Traumatic brain injury (TBI) has become an increasingly unmet clinical need due to intense military conflicts worldwide. Directly impacted brain cells suffer massive death, with neighboring cells succumbing to progressive neurodegeneration accompanied by inflammatory and other secondary cell death events. Subsequent neurodegenerative events may extend to normal areas beyond the core of injury, thereby exacerbating the central nervous system’s inflammatory response to TBI. Recently CD-36 (cluster of differentiation 36/fatty acid translocase (FAT), a class B scavenger receptor of modified low-density lipoproteins (mLDLs) in macrophages, has been implicated in lipid metabolism, atherosclerosis, oxidative stress, and tissue injury in cerebral ischemia, and in certain neurodegenerative diseases. Accordingly, we proposed that CD-36 has a pivotal role in the neuroinflammatory cascade that further contributes to the pathology of TBI. First, we explored the neuroinflammatory role of CD-36 after acute and chronic stages of TBI. Second, we employed a neuroinflammatory model to test the therapeutic effect of the soluble receptor of advanced end-glycation product (sRAGE); previously shown to abrogate increased CD-36 expression in stroke. Third, we further examined ameliorating TBI related inflammation as a therapeutic pathway by combination of stem cell therapy and sRAGE. At acute stages of TBI, we observed brain co-localization of CD-36, monocyte chemoattractant protein 1 (MCP-1) and ionized calcium-binding adapter molecule 1 (Iba-1) on impacted cortical areas, significant increases of CD-36 and MCP-1 positive cells in the ipsilateral vs. contralateral hemispheres of TBI animals in acute, but no significant increases of Iba-1 expressing cells over time. In early acute stages of TBI immunoblotting showed overexpression of CD-36 in brain cortex when comparing ipsilateral and contralateral hemispheres vs. sham. Spleen CD-36 protein expression at acute post-TBI stages showed no significant difference between TBI and sham groups. In addition, immunohistochemistry revealed minimal CD-36 detection on the cortical area of impact on our chronic group. Spleen immunohistochemistry also showed co-localization of CD-36 and MCP-1 in the red pulp of spleen in acute stages of TBI animals when compared to sham. Ongoing ischemic and hyperlipidemic rodent models suggest that infiltrating monocytes/macrophages from the periphery are the major source of CD-36 in the post-ischemic brain. Likewise, CD-36 expressing monocytes in the spleen after TBI may suggest its role in peripheral immune response, which may exacerbates the inflammatory response after TBI. Therefore, CD-36 may play a key role as a pathological link between inflammation and TBI. Our results suggest an intimate involvement of CD-36 mediated inflammation in TBI, providing novel insights into the understanding of disease neuroinflammation and as a potent therapeutic target for TBI treatment. The critical timing (i.e., 24-48 hours) of CD-36 expression (from downregulation to upregulation) may signal the transition of functional effects of this immune response from pro-survival to cell death. This observed dynamic CD-36 expression also suggests the therapeutic window for TBI. The detection of CD-36 expression in brain areas proximal, as well as distal, to the site of impacted injury suggests its role in both acute and progressive evolution of TBI. CD-36 neuroinflammatory role has clinical relevance for treating patients who have suffered any TBI condition at acute and chronic stages.

Arterial system is a system of vessels distributing blood. Ageing of arterial system leads to two distinct pathologies: atherosclerosis and arteriosclerosis - stiffening of arterial wall. These pathologies can coexist and interfere; however, they differ in their pathogenesis, location, scope and consequences. Progressive loss of elastic properties of large arteries is natural part of vascular ageing. It is directly responsible for several age dependent consequences, such as increase of central systolic pressure or prevalence of isolated systolic hypertension in the elderly. Clinically, central arteries stiffness manifests as aortic pulse wave velocity, which can be quantified, among other methods, using applanation tonometry. There is abundant evidence that aortic pulse wave velocity represents an independent predictor of cardiovascular mortality and morbidity. The most important mechanism in arterial stiffening is repeated mechanical damage which leads to fractures, fragmentation and thinning of elastin. Stiffening of large arteries can be accelerated by several other mechanisms, e.g. deposition of several substances (calcium, advanced glycation end-products, etc.), metabolic turnover of key elements of vascular extracellular matrix (collagen and elastin) or individual genetic susceptibility. In...

Humans have two plasminogen activators (PAs), tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), which generate plasmin to breakdown fibrin and other barriers to cell migration. Both PAs are used as pharmaceuticals but their efficacies are limited by their rapid clearance from the circulation, predominantly by parenchymal cells of the liver. At the commencement of the work presented here, the hepatic receptors responsible for mediating the catabolism of the PAs were little understood. tPA degradation by hepatic cell lines was known to depend on the formation of binary complexes with the major PA inhibitor, plasminogen activator inhibitor type-1 (PAI-1). Initial studies presented here established that uPA was catabolised in a fashion similar to tPA by the hepatoma cell line, HepG2. Other laboratories around this time found that the major receptor mediating the binding and endocytosis of the PAs is Low Density Lipoprotein Receptor-related Protein (LRP1). LRP1 is a giant 600 kDa protein that binds a range of structurally and functionally diverse ligands including, activated α2 macroglobulin, apolipoproteins, β amyloid precursor protein, and a number of serpin-enzymes complexes, including PA??PAI-1 complexes. Further studies for the work presented here centred on this receptor. By using radiolabelled binding assays, ligand blots, and Western blots on cultured cells, the major findings are that: (1) basal LRP1 expression on HepG2 is low compared to a clone termed, HepG2a16, but appears to increase in long term culture; (2) a soluble form of LRP1, which retains ligand-binding capacity, is present in human circulation; (3) soluble LRP1 is also present in cerebral spinal fluid where its role in neurological disorders such as Alzheimer??s disease is a developing area of interest; and (4) the release of LRP1 is a mechanism conserved in evolution, possibly as distantly as molluscs. The discovery, identification, and characterisation of soluble LRP1 introduces this protein in the human circulation, and presents a possible further level of regulation for its associated receptor system.

Τα τελικά προϊόντα προχωρημένης γλυκοζυλίωσης (AGEs: Advanced Glycation Endproducts) παίζουν σημαντικό ρόλο στην παθογένεια των διαβητικών αγγειακών επιπλοκών. Το καλύτερα χαρακτηριζόμενο είναι η N-καρβοξυμεθυλ-λυσίνη (CML). Τα AGEs προκαλούν σημαντικές επιδράσεις στα αγγεία με την πρόσδεσή τους σε ειδικούς υποδοχείς της κυτταρικής επιφάνειας, όπως τον RAGE (Receptor for Advanced Glycation Endproducts). Διαλυτές μορφές του RAGE (sRAGE) εμφανίζονται στο ανθρώπινο αίμα και δρουν ως παγίδα αιχμαλωτίζοντας τους φλεγμονώδεις προσδέτες του RAGE εξωκυττάρια, προστατεύοντας με αυτό τον τρόπο τα κύτταρα από τη βλάβη που προάγεται από τα AGEs. Σκοπός αυτής της εργασίας ήταν να μελετηθούν τα επίπεδα του sRAGE, η πρωτεϊνική έκφραση του RAGE, καθώς και τα επίπεδα CML σε σχέση με διάφορες κλινικές και βιοχημικές παραμέτρους σε παιδιά, εφήβους και νεαρούς ενήλικες με ΣΔ1. Τα επίπεδα sRAGE και CML προσδιορίστηκαν με ELISA και η πρωτεϊνική έκφραση του RAGE στα μονοπύρηνα του περιφερικού αίματος με ανοσοαποτύπωση κατά Western σε 74 παιδιά, εφήβους και νεαρούς ενήλικες με ΣΔ1 (13± 4 χρονών) και 43 μάρτυρες αντίστοιχης ηλικίας, φύλου και σταδίου Tanner. Σ’ αυτή την εργασία τα αυξημένα επίπεδα sRAGE στα παιδιά με ΣΔ1 και πιο ειδικά, σ’ αυτά ηλικίας κάτω από 13 ετών και με διάρκεια διαβήτη κάτω από 5 έτη, μπορεί να είναι ένα προσωρινό προστατευτικό μέτρο ενάντια στην κυτταρική βλάβη και πιθανόν να είναι επαρκές για να εξουδετερώσει επαρκώς τα κυκλοφορούντα CML, εμποδίζοντας έτσι τις διαβητικές αγγειακές επιπλοκές. Επίσης, μια ήπια αύξηση της LDL θα μπορούσε να είναι ένα ερέθισμα για την αύξηση του sRAGE, οδηγώντας στη δέσμευση του CML και τελικά τη μείωση των επιπέδων CML στην κυκλοφορία. Τα μειωμένα επίπεδα της πρωτεϊνικής έκφρασης του RAGE 55 kd (υποδοχέα πλήρους μήκους) μπορεί να αντανακλούν την αυξημένη έκφραση του sRAGE στους ασθενείς με ΣΔ1 συνολικά λόγω της αποκοπής του RAGE με μεταλλοπρωτεϊνάσες. Με την παρουσία κάποιου παράγοντα κινδύνου, όπως αύξηση ηλικίας, περιμέτρου κοιλίας, BMI, συστολικής ή διαστολικής αρτηριακής πίεσης ή επιδείνωση λιπιδαιμικού προφίλ αυξάνεται η πρωτεϊνική έκφραση της ισομορφής αυτής, ενώ φαίνεται αντίστοιχα να μειώνονται τα επίπεδα του sRAGE. Φαίνεται τελικά ότι συνολικά στα παιδιά, τους εφήβους και τους νεαρούς ενήλικες με ΣΔ1 υπάρχει μια υποκλινική διαταραχή του άξονα sRAGE-RAGE-CML, η οποία δύναται να μετατραπεί σε κλινικά εμφανείς αγγειακές βλάβες, αν προστεθούν περαιτέρω επιβαρυντικοί παράγοντες. / The binding of Advanced Glycation Endproducts (AGEs) to their receptor (RAGE) plays a major role in the development of diabetic vascular complications. This work is based on the relation between circulating soluble RAGE (sRAGE) levels in children, adolescents and young adults with IDDM and RAGE protein expression in association with N-(carboxymethyl)lysine (CML), a major antigenic AGEs component. Circulating sRAGE and CML levels were determined by ELISA and RAGE protein expression was evaluated in peripheral blood mononuclear cells by western immunoblotting in 74 children, adolescents and young adults with IDDM (134 years old) and 43 age, sex and Tanner stage-matched controls. Serum sRAGE levels were significantly higher in IDDM than in controls, inversely correlated to diabetes duration and directly correlated to LDL levels. Furthermore, circulating CML levels were not significantly different between IDDM and controls. Also, the protein expression of the RAGE isoforms 55 kd (full-length), 64 kd and 100 kd, measured by western immunoblotting, was significantly lower in IDDM than in controls, whereas RAGE 37 kd levels were not significantly different between IDDM and controls. Finally, when there was a risk factor, such as increased age, poor lipid profile, increased BMI or waist circumference or increased systolic or diastolic pressure, then it seemed that isoforms RAGE 55, 64 and 100 kd were increased. Isoform RAGE 64 kd could be RAGE-v5, a splice variant which resulted in a change of amino acid sequence in the extracellular ligand-binding domain of RAGE. Isoform RAGE 37 kd seemed to be Δ8-RAGE, a soluble splice variant with probably protective function, which had been found increased in patients with increased HDL. Finally, isoform RAGE 100 kd seemed to be some other splice variant in peripheral mononuclear cells. In conclusion, increased serum levels of sRAGE seen in IDDM children may be a temporary protective measure against cell damage and may be sufficient to efficiently eliminate excessive circulating CML. Moreover, the lower protein expression of the full-length RAGE in IDDM may also reflect the increased sRAGE expression in patients due to RAGE cleavage by metalloproteases. Consequently, in IDDM children, adolescents and young adults there may be a subclinical perturbation of the sRAGE-RAGE-CML axis, which could lead to future clinical vascular damage if additional risk factors are added over time.

Aims: 1. Determination of AGEs (Advanced Glycation End products) in patients with various types of nephropathy. 2. Association AGEs with nutritional parameters and anemia. 3. Influence of renal parameters on sRAGE (soluble form of Receptor for Advanced Glycation End products) levels. 4. Technics and proceeding methods of the podocytes cultivation. 5. Determination of urine podocytes. Methods: We determined fluorescent AGEs by spectrofluorometry, sRAGE by Enzyme-Linked ImmunoSorbent Assay (ELISA). Podocytes were passaged and identified immunocytochemically. Podocytes in urine were specified by flow cytometry method. Results: 1. We did not find significant differences in AGEs serum levels among various types of nephropathy, even though the pathogenesis differs. 2. The albumin and prealbumin levels positively and haemoglobin levels negatively correlate with AGEs in patients with CKD grade 1-5, without necessity of dialysis. 3. Serum sRAGE levels are increased in patients with decreased renal function independently on the course of renal disease. 4. We implemented the methods and technics of podocyte cultivation. 5. Urine podocytes observation and confirmation that podocyturia relates to disease activity. Conclusion: We confirmed that AGEs serum levels depend more on renal function than the type of...

Aims: 1. Determination of AGEs (Advanced Glycation End products) in patients with various types of nephropathy. 2. Association AGEs with nutritional parameters and anemia. 3. Influence of renal parameters on sRAGE (soluble form of Receptor for Advanced Glycation End products) levels. 4. Technics and proceeding methods of the podocytes cultivation. 5. Determination of urine podocytes. Methods: We determined fluorescent AGEs by spectrofluorometry, sRAGE by Enzyme-Linked ImmunoSorbent Assay (ELISA). Podocytes were passaged and identified immunocytochemically. Podocytes in urine were specified by flow cytometry method. Results: 1. We did not find significant differences in AGEs serum levels among various types of nephropathy, even though the pathogenesis differs. 2. The albumin and prealbumin levels positively and haemoglobin levels negatively correlate with AGEs in patients with CKD grade 1-5, without necessity of dialysis. 3. Serum sRAGE levels are increased in patients with decreased renal function independently on the course of renal disease. 4. We implemented the methods and technics of podocyte cultivation. 5. Urine podocytes observation and confirmation that podocyturia relates to disease activity. Conclusion: We confirmed that AGEs serum levels depend more on renal function than the type of...

Chronic kidney disease (CKD) and acute kidney injury (AKI) are major public health problems. It is important to be able to identify those at high risk of adverse outcome, CKD progression and associated cardiovascular disease. The aim of the thesis was to study novel promising biomarkers, their relationship to kidney function, chronic inflammation and/or cardiovascular risk - placental growth factor (PlGF), pregnancy associated plasma protein A (PAPP-A), matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), soluble receptor for advanced glycation end products (sRAGE), calcium binding protein S100A12 or extracellular newly identified RAGE binding protein (EN-RAGE), and high mobility group box protein-1 (HMGB-1) in patients with renal diseases including CKD, haemodialysis (HD), AKI patients, and healthy controls for comparison. First study revealed that PlGF is elevated in patients with decreased renal function. Second study demonstrated the association of MMP-2 and PAPP-A with proteinuria in patients with CKD. Moreover, serum MMP-2, MMP-9 and PAPP-A levels significantly differed in patients with various nephropathies. EN-RAGE levels are not elevated in patients with CKD, but are related to inflammatory status. PAPP-A, EN-RAGE and HMGB-1 levels are significantly elevated, but sRAGE and PlGF...

Chronic kidney disease (CKD) and acute kidney injury (AKI) are major public health problems. It is important to be able to identify those at high risk of adverse outcome, CKD progression and associated cardiovascular disease. The aim of the thesis was to study novel promising biomarkers, their relationship to kidney function, chronic inflammation and/or cardiovascular risk - placental growth factor (PlGF), pregnancy associated plasma protein A (PAPP-A), matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), soluble receptor for advanced glycation end products (sRAGE), calcium binding protein S100A12 or extracellular newly identified RAGE binding protein (EN-RAGE), and high mobility group box protein-1 (HMGB-1) in patients with renal diseases including CKD, haemodialysis (HD), AKI patients, and healthy controls for comparison. First study revealed that PlGF is elevated in patients with decreased renal function. Second study demonstrated the association of MMP-2 and PAPP-A with proteinuria in patients with CKD. Moreover, serum MMP-2, MMP-9 and PAPP-A levels significantly differed in patients with various nephropathies. EN-RAGE levels are not elevated in patients with CKD, but are related to inflammatory status. PAPP-A, EN-RAGE and HMGB-1 levels are significantly elevated, but sRAGE and PlGF...