Cytochemical investigation of neutral proteases in polymorphonuclear (PMN) neutrophils in acute inflammatory diseases

Role of proteases in patients with acute renal failure and regular hemodialysis therapy

The potential role of proteases in patients with acute renal failure and regular hemodialysis therapy was investigated. Proteases released from blood cells, damaged kidney cortex and different strains of Pseudomonas aeruginosa in patients with septicemia may contribute to an accelerated protein catabolism. The imbalance of the protease-antiprotease system suggests the valve of active antiproteolytic agents in the treatment of these pathologic states. Our own observation of an in vitro suppression of enhanced proteolysis by the administration of alpha 2-macroglobulin seems to support the usefulness of such a procedure (W.H. Hörl, C. Gautert, I.O. Auer et al., Am. J. Nephrol., 2 (1982) 32-35). As long as alpha 2-macroglobulin is not available, the value of its treatment has to be confirmed by the administration of fresh frozen plasma containing alpha 2-macroglobulin. Also the search for other active antiproteolytic agents is required.

Granulocyte lysosomal factors and plasma elastase in uremia: a potential factor of catabolism

In uremic intoxication proteolytic activity in plasma and striated muscle is enhanced. To get further insights into the underlying mechanisms the lysosomal factors of polymorphonuclear (PMN) leukocytes and the plasma elastase-alpha 1-proteinase inhibitor complex were investigated in patients with acute and chronic renal failure. Lysosomal activity was evaluated in peripheral blood smears by the lysis of erythrocytes and plasma (halo formation) around each neutrophil induced by 0.25 M NaC1 borate buffer. In about half of the patients with chronic renal insufficiency on dietary treatment lysosomal activity of PMN leukocytes was reduced. The plasma concentration of elastase-alpha 1-proteinase inhibitor complex was normal in most subjects, but increased in three patients with the highest serum creatinine levels (greater than 13 mg/d1). In the patients with acute renal failure (ARF) of various origin (postoperatively, septicemia, pancreatitis, or dye-induced) halo formation was either reduced or absent. The plasma elastase-alpha 1-proteinase inhibitor complex was increased in 5/6 of the patients by a factor of two to four. Also in the patients on regular hemodialysis treatment halo formation of PMN leukocytes was substantially reduced, whereas the plasma levels of elastase-alpha 1-proteinase inhibitor complex was slightly increased. The finding of reduced lysosomal activity of PMN neutrophils in uremia may be partly due to an enhanced release of neutral proteinases into the circulation as indicated by the elevated plasma levels of elastase-alpha 1-proteinase inhibitor complex in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Release of granulocyte neutral proteinases in patients with acute and chronic renal failure

In uremic intoxication proteolytic activity in plasma and striated muscle is enhanced. To get further insight into the underlying mechanisms the neutral proteinases of polymorphonuclear (PMN) leukocytes were investigated in patients with acute and chronic renal failure. The following studies were performed: 1. Neutral proteolytic activity of PMN neutrophils in blood smears (according to Klessen, 1978). 2. Serum levels of elastase alpha 1 proteinase inhibitor complex (Neumann et al., 1981). In about half of the patients with chronic renal insufficiency on dietary treatment the proteolytic activity of PMN leukocytes (halo formation are due to digestion of erythrocytes and plasma) was reduced. The serum concentration of elastase alpha 1 proteinase inhibitor complex was normal in most subjects, but increased in 3 patients with the highest serum creatinine levels (greater than 13 mg/dl). In the patients with acute renal failure (ARF) of various origin (postoperatively, septicemia, pancreatitis or dye induced) halo formation was either reduced or absent. Serum elastase alpha 1 proteinase inhibitor was increased in 5/6 patients by a factor of two to four. Also in the 15 patients on regular hemodialysis treatment halo formation was substantially reduced, while the serum levels of elastase alpha 1 proteinase inhibitor complex was slightly increased. The finding of reduced proteolytic activity of PMN neutrophils in uremia is probably due to an enhanced release of proteinases into the circulation as indicated by the elevated serum levels of elastase alpha 1 proteinase inhibitor complex in some patients. The release of proteinases might be in part due to the effect of "uremic toxins". In the RDT patients the contact of the blood with the dialyzer (cuprophane) membrane might be an additional factor. In the patients with ARF the underlying disease (infection, shock, trauma) contributes to the release of proteinases. These disturbances may be harmful for the patient, if the blood concentration or function of the most important proteinase inhibitors (alpha 1 proteinase inhibitor, alpha 2 macroglobulin) is reduced.

Cytochemical demonstrations of protease in human peripheral blood cells by use of new alpha-naphthyl ester substrates

The proteases of human leukocytes were cytochemically studied by use of new alpha-naphthyl esters, tosyl-L-lysine-alpha-naphthyl ester (TLNE) and acetyl-L-tyrosine-alpha-naphthyl ester (ATNE). The hydrolytic activities were strong only in neutrophils, with both substrates. They were inhibited completely by DFP and chymostatin, but not by leupeptin and iodoacetate. These results indicate that chymotrypsin-like enzyme(s), capable of hydrolyzing both substrates, exist in neutrophils.

Cytochemical detection of proteases in synovial fluid of arthritic joints

A cytochemical method can be used to detect neutral proteases in polymorphonuclear leukocytes (PMN cells) in synovial fluid smears obtained from arthritic joints. Using this method, incubation of fixed smears in NaCl-borate buffer causes release of neutral PMN proteases, the enzymatic activity of which id documented in the degradation of exudate protein in ring-shaped areas centered around the neutrophils(halo effect). Such halo formation can also be detected around certain large mononuclear cells, as well as around very small particles - which may represent thrombocytes. Application of trypsin inhibitors and various antirheumatic agents causes concentration-dependent inhibition of halo formation.