Fibrinogen deposition promotes neuroinflammation and fibrin-derived γ377-395 peptide ameliorates neurological deficits after ischemic stroke

BACKGROUND

Fibrin(ogen) deposition in the central nervous system (CNS) contributes to neuropathological injury; however, its role in ischemic stroke is unknown. In this study, we identified fibrinogen as a novel proinflammatory regulator of post-stroke neuroinflammation and revealed the neuro-protection effect of fibrin-derived γ377-395peptide in stroke.

METHODS

Fibrinogen depletion and fibrinogen-derived γ377-395peptide treatment were performed 2 h after establishing a permanent middle cerebral artery occlusion (pMCAO) model. The infarction volume, neurological score, fibrin(ogen) deposition, and inflammatory response were evaluated 24 h after occlusion. Both in vivo and in vitro studies were conducted to assess the therapeutic potential of the γ377-395peptide in blocking the interactions between fibrin(ogen) and neutrophils.

RESULTS

Fibrin(ogen) deposited in the infarct core promoted post-stroke inflammation and exacerbated neurological deficits in the acute phase after stroke onset. Reducing fibrinogen deposition resulted in a decrease in infarction volume, improved neurological scores, and reduced inflammation in the brain. Additionally, the presence of neutrophil accumulation near fibrin(ogen) deposits was observed in ischemic lesions, and the engagement of fibrin(ogen) by integrin receptor αMβ2 promoted neutrophil activation and post-stroke inflammation. Finally, inhibiting fibrin(ogen)-mediated neutrophil activation using a fibrinogen-derived γ377-395peptide significantly attenuated neurological deficits.

CONCLUSIONS

Fibrin(ogen) is a crucial regulator of post-stroke inflammation and contributes to secondary brain injury. The inflammation induced by fibrin(ogen) is primarily driven by neutrophils during acute ischemic stroke and can be ameliorated using the fibrin-derived γ377-395peptide. Targeting the fibrin(ogen)-mediated neuropathological process represents a promising approach for neuroprotective therapy after stroke while preserving its beneficial coagulation function.

Glomerular deposition of fibrinogen predicts good prognosis of IgA nephropathy: a single-center cohort study

PURPOSE

It has been proven that fibrinogen deposition exists in IgA nephropathy (IgAN), but its clinical significance has not been identified. We aim to investigate the clinical implication of fibrinogen deposition in evaluating the activity and prognosis of IgA nephropathy.

METHODS

In this cohort, 935 adult IgAN patients were divided into 3 groups according to the intensity of glomerular fibrinogen deposition. Primary outcome refers to a composite event of either a ≥ 50% reduction in eGFR or ESRD (eGFR < 15 ml/min/1.73m2, dialysis, or renal transplantation). Factors associated with fibrinogen deposition and prognosis were identified.

RESULTS

The results showed that the intensity of fibrinogen deposition was positively correlated with eGFR (P < 0.001), serum albumin (P = 0.041), and hemoglobin levels (P < 0.05), but negatively correlated with age (P = 0.04), serum fibrinogen levels (P < 0.001), serum C4 (P = 0.023), the proportion of patients with hypertension (P = 0.003), and the percentage of glomeruli sclerosis (P < 0.001). The prognostic analyses identified that fibrinogen deposition was an independent predictor for the progression of IgAN (P = 0.033).

CONCLUSION

Our study indicated that the deposition of renal fibrinogen can predict the prognosis of IgAN with high reliability.

Significance of glomerular fibrinogen deposition in children with Henoch-Schönlein purpura nephritis

BACKGROUND

Henoch-Schönlein purpura nephritis (HSPN) is the most common pediatric secondary glomerular disease. This study aimed to investigate the significance of glomerular fibrinogen (Fib) deposition in children with HSPN.

METHODS

Eighty-two patients with HSPN were enrolled retrospectively at the Children's Hospital of Soochow University from January 2015 to March 2017. Patients were divided into groups according to the presence or absence and intensity of glomerular Fib deposits, and clinical and pathological features were compared among the groups.

RESULTS

Glomerular Fib deposition was observed in 64 children (78.05%), including 1 Fib± case (1.22%), 23 Fib+ cases (28.05%), 37 Fib++ cases (45.12%), and 3 Fib+++ cases (3.66%). Significantly different levels of high-sensitivity C-reactive protein (hs-CRP), D-dimer (DD), proportions of CD19 + CD23+ cells and urine microalbumin:creatinine ratios (UMA/Cr) were noted among the different Fib deposition groups (no, mild and severe). Pairwise comparison in multiple groups revealed significantly increased hs-CRP, proportion of CD19 + CD23+ cells and UMA/Cr in the severe deposition group compared with the mild and no deposition groups, and remarkably increased DD levels were noted in the severe and mild deposition groups compared with the no deposition group. The degree of glomerular Fib deposition was positively correlated with the degree of glomerular IgA deposition, and the incidence of glomerular IgG deposition in the severe deposition group was increased compared with the no deposition group.

CONCLUSION

HSPN children with glomerular Fib deposition, especially those with severe Fib deposition, exhibit more severely disordered immunologic function, inflammatory reactions and hypercoagulability; glomerular damage in these patients may also be more severe.