Morphological and functional determinants of fluoxetine (Prozac)-induced pulmonary disease in an experimental model

Effect of High Selective Serotonin-Reuptake Inhibitor Doses on the Development and Treatment of Sarcoid-Like Reaction

Sarcoidosis is a systemic disorder characterized by the presence of noncaseating granulomas that are most commonly observed in the lungs. Sarcoid-like reaction has been reported to develop in response to several immune modulator agents and antidepressants. In this report, a case of pulmonary sarcoidosis that was strongly related to the use of more than the average recommended dose of selective serotonin-reuptake inhibitor (SSRI) medications has been described. The patient, a 37-year-old, single, Caucasian woman, who suffered from severe depression and who presented to the emergency department with shortness of breath, low-grade fever, a dry cough, fatigue, and the loss of appetite, was diagnosed with this condition, and she failed to respond to the administered sarcoidosis treatment until the SSRI medications that she was using were discontinued; furthermore, she relapsed when one of these medications was reintroduced. Based on these observations, we were able to show a possible relationship between sarcoid-like reaction and SSRIs, and therefore, in the case of patients with interstitial lung diseases who are using SSRIs, we recommend that meticulous precautions be taken while planning their treatment and careful follow-ups be implemented to monitor their progress.

Sertraline-induced hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is a granulomatous, non-IgE-mediated hypersensitivity reaction of the alveoli and distal bronchioles presenting as an acute, subacute or chronic condition. It is most commonly associated with exposure to extrinsic allergens (eg, avian dust, mould and tobacco) and medications including antiarrhythmics (eg, amiodarone), cytotoxics (eg, methotrexate) and antiepileptics (eg, carbamazepine). Individuals diagnosed with this condition can present with severe hypoxia and respiratory failure. The fundamental principle of management is to remove the causative allergen. Evidence implicating selective serotonin reuptake inhibitors as a causative agent is limited, and this case report describes a rare clinical presentation of HP associated with sertraline, how it was diagnosed and subsequently treated. It is anticipated that raising awareness of this interaction will assist multidisciplinary teams, managing patients diagnosed with HP, to be more cognisant of sertraline as being an aetiological factor for this condition.

The relationship of SSRI and SNRI usage with interstitial lung disease and bronchiectasis in an elderly population: a case-control study

Background

The association between interstitial lung disease (ILD) and selective serotonin reuptake inhibitors and serotonin norepinephrine reuptake inhibitors (SSRI/SNRI) has been previously described in published case reports. However, its prevalence may be more common than expected. We examined the association between SSRI/SNRI usage and presence of ILD and or bronchiectasis (ILD/B) in an elderly population.

Methods

We conducted a retrospective case series and case–control study involving all 296 eligible elderly patients in one primary care geriatric practice in Victoria, BC, Canada. Cases required the presence of ILD/B on computed tomography (CT) or chest X-ray (CXR). Cases were excluded if they had other causes for ILD/B on CXR or CT such as exposure to known pneumotoxic drugs, metastatic cancer, rheumatoid lung disease, sarcoidosis, previous pulmonary tuberculosis, or pneumoconiosis. Data were abstracted from the patients’ medical record. The exposure variable was standardized cumulative person-month (p-m) dose of SSRI/SNRI. The study was approved by the Clinical Research Ethics Board of University of British Columbia with a waiver of informed consent.

Results

A total of 12 cases and 273 controls were identified. Their mean ages were 89.0 and 88.7 years, respectively (p=0.862). A total of 10/12 cases and 99/273 controls were exposed to SSRI/SNRI. The odds ratio was 8.79, 95% confidence interval 2.40–32.23 (p=0.001). The median p-m exposure to SSRI/SNRI was 110.0 months for cases and 29.5 for controls (p=0.003).

Conclusion

SSRIs and SNRIs were significantly associated with the risk of ILD/B in this elderly population. Because of their widespread usage, further studies should be done to validate these findings. Prescribers should cautiously monitor patients for development of insidious pulmonary symptoms when these drugs are used.

Effects of repeated stress on distal airway inflammation, remodeling and mechanics in an animal model of chronic airway inflammation

BACKGROUND/AIMS

Epidemiological studies suggest that stress has an impact on asthmatic exacerbations. We evaluated if repeated stress, induced by forced swimming, modulates lung mechanics, distal airway inflammation and extracellular matrix remodeling in guinea pigs with chronic allergic inflammation.

METHODS

Guinea pigs were submitted to 7 ovalbumin or saline aerosols (1-5 mg/ml during 4 weeks; OVA and SAL groups). Twenty-four hours after the 4th inhalation, guinea pigs were submitted to the stress protocol 5 times a week during 2 weeks (SAL-S and OVA-S groups). Seventy-two hours after the 7th inhalation, guinea pigs were anesthetized and mechanically ventilated. Resistance and elastance of the respiratory system were obtained at baseline and after ovalbumin challenge. Lungs were removed, and inflammatory and extracellular matrix remodeling of distal airways was assessed by morphometry. Adrenals were removed and weighed.

RESULTS

The relative adrenal weight was greater in stressed guinea pigs compared to non-stressed animals (p < 0.001). Repeated stress increased the percent elastance of the respiratory system after antigen challenge and eosinophils and lymphocytes in the OVA-S compared to the OVA group (p < 0.001, p = 0.003 and p < 0.001). Neither collagen nor elastic fiber contents were modified by stress in sensitized animals.

CONCLUSIONS

In this animal model, repeated stress amplified bronchoconstriction and inflammatory response in distal airways without interfering with extracellular matrix remodeling.

Inducible nitric oxide synthase inhibition attenuates physical stress-induced lung hyper-responsiveness and oxidative stress in animals with lung inflammation

Mechanisms involved in stress-induced asthmatic alterations have been poorly characterised. We assessed whether inducible nitric oxide synthase (iNOS) inhibition modulates the stress-amplified lung parenchyma responsiveness, oxidative stress and extracellular matrix remodelling that was previously increased by chronic lung inflammation. Guinea pigs were subjected to 7 exposures to ovalbumin (1-5 mg/ml) or saline (OVA and SAL groups) over 4 weeks. To induce behavioural stress, animals were subjected to a forced swimming protocol (5 times/week, over 2 weeks; SAL-Stress and OVA-Stress groups) 24 h after the 4th inhalation. 1400W (iNOS-specific inhibitor) was administered intraperitoneally in the last 4 days of the protocol (SAL-1400W, OVA-1400W, SAL-Stress+1400W and OVA-Stress+1400W groups). Seventy-two hours after the last inhalation, animals were anaesthetised and exsanguinated, and adrenal glands were removed. Lung tissue resistance and elastance were evaluated by oscillatory mechanics and submitted for histopathological evaluation. Stressed animals had higher adrenal weights compared to non-stressed groups, which were reduced by 1400W treatment. Behavioural stress in sensitised animals amplified the resistance and elastance responses after antigen challenge, numbers of eosinophils and iNOS+ cells, actin content and 8-iso-PGF2α density in the distal lung compared to the OVA group. 1400W treatment in ovalbumin-exposed and stressed animals reduced lung mechanics, iNOS+ cell numbers and 8-iso-PGF2α density compared to sensitised and stressed animals that received vehicle treatment. We concluded that stress amplifies the distal lung constriction, eosinophilic inflammation, iNOS expression, actin content and oxidative stress previously induced by chronic lung inflammation. iNOS-derived NO contributes to stress-augmented lung tissue functional alterations in this animal model and is at least partially due to activation of the oxidative stress pathway.

Repeated stress reduces mucociliary clearance in animals with chronic allergic airway inflammation

We evaluated if repeated stress modulates mucociliary clearance and inflammatory responses in airways of guinea pigs (GP) with chronic inflammation. The GP received seven exposures of ovalbumin or saline 0.9%. After 4th inhalation, animals were submitted to repeated forced swim stressor protocol (5x/week/2 weeks). After 7th inhalation, GP were anesthetized. We measured transepithelial potential difference, ciliary beat frequency, mucociliary transport, contact angle, cough transportability and serum cortisol levels. Lungs and adrenals were removed, weighed and analyzed by morphometry. Ovalbumin-exposed animals submitted to repeated stress had a reduction in mucociliary transport, and an increase on serum cortisol, adrenals weight, mucus wettability and adhesivity, positive acid mucus area and IL-4 positive cells in airway compared to non-stressed ovalbumin-exposed animals (p<0.05). There were no effects on eosinophilic recruitment and IL-13 positive cells. Repeated stress reduces mucociliary clearance due to mucus rheological-property alterations, increasing acid mucus and its wettability and adhesivity. These effects seem to be associated with IL-4 activation.

The guinea pig forced swim test as a new behavioral despair model to characterize potential antidepressants

RATIONALE

Behavioral despair is a model of high predictivity for antidepressant activity in murids. For some drug targets, guinea pigs exhibit a higher homology to their human counterparts compared to murids.

OBJECTIVES

In this paper, we established a model of behavioral despair namely, the forced swim test (FST) in guinea pigs.

MATERIALS AND METHODS

Male guinea pigs underwent the FST similar to rats. Animals received intraperitoneal injections of either vehicle or drugs 24, 4, and 0.5 h before testing. We tested the tricyclic antidepressants desipramine and amitriptyline, the monoamine oxidase inhibitor tranylcypromine, the selective serotonin reuptake inhibitors fluoxetine and paroxetine, and the neurokinin 1 (NK(1)) receptor antagonist, L-733,060, and for comparison the antipsychotic clozapine and the stimulant methamphetamine.

RESULTS

Desipramine (> or =3 mg/kg) and amitriptyline (>10 mg/kg) increased the latency to immobility (LTI) to greater than 230 s, and tranylcypromine (10 mg/kg) it to greater than 190 s. Paroxetine (>0.3 mg/kg) and fluoxetine (>10 mg/kg) also increased LTI significantly but only to greater than 120 s. Methamphetamine (3 mg/kg) completely eliminated immobility, whereas clozapine (5-20 mg/kg) had no effect. L-733,060 (10 mg/kg) increased LTI to 270 s. Doses producing significant effects in FST were investigated in the open field. Antidepressants did not affect locomotion, whereas methamphetamine induced hyperlocomotion.

CONCLUSIONS

We demonstrate the suitability of a modified procedure of the FST for a nonmurid species: the guinea pig. Known antidepressants showed similar effects as in rats and mice. It is interesting to note that the NK(1) antagonist L-733,060 increased forced swimming, suggesting its antidepressant potential. Thus, the guinea pig FST allows the study of antidepressant activity also in NK(1) antagonists that cannot be studied appropriately in murids.