Alpha-2-macroglobulin decreases parallel to albumin and haemoglobin after elective surgery

Abstract

Plasma levels of the plasma protease inhibitor alpha-2-macroglobulin (alpha 2-M) were followed for 7 days in 90 patients subjected to various surgical procedures. Alpha 2-M was found to decrease strictly in parallel with the decrease seen for haemoglobin and albumin levels in all patients. Changes were most pronounced after extensive operations; total hip replacement (n = 7), pulmonary resection (n = 11), extensive colo-rectal resection (n = 15), and less pronounced after 'minor' operations; mastectomy (n = 23) proximal gastric vagotomy (n = 5) and moderate colo-rectal resection (n = 29). Levels were lowest on the second to third postoperative day, whereafter they slowly returned to normal, preoperative levels during the 7-day study period. Functional and quantitative alpha 2-M levels almost paralleled each other throughout the 7 days studied. Chromogenic peptide substrate assays indicated circulating plasmin-alpha 2-M complexes, while no protease-alpha 2-M complexes could be demonstrated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) or isoelectric focusing (IEF) analyses. Local accumulation and consumption of proteins within wounded tissues, together with haemodilution, were probably the major factors responsible for the decreased plasma levels seen. It is concluded that the plasma levels of alpha 2-M decrease after major elective surgery strictly in parallel with the decrease seen in haemoglobin and albumin levels, and that circulating plasmin-alpha 2-M complexes are probable. The decrease seems to be graded, that is, proportional to the extent of the operative trauma, similar to the postoperative increase seen in positive acute-phase proteins. Thus, alpha 2-M cannot be used as an internal, unchanged plasma protein standard for other protein changes seen after trauma.

Profiling the Expression of Circulating Acute-Phase Proteins, Cytokines, and Checkpoint Proteins in Patients with Severe Trauma: A Pilot Study

“… 58 Decreased A2M was noted due to hemodilution by fluid treatment, first extravasation and accumulation of proteins at the wound site, and altered hepatic protein production. 59 The severity of trauma and the extent of wound tissue induces a parallel decrease in both albumin and A2M. 59 In addition, vWF plays an important role in both hemostasis and thrombosis.…”

“… 59 The severity of trauma and the extent of wound tissue induces a parallel decrease in both albumin and A2M. 59 In addition, vWF plays an important role in both hemostasis and thrombosis. A decreased plasma level of vWF points to a bleeding disorder.…”

Rodent laparoscopy: Refinement for rodent drug studies and model development, and monitoring of neoplastic, inflammatory and metabolic diseases

“…Laparotomy results in significant postoperative immune suppression, due to decreases in lymphocyte count and lymphocyte/macrophage interactions, neutrophil Chemotaxis, natural killer cell activity, alpha-2-macroglobulin release and delayed hypersensitivity responses. 77–82 This immune suppression compromises the rodent's defences at the time, when the risk for introducing pathogens is maximal and can lead to increased morbidity and mortality. This effect can last up to nine days after surgery, and is a specifically important confounding variable in cancer models, as immune suppression may effect tumour cell proliferation and engraftment rates.…”