% (4 pts), lymphopenia and leucocytopenia each 2% (1 pt). Cumulative non-hematological toxicities grade 3/4 were nausea and fatigue each 6% (3 pts), hypertension, vomiting and hemorrhage, each 4% (2 pts), thrombosis/embolism, infection, constipation, anorexia, elevation of alkaline phosphatase, bilirubin, GGT, ALT and AST each 2% (1 pt). Conclusion: In metastatic melanoma the combination of Tem/Bev is a safe regimen with a promising efficacy and few grade 3/4 toxicities. Updated results of all 62 pts will be presented.