A novel fibrinolytic enzyme from marine Pseudomonas aeruginosa KU1 and its rapid in vivo thrombolysis with little haemolysis.

A direct acting, extracellular, fibrinolytic enzyme, ~50 KDa from marine Pseudomonas aeruginosa KU1 (PEKU1), was purified. It was found to be a metalloprotease. 60% of the total activity of the purified PEKU1 was retained at 70 °C and the enzyme was practically denatured at 80 °C, 2 h. Metal ions, such as Na+, K+ and Co2+, were found to enhance slightly the fibrinolytic activity, while Fe2+, Mn2+ and Zn2+ were found to be inhibiting. The enzyme showed only less than 5% haemolysis, suggesting its thrombolytic administration safe. Tryptic digestion revealed its similarity to serralysin like alkaline protease of P. aeruginosa. In silico studies showed its binding of protease substrates and fibrin D-dimer in its active site. High affinity binding of bradykinin to the active site of PEKU1, confirmed by in vitro cleaving, suggested its future use as an analgesic. The purified enzyme with Na+, K+ and Co2+, and without Fe2+, Mn2+ and Zn2+ showed thrombolysis in vivo in carrageenan induced murine tail thrombolytic model. The enzyme PEKU1, a novel protease from marine isolate Pseudomonas aeruginosa KU1 has great potential to be developed as a therapeutic agent to combat cardiovascular diseases, as well as analgesic and anti-inflammatory drug in appropriate sites.

Fibrinolytic Enzymes for Thrombolytic Therapy.

Cardiovascular diseases are a group of disorders consisting importantly of coronary heart disease, peripheral arterial disease, cerebrovascular disease, rheumatic heart disease, congenital heart disease, deep vein thrombosis and pulmonary embolism. Severe cardiovascular disease conditions lead to acute myocardial infarction and stroke. One of the reasons for this is formation of blood clots inside the vessel. Anticoagulants and antiplatelet drugs are used for managing cardiovascular diseases for a long time. However, they were unable to dissolve an existing thrombus. Fibrinolytic enzymes have become more substantial for treating cardiovascular diseases since they could lyse the fibrin clot within the blood vessel. Inability of plasma fibrinolytic system demands better thrombolytic drugs. Major thrombolytic enzymes belonging to plasminogen activators and plasmin like enzymes. Currently used fibrinolytic enzymes and their limitations are revisited in the present chapter. Reported enzymes from various sources with potential to be used as cardiovascular therapeutic is also discussed here.

Canine filarial infections in a human Brugia malayi endemic area of India.

A very high prevalence of microfilaremia of 42.68 per cent out of 164 canine blood samples examined was observed in Cherthala (of Alappuzha district of Kerala state), a known human Brugia malayi endemic area of south India. The species of canine microfilariae were identified as Dirofilaria repens, Brugia malayi, and Acanthocheilonema reconditum. D. repens was the most commonly detected species followed by B. pahangi. D. immitis was not detected in any of the samples examined. Based on molecular techniques, microfilariae with histochemical staining pattern of "local staining at anal pore and diffuse staining at central body" was identified as D. repens in addition to those showing acid phosphatase activity only at the anal pore. Even though B. malayi like acid phosphatase activity was observed in few dogs examined, they were identified as genetically closer to B. pahangi. Hence, the possibility of dogs acting as reservoirs of human B. malayi in this area was ruled out.