α2-Macroglobulin-Rich Serum As a Master Inhibitor of Inflammatory Factors Attenuates Cartilage Degeneration in a Mini Pig Model of Osteoarthritis Induced By “Idealized” Anterior Cruciate Ligament Reconstruction

Background: α2-Macroglobulin (α2M) is important for chondral protection in post-traumatic osteoarthritis (PTOA). However, its injection into xenogeneic joint cavities has safety hazards, limiting clinical applications. Exploring serum α2M-enriching strategies and the therapeutic effect and mechanism of α2M-rich serum (α2MRS) autologous joint injection to treat PTOA has significant value.Methods: A unique filtration process was used to concentrate α2M from serum. Human osteoarthritic chondrocytes induced with interleukin (IL)-1β were used to evaluate catabolic enzymes, cell proliferation, apoptosis, and gene expression 24h after α2MRS treatment. Eighteen mature female mini pigs were randomized to three groups, sham (n = 6), “idealized” anterior cruciate ligament autograft reconstruction (IACL-R) (n = 6), and IACL-R+α2MRS (n = 6). Expression of inflammatory factors in the synovial fluid (SF) was measured using Luminex assays. Gait features were recorded using the Tekscan Walkway system. The extent of PTOA progression was evaluated using imaging, real-time PCR , and histology 3 months post-surgery.Results: The α2M concentration in α2MRS was higher than that in human and mini pig serum, respectively. In vitro, α2MRS significantly promoted human chondrocyte proliferation (p < 0.001) and reduced apoptosis (p < 0.001) and chondrocyte catabolic cytokine gene transcription (p < 0.001) and secretion (p < 0.001). In vivo, SF concentrations of all tested inflammatory factors were significantly lower in the IACL-R+α2MRS group than in the IACL-R group (p < 0.001). All gait parameters in the IACL-R+α2MRS group returned to normal significantly early compared to those in the IACL-R group (p < 0.05). Imaging , histology, and biochemistry data showed that cartilage degeneration in the IACL-R+α2MRS group was significantly diminished relative to that in the IACL-R group (p < 0.001).Conclusion: Injecting α2MRS into the joint cavity after IACL-R can significantly delay articular cartilage degeneration.

May be Urinary Excretion of α2-macroglobulin (MW 720 kDa) a Proteinuric Marker of Podocytopathy? Insight from Analysis of 204 Patients with Glomerulonephritis (GN) and Nephrotic Syndrome, 177 with Functional Outcome

Background: In IgAN with cellular crescents (CIgAN) urinary excretion of α2-macroglobulin (α2m/C, MW 720 kDa) may be a marker of podocytes damage induced by crescents. The purpose of the study was the evaluation of the clinical significance of α2m/C excretion in 177 patients with glomerulonephritis (GN), nephrotic syndrome (NS) and functional outcome. Methods: In all 177 patients α2m/C excretion was measured; the patients were divided in 2 groups: α2mC=0 (n. 72) and α2m/C >0 (n. 105); for each group were assessed the outcomes considered in combination: Remission & persistent nephrotic syndrome (PNS) with long lasting NRF designed “Remission & NRF”; ESRD & eGFR < 50% & PNS with CRF designed “Progression and progression risk”. Results: In 72 patients with α2m/C=0 “Remission & NRF” was 78% and “Progression & progression risk” was 22%; in 105 patients with α2m/C>0 “remission & NRF” was 52% and “Progression & progression risk” was 48%. “Remission & NRF” in each GN type with α2m/C=0 was: 100% in MCD and LN; 82%, 79%, 67% in FSGS, IMN, MPGN; in α2m/C>0 “Progression and progression risk” was 0%, 38%, 46%, 54%, 56%, 85% in MCD, LN, IMN, MPGN, FSGS, CIgAN with cellular crescents, respectively. Conclusion: Urinary excretion of α2m is a very simple marker available in all clinical practice laboratories, marker of damage of podocytes at least in CIgAN and LN with crescents and marker of GFB damage in different GN types and useful to predict outcome and treatment responsiveness.

Indomethacin Disrupts the Formation of β-Amyloid Plaques via an α2-Macroglobulin-Activating lrp1-Dependent Mechanism

Epidemiological studies have implied that the nonsteroidal anti-inflammatory drug (NSAID) indomethacin slows the development and progression of Alzheimer’s disease (AD). However, the underlying mechanisms are notably understudied. Using a chimeric mouse/human amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) (APP/PS1) expressing transgenic (Tg) mice and neuroblastoma (N) 2a cells as in vivo and in vitro models, we revealed the mechanisms of indomethacin in ameliorating the cognitive decline of AD. By screening AD-associated genes, we observed that a marked increase in the expression of α2-macroglobulin (A2M) was markedly induced after treatment with indomethacin. Mechanistically, upregulation of A2M was caused by the inhibition of cyclooxygenase-2 (COX-2) and lipocalin-type prostaglandin D synthase (L-PGDS), which are responsible for the synthesis of prostaglandin (PG)H2 and PGD2, respectively. The reduction in PGD2 levels induced by indomethacin alleviated the suppression of A2M expression through a PGD2 receptor 2 (CRTH2)-dependent mechanism. Highly activated A2M not only disrupted the production and aggregation of β-amyloid protein (Aβ) but also induced Aβ efflux from the brain. More interestingly, indomethacin decreased the degradation of the A2M receptor, low-density lipoprotein receptor-related protein 1 (LRP1), which facilitated the brain efflux of Aβ. Through the aforementioned mechanisms, indomethacin ameliorated cognitive decline in APP/PS1 Tg mice by decreasing Aβ production and clearing Aβ from the brains of AD mice.

Proteomic characterisation of serum proteins from Atlantic salmon (Salmo salar L.) from an outbreak with Cardiomyopathy Syndrome

Cardiomyopathy syndrome (CMS), caused by piscine myocarditis virus (PMCV), is a serious challenge to Atlantic salmon (Salmo salar L.) aquaculture. Regrettably, husbandry techniques are the only tool to manage CMS outbreaks, and no prophylactic measures are available at present. Early diagnosis of CMS is therefore desirable, preferably with non-lethal diagnostic methods, such as serum biomarkers. To identify candidate biomarkers for CMS, the protein content of pools of sera (4 fish/pool) from salmon a CMS outbreak (3 pools) and from clinically healthy salmon (3 pools) were compared using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Overall, seven proteins were uniquely identified in the sera of clinically healthy fish, while twenty seven proteins were unique to the sera of CMS fish. Of the latter, 24 have been associated with cardiac disease in humans. These were grouped as leakage enzymes (creatine kinase, lactate dehydrogenase, glycogen phosphorylase and carbonic anhydrase); host reaction proteins (acute phase response proteins - haptoglobin, fibrinogen, α2-macroglobulin, ceruloplasmin; and complement-related proteins); and regeneration/remodelling proteins (fibronectin, lumican and retinol). Clinical evaluation of the suitability of these proteins as biomarkers of CMS, either individually or as part of a panel, is a logical next step for the development of early diagnostic tools for CMS.

Proteomic characterisation of serum proteins from Atlantic salmon (Salmo salar L.) from an outbreak with Cardiomyopathy Syndrome

Cardiomyopathy syndrome (CMS), caused by piscine myocarditis virus (PMCV), is a serious challenge to Atlantic salmon (Salmo salar L.) aquaculture. Regrettably, husbandry techniques are the only tool to manage CMS outbreaks, and no prophylactic measures are available at present. Early diagnosis of CMS is therefore desirable, preferably with non-lethal diagnostic methods, such as serum biomarkers. To identify candidate biomarkers for CMS, the protein content of pools of sera (4 fish/pool) from salmon a CMS outbreak (3 pools) and from clinically healthy salmon (3 pools) were compared using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Overall, seven proteins were uniquely identified in the sera of clinically healthy fish, while twenty seven proteins were unique to the sera of CMS fish. Of the latter, 24 have been associated with cardiac disease in humans. These were grouped as leakage enzymes (creatine kinase, lactate dehydrogenase, glycogen phosphorylase and carbonic anhydrase); host reaction proteins (acute phase response proteins - haptoglobin, fibrinogen, α2-macroglobulin, ceruloplasmin; and complement-related proteins); and regeneration/remodelling proteins (fibronectin, lumican and retinol). Clinical evaluation of the suitability of these proteins as biomarkers of CMS, either individually or as part of a panel, is a logical next step for the development of early diagnostic tools for CMS.

Proteomic characterisation of serum proteins from Atlantic salmon (Salmo salar L.) from an outbreak with Cardiomyopathy Syndrome

Cardiomyopathy syndrome (CMS), caused by piscine myocarditis virus (PMCV), is a serious challenge to Atlantic salmon (Salmo salar L.) aquaculture. Regrettably, husbandry techniques are the only tool to manage CMS outbreaks, and no prophylactic measures are available at present. Early diagnosis of CMS is therefore desirable, preferably with non-lethal diagnostic methods, such as serum biomarkers. To identify candidate biomarkers for CMS, the protein content of pools of sera (4 fish/pool) from salmon a CMS outbreak (3 pools) and from clinically healthy salmon (3 pools) were compared using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Overall, seven proteins were uniquely identified in the sera of clinically healthy fish, while twenty seven proteins were unique to the sera of CMS fish. Of the latter, 24 have been associated with cardiac disease in humans. These were grouped as leakage enzymes (creatine kinase, lactate dehydrogenase, glycogen phosphorylase and carbonic anhydrase); host reaction proteins (acute phase response proteins - haptoglobin, fibrinogen, α2-macroglobulin, ceruloplasmin; and complement-related proteins); and regeneration/remodelling proteins (fibronectin, lumican and retinol). Clinical evaluation of the suitability of these proteins as biomarkers of CMS, either individually or as part of a panel, is a logical next step for the development of early diagnostic tools for CMS.