Bronchiolitis obliterans organizing pneumonia associated with massive L-tryptophan ingestion

Tryptophan self-assembly yields cytotoxic nanofibers containing amyloid-mimicking and cross-seeding competent conformers

Dietary consumption of Trp via protein-based foods is essential for the maintenance of crucial metabolic processes including the synthesis of proteins and several vital metabolites such as serotonin, melatonin, acetyl CoA, and NADP. However, the abnormal build-up of Trp is known to cause familial hypertryptophanemia and several brain-related medical complications. The molecular mechanism of the onset of such Trp-driven health issues is largely unknown. Here, we show that Trp, under the physiologically mimicked conditions of temperature and buffer, undergoes a concentration driven self-assembly process, yielding amyloid-mimicking nanofibers. Viable H-bonds, π-π interactions and hydrophobic contacts between optimally coordinated Trp molecules become important factors for the formation of a Trp nanoassembly that displays a hydrophobic exterior and a hydrophilic interior. Importantly, Trp nanofibers were found to possess high affinity for native proteins, and they act as cross-seeding competent conformers capable of nucleating amyloid formation in globular proteins including whey protein β-lactoglobulin and type II diabetes linked insulin hormone. Moreover, these amyloid mimicking Trp nanostructures showed toxic effects on neuroblastoma cells. Since the key symptoms in hypertryptophanemia such as behavioural defects and brain-damaging oxidative stress are also observed in amyloid related disorders, our findings on amyloid-like Trp-nanofibers may help in the mechanistic understanding of Trp-related complications and these findings are equally important for innovation in applied nanomaterials design and strategies.

Drug-induced bronchiolitis obliterans organizing pneumonia

Several medications have been associated with the development of the BOOP lesion. Often, symptoms include nonproductive cough and shortness of breath with bilateral crackles by examination. Occasionally, there is fever and rash, and, rarely, eosinophilia. The chest radiograph usually shows bilateral patchy infiltrates. In rare situations, the outcome is fatal, although cessation of the medication or treatment with corticosteroid therapy results in resolution of symptoms and radiographic abnormalities for most patients.

Organizing pneumonia: prognostic implication of high-resolution computed tomography features

PURPOSE

Most patients with biopsy-proven organizing pneumonia (OP) show complete resolution of radiographic lesions with treatment, but some patients do not respond to treatment and progress to pulmonary fibrosis. The authors investigated the prognostic implication of high-resolution computed tomography (CT) features in this condition.

METHOD

We reviewed the high-resolution CT findings of 26 patients diagnosed with OP by histopathology, who had radiographic follow-up for a median of 44 weeks after treatment. We scored the presence and extent of each pretreatment high-resolution CT finding (ground-glass opacity, consolidation, nodules, reticular opacity, and honeycombing). The predominant pattern and distribution of the lesions were recorded. Follow-up radiographs were used to determine whether the parenchymal abnormalities had regressed or progressed in response to treatment.

RESULTS

Of the 26 patients, 9 had persistent or progressive parenchymal abnormalities at follow-up (group 1), whereas 17 had complete or partial resolution of abnormalities (group 2). Consolidation was present on the initial CT scan in 14 (82%) of the 17 patients in group 2, but in only 2 of the 9 patients in group 1 (P = 0.009). None of the 6 patients who had reticular abnormality as the predominant pattern on initial CT showed complete resolution on follow-up imaging (P = 0.02).

CONCLUSION

In patients with OP, the CT finding of consolidation is associated with partial or complete resolution, whereas reticular opacity is associated with persistent or progressive disease.

Lupus and pulmonary nodules consistent with bronchiolitis obliterans organizing pneumonia induced by carbamazepine

Carbamazepine-induced lupus is uncommon; its frequency is less than 0.001% of the cases of lupus treated. Herein we describe a 52-year-old woman who had development of facial erythema, arthralgia, dyspnea, and multiple pulmonary rounded masses and nodules while she was taking carbamazepine for epilepsy. Pulmonary histologic examination showed bronchiolitis obliterans organizing pneumonia. Antinuclear antibodies and antihistone antibodies were present without antibodies to double-stranded DNA. Thirteen months after carbamazepine had been withdrawn, all symptoms had disappeared without the use of anti-inflammatory drugs. Even though pulmonary involvement is possible during carbamazepine treatment, to our knowledge, bronchiolitis obliterans organizing pneumonia on its own or associated with carbamazepine-induced lupus has not been previously described.

Bronchiolitis obliterans organising pneumonia: a clinical and radiological review

BACKGROUND

The clinical presentation, course, and radiological spectrum of bronchiolitis obliterans organising pneumonia (BOOP) is still being characterised to aid differentiation from other causes of organising pneumonia.

AIMS

To define the clinical presentation, response to therapy, and radiological spectrum of BOOP.

METHODS

Fifteen cases of BOOP were retrospectively reviewed. The clinical presenting features, treatment and outcome of each patient were determined. Three independent readers and chest X-rays (CXRs) were blinded. CXRs were scored by a semi-quantitative method. Modal scores were calculated for type and profusion of opacification of each CXR.

RESULTS

The mean age of presentation was 64 years and the median duration of follow-up was 12.5 months. Thirteen patients received corticosteroid therapy. Outcome was varied. One patient had progressive loss of lung function, five had persisting symptoms with stable abnormal lung function, and nine were asymptomatic with near normal lung function. Five patients had a disease relapse. Symptoms length prior to presentation, duration and intensity of treatment were not associated with outcome (p = 0.23-0.9). Radiological opacities were alveolar in 73%, large localised infiltrates in 13%, nodular in 20% and mobile in 33% of CXR series. There was no relationship between overall profusion, type of CXR opacities and patient outcome, treatment duration or treatment intensity (p = 0.42-1.0).

CONCLUSIONS

The clinical spectrum of BOOP includes mild subacute, chronic progressive, and acute life threatening illness. Prognosis and response to treatment is variable. The diversity of radiological findings and clinical presentations should prompt consideration of the diagnosis in patients with undiagnosed respiratory tract symptoms and persisting or varying radiological abnormalities.