Antibody-like proteins that capture and neutralize SARS-CoV-2

To combat severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) and any unknown emerging pathogens in the future, the development of a rapid and effective method to generate high-affinity antibodies or antibody-like proteins is of critical importance. We here report high-speed in vitro selection of multiple high-affinity antibody-like proteins against various targets including the SARS-CoV-2 spike protein. The sequences of monobodies against the SARS-CoV-2 spike protein were successfully procured within only 4 days. Furthermore, the obtained monobody efficiently captured SARS-CoV-2 particles from the nasal swab samples of patients and exhibited a high neutralizing activity against SARS-CoV-2 infection (half-maximal inhibitory concentration, 0.5 nanomolar). High-speed in vitro selection of antibody-like proteins is a promising method for rapid development of a detection method for, and of a neutralizing protein against, a virus responsible for an ongoing, and possibly a future, pandemic.

Effects of blood pressure and the renin-angiotensin system on platelet activation in type 2 diabetes

Aims/Introduction:  Platelet‐derived microparticles (PDMP) are released from the platelets either after activation or in response to physical stimulation in vivo. The present study examined the association between blood pressure and PDMP, and the effects of high‐dose angiotensin receptor blockers (ARB) on PDMP in patients with type 2 diabetes.

Materials and Methods:  The study subjects consisted of 28 type 2 diabetes patients with blood pressure ≥130/80 mmHg who were treated with valsartan (80 mg daily). The patients were randomly assigned to take either 80 mg of telmisartan (Tel group) or 160 mg of valsartan (Val group) and then were followed up for 24 weeks. Thereafter, the patients were switched to combination therapy (5 mg of amlodipine with 40 mg of telmisartan [Tel group] or 80 mg of valsartan [Val group]) for 12 weeks.

Results:  Although the ambulatory blood pressure did not change, the PDMP levels were significantly decreased from baseline to week 24 (high dose ARB). In contrast, combination therapy reduced both blood pressure and PDMP levels compared with the baseline. Although the PDMP level was significantly correlated with the morning BP elevation at baseline and week 36 (combination therapy), this same relationship was not found at week 24. There were no significant differences in the blood pressure and PDMP levels between the two groups.

Conclusions:  Patients with morning hypertension might be at risk for cardiovascular diseases. High‐dose renin‐angiotensin system inhibition and blood pressure control are both considered to reduce cardiovascular events in patients with type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00048.x, 2010)

Renoprotective effects of asialoerythropoietin in diabetic mice against ischaemia-reperfusion-induced acute kidney injury

AIM

Diabetic patients are at higher risk of failure to recover after acute kidney injury, however, the mechanism and therapeutic strategies remain unclear. Erythropoietin is cytoprotective in a variety of non-haematopoietic cells. The aim of the present study was to clarify the mechanism of diabetes-related acceleration of renal damage after ischaemia-reperfusion injury and to examine the therapeutic potential of asialoerythropoietin, a non-haematopoietic erythropoietin derivative, against ischaemia-reperfusion-induced acute kidney injury in diabetic mice.

METHODS

C57BL/6J mice with and without streptozotocin-induced diabetes were subjected to 30 min unilateral renal ischaemia-reperfusion injury at 1 week after induction of diabetes. They were divided into four group: (i) non-diabetic plus ischaemia-reperfusion injury; (ii) non-diabetic plus ischaemia-reperfusion injury plus asialoerythropoietin (3000 IU/kg bodyweight); (iii) diabetic plus ischaemia-reperfusion injury; and (iv) diabetic plus ischemia-reperfusion injury plus asialoerythropoietin. Experiments were conducted at the indicated time periods after ischaemia-reperfusion injury.

RESULTS

Ischaemia-reperfusion injury of diabetic kidney resulted in significantly low protein expression levels of bcl-2, an anti-apoptotic molecule, and bone morphogenetic protein-7 (BMP-7), an anti-fibrotic and pro-regenerative factor, compared with non-diabetic kidneys. Diabetic kidney subsequently showed severe damage including increased tubular cell apoptosis, tubulointerstitial fibrosis and decreased tubular proliferation, compared with non-diabetic kidney. Treatment with asialoerythropoietin induced bcl-2 and BMP-7 expression in diabetic kidney and decreased tubular cell apoptosis, tubulointerstitial fibrosis and accelerated tubular proliferation.

CONCLUSION

Reduced induction bcl-2 and BMP-7 may play a role in the acceleration of renal damage after ischaemia-reperfusion injury in diabetic kidney. The renoprotective effects of asialoerythropoietin on acute kidney injury may be mediated through the induction of bcl-2 and BMP-7.

Does the concomitant intra-arterial injection of asialoerythropoietin and edaravone mitigate ischaemic mucosal damage after acute superior mesenteric artery thromboembolism in a rabbit autologous fibrin clot model?

To increase the survival rate of patients with acute superior mesenteric artery thromboembolism (ASMAT) treated by catheter thrombolysis, we examined the effects of delivering edaravone and asialoerythropoietin, agents with tissue-protective activities, using a rabbit autologous fibrin clot ASMAT model. Japanese white rabbits (n=32) were randomly separated into four equal groups. 45 min after introducing autologous fibrin clot, Group U received urokinase and heparin; Group E received urokinase and heparin plus edaravone; Group A received urokinase and heparin plus asialoerythropoietin; and Group EA received urokinase, heparin and edaravone plus asialoerythropoietin via a catheter. The intestines were removed 6 h later and intestinal mucosal damage was scored using the Park's injury score. Survival time was assessed. Average mucosal injury was 5.78+/-1.52 (Group U), 2.88+/-0.72 (Group E), 1.90+/-1.23 (Group A) and 1.18+/-1.25 (Group EA). The degree of mucosal injury was significantly lower in Group EA than in Groups U and E (p<0.05). Conversely, there was no significant difference between Group A and Group EA, or between Group A and Group E. The survival times were 31.50+/-13.30 h (Group U), 51.00+/-24.74 h (Group E), 48.00+/-16.97 h (Group A) and 82+/-51.07 h (Group EA); the difference among the four groups was not significant. In conclusion, the concomitant administration of asialoerythropoietin and edaravone reduced mucosal membrane injury significantly compared with edaravone alone. However, to improve the survival of ASMAT rabbit models, the delivery of an appropriate dose of asialoerythropoietin is required, together with the development of methods to assess peripheral recanalisation.

Asialoerythropoietin prevents contrast-induced nephropathy

Strategies to prevent contrast-induced nephropathy (CIN) are suboptimal. Erythropoietin was recently found to be cytoprotective in a variety of nonhematopoietic cells, so it was hypothesized that the nonhematopoietic erythropoietin derivative asialoerythropoietin would prevent CIN. Nephropathy was induced in rats by injection of the radiocontrast medium Ioversol in addition to inhibition of prostaglandin and nitric oxide synthesis. Administration of a single dose of asialoerythropoietin before the induction of nephropathy significantly attenuated the resulting renal dysfunction and histologic renal tubular injury. Contrast-induced apoptosis of renal tubular cells was inhibited by asialoerythropoietin both in vivo and in vitro, and this effect was blocked by a Janus kinase 2 (JAK2) inhibitor in vitro. Furthermore, phospho-JAK2/signal transducer and activator of transcription 5 (STAT5) and heat-shock protein 70 increased after injection of asialoerythropoietin, suggesting that the effects of asialoerythropoietin may be mediated by the activation of the JAK2/STAT5 pathway. Overall, these findings suggest that asialoerythropoietin may have potential as a new therapeutic approach to prevent CIN given its ability to preserve renal function and directly protect renal tissue.

Systemic cholesterol embolization syndrome associated with myeloperoxidase-anti-neutrophil cytoplasmic antibody

A 75-year-old man was transferred to our department because of development of severe renal impairment after coronary artery bypass grafting. Hemodialysis was initiated for postsurgical oliguria and lung congestion. On transfer, he showed systemic purpura rashes and diffuse blue mottlings on his toes with marked eosinophilia and an elevated level of C-reactive protein. Cutaneous biopsy revealed cholesterol crystal embolism and leukocytoclastic vasculitis in dermal arterioles. Myeloperoxidase-anti-neutrophil cytoplasmic antibody titer was increased. Upon oral corticosteroid therapy following intravenous pulse steroid therapy, the purpura dramatically diminished, renal function improved, and hemodialysis was discontinued. Active treatment with corticosteroids may be effective for cholesterol embolization syndrome, particularly when clinical and laboratory manifestations mimic systemic vasculitis.

A case of myeloperoxidase-antineutrophil cytoplasmic antibody positive-polyarteritis nodosa complicated by interstitial pneumonia and rapidly progressive renal failure

A 73-year-old woman was admitted to our hospital because of persistent high fever and cough, generalized myalgia, and renal dysfunction. Laboratory examination revealed severe inflammatory signs, pulmonary fibrosis, progression of renal impairment with active nephritic urinary sediments, and a high titer of myeloperoxidase-antineutrophil cytoplasmic antibody, indicating that she might have microscopic polyangiitis with interstitial pneumonia and rapidly progressive glomerulonephritis. Her renal biopsy, however, showed tubulointerstitial changes with mild glomerular abnormalities, and renal angiography revealed that she had vascular lesions of medium-sized arteries, which were compatible with classical polyarteritis nodosa. Tissue biopsy of the clinically affected organ should be considered in anyone suspected to have vasculitis.

Lupus vasculopathy combined with renal infarction: unusual manifestation of lupus nephritis

A 30-year-old woman with a 10-year history of systemic lupus erythematosus was admitted to our hospital because of the onset of hypertension and renal dysfunction. Renal arteriogram revealed multiple renal infarctions, and cut-off or tapering-stenosis in the interlobular arteries. Renal biopsy showed concentric intimal thickening with narrowed lumen in some arterioles and deposition of IgG/IgM/complement 3 in the wall of arteriole without any active lesions or immune complex deposition in glomeruli. The present case indicates that this type of renal vascular lesion in lupus nephritis, lupus vasculopathy, may cause renal infarction and the loss of renal function without active glomerular lesions.