A novel soluble ACE2 protein totally protects from lethal disease caused by SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) uses full-length angiotensin converting enzyme 2 (ACE2), which is membrane bound, as its initial cell contact receptor preceding viral entry. Here we report a human soluble ACE2 variant fused with a 5kD albumin binding domain (ABD) and bridged via a dimerization motif hinge-like 4-cysteine dodecapeptide, which we term ACE2 1-618-DDC-ABD. This protein is enzymatically active, has increased duration of action in vivo conferred by the ABD-tag, and displays 20-30-fold higher binding affinity to the SARS-CoV-2 receptor binding domain than its des-DDC monomeric form (ACE2 1-618-ABD) due to DDC-linked dimerization. ACE2 1-618-DDC-ABD was administered for 3 consecutive days to transgenic k18-hACE2 mice, a model that develops lethal SARS-CoV-2 infection, to evaluate the preclinical preventative/ therapeutic value for COVID-19. Mice treated with ACE2 1-618-DDC-ABD developed a mild to moderate disease for the first few days assessed by a clinical score and modest weight loss. The untreated control animals, by contrast, became severely ill and had to be sacrificed by day 6/7 and lung histology revealed extensive pulmonary alveolar hemorrhage and mononuclear infiltrates. At 6 days, mortality was totally prevented in the treated group, lung histopathology was improved and viral titers markedly reduced. This demonstrates for the first time in vivo the preventative/ therapeutic potential of a novel soluble ACE2 protein in a preclinical animal model.

Diffuse alveolar hemorrhage secondary to plastic fume exposure: A case report

A 31-year non-smoker man, working in plastic making industry for 12 years presented with cough and streaking hemoptysis for 2 days. Computed tomography (CT) of chest showed patchy ground glass opacities with interlobular septal thickening in bilateral lung parenchyma. Fiber optic bronchoscopy (FOB) was done. Sequential lavage was taken which showed progressively increasing hemorrhagic fluid. His diffusion capacity for carbon monoxide (DLCO) was 38.08 mL/mmHg/Mi (126%) predicted on day 2 of admission, 32.36 ml/mmHg/Mi (106%) predicted on discharge and 39.63 mL/mmHg/Mi (130%) predicted on going back to work. He was diagnosed with plastic fume exposure related pulmonary alveolar hemorrhage.

Microscopic Polyangitis in Pediatric Systemic Lupus Erythematosus: A Unique Presentation of Pulmonary - Renal Syndrome and Case Report of an Overlap Syndrome

Background: Secondary vasculitis is encountered in about one third of all cases of systemic lupus erythematosus (SLE). Skin is most commonly involved in lupus-related small vasculitis. Although antineutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) is relatively uncommon, it can be the most dangerous manifestation associated with high mortality. SLE and AAV are separate diseases with different pathophysiologies and an overlap syndrome has only been reported few times in previous literature. Case Presentation: We present a unique case of a pediatric patient of pulmonary-renal syndrome, presenting with pulmonary alveolar hemorrhage and rapidly progressive glomerulonephritis. Serological and biopsy findings were suggestive of SLE and AAV occurring simultaneously. Renal biopsy demonstrated necrotizing and crescentic glomerulonephritis, superimposed on diffuse segmental proliferative lupus glomerulonephritis class IV. Conclusions: Presentations of autoimmune diseases and vasculitis can be multi-systemic. Considering overlap syndromes, especially in patients with underlying connective tissue disease or systemic vasculitis, is vital for prompt therapy and prevention of morbidity in this population.