THU0297 SERIOUS INFECTIONS IN 134 PATIENTS WITH GIANT CELL ARTERITIS WITH TOCILIZUMAB IN CLINICAL PRACTICE. FREQUENCY, TYPE AND CLINICAL ASSOCIATIONS

Background:

Infections are the most common adverse event of Tocilizumab (TCZ) in Giant Cell Arteritis (GCA). In GiACTA study(1),serious infections were observed in 7% (9.6/100 patient-years) of patients who received TCZ weekly. Randomized clinical trials (RCTs) are conducted under highly standardized design excluding some real-world patients. Therefore, adverse events may be underestimated in RCTs. In our series of real-life, serious infections occurred in 11.9% (10.6/100 patient-years)(2).

Objectives:

In a wide series of GCA of clinical practice treated with TCZ, we assess the frequency, type and predisposing factors of serious infections.

Methods:

Multicenter study of 134 patients diagnosed with GCA, all of them refractory to conventional therapy, treated with TCZ. Serious infection was considered when a life-threatening infection, fatal, or requiring hospitalization occurred, intravenous antibiotics were required, or the infectious process led to persistent or significant disability.

Results:

16 of 134 (11.9%, 10.6/100 patient-years) patients developed serious infections during follow-up. The most frequent infections were pneumonia (n=4), urinary tract infection (n=4), and facial herpes zoster (n=2). At TCZ onset, serious infections were more frequent in older patients (74.3±9.6 vs 72.9±8.7 years), with a longer GCA evolution (20 [4.3-45.6] vs 13 [5-29.3] months), with visual manifestations (43.75% vs 17.8%) and a higher dose of prednisone at TCZ onset (30.4±15.5 vs 21.1±16.1 mg/day) (TABLE). Presence of comorbidities were similar in both groups. 13 of the 16 patients who had infections received a dose of prednisone greater than 15 mg/day (16.3/100 patient-years) compared to 3 patients under treatment with less than 15 mg/day of prednisone (4.2/100 patient-years).

Conclusion:

The age, GCA duration, ocular involvement and the dose of glucocorticoids, at TCZ onset, seem to be predisposing factors related to an increased risk of developing serious infections in GCA patients.

References:

[1]Stone JH, et al. N Engl J Med. 2017; 377:317-28.

[2]Calderón-Goercke M et al. Semin Arthritis Rheum 2019 Aug;49(1): 126-135.

TABLESERIOUS INFECTIONS(n=16)WITHOUT SERIOUS INFECTIONS(n=118)pBASAL FEATURES AT TCZ ONSETGENERAL FEATURES Age, years, mean± SD74.3±9.672.9±8.70.552 Sex, female/male n(%)13/388/300.760 Time from GCA diagnosis to TCZ onset (months), median [IQR]20[4.3-45.6]13[5-29.3]0.604COMORBIDITIES Hypertension, n(%)9(56)86(73)0.551 Diabetes, n(%)3(19)39(33)0.677 Chronic kidney disease, n(%)3(19)27(23)0.512CLINICAL FEATURES OF GCA PMR, n(%)9(56.25)64(54.2)0.879 Aortitis, n(%)5(31.25)53(45)0.301 Visual manifestations, n(%)7(43.75)21(17.8)0.017CORTICOSTEROIDS AT TCZ ONSET Prednisone dose mg/d, mean (SD)30.4±15.521.1±16.10.031

Disclosure of Interests:

Monica Calderón-Goercke: None declared, D. Prieto-Peña: None declared, Santos Castañeda: None declared, Clara Moriano: None declared, Elena Becerra-Fernández: None declared, Marcelino Revenga: None declared, Noelia Alvarez-Rivas: None declared, Carles Galisteo: None declared, Águeda Prior-Español: None declared, E. Galindez: None declared, Cristina Hidalgo: None declared, Sara Manrique Arija: None declared, Eugenio de Miguel Grant/research support from: Yes (Abbvie, Novartis, Pfizer), Consultant of: Yes (Abbvie, Novartis, Pfizer), Paid instructor for: yes (AbbVie, Novartis, Pfizer, MSD, BMS, UCB, Roche, Grunental, Janssen, Sanofi), Speakers bureau: yes (AbbVie, Novartis, Pfizer, MSD, BMS, UCB, Roche, Grunental, Janssen, Sanofi), Eva Salgado-Pérez: None declared, Vicente Aldasoro Speakers bureau: Roche, Abbvie, MSD, UCB, Pfizer, Menarini, Grunenthal, Gebro, Novartis, Janssen, Ignacio Villa-Blanco Consultant of: UCB, Speakers bureau: Novartis, MSD, Lilly, Susana Romero-Yuste: None declared, J. Narváez: None declared, Catalina Gomez-Arango: None declared, Eva Perez-Pampín: None declared, Rafael Melero: None declared, Francisca Sivera: None declared, Carlos Fernández-Díaz Speakers bureau: Brystol Meyers Squibb, Alejandro Olive: None declared, María Álvarez del Buergo: None declared, Luisa Marena Rojas: None declared, Carlos Fernández-López: None declared, Francisco Navarro: None declared, Enrique Raya: None declared, Beatriz Arca: None declared, Roser Solans-Laqué: None declared, Arantxa Conesa: None declared, Carlos Vázquez: None declared, Jose Andrés Román-Ivorra: None declared, Pau Lluch: None declared, Paloma Vela-Casasempere: None declared, Carmen Torres-Martín: None declared, Juan Carlos Nieto Speakers bureau: Pfizer, Abbvie, MSD, Novartis, Janssen, Lilly, Nordic Pharma, BMS, Gebro, FAES Farma, Roche, Sanofi, Carmen Ordas-Calvo: None declared, Cristina Luna-Gomez: None declared, Francisco J. Toyos Sáenz de Miera: None declared, Nagore Fernández-Llanio: None declared, Antonio García: None declared, Carmen González-Vela: None declared, Javier García-Fernández: None declared, Patricia Vicente-Gómez: None declared, Ángel García-Manzanares: None declared, Norberto Ortego: None declared, Francisco Ortiz-Sanjuán: None declared, Montserrat Corteguera: None declared, J. Luis Hernández: None declared, Miguel A González-Gay Grant/research support from: Pfizer, Abbvie, MSD, Speakers bureau: Pfizer, Abbvie, MSD, Ricardo Blanco Grant/research support from: AbbVie, MSD, and Roche, Speakers bureau: AbbVie, Pfizer, Roche, Bristol-Myers, Janssen, and MSD

OP0033 OPTIMIZATION OF TOCILIZUMAB THERAPY IN GIANT CELL ARTERITIS. A MULTICENTER REAL-LIFE STUDY OF 134 PATIENTS

Background:

Tocilizumab (TCZ) is the only biological agent approved in Giant Cell Arteritis (GCA). There is general agreement on the initial and the standard maintenance dose of TCZ. However, information on duration and optimization of TCZ in GCA is scarce.

Objectives:

Our aim was to assess efficacy and safety of TCZ therapy optimization in an unselected wide series of GCA in clinical practice.

Methods:

Multicenter study, 134 patients with GCA who received TCZ due to inefficacy/adverse events of previous therapy. Once complete remission was reached and based on a shared decision between patient and physician TCZ was optimized in some cases. Optimization was done by decreasing the dose and/or prolonging the TCZ dosing interval progressively.

Results:

134 GCA patients treated with TCZ (101w/33m); mean age 73.0±8.8 years. TCZ was administered IV to 106 (79.1%) patients and SC to 28 (20.9%). TCZ was optimized in 43 (32.1%) patients. No demographic, clinical manifestations or laboratory data differences had been found at TCZ onset (TABLE). After a follow up of 12 [6-15.5] months, and a complete remission for 6 [3-12] months; the first TCZ optimization was performed. Median prednisone dose at first TCZ optimization was 2.5 [0-5] mg/day. TCZ IV was optimized from 8 to 4 mg/kg/4weeks in 12 of 106 (11.3%) and from 162 mg/SC/week to 162 mg/SC/2weeks in 9 of 28 (32.1%) cases. Five (11.6%) of the 43 optimized cases relapsed. In 4 cases, the relapses were treated increasing TCZ up to the pre-optimization dose, in 1 case the route of administration was change (4 mg/kg/4week to 162 mg/SC/week). In 8 of 43 optimized patients (18.6%), it was possible to withdraw TCZ after complete remission for 30 [16.25-45.75] months. Regarding adverse events and severe infections were similar in both groups. The mean TCZ treatment costs were lower in the optimized group.

Conclusion:

Once remission is reached in GCA patients under TCZ treatment, optimization of TCZ may be performed. Based on our experience it could be performed by reducing the dose with IV TCZ or by prolonging dosing interval with SC TCZ.

References:

[1]Calderón-Goercke M et al. Semin Arthritis Rheum 2019 Aug;49(1): 126-135.

TABLE.OPTIMIZED-TCZ GROUP (n=43)NON-OPTIMIZED TCZ GROUP (n=91)pBASAL FEATURES AT TCZ ONSETGENERAL FEATURESAge, years, mean± SD68.9±8.771.4±8.50.125Sex, female/male n(%)32/1068/240.779Time from GCA diagnosis to TCZ onset (months), median [IQR]19.5[7.75-45]10.5[4 – 25]0.047SYSTEMIC MANIFESTATIONSFever, n(%)1(2.4)8(8.7)0.176Constitutional syndrome, n(%)11(26.2)19(20.7)0.476PMR, n(%)18(42.9)56(60.9)0.052ISCHEMIC MANIFESTATIONSVisual involvement, n(%)5(11.9)23(25)0.084Headache, n(%)26(61.9)42(45.7)0.081Jaw claudication, n(%)1(2.4)11(12)0.072CORTICOSTEROIDS AT TCZ ONSETPrednisone dose, mg/d mean (SD)15.1±11.125±17.40.001FOLLOW-UP ON TCZ THERAPY (MONTHS), MEDIAN [IQR]24[18-27]6 [3-18]0.000Relapses, n(%)5(11.6)5(5.5)0.207End follow-up remission, n(%)40(93)84(92)0.99Severe side efects, n(%)14(32.6)22(24.2)0.307Seriuos infections, n(%)6(14)10(11)0.878Cost, (mean) euros per yearIVSC7 538.47 329.011 726.411 726.4--

Disclosure of Interests:

Monica Calderón-Goercke: None declared, D. Prieto-Peña: None declared, Santos Castañeda: None declared, Clara Moriano: None declared, Elena Becerra-Fernández: None declared, Marcelino Revenga: None declared, Noelia Alvarez-Rivas: None declared, Carles Galisteo: None declared, Águeda Prior-Español: None declared, E. Galindez: None declared, Cristina Hidalgo: None declared, Sara Manrique Arija: None declared, Eugenio de Miguel Grant/research support from: Yes (Abbvie, Novartis, Pfizer), Consultant of: Yes (Abbvie, Novartis, Pfizer), Paid instructor for: yes (AbbVie, Novartis, Pfizer, MSD, BMS, UCB, Roche, Grunental, Janssen, Sanofi), Speakers bureau: yes (AbbVie, Novartis, Pfizer, MSD, BMS, UCB, Roche, Grunental, Janssen, Sanofi), Eva Salgado-Pérez: None declared, Vicente Aldasoro Speakers bureau: Roche, Abbvie, MSD, UCB, Pfizer, Menarini, Grunenthal, Gebro, Novartis, Janssen, Ignacio Villa-Blanco Consultant of: UCB, Speakers bureau: Novartis, MSD, Lilly, Susana Romero-Yuste: None declared, J. Narváez: None declared, Catalina Gomez-Arango: None declared, Eva Perez-Pampín: None declared, Rafael Melero: None declared, Francisca Sivera: None declared, Alejandro Olive: None declared, María Álvarez del Buergo: None declared, Luisa Marena Rojas: None declared, Carlos Fernández-López: None declared, Francisco Navarro: None declared, Enrique Raya: None declared, Beatriz Arca: None declared, Roser Solans-Laqué: None declared, Arantxa Conesa: None declared, Carlos Vázquez: None declared, Jose Andrés Román-Ivorra: None declared, Pau Lluch: None declared, Paloma Vela-Casasempere: None declared, Carmen Torres-Martín: None declared, Juan Carlos Nieto Speakers bureau: Pfizer, Abbvie, MSD, Novartis, Janssen, Lilly, Nordic Pharma, BMS, Gebro, FAES Farma, Roche, Sanofi, Carmen Ordas-Calvo: None declared, Cristina Luna-Gomez: None declared, Francisco J. Toyos Sáenz de Miera: None declared, Nagore Fernández-Llanio: None declared, Antonio García: None declared, J. Luis Hernández: None declared, Miguel A González-Gay Grant/research support from: Pfizer, Abbvie, MSD, Speakers bureau: Pfizer, Abbvie, MSD, Ricardo Blanco Grant/research support from: AbbVie, MSD, and Roche, Speakers bureau: AbbVie, Pfizer, Roche, Bristol-Myers, Janssen, and MSD

Tocilizumab in giant cell arteritis: differences between the GiACTA trial and a multicentre series of patients from the clinical practice

OBJECTIVES

A potential point of concern among clinicians is whether results derived from the clinical trials can be reasonably applied or generalised to a definable group of patients seen in real world. It can be the case of the GiACTA study that is a phase III randomised controlled trial of tocilizumab (TCZ) in giant cell arteritis (GCA). To address this question, we compared the clinical features and the responses to TCZ from the GiACTA trial patients with those from a series of GCA seen in the daily clinical practice.

METHODS

Comparative study of clinical features between patients from the GiACTA trial (overall n=251) and those from a multicentre series of real-world GCA patients undergoing TCZ therapy (n=134). The diagnosis of GCA in the GiACTA trial was established by the ACR modified criteria whereas in the series of real-world patients it was made by using the ACR criteria, a positive biopsy of temporal artery or the presence of imaging techniques consistent with large-vessel vasculitis in individuals who presented cranial symptoms of GCA. GiACTA trial patients received subcutaneous TCZ (162 mg every 1 or 2 weeks) whereas those from the clinical practice series were treated using standard IV dose (8 mg/kg/month) or subcutaneous (162 mg/week).

RESULTS

Real-life patients undergoing TCZ were older with longer disease duration and higher values of ESR and had received conventional immunosuppressive therapy (mainly methotrexate) more commonly than those included in the GiACTA trial. Despite clinical differences, TCZ was equally effective in both GiACTA trial and clinical practice patients. However, serious infections were more commonly observed in GCA patients recruited from the clinical practice.

CONCLUSIONS

Despite clinical differences with patients recruited in clinical trials, data from real-life patients confirm the efficacy of TCZ in GCA.

Tocilizumab in giant cell arteritis. Observational, open-label multicenter study of 134 patients in clinical practice

OBJECTIVE

Tocilizumab (TCZ) has shown efficacy in clinical trials on giant cell arteritis (GCA). Real-world data are scarce. Our objective was to assess efficacy and safety of TCZ in unselected patients with GCA in clinical practice Methods: Observational, open-label multicenter study from 40 national referral centers of GCA patients treated with TCZ due to inefficacy or adverse events of previous therapy. Outcomes variables were improvement of clinical features, acute phase reactants, glucocorticoid-sparing effect, prolonged remission and relapses. A comparative study was performed: (a) TCZ route (SC vs. IV); (b) GCA duration (≤6 vs. >6 months); (c) serious infections (with or without); (d) ≤15 vs. >15 mg/day at TCZ onset.

RESULTS

134 patients; mean age, 73.0 ± 8.8 years. TCZ was started after a median [IQR] time from GCA diagnosis of 13.5 [5.0-33.5] months. Ninety-eight (73.1%) patients had received immunosuppressive agents. After 1 month of TCZ 93.9% experienced clinical improvement. Reduction of CRP from 1.7 [0.4-3.2] to 0.11 [0.05-0.5] mg/dL (p < 0.0001), ESR from 33 [14.5-61] to 6 [2-12] mm/1st hour (p < 0.0001) and decrease in patients with anemia from 16.4% to 3.8% (p < 0.0001) were observed. Regardless of administration route or disease duration, clinical improvement leading to remission at 6, 12, 18, 24 months was observed in 55.5%, 70.4%, 69.2% and 90% of patients. Most relevant adverse side-effect was serious infections (10.6/100 patients-year), associated with higher doses of prednisone during the first three months of therapy.

CONCLUSION

In clinical practice, TCZ yields a rapid and maintained improvement of refractory GCA. Serious infections appear to be higher than in clinical trials.

Tocilizumab in refractory aortitis: study on 16 patients and literature review

OBJECTIVES

Non-infectious aortitis is often refractory to standard immunosuppressive therapy. Since IL-6 has been implicated in the pathogenesis of aortitis, we assessed the efficacy of the anti-IL6 receptor monoconal antibody tocilizumab (TCZ) in a series of patients with refractory non-infectious aortitis.

METHODS

Review of 16 patients (14 women/2 men) with refractory aortitis diagnosed by imaging (CT angiography, MR angiography, and/or PET) that were treated with TCZ.

RESULTS

The mean age±SD was 51.4±20.1 years. The underlying conditions were: Takayasu arteritis (TakA) (n=7 cases), giant cell arteritis (GCA) (n=7), relapsing polychondritis (RP) (n=1), and aortitis associated with retroperitoneal fibrosis (n=1). TCZ was the first biologic drug used in all patients with GCA and in the patient with aortitis associated with retroperitoneal fibrosis but in only 2 of 7 TakA patients. In the remaining cases anti-TNF inhibitors were prescribed before TCZ (standard dose was 8 mg/kg/iv/4 weeks). After a mean±SD follow-up of 11.8±6.6 months most patients experienced clinical improvement, showing reduction of erythrocyte sedimentation rate from 43±36 mm/1st h to 5±4 mm/1st h at last visit. At TCZ onset, 25% of patients had fever and 19% polymyalgia rheumatica. These manifestations disappeared after 3 months of TCZ therapy. A corticosteroid sparing effect was also achieved (from 27.3±17.6 mg/day of prednisone at TCZ onset to 4.2±3.8 mg/day at last visit). TCZ had to be discontinued in a patient because of severe neutropenia.

CONCLUSIONS

TCZ appears to be effective and relatively safe in patients with inflammatory aortitis refractory to corticosteroids or to other biologic immunosuppressive drugs.

Gender dimorphism in body composition abnormalities in acromegaly: males are more affected than females

BACKGROUND

Acromegaly changes body composition (BC), but long-term gender differences have not been reported.

OBJECTIVE

To evaluate BC in active and controlled acromegalic patients.

DESIGN AND METHODS

Clinical and biochemical variables and BC (by dual-energy X-ray absorptiometry) were evaluated in 60 acromegalic patients (19 active, 41 controlled) and 105 controls, matched for age and gender.

RESULTS

Acromegalic males (n=24) had more total mass (89+/-13 vs 76.5+/-15.3 kg, P<0.001), lean body mass (LBM; 64.6+/-8.7 vs 56.4+/-5.8 kg, P<0.001), and bone mineral content (BMC; 2.9+/-0.5 vs 2.6+/-0.3 kg, P<0.05) than controls (n=33). Controlled male patients (n=14) had more total mass (89+/-14.7 vs 76.5+/-15.3 kg, P<0.05) and a trend to have more LBM (61.8+/-9.4 vs 56.4+/-5.8 kg, P=0.065) than controls. Only in active disease was a decrease in fat mass (FM) observed, compared with controlled patients and controls (males: 19.5+/-5.3 vs 27+/-6.2 and 25.9+/-4%, P<0.001; females: 30.3+/-6.7 vs 37.1+/-5.8 and 36.5+/-6.6%, P<0.01). In females, no further differences were observed. No differences in BMC were found between eugonadal and hypogonadal acromegalic patients, but in hypogonadal females, acromegaly appeared to prevent the BMC loss seen in hypogonadal postmenopausal controls. GH and IGF1 levels were negatively correlated with FM (males, P<0.05; females, P<0.001), but in the regression analysis GH was a predictor of FM only in women.

CONCLUSIONS

Control of acromegaly reverts decreased FM in both genders; only in males more total mass and a trend for more LBM persist. The anabolic effect of GH on bone reverted in cured males, but persisted in females and appeared to override the bone loss of menopause.

Bone mass of a 113-year-old man

Osteoporosis is a common disease that affects elderly people. Aging induces loss of bone density and quality resulting in a progressive incidence of fragility fractures. In this study, we report the bone density of one of the oldest men in the world and of several of his first-degree relatives, as well as a genetic screen of these cases. No fractures have been suffered by any of them, and their bone mineral density (BMD) values in terms of z score were normal or lightly decreased. Neither mutations at the longevity-related gene KLOTHO nor the Gly171Val mutation of LRP5 associated with high bone mass was detected in the two centenarian stepbrothers.

Clinical evaluation of drug-induced hepatitis

OBJECTIVE

To ascertain the epidemiological characteristics, clinical symptoms, and evolution of drug-induced hepatitis over the last 22 years. EXPERIMENTAL DESIGN AND SUBJECTS: An observational, retrospective study between 1982 and 1993, and prospective study between 1994 and 2003. All patients in our department diagnosed with having drug-induced hepatitis were studied analyzing epidemiological (age, sex, cases per year, hospitalization) and clinical features (previous liver disease, hepatic symptoms, laboratory results), and follow-up (complete recovery or chronicity).

RESULTS

A total of 61 patients were diagnosed as having drug-induced hepatitis, 26 men and 35 women (57%), mean age 52.4 years +/- 17 years, of which 72.2% were older than 40 years. A total of 43% were admitted to hospital. In 87% of cases, two or more drugs were involved, the most frequent being antituberculosis (19 cases), psychotropic (26 cases), and non-steroidal anti-inflammatory drugs (45 cases). Evolution showed that 94% of patients recovered after the withdrawal of suspected causal drugs.

CONCLUSIONS

The incidence of drug-induced hepatitis is higher in patients over 40 years of age, it being more common in females. Non-steroidal anti-inflammatory, psychotropic, and anti-tuberculosis agents were the main drugs involved. Most patients made a complete recovery after withdrawal of the suspected causal drug.

Contractile effects of arginine analogues on human internal thoracic and radial arteries

OBJECTIVES

Plasma levels of endogenous guanidino-substituted analogues of L -arginine are increased in various pathologic conditions. In the present study we determined the effects of some of these compounds on basal and stimulated release of nitric oxide in human internal thoracic and radial arteries.

METHODS

Rings of human internal thoracic and radial arteries were obtained from 16 multiorgan donors. The rings were suspended in organ baths for isometric recording of tension.

RESULTS

N(G)-monomethyl L -arginine (10(-6) to 10(-3) mol/L) and N(G),N(G)-dimethyl L -arginine (10(-6) to 10(-3) mol/L) caused concentration- and endothelium-dependent contractions. Maximal force of contractions for N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine in the internal thoracic artery were 18.0% +/- 4.3% and 17.8% +/- 3.8%, respectively, of the contraction to 100 mmol/L KCl, and those found in the radial artery were 9.6% +/- 2.5% and 9.1% +/- 2.4%, respectively. Aminoguanidine (10(-5) to 3 x 10(-3) mol/L) and methylguanidine (10(-5) to 3 x 10(-3) mol/L) produced endothelium-independent contractions. L -Arginine (10(-3) mol/L) prevented the contractions by N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine but did not change contractions induced by aminoguanidine and methylguanidine. N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine inhibited, in a concentration-dependent manner, the endothelium-dependent relaxation to acetylcholine in the internal thoracic artery and had little attenuating effect in the radial artery; aminoguanidine and methylguanidine were without effect.

CONCLUSIONS

The results suggest that the contractions induced by N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine are due to inhibition of both basal and stimulated nitric oxide production, whereas aminoguanidine and methylguanidine do not affect the synthesis of nitric oxide. An increase in the plasma concentration of N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine is likely to represent a risk factor for abnormal vasomotor tone in conduit arteries used as coronary grafts.

Effects of some guanidino compounds on human cerebral arteries

BACKGROUND AND PURPOSE

Accumulation of endogenous guanidino-substituted analogues of L-arginine in chronic renal failure might contribute to some of the vascular and neurological disorders of this pathology. We tested the hypothesis that in human cerebral arteries, some guanidino compounds may increase vascular tone, through nitric oxide (NO) synthase inhibition, and impair endothelium-dependent relaxation.

METHODS

Rings of human middle cerebral artery were obtained during autopsy of 26 patients who had died 3 to 12 hours before. The rings were suspended in organ baths for isometric recording of tension. We then studied the responses to N(G)-monomethyl-L-arginine (L-NMMA), N(G),N(G)-dimethyl-L-arginine (asymmetrical dimethylarginine; ADMA), aminoguanidine (AG), and methylguanidine (MG).

RESULTS

L-NMMA (10(-6) to 3x10(-4) mol/L) and ADMA (10(-6) to 3x10(-4) mol/L) caused concentration- and endothelium-dependent contractions (median effective concentrations [EC(50)]=1.1x10(-5) and 1.6x10(-5) mol/L, respectively; E(max)=35. 5+/-7.9% and 43.9+/-5.9% of the response to 100 mmol/L KCl). AG (10(-5) to 3x10(-3) mol/L) and MG (10(-5) to 3x10(-3) mol/L) produced endothelium-independent contractions (E(max)=44.3+/-8.8% and 45.7+/-5.8% of the response to 100 mmol/L KCl, respectively). L-Arginine (10(-3) mol/L) prevented the contractions by L-NMMA and ADMA but did not change contractions induced by AG and MG. L-NMMA and ADMA inhibited endothelium-dependent relaxation induced by acetylcholine in a concentration-dependent manner; AG and MG were without effect.

CONCLUSIONS

The results suggest that the contractions induced by L-NMMA and ADMA are due to inhibition of endothelial NO synthase activity, whereas AG and MG do not affect the synthesis of NO. An increase in the plasma concentration of L-NMMA and ADMA associated with uremia is likely to represent a diminished release or effect of NO, and consequently, an increased cerebrovascular tone in uremic patients is highly conceivable.

Relaxant effects of antidepressants on human isolated mesenteric arteries

AIMS

The therapeutic action of tricyclic agents may be accompanied by unwanted effects on the cardiovascular system. The evidence for the effects on vascular and nonvascular smooth muscle comes from animal studies. Whether these studies can be extrapolated to human vessels remains to be determined. Therefore, the present study was designed to investigate the influence of amitriptyline, nortriptyline and sertraline on the contractile responses of human isolated mesenteric arteries to electrical field stimulation, noradrenaline and potassium chloride.

METHODS

Arterial segments (lumen diameter 0.8-1.2 mm) were obtained from portions of the human omentum during the course of 41 abdominal operations (22 men and 19 women), and rings 3 mm long were mounted in organ baths for isometric recording of tension. In some artery rings the endothelium was removed mechanically.

RESULTS

In precontracted artery rings amitriptyline, nortriptyline and sertraline (3x10(-7)-10(-4) m ) produced concentration-dependent relaxation that was independent of the presence or absence of vascular endothelium. Incubation with indomethacin (3x10(-6) m ) reduced the pD2 values thus indicating the participation of dilating prostanoid substances in this response. Amitriptyline and nortriptyline inhibited both the neurogenic-and noradrenaline-induced contractions. In contrast, only the highest concentration of sertraline reduced the adrenergic responses. Amitriptyline, nortriptyline and sertraline inhibited contractions elicited by KCl and produced rightward shifts of the concentration-response curve to CaCl2 following incubation in calcium-free solution.

CONCLUSIONS

These results indicate that amitriptyline and nortriptyline could act as adrenoceptor antagonists and direct inhibitors of smooth muscle contraction of human mesenteric arteries, whereas sertraline might principally exert its action only as direct inhibitor of smooth muscle contraction. This relaxant mechanism involves an interference with the entry of calcium.