Snake venom-derived bradykinin-potentiating peptides: A promising therapy for COVID-19?

The severe acute respiratory syndrome coronavirus-2 (SARS-COV-2), a novel coronavirus responsible for the recent infectious pandemic, is known to downregulate angiotensin-converting enzyme-2 (ACE2). Most current investigations focused on SARS-COV-2-related effects on the renin-angiotensin system and especially the resultant increase in angiotensin II, neglecting its effects on the kinin-kallikrein system. SARS-COV-2-induced ACE2 inhibition leads to the augmentation of bradykinin 1-receptor effects, as ACE2 inactivates des-Arg9-bradykinin, a bradykinin metabolite. SARS-COV-2 also decreases bradykinin 2-receptor effects as it affects bradykinin synthesis by inhibiting cathepsin L, a kininogenase present at the site of infection and involved in bradykinin production. The physiologies of both the renin-angiotensin and kinin-kallikrein system are functionally related suggesting that any intervention aiming to treat SARS-COV-2-infected patients by triggering one system but ignoring the other may not be adequately effective. Interestingly, the snake-derived bradykinin-potentiating peptide (BPP-10c) acts on both systems. BPP-10c strongly decreases angiotensin II by inhibiting ACE, increasing bradykinin-related effects on the bradykinin 2-receptor and increasing nitric oxide-mediated effects. Based on a narrative review of the literature, we suggest that BPP-10c could be an optimally effective option to consider when aiming at developing an anti-SARS-COV-2 drug.

Management of hereditary angioedema in Japan: Focus on icatibant for the treatment of acute attacks.

Hereditary angioedema (HAE) is characterized by unpredictable, recurring and painful swelling episodes that can be disabling or even life-threatening. Awareness of HAE has progressively grown worldwide, and options for treatment of acute attacks and prevention of future attacks continue to expand; however, unmet needs in diagnosis and treatment remain. In Japan, recognition of HAE within the medical community remains low, and numerous obstacles complicate diagnosis and access to treatment. Importance of timely treatment of HAE attacks with on-demand therapies is continually demonstrated; recommended agents per the WAO/EAACI treatment guidelines published in 2018 include C1 inhibitor (C1-INH) concentrate, ecallantide, and icatibant. In Japan, multiple factors contribute to delayed HAE treatment (potentially leading to life-threatening consequences), including difficulties in finding facilities at which C1-INH agents are readily available. Recognition of challenges faced in Japan can help promote efforts to address current needs and expand access to effective therapies. Icatibant, a potent, selective bradykinin B2 receptor antagonist, has demonstrated inhibition of various bradykinin-induced biological effects in preclinical studies and has shown efficacy in treating attacks in various clinical settings (e.g. clinical trials, real-world studies), and HAE patient populations (e.g. with C1-INH deficiency, normal C1-INH). Icatibant was approved in Japan for the treatment of HAE attacks in September 2018; its addition to the HAE treatment armamentarium contributes to improved patient care. In Japan, disease awareness and education campaigns are warranted to further advance the management of HAE patients in light of the unmet needs and the emerging availability of modern diagnostic approaches and therapies.

PIP2 Mediated Inhibition of TREK Potassium Currents by Bradykinin in Mouse Sympathetic Neurons.

Bradykinin (BK), a hormone inducing pain and inflammation, is known to inhibit potassium M-currents (IM) and to increase the excitability of the superior cervical ganglion (SCG) neurons by activating the Ca2+-calmodulin pathway. M-current is also reduced by muscarinic agonists through the depletion of membrane phosphatidylinositol 4,5-biphosphate (PIP2). Similarly, the activation of muscarinic receptors inhibits the current through two-pore domain potassium channels (K2P) of the "Tandem of pore-domains in a Weakly Inward rectifying K+ channel (TWIK)-related channels" (TREK) subfamily by reducing PIP2 in mouse SCG neurons (mSCG). The aim of this work was to test and characterize the modulation of TREK channels by bradykinin. We used the perforated-patch technique to investigate riluzole (RIL) activated currents in voltage- and current-clamp experiments. RIL is a drug used in the palliative treatment of amyotrophic lateral sclerosis and, in addition to blocking voltage-dependent sodium channels, it also selectively activates the K2P channels of the TREK subfamily. A cell-attached patch-clamp was also used to investigate TREK-2 single channel currents. We report here that BK reduces spike frequency adaptation (SFA), inhibits the riluzole-activated current (IRIL), which flows mainly through TREK-2 channels, by about 45%, and reduces the open probability of identified single TREK-2 channels in cultured mSCG cells. The effect of BK on IRIL was precluded by the bradykinin receptor (B2R) antagonist HOE-140 (d-Arg-[Hyp3, Thi5, d-Tic7, Oic8]BK) but also by diC8PIP2 which prevents PIP2 depletion when phospholipase C (PLC) is activated. On the contrary, antagonizing inositol triphosphate receptors (IP3R) using 2-aminoethoxydiphenylborane (2-APB) or inhibiting protein kinase C (PKC) with bisindolylmaleimide did not affect the inhibition of IRIL by BK. In conclusion, bradykinin inhibits TREK-2 channels through the activation of B2Rs resulting in PIP2 depletion, much like we have demonstrated for muscarinic agonists. This mechanism implies that TREK channels must be relevant for the capture of information about pain and visceral inflammation.

[Use of simulation in healthcare for therapeutic training of the parents of children with hereditary angioedema]. / Utilisation de la simulation en santé pour l'éducation thérapeutique des parents d'enfants souffrant d'un angio-œdème héréditaire.

BACKGROUND: C1INH-deficiency hereditary angioedema (HAE) is characterized by recurrent episodes of potentially severe oedema. Icatibant for SC injection will soon be approved for use in children and it is necessary to train parents in recognising severe episodes of AOH and in the technique for injection of icatibant. Simulation in healthcare (SH) is a set of educational methods for improving skills in a safe environment. We wished to assess the feasibility of a therapeutic training session (TTS) involving scripted scenarios for the parents of children with HAE. PATIENTS AND METHODS: The TTS session included pre- and post-training testing on AOH, two scenarios (calling emergency services for lingual AO; gastrointestinal AO) involving actors and a volunteer parent, a workshop for learning the SC injection technique, and a satisfaction questionnaire. We analysed the answers on the questionnaire and noted down parents' verbatim observations during debriefing sessions. RESULTS: Eight parents from 5 families took part in this session. Parents rated their overall satisfaction as 9.3/10. The parents commented that during the simulations, they felt "in the thick of it" and that they "experienced stress while viewing the scenes", thus attesting to the realism and relevance of the simulated scenarios. DISCUSSION: This session met the parents' expectations in terms of being able to cope and having adequate know-how, based on both the simulations and the level of knowledge acquired. The main limitation lay in the parents' difficulty in confronting certain situations reminiscent of traumatic past experiences. TTS shares many common features with SH for the parents of sick children. The place of the latter in TTS must be evaluated.

Bradykinin sensitizes the cough reflex via a B2 receptor dependent activation of TRPV1 and TRPA1 channels through metabolites of cyclooxygenase and 12-lipoxygenase.

BACKGROUND: Inhaled bradykinin (BK) has been reported to both sensitize and induce cough but whether BK can centrally sensitize the cough reflex is not fully established. In this study, using a conscious guinea-pig model of cough, we investigated the role of BK in the central sensitization of the cough reflex and in airway obstruction. METHODS: Drugs were administered, to guinea pigs, by the intracerebroventricular (i.c.v.) route. Aerosolized citric acid (0.2 M) was used to induce cough in a whole-body plethysmograph box, following i.c.v. infusion of drugs. An automated analyser recorded both cough and airway obstruction simultaneously. RESULTS: BK, administered by the i.c.v. route, dose-dependently enhanced the citric acid-induced cough and airway obstruction. This effect was inhibited following i.c.v. pretreatment with a B2 receptor antagonist, TRPV1 and TRPA1 channels antagonists and cyclooxygenase (COX) and 12-lipoxygenase (12-LOX) inhibitors. Furthermore, co-administration of submaximal doses of the TRPV1 and TRPA1 antagonists or the COX and 12-LOX inhibitors resulted in a greater inhibition of both cough reflex and airway obstruction. CONCLUSIONS: Our findings show that central BK administration sensitizes cough and enhances airway obstruction via a B2 receptor/TRPV1 and/or TRPA1 channels which are coupled via metabolites of COX and/or 12-LOX enzymes. In addition, combined blockade of TRPV1 and TRPA1 or COX and 12-LOX resulted in a greater inhibitory effect of both cough and airway obstruction. These results indicate that central B2 receptors, TRPV1/TRPA1 channels and COX/12-LOX enzymes may represent potential therapeutic targets for the treatment of cough hypersensitivity.

Hereditary angioedema in children: a review and update.

PURPOSE OF REVIEW: Hereditary angioedema (HAE) most often presents in the first two decades of life. Despite these patients often see multiple doctors and go many years before confirmation of the diagnosis. the impact on quality of life, productivity and risk of anxiety, depression, and posttraumatic stress emphasizes the need for early diagnosis and appropriate treatment. RECENT FINDINGS: Over the past decade, therapy in the USA has emerged from fresh-frozen plasma and androgens to more than seven medications that are specific for bradykinin-induced disease. During the same time, treatment has evolved from intravenous to subcutaneous and the future will be a focus on oral therapy. SUMMARY: Much optimism exists that patients with HAE will live a life with minimal disease and impact on their quality of life making it even more important to diagnose children at an early age.

Self-administration of icatibant in acute attacks of Type I hereditary angioedema: A case report and review of hereditary angioedema.

Hereditary angioedema (HAE) is a rare group of genetic disease characterized by non-itchy swelling of subcutaneous and submucosal tissues of the extremities, genitalia, gastrointestinal tract, and upper airways, which can be life threatening. Moreover, unpredictability and recurrence of HAE attacks significantly affect patients' quality of life. Short- and long-term prophylaxis is used to decrease the severity and frequency of attacks, but during severe or potentially severe acute episodes, treatment with C1-INH replacement or icatibant is mandatory. Icatibant is a selective bradykinin B2 receptor antagonist that has been licensed for self-administration at home, resulting in earlier treatment of the attack and quicker recovery, less emergency admittance with a significant improvement of patients' quality of life, and decrease of health care costs. The authors present a case of a young woman, affected by Type I HAE, who has been successfully treated with icatibant on demand at home, resulting in reduction of emergency admissions and improvement of quality of life. The authors also review the different types HAE, their clinical aspects, diagnosis, and management.

Activation of bradykinin B2 receptor induced the inflammatory responses of cytosolic phospholipase A2 after the early traumatic brain injury.

Phospholipase A2 is a known aggravator of inflammation and deteriorates neurological outcomes after traumatic brain injury (TBI), however the exact inflammatory mechanisms remain unknown. This study investigated the role of bradykinin and its receptor, which are known initial mediators within inflammation activation, as well as the mechanisms of the cytosolic phospholipase A2 (cPLA2)-related inflammatory responses after TBI. We found that cPLA2 and bradykinin B2 receptor were upregulated after a TBI. Rats treated with the bradykinin B2 receptor inhibitor LF 16-0687 exhibited significantly less cPLA2 expression and related inflammatory responses in the brain cortex after sustaining a controlled cortical impact (CCI) injury. Both the cPLA2 inhibitor and the LF16-0687 improved CCI rat outcomes by decreasing neuron death and reducing brain edema. The following TBI model utilized both primary astrocytes and primary neurons in order to gain further understanding of the inflammation mechanisms of the B2 bradykinin receptor and the cPLA2 in the central nervous system. There was a stronger reaction from the astrocytes as well as a protective effect of LF16-0687 after the stretch injury and bradykinin treatment. The protein kinase C pathway was thought to be involved in the B2 bradykinin receptor as well as the cPLA2-related inflammatory responses. Rottlerin, a Protein Kinase C (PKC) δ inhibitor, decreased the activity of the cPLA2 activity post-injury, and LF16-0687 suppressed both the PKC pathway and the cPLA2 activity within the astrocytes. These results indicated that the bradykinin B2 receptor-mediated pathway is involved in the cPLA2-related inflammatory response from the PKC pathway.

Opposing effects of bronchopulmonary C-fiber subtypes on cough in guinea pigs.

We have addressed the hypothesis that the opposing effects of bronchopulmonary C-fiber activation on cough are attributable to the activation of C-fiber subtypes. Coughing was evoked in anesthetized guinea pigs by citric acid (0.001-2 M) applied topically in 100-µl aliquots to the tracheal mucosa. In control preparations, citric acid evoked 10 ± 1 coughs cumulatively. Selective activation of the pulmonary C fibers arising from the nodose ganglia with either aerosols or continuous intravenous infusion of adenosine or the 5-HT3 receptor-selective agonist 2-methyl-5-HT nearly abolished coughing evoked subsequently by topical citric acid challenge. Delivering adenosine or 2-methyl-5-HT directly to the tracheal mucosa (where few if any nodose C fibers terminate) was without effect on citric acid-evoked cough. These actions of pulmonary administration of adenosine and 2-methyl-5-HT were accompanied by an increase in respiratory rate, but it is unlikely that the change in respiratory pattern caused the decrease in coughing, as the rapidly adapting receptor stimulant histamine also produced a marked tachypnea but was without effect on cough. In awake guinea pigs, adenosine failed to evoke coughing but reduced coughing induced by the nonselective C-fiber stimulant capsaicin. We conclude that bronchopulmonary C-fiber subtypes in guinea pigs have opposing effects on cough, with airway C fibers arising from the jugular ganglia initiating and/or sensitizing the cough reflex and the intrapulmonary C fibers arising from the nodose ganglia actively inhibiting cough upon activation.

Icatibant Outcome Survey in Patients with Hereditary Angioedema: Experience in Israel Compared with Other Countries.

BACKGROUND: Management of patients with hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is evolving worldwide. Evaluating the Israeli experience may provide valuable insights. OBJECTIVES: To compare demographics and icatibant treatment patterns and outcomes in patients with C1-INH-HAE enrolled in the Icatibant Outcome Survey (IOS) in Israel with those in other countries. METHODS: The IOS is an ongoing observational study that prospectively monitors real-world icatibant safety/tolerability and treatment outcomes. RESULTS: By July 2016, 58 patients from Israel and 594 patients from other countries were enrolled. Median age at diagnosis (16.7 vs. 21.3 years, P = 0.036) and median delay between symptom onset and diagnosis (0.8 vs. 6.6 years, P = 0.025) were lower in Israel compared with other countries, respectively. Differences in attack severity were not significant (P = 0.156); however, during follow-up, Israeli patients were less likely to miss > 7 days of work/school due to C1-INH-HAE-related complications (P = 0.007). A trend was also shown in Israel for earlier time to treatment (median 0.5 vs. 1.3 hours, P = 0.076), attack duration was shorter (median 5.0 vs. 9.0 hours, P = 0.026), and patients more often self-administered icatibant (97.2% vs. 87.5%, P = 0.003), respectively. However, Israeli patients were less likely to treat attacks (P = 0.036). Whereas patients in Israel reported exclusive use of danazol for long-term prophylaxis, those in other countries used various agents, including C1-INH. CONCLUSIONS: Recognition of C1-INH-HAE and timeliness of icatibant treatment appear more favorable, and attack duration shorter, in Israel compared with other countries.

Comparing acquired angioedema with hereditary angioedema (types I/II): findings from the Icatibant Outcome Survey.

Icatibant is used to treat acute hereditary angioedema with C1 inhibitor deficiency types I/II (C1-INH-HAE types I/II) and has shown promise in angioedema due to acquired C1 inhibitor deficiency (C1-INH-AAE). Data from the Icatibant Outcome Survey (IOS) were analysed to evaluate the effectiveness of icatibant in the treatment of patients with C1-INH-AAE and compare disease characteristics with those with C1-INH-HAE types I/II. Key medical history (including prior occurrence of attacks) was recorded upon IOS enrolment. Thereafter, data were recorded retrospectively at approximately 6-month intervals during patient follow-up visits. In the icatibant-treated population, 16 patients with C1-INH-AAE had 287 attacks and 415 patients with C1-INH-HAE types I/II had 2245 attacks. Patients with C1-INH-AAE versus C1-INH-HAE types I/II were more often male (69 versus 42%; P = 0·035) and had a significantly later mean (95% confidence interval) age of symptom onset [57·9 (51·33-64·53) versus 14·0 (12·70-15·26) years]. Time from symptom onset to diagnosis was significantly shorter in patients with C1-INH-AAE versus C1-INH-HAE types I/II (mean 12·3 months versus 118·1 months; P = 0·006). Patients with C1-INH-AAE showed a trend for higher occurrence of attacks involving the face (35 versus 21% of attacks; P = 0·064). Overall, angioedema attacks were more severe in patients with C1-INH-HAE types I/II versus C1-INH-AAE (61 versus 40% of attacks were classified as severe to very severe; P < 0·001). Median total attack duration was 5·0 h and 9·0 h for patients with C1-INH-AAE versus C1-INH-HAE types I/II, respectively.

Treatment of hereditary angioedema due to C1 inhibitor deficiency in Argentina.

The benefits of the worldwide approval of new drugs for the treatment of acute C1-INH-HAE attacks may still not reach all patients. Identifying the current barriers in the access to medication, as well as conducting a detailed assessment of the progress in this area, is essential to achieve universal treatment. Two hundred and twenty five patients registered in the Argentina Hereditary Angioedema Patient Association (AHAEPA) were randomly selected and invited to participate in a web based questionnaire on accessibility to icatibant and pdC1-INH, self-treatment, delay to treatment, and coverage. The data retrieved was compared to our previous reports in 2008 and 2013. We collected 156/225 answers. One hundred and eighteen (76%) patients have either pdC1-INH (n = 86), icatibant (n = 10) or both (n = 22), while 38 (24%) do not have access to treatment. In 2008, 26% had access while 82% had it in 2013. Thirty-two subjects (22%) self-inject themselves, similar to 29% in 2013, even though between studies, widespread self-injection training activities have taken place. However, considering injections by proxy, home treatment reached 56%. Only half of the patients decide to receive treatment early during the attack. Ninety-nine patients (63%) have full coverage, thirty (19%) have no coverage at all and the rest only obtain partial reimbursement. Twenty-nine families (31%) share a single treatment dose of the medication, better than 36% in 2013. Argentina's C1-INH-HAE patients had a sustained improvement in their access to medication. Efforts should continue to further improve accessibility and optimal management of HAE acute attacks to all patients in the country.

Angioedema Triggered by Medication Blocking the Renin/Angiotensin System: Retrospective Study Using the French National Pharmacovigilance Database.

INTRODUCTION: Bradykinin-mediated angioedema (AE) is a rare side effect of some medications, including angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB). In France, side-effects to treatments are reported to the national pharmacovigilance database. METHODS: The national MedDRA database was searched using the term "angioedema". Patients were included if they met the clinical criteria corresponding to bradykinin-mediated AE, if their C1-inhibitor levels were normal, and if they were treated with an ACEi or an ARB. RESULTS: 7998 cases of AE were reported between 1994 and 2013. Among these, 112 met the criteria for bradykinin-mediated AE with normal C1-inhibitor levels. On the 112 drug-AE, patients were treated with an ARB in 21% of cases (24 patients), or an ACEi in 77% of cases (88 patients), in combination with another treatment in 17 cases (mTORi for 3 patients, iDPP-4 for 1 patient, hormonal treatment for 7 patients). ENT involvement was reported in 90% of cases (tongue: 48.2%, larynx: 23.2%). The median duration of treatment before the first attack was 720 days, and the mean duration of attacks was 36.6 h. Forty-one percent (19/46) of patients relapsed after discontinuing treatment. CONCLUSION: Angioedema triggered by medication blocking the renin/angiotensin system is rare but potentially severe, with a high risk of recurrence despite cessation of the causative drug.

Activated central galanin type 1 receptor alleviated insulin resistance in diabetic rat muscle.

Evidence indicates that central galanin is involved in regulation of insulin resistance in animals. This study investigates whether type 1 galanin receptor (GAL1) in the brain mediates the ameliorative effect of galanin on insulin resistance in skeletal muscles of type 2 diabetic rats. Rats were intracerebroventricularly (i.c.v.) injected with galanin(1-13)-bradykinin(2-9) amide (M617), a GAL1 agonist, and/or Akti-1/2, an Akt inhibitor, via caudal veins once per day for 10 days. Insulin resistance in muscle tissues was evaluated by glucose tolerance and 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) tests, peroxisome proliferator-activated receptor-γ (PPARγ), glucose transporter 4 (GLUT4) mRNA expression levels, Akt phosphorylation, and GLUT4 and vesicle-associated membrane protein 2 (VAMP2) concentration at plasma membranes in muscle cells. The results show that i.c.v. treatment with M617 increased glucose tolerance, 2-NBDG uptake, PPARγ levels, Akt phosphorylation, GLUT4 protein, and GLUT4 mRNA expression levels as well as GLUT4 and VAMP2 concentration at plasma membranes. All increases may be blocked by pretreatment with Akti-1/2. These results suggest that activated central GAL1 may trigger the Akt signaling pathway to alleviate insulin resistance in muscle cells. Therefore, the impact of galanin on insulin resistance is mediated mainly by GAL1 in the brain, and the GAL1 agonist may be taken as a potential antidiabetic agent for treatment of type 2 diabetes mellitus. © 2016 Wiley Periodicals, Inc.

Differential effect of intranasally administrated kinin B1 and B2 receptor antagonists in Alzheimer's disease mice.

An Increasing body of evidence supports a critical role of brain inflammation in the pathogenesis of Alzheimer's disease. A principal aspect of the brain immune response to inflammation is the activation of microglia. It has been shown that the kinin system is activated during brain inflammation and previously we demonstrated that bradykinin B1 receptor agonist reduced microglial activation in vitro. The aim of the present study was to investigate the effects of bradykinin B1 or B2 receptor antagonists on microglial release of pro-inflammatory factors in BV2 microglia. In vivo, we focused on the effects of intranasally given kinin antagonists on amyloid burden and microglia/macrophage marker expression in brains of 5X familial Alzheimer's disease mice. The present data show that pharmacological antagonism of B1 receptor (R-715) but not B2 receptor (HOE-140) markedly increased nitric oxide and tumor necrosis factor alpha release from BV2 microglial cells. We also showed that intranasal treatment with R-715 but not HOE-140 of Alzheimer's mice enhanced amyloid beta burden and microglia/macrophages activation. Taken together, our data reveal a possible role for the bradykinin B1 receptor in neuroinflammation and in the control of Abeta accumulation in transgenic mice, possibly through regulation of glial cell responses.

Antinociceptive effects induced by intra-lateral habenula complex injection of the galanin receptor 1 agonist M617 in rats.

The present study was performed to explore the antinociceptive effects of the galanin receptor 1 agonist M617 in lateral habenula complex in rats. Intra-lateral habenula injection of 0.1, 0.5, 1 or 2 nmol of galanin induced dose-dependent increases in hindpaw withdrawal latencies (HWLs) to noxious thermal and mechanical stimulations in rats. Furthermore, intra-lateral habenula injection of 0.1, 0.5, 1 or 2 nmol of the galanin receptor 1 agonist M617 also induced dose-dependent increases in HWLs to noxious thermal and mechanical stimulations in rats. Interestingly, there were no significant differences between the antinociceptive effects induced by intra-lateral habenula injection of 2 nmol of M617 and 2 nmol of galanin. The results indicate that galanin receptor 1 may be involved in the galanin-induced antinociceptive effects in the lateral habenula.

Delayed bradykinin postconditioning modulates intrinsic neuroprotective enzyme expression in the rat CA1 region after cerebral ischemia: a proteomic study.

Pyramidal cells in the CA1 brain region exhibit an ischemic tolerance after delayed postconditioning; therefore, this approach seems to be a promising neuroprotective procedure in cerebral postischemic injury improvement. However, little is known about the effect of postconditioning on protein expression patterns in the brain, especially in the affected hippocampal neurons after global cerebral ischemia. This study is focused on the examination of the ischemia-vulnerable CA1 neuronal layer and on the acquisition of protection from delayed neuronal death after ischemia. Ischemic-reperfusion injury was induced in Wistar rats and bradykinin was applied 2 days after the ischemic insult in an attempt to overcome delayed cell death. Analysis of complex peptide CA1 samples was performed by automated two dimensional liquid chromatography (2D-LC) fractionation coupled to tandem matrix assisted laser desorption/ionization time-of-flight (MALDI TOF/TOF) mass spectrometry instrumentation. We devoted our attention to differences in protein expression mapping in ischemic injured CA1 neurons in comparison with equally affected neurons, but with bradykinin application. Proteomic analysis identified several proteins occurring only after postconditioning and control, which could have a potentially neuroprotective influence on ischemic injured neurons. Among them, the prominent position occupies a regulator of glutamate level aspartate transaminase AATC, a scavenger of glutamate in brain neuroprotection after ischemia-reperfusion. We identified this enzyme in controls and after postconditioning, but AATC presence was not detected in the ischemic injured CA1 region. This finding was confirmed by two-dimensional differential electrophoresis followed by MALDI-TOF/TOF MS identification. Results suggest that bradykinin as delayed postconditioning may be associated with modulation of protein expression after ischemic injury and thus this procedure can be involved in neuroprotective metabolic pathways.

Prophylaxis in hereditary angioedema (HAE) with C1 inhibitor deficiency.

Hereditary angioedema (HAE) is a rare congenital disorder characterized by recurrent episodes of subcutaneous or submucosal edema. Laryngeal manifestations can be life-threatening. In the majority of cases, the disease can be adequately treated with an on-demand approach--in some cases, however, short- or long-term prophylaxis is indicated. Attenuated androgens used to be the drugs of choice, but they are associated with considerable side effects and no longer commercially available in the German-speaking countries of the EU. They are currently being replaced by more effective and more tolerable agents such C1-inhibitors, the kallikrein inhibitor ecallantide, and the B2 receptor antagonist icatibant, which have recently obtained market authorization. These new drugs have had a major impact, especially on the indications and procedures for long-term prophylaxis. According to the most recent international consensus papers and our own experience, self-administered C1-inhibitors are now the first option for long-term prophylactic therapy. The decision for prophylaxis should no longer be based on single parameters such as the frequency of attacks but on adequate overall disease control including quality of life. More drugs are currently being developed, which may lead to further changes in the treatment algorithms of HAE.

Kinin receptor agonism restores hindlimb postischemic neovascularization capacity in diabetic mice.

Limb ischemia is a major complication of thromboembolic diseases. Diabetes worsens prognosis by impairing neovascularization. Genetic or pharmacological inactivation of the kallikrein-kinin system aggravates limb ischemia in nondiabetic animals, whereas angiotensin I-converting enzyme/kininase II inhibition improves outcome. The role of kinins in limb ischemia in the setting of diabetes is not documented. We assessed whether selective activation of kinin receptors by pharmacological agonists can influence neovascularization in diabetic mice with limb ischemia and have a therapeutic effect. Selective pseudopeptide kinin B1 or B2 receptor agonists resistant to peptidase action were administered by osmotic minipumps at a nonhypotensive dosage for 14 days after unilateral femoral artery ligation in mice previously rendered diabetic by streptozotocin. Comparison was made with ligatured, nonagonist-treated nondiabetic and diabetic mice. Diabetes reduced neovascularization, assessed by microangiography and histologic capillary density analysis, by roughly 40%. B1 receptor agonist or B2 receptor agonist similarly restored neovascularization in diabetic mice. Neovascularization in agonist-treated diabetic mice was indistinguishable from nondiabetic mice. Both treatments restored blood flow in the ischemic hindfoot, measured by laser-Doppler perfusion imaging. Macrophage infiltration increased 3-fold in the ischemic gastrocnemius muscle during B1 receptor agonist or B2 receptor agonist treatment, and vascular endothelial growth factor (VEGF) level increased 2-fold. Both treatments increased, by 50-100%, circulating CD45/CD11b-positive monocytes and CD34(+)/VEGFR2(+) progenitor cells. Thus, selective pharmacological activation of B1 or B2 kinin receptor overcomes the effect of diabetes on postischemic neovascularization and restores tissue perfusion through monocyte/macrophage mobilization. Kinin receptors are potential therapeutic targets in limb ischemia in diabetes.

Kinin B1 Receptor Antagonist BI113823 Reduces Acute Lung Injury.

OBJECTIVES: This study was undertaken to examine the effects of BI113823, a potent small molecule orally active nonpeptide B1 receptor antagonist, in an experimental model of endotoxin-induced direct lung injury in mice and indirect lung injury and survival in cecal ligation and puncture-induced polymicrobial sepsis in rats. DESIGN: Experimental, prospective study. SETTING: University research laboratory. SUBJECTS: Male BALB/c mice and male Wistar rats. INTERVENTIONS: Series 1: acute lung injury was induced in mice by intratracheal injection of lipopolysaccharide. Mice were then randomly assigned to receive treatment of vehicle, BI113823, or dexamethasone. Bronchoalveolar lavage fluid and lung tissues were analyzed for inflammatory cell influx and various histologic variables. Series 2: sepsis was induced by cecal ligation and puncture in anesthetized rats. Animals were then randomly assigned to receive treatment of vehicle or BI113823. Experiments were terminated at 20 hours and 7 days following cecal ligation and puncture, respectively. MEASUREMENTS AND MAIN RESULTS: Series 1: treatment with BI113823 significantly reduced lipopolysaccharide-induced neutrophil influx in bronchoalveolar lavage fluid. The BI113823 group had significantly lower lung vascular permeability, lung water content, myeloperoxidase activity, lung apoptosis and lung injury scores, total protein content, and tumor necrosis factor-α and interleukin-1ß levels compared with vehicle controls. In addition, nuclear factor-κB phosphorylation, nuclear translocation, and cyclooxygenase-2 and inducible nitric oxide synthase expression in the lung were attenuated in BI113823-treated animals compared with vehicle controls. Series 2: BI113823 significantly reduced sepsis-induced macrophage recruitment, protein content, and tumor necrosis factor-α and interleukin-1ß levels in lavage fluid and also reduced lung water content and plasma levels of tumor necrosis factor-α and interleukin-6 compared with vehicle controls. Most importantly, treatment with BI113823 significantly improved survival following severe sepsis in rats. CONCLUSIONS: Administration of B1 receptor antagonist BI113823 significantly reduced endotoxin-induced direct lung injury and also reduced sepsis-induced lung inflammatory response. Most importantly, BI113823 improved survival following severe polymicrobial sepsis.