Telmisartan for treatment of Covid-19 patients: an open randomized clinical trial

Background

The imbalance of the Renin Angiotensin System in favor of the angiotensin II has been described in Covid-19-patients. Angiotensin II regulates life processes, such as cell growth and division and can promote apoptosis initiating an inflammatory process with release of proinflammatory cytokines. Angiotensin receptor blockers (ARBs) block the AT1 receptor and could have a beneficial effect reducing Covid-19 inflammation.

Purpose

To assess whether Telmisartan is effective in reducing C-reactive protein (CRP) plasma levels in hospitalized patients with Covid-19, and improves clinical outcomes and length of stay and morbimortality.

Trial design

This is a parallel-group, randomized, two-arm, open-label, multicenter superiority trial with 1:1 allocation ratio.

Methods

Inclusion criteria: patients aged more than 18 years with less than 5 days of symptoms onset and after informed consent was obtained.

Exclusion criteria: Patients admitted to intensive care unit (ICU) or using mechanical ventilatory support or ongoing ARBs / angiotensin-converting enzyme inhibitors treatment at the time of randomization. Control arm received standard care alone and treatment arm Telmisartan 80 mg bid 14 days added to standard care. Primary outcome were CRP plasma levels at day 5 and 8 after randomization. Secondary outcomes included time to discharge at 15 days, admission to ICU and death at 15 and 30 days.

Results

158 patients were included in the analysis, 80 in the control and 78 in the telmisartan group. Day 5 control-group CRP levels were 6.06±6.95 mg/dL (n=66) while telmisartan group were 3.83±5.08 mg/dL (mean±SD; n=66, p<0.05). Day 8 CRP levels were 6.30±8.19 mg/dL (n=44) and 2.37±3.47 mg/dl (mean±SD; n=43, p<0.05) in the control and telmisartan groups, respectively. Kaplan-Meier analysis showed that Telmisartan-treated patients had lower median time to discharge (control=15 days; telmisartan=9 days). Death by day 30 was reduced by 81% in the telmisartan-treated group (control 22.54%, 16/71; telmisartan 4.29%, 3/70 participants; p=0.0023). Composite ICU, mechanical ventilation or death was reduced by telmisartan treatment at days 15 and 30. No telmisartan-related adverse events were reported.

Conclusions

Telmisartan, an inexpensive safe drug, in high doses, demonstrated anti-inflammatory effects and reduced morbimortality in Covid-19-hospitalized patients.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s):Hospital Escuela José de San Martín, ArgentinaHospital Español de Buenos Aires, Argentina Probability of discharge up to

Pathophysiology and therapeutic possibilities of calcitonin gene-related peptide in hypertension

Calcitonin gene related peptide (CGRP), a 37 amino acid neuropeptide, is the most potent vasodilator known. Participation of CGRP in hypertension and related diseases, such as preeclampsia or vasospasm after subarachnoid haemorrage, is one of the most studied topics. In this review we summarize the published roles of CGRP in pathophysiology of hypertension in humans and in experimental models. We also discuss the effects of direct administration of CGRP in the treatment of hypertension and of anti-hypertensive drugs that enhance the release or response of endogenous calcitonin gene-related peptide: angiotensin converting enzyme inhibitors, selective antagonists for the angiotensin II receptor, beta-blockers, magnesium sulphate for preeclampsia and rutaecarpine, as well as the possibilities using CGRP in gene therapy for prevention of vasospasm after subarachnoid haemorrage.

Human umbilical vein: involvement of cyclooxygenase-2 pathway in bradykinin B1 receptor-sensitized responses

In isolated human umbilical vein (HUV), the contractile response to des-Arg9-bradykinin (des-Arg9-BK), selective BK B1 receptor agonist, increases as a function of the incubation time. Here, we evaluated whether cyclooxygenase (COX) pathway is involved in BK B1-sensitized response obtained in 5-h incubated HUV rings. The effect of different concentrations of indomethacin, sodium salicylate, ibuprofen, meloxicam, lysine clonixinate or NS-398 administrated 30 min before concentration-response curves (CRC) was studied. All treatments produced a significant rightward shift of the CRC to des-Arg9-BK in a concentration-dependent manner, which provides pharmacological evidence that COX pathway is involved in the BK B1 responses. Moreover, in this tissue, the NS-398 pKb (5.2) observed suggests that COX-2 pathway is the most relevant. The strong correlation between published pIC50 for COX-2 and the NSAIDs' pKbs estimated further supports the hypothesis that COX-2 metabolites are involved in BK B1 receptor-mediated responses. In other rings, indomethacin (30, 100 micromol/l) or NS-398 (10, 30 micromol/l) produced a significant rightward shift of the CRC to BK, selective BK B2 agonist, and its pKbs were similar to the values to inhibit BK B1 receptor responses, suggesting that COX-2 pathway also is involved in BK B2 receptor responses. Western blot analysis shows that COX-1 and COX-2 isoenzymes are present before and after 5-h in vitro incubation and apparently COX-2 does not suffer additional induction.

Retinoids inhibit bradykinin B1 receptor-sensitized responses in human umbilical vein

Bradykinin B1 receptors are not expressed under physiological conditions but are induced under inflammatory conditions. In isolated human umbilical vein, a spontaneous bradykinin B1 receptor sensitization process has been demonstrated. On the other hand, retinoids have been shown to exert anti-inflammatory and immunomodulatory actions. We have now examined the effects of all-trans-retinoic acid and 9-cis-retinoic acid on the bradykinin B1 receptor-sensitized responses in human umbilical vein. Both retinoids produced a concentration-dependent rightward shift of the concentration-response curves for the bradykinin B1 receptor agonist, des-Arg(9)-bradykinin. Retinoid treatment did not modify the responses to bradykinin B1 receptor-unrelated agonists, bradykinin or serotonin. In conclusion, retinoids inhibit bradykinin B1 receptor-sensitized responses and this action could participate in their anti-inflammatory and immunomodulatory effects.

Bradykinin B1 receptor in isolated human umbilical vein: an experimental model of the in vitro up-regulation process

Bradykinin (BK) B1 receptors are not normally expressed in physiological conditions but could be induced in immunopathological states. Molecular approaches have confirmed that BK B1 receptor gene is transcriptionally induced in injured tissues. In these situations, the cytokine network and other proinflammatory mediators are close linked to BK B1 receptor expression. In this article, we describe the functional characterization of the BK B1 receptor up-regulation process in the isolated human umbilical vein and the pharmacological tools employed to demonstrate the de novo synthesis of these receptors. BK B1 receptors are up-regulated in a time- and protein synthesis-dependent process. Furthermore, in this tissue we have demonstrated the close link between the BK B1 receptor sensitization and proinflammatory cytokines, such as interleukin-1 beta and tumor necrosis factor-alpha. We also discuss the possible relationship between nuclear factor-kappa B and BK B1 receptor induction in human umbilical vein.

Further pharmacological characterization of bradykinin B1 receptor up-regulation in human umbilical vein

Previous reports have provided evidence to support the view that the de novo synthesis of bradykinin (BK) B(1) receptor is involved in the induction of vascular responses in human umbilical vein (HUV). In the present study, we evaluated different pharmacological tools to further analyze this up-regulation process in HUV. Concentration-response curves to des-Arg(9)-BK, a selective BK B(1) receptor agonist, were performed after 5 h of incubation. Tumor necrosis factor-alpha potentiated BK B(1) receptor responses at 5 h without modifying the maximal response to des-Arg(9)-BK. Pyrrolidine dithiocarbamate, an inhibitor of nuclear factor-kappaB activation, produced a concentration-dependent decrease of the BK B(1) receptor sensitization. When tissues were continuously exposed to actinomycin D, a transcription inhibitor, or cycloheximide, a protein synthesis inhibitor, concentration-response curves to des-Arg(9)-BK were markedly diminished. On the other hand, transitory exposure to cycloheximide allowed the full recovery of BK B(1) receptor-sensitized responses at 5 h. Finally, continuous incubation with the N-linked glycosylation inhibitor, tunicamycin, almost completely abolished des-Arg(9)-BK-mediated responses. In summary, this sensitization process is potentiated by tumor necrosis factor-alpha and is selectively inhibited by pyrrolidine dithiocarbamate, suggesting that BK B(1) receptor up-regulation in HUV involves nuclear factor-kappaB activation. The effects of actinomycin D and tunicamycin provide evidence that the de novo synthesis of a transmembrane glycoprotein has an obligatory role in the BK B(1) up-regulation. The reversion of the cycloheximide effect on BK B(1) response indicates that the time necessary for synthesis, trafficking, and functional membrane expression of this receptor would be less than 1 h.

[Quinolones: historic review]

The pharmacotherapeutic development of quinolones was produced in the last three decades. In 1965, the first commercial product was nalidixic acid (first-generation quinolone) an then, chemists have been able to synthesize several thousands of quinolone molecules's derivatives modifying primarily at the N-1 position and at the C-6, C-7 and C-8 positions. The structural changes incorporated into these new compounds enhanced pharmacodynamic characteristics and pharmacokinetic profiles. Third-generation quinolones (levofloxacin, clinafloxacin, sparfloxacin, grepafloxacin, DU-6859a and trovafloxacin) have several advantages over first-generation quinolones (nalicixic acid, cinoxacin and oxolinic acid) and second-generation quinolones (norfloxacin, enoxacin, ciprofloxacin, pefloxacin, ofloxacin, lomefloxacin and fleroxacin). The new fluroquinolones are well absorbed in the duodenum and jejunum. They have large volumes of distribution and their penetration into different tissues and body fluids in humans has been demonstrated, reaching concentrations equal to or greater than those observed in plasma. The third-generation quinolones are broad-spectrum antimicrobials with an improved in vitro potency against gram-positive and gram-negative bacteria, including anaerobes and intracellular pathogens.

Bradykinin B1 receptors in human umbilical vein: pharmacological evidence of up-regulation, and induction by interleukin-1 beta

Bradykinin B1 receptor-mediated responses increase as a function of in vitro incubation in the human umbilical vein. When tissues were continuously treated with the protein synthesis inhibitor, cycloheximide, or with the protein trafficking inhibitor, brefeldin A, pEC50 and maximal response to the selective bradykinin B1 receptor agonist, des-Arg9-bradykinin, were significantly diminished. The anti-inflammatory steroid, dexamethasone, produced a rightward shift of the concentration-response curve to des-Arg9-bradykinin, without affecting the maximal response. Furthermore, lipopolysaccharide or recombinant human interleukin-1 beta potentiate the bradykinin B1-sensitized responses, showing a leftward shift of the concentration-response curve to des-Arg9-bradykinin, without modifying the maximal response. On the other hand, bradykinin B2 receptor-mediated responses were unaffected by continuous exposure to cycloheximide, dexamethasone or lipopolysaccharide. These results provide pharmacological evidence to support the view that the de novo synthesis of bradykinin B1 receptors is involved in the induction of vascular responses in the human umbilical vein. This up-regulation process seems to be selective for bradykinin B1 receptors. The inhibitory effect of dexamethasone and the potentiating actions of lipopolysaccharide and exogenous human recombinant interleukin-1 beta on des-Arg9-bradykinin-mediated responses, suggest the possible role of interleukin-1 beta in the bradykinin B1 receptor up-regulation phenomenon in human umbilical vein.

Bradykinin B1 receptors in human umbilical vein

The present study was undertaken to demonstrate the presence of bradykinin B1 receptors mediating contraction of human umbilical vein. The bradykinin B1 receptor selective agonist, des-Arg9-bradykinin, produced a dose-dependent contractile response of human umbilical vein rings. Furthermore, des-Arga-bradykinin-mediated response increased in a time-dependent manner in vitro. The maximal response to des-Arg9-bradykinin, expressed as percentage of the maximum elicited by serotonin, was: 10 +/- 2 at 15 min, 55 +/- 5 at 120 min and 80 +/- 3 at 300 min. Des-Arg9-bradykinin-mediated contractions were inhibited by the specific bradykinin B1 receptor antagonist des-Arg9-[Leu8]bradykinin which produced parallel shifts in the dose-response curve to the selective bradykinin B1 receptor agonist. Schild regression analysis of data established a pA2 value of 6.16 +/- 0.06. Kinin-induced contraction was not modified by pre-treatment with indomethacin (10 microM), a cyclo-oxygenase inhibitor. On the other hand, continuous exposure to the anti-inflammatory steroid dexamethasone (100 microM) or to the protein synthesis inhibitor cycloheximide (70 microM) largely prevented the sensitization to des-Arg9-bradykinin in incubated human umbilical vein rings. These results confirm the presence of bradykinin B1 receptors which mediate contraction in isolated human umbilical vein. These responses are up-regulated in a time- and protein synthesis-dependent process.

Role of the alpha-adrenoceptor in regulating noradrenaline overflow by nerve stimulation. 1971

A study of the actions of phenoxybenzamine on transmitter overflow, neuronal and extraneuronal uptake of noradrenaline and in causing α-adrenoceptor blockade was carried out using the isolated cat nictitating membrane preparation. Phenoxybenzamine increased transmitter overflow elicited by nerve-stimulation at 10 Hz in a concentration dependent manner in the range 10−8 to 10−5 g/ml. Neuronal uptake of [3H]-noradrenaline was not inhibited by concentrations lower than 10−6 g/ml of phenoxybenzamine. With 10−7 g/ml of phenoxybenzamine a significant increase in transmitter overflow was obtained, although neuronal uptake of noradrenaline was not affected. Higher concentrations of phenoxybenzamine (10−6 and 10−5 g/ml) inhibited the neuronal uptake of noradrenaline and further increased transmitter overflow. Extraneuronal uptake of [3H]-noradrenaline was inhibited only with the highest concentration of phenoxybenzamine tested (10−5 g/ml) and therefore appears to be unrelated to the effects on transmitter overflow. There was a significant correlation between the degree of α-adrenoceptor block produced by phenoxybenzamine and the increase in transmitter overflow obtained by nerve stimulation. These results indicate that phenoxybenzamine, in addition to increasing overflow by preventing reuptake of noradrenaline, may increase transmitter release. The possibility that phenoxybenzamine acts on α-adrenoceptors in the adrenergic nerve terminal is discussed. These receptors would be involved in a negative feedback mechanism regulating transmitter release.

Decrease of extracellular pH associated with the secretion of catecholamines induced by barium in perfused bovine adrenal medulla

1. The possible modifications of extracellular pH produced during buffer-free 5 mM Ba2+ stimulation was studied in decorticated perfused bovine adrenal glands. 2. A significant and reversible drop of pH accompanied the release of catecholamines each time the tissue was exposed to a buffer-free 5 mM Ba2+ solution. 3. A progressive declination of the magnitude of this acidification associated with a gradual attenuation of the secretory response was observed consecutive to successive periods of Ba(2+)-stimulation. 4. D-600 (methoxyverapamil), in a concentration of 3 x 10(-4) M, markedly antagonized both Ba(2+)-induced secretory response and extracellular pH drop. 5. Perfusion of adrenal medulla for 4 min period with Locke solution buffered at pH 6.9, significantly and reversibly reduced the secretory response to 5 mM Ba2+ (pH 6.9) compared to a first control response obtained 35 min before at pH 7.4. 6. These results are compatible with the view that Ba(2+)-induced secretory activity is accompanied by the release of protons which could be involved in a local negative automodulatory mechanism of adrenomedullary secretion.

Acute effects of doxorubicin on chronotropic and inotropic mechanisms in guinea pig atria

This study was designed to test the possible acute effects of doxorubicin (DOX) on isolated guinea pig atria incubated in Locke's solution. Different concentrations of DOX (10(-6) to 10(-4) M) were added to the medium 30 minutes before the concentration-response curves to noradrenaline and histamine were carried out. DOX (10(-4) M) significantly reduced spontaneous atrial rate. Atropine (10(-6) g/ml) was unable to modify this cardiodepressant effect. DOX (10(-4) M) produced a competitive beta blocking effect, shifting to the right the concentration-response curve to noradrenaline without altering the maximal chronotropic response. On the other hand, this anthracycline (10(-4) M) not only antagonized chronotropic responses to histamine, but significantly reduced the maximal effect mediated by this amine. Isolated left guinea pig atria electrically paced were used to determine the effects of DOX on positive inotropic activity promoted by noradrenaline and histamine. Similarly to what was observed in chronotropic experiments, DOX (10(-4) M) produced a competitive beta blocking action and a noncompetitive inhibition of the positive inotropic action developed by histamine. Lower concentrations of DOX failed to modify the chronotropic responses to both amines. However, after 60 minutes of incubation with DOX, 10(-5) M of this drug produced a shift to the right of the concentration-response curves to noradrenaline and histamine and depressed the maximal chronotropic response to these amines. These effects were not observed with 3 X 10(-6) M DOX. These results are compatible with the idea that a nonspecific interaction of DOX with cardiac beta and histaminergic receptors could be involved in the acute cardiotoxic mechanism produced by this anthracycline.

Role of the -adrenoceptor in regulating noradrenaline overflow by nerve stimulation

1. A study of the actions of phenoxybenzamine on transmitter overflow, neuronal and extraneuronal uptake of noradrenaline and in causing alpha-adrenoceptor blockade was carried out using the isolated cat nictitating membrane preparation.2. Phenoxybenzamine increased transmitter overflow elicited by nerve-stimulation at 10 Hz in a concentration dependent manner in the range 10(-8) to 10(-5) g/ml.3. Neuronal uptake of [(3)H]-noradrenaline was not inhibited by concentrations lower than 10(-6) g/ml of phenoxybenzamine. With 10(-7) g/ml of phenoxybenzamine a significant increase in transmitter overflow was obtained, although neuronal uptake of noradrenaline was not affected. Higher concentrations of phenoxybenzamine (10(-6) and 10(-5) g/ml) inhibited the neuronal uptake of noradrenaline and further increased transmitter overflow.4. Extraneuronal uptake of [(3)H]-noradrenaline was inhibited only with the highest concentration of phenoxybenzamine tested (10(-5) g/ml) and therefore appears to be unrelated to the effects on transmitter overflow.5. There was a significant correlation between the degree of alpha-adrenoceptor block produced by phenoxybenzamine and the increase in transmitter overflow obtained by nerve stimulation.6. These results indicate that phenoxybenzamine, in addition to increasing overflow by preventing reuptake of noradrenaline, may increase transmitter release.7. The possibility that phenoxybenzamine acts on alpha-adrenoceptors in the adrenergic nerve terminal is discussed. These receptors would be involved in a negative feedback mechanism regulating transmitter release.