Ancrod in the treatment of acute ischaemic stroke

Plasma fibrinogen as a potential biomarker of cognitive impairment after acute ischemic stroke

Fibrinogen (FBG) has been discovered to be associated with cognitive impairment (CI) and dementia. However, the exact correlation between FBG levels and CI after acute ischemic stroke (AIS) remains uncertain. Plasma FBG levels were measured in 398 patients with AIS who underwent comprehensive neuropsychological evaluation. To assess the correlation of FBG with global cognitive function, physical status, anxiety, depression, and psychiatric symptoms. Multifactorial logistic regression was used to analyze risk factors for CI. Constructed and plotted a nomogram graph to visualize the CI prediction model. The model was further evaluated for discrimination, calibration, and clinical utility. The results indicate that plasma FBG levels are significantly elevated in patients with CI compared to those with non-cognitive impairment (NCI). Analysis of the overall population reveals that elevated FBG levels are correlated with both reduced cognitive function and decreased activity status. After adjusting for other influencing factors, high FBG levels were identified as a risk factor for the incidence of CI. We developed an intuitive and valid predictive model for CI, demonstrating its suitability for clinical application. In conclusion, our study demonstrates that plasma FBG serves as a potential biomarker of CI following AIS, offering a novel perspective for the identification of CI.

High levels of plasma fibrinogen are related to post-stroke cognitive impairment

INTRODUCTION

Studies have shown that high levels of the fibrinogen (FIB) are related to cognitive deficits. However, the relationship between fibrinogen and cognitive deficit after stroke remains unclear. Therefore, we explored the relationship between plasma fibrinogen and post-stroke cognitive impairment (PSCI).

METHODS

This study is carried out in the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China. A total of 210 patients with acute ischemic stroke were enrolled in this study. Ultimately, 134 patients completed 3-month follow-up. Blood samples were collected at hospital admission. Cognitive function was evaluated 3 months after stroke. All patients underwent the Mini-Mental State Examination (MMSE) after 3 months.

RESULTS

Higher levels of fibrinogen were observed in patients with post-stroke cognitive impairment compared with the non-PSCI group (p < .001). Additionally, elevated plasma fibrinogen levels were independently associated with PSCI (odds ratio [OR] = 2.000, 95% CI 1.062-3.770 p = .032). The plasma fibrinogen levels were negatively correlated with the 3-month MMSE scores (r = -.171, p = .048). In a multivariate linear regression, FIB was negatively associated with the 3-month MMSE scores after adjustment for the other variables (β = -0.782, p = .035).

CONCLUSION

High levels of plasma fibrinogen were associated with the presence and severity of PSCI.

Defibrinogenating enzymes

The venoms from 3 snakes have been shown to induce defibrinogenation: ancrod from the venom of Calloselasma rhodostoma (formerly known as Agkistrodon rhodostoma), batroxobin from the venom of Bothrops atrox moojeni, and crotalase from the venom of Crotalus adamanteus. The purified fractions of ancrod, batroxobin, and crotalase possess coagulant, proteolytic and esterolytic properties, although their primary mechanism of action is a proteolytic effect on circulating fibrinogen. Ancrod cleaves only the A-fibrinopeptides, but not the B-fibrinopeptides, from fibrinogen; this contrasts with thrombin, batroxobin and crotalase, which cleave both fibrinopeptides A and B. Within minutes of administration of ancrod or batroxobin, there is a significant reduction in plasma fibrinogen levels, and these remain exceedingly low with repeated administration (once or twice daily). The rapid fall in plasma fibrinogen levels is accompanied by a slightly delayed but marked rise in the level of fibrinogen-fibrin degradation products. Plasminogen levels are decreased and blood viscosity is reduced, but formed elements in the circulating blood remain unaltered. Ancrod and batroxobin have been investigated in patients with stroke, deep-vein thrombosis, myocardial infarction, peripheral arterial thrombosis, priapism, and sickle-cell crisis; crotalase has not been administered to humans. However, results have been difficult to interpret, and additional well designed trials are needed to better define the optimum role of ancrod and batroxobin in the management of these conditions. Overall, treatment is well tolerated and serious adverse events are infrequent. In the coagulation laboratory, ancrod, batroxobin and crotalase may be used as reagents to perform coagulation studies on specimens of blood that contain heparin. These venom fractions can be substituted for thrombin in performing the thrombin time and in removing fibrinogen from plasma for accurate determination of fibrinogen-fibrin degradation products.

Update on therapies for acute ischemic stroke

Acute ischemic stroke is now considered a neurological emergency for which there are new therapies. Neurosurgeons and neurologists need to remain apprised of advances in this field. The authors discuss approved and emerging therapies for patients suffering from acute ischemic stroke, based on a review of recent publications. Currently, intravenous tissue-type plasminogen activator is the only Food and Drug Administration–approved therapy for acute ischemic stroke. Intraarterial delivery of thrombolytics is a promising treatment and may be effective in selected patients. Other therapies for acute cerebral ischemia are intriguing but still in the investigational stages.