Lycopene is a potent carotenoid antioxidant shown to decrease the risk of chronic diseases associated with oxidative stress and has recently begun to be studied in relation to osteoporosis. However, studies specifically associating intervention with lycopene and a decreased risk for osteoporosis have not yet been conducted, and the mechanisms by which lycopene affects bone have yet to be elucidated. The purpose of this thesis was to explore the hypotheses that supplementation with lycopene would increase antioxidant capacity while decreasing oxidative stress parameters; subsequently decreasing bone turnover markers, and thus the risk of osteoporosis in postmenopausal women. Specifically, experiments were designed to determine whether lycopene acts in its antioxidant capacity to improve bone health, and to delineate the mechanisms of these effects. These hypotheses were investigated through a cross-sectional study, a randomized controlled clinical study, and in vitro studies on human osteoblast cells. The results presented in this thesis demonstrate that intervention with the potent antioxidant lycopene significantly increased concentrations of the 5-cis isomer and resulted in significantly decreased oxidative stress parameters in postmenopausal women. This decrease in oxidative stress parameters resulted in significantly decreased concentrations of the bone resorption marker crosslinked N-telopeptides of type I collagen (NTx). The typical diet of participants included a relatively low intake of lycopene, and the corresponding serum lycopene concentrations were not as effective in decreasing biomarkers of oxidative stress and bone resorption as those obtained from supplementation with lycopene to increase 5-cis serum lycopene. Studies on the paraoxonase enzyme suggest that lycopene is most effective in quenching oxidative stress to decrease bone turnover markers when the internal antioxidant defenses are insufficient or decremented. Mechanisms demonstrated by the in vitro findings suggest that cis lycopene is capable of both preventing and repairing the damaging effects of oxidative stress in osteoblasts. Overall, this thesis provides evidence that lycopene acts through its antioxidant capacity to decrease oxidative stress parameters and bone turnover markers, and may, therefore, reduce the risk for osteoporosis. Based on these findings, the consumption of lycopene by women to improve overall bone health should be considered.

Lycopene is a potent carotenoid antioxidant shown to decrease the risk of chronic diseases associated with oxidative stress and has recently begun to be studied in relation to osteoporosis. However, studies specifically associating intervention with lycopene and a decreased risk for osteoporosis have not yet been conducted, and the mechanisms by which lycopene affects bone have yet to be elucidated. The purpose of this thesis was to explore the hypotheses that supplementation with lycopene would increase antioxidant capacity while decreasing oxidative stress parameters; subsequently decreasing bone turnover markers, and thus the risk of osteoporosis in postmenopausal women. Specifically, experiments were designed to determine whether lycopene acts in its antioxidant capacity to improve bone health, and to delineate the mechanisms of these effects. These hypotheses were investigated through a cross-sectional study, a randomized controlled clinical study, and in vitro studies on human osteoblast cells. The results presented in this thesis demonstrate that intervention with the potent antioxidant lycopene significantly increased concentrations of the 5-cis isomer and resulted in significantly decreased oxidative stress parameters in postmenopausal women. This decrease in oxidative stress parameters resulted in significantly decreased concentrations of the bone resorption marker crosslinked N-telopeptides of type I collagen (NTx). The typical diet of participants included a relatively low intake of lycopene, and the corresponding serum lycopene concentrations were not as effective in decreasing biomarkers of oxidative stress and bone resorption as those obtained from supplementation with lycopene to increase 5-cis serum lycopene. Studies on the paraoxonase enzyme suggest that lycopene is most effective in quenching oxidative stress to decrease bone turnover markers when the internal antioxidant defenses are insufficient or decremented. Mechanisms demonstrated by the in vitro findings suggest that cis lycopene is capable of both preventing and repairing the damaging effects of oxidative stress in osteoblasts. Overall, this thesis provides evidence that lycopene acts through its antioxidant capacity to decrease oxidative stress parameters and bone turnover markers, and may, therefore, reduce the risk for osteoporosis. Based on these findings, the consumption of lycopene by women to improve overall bone health should be considered.

Με τον όρο «Έκτοπη Οστεοποίηση» περιγράφεται ο σχηματισμός οστού σε σημεία που υπό φυσιολογικές συνθήκες δεν υφίσταται. Τα σημεία αυτά μπορεί να είναι μύες, τένοντες ή σύνδεσμοι και γενικότερα μεσεγχυματικού τύπου μαλακά μόρια, κυρίως γύρω από τις μεγαλύτερες αρθρώσεις. Η επίκτητη μορφή της νόσου, που είναι και η πιο κοινή, εμφανίζεται μετά από μυοσκελετικούς τραυματισμούς, κακώσεις του νωτιαίου μυελού και του κεντρικού νευρικού συστήματος γενικότερα, αλλά και σε περιπτώσεις σοβαρών εγκαυμάτων. Η παθοφυσιολογία της έκτοπης οστεοποίησης παραμένει άγνωστη, αυτό που γνωρίζουμε με βεβαιότητα είναι ότι για τον σχηματισμό της απαιτούνται τρείς βασικές προϋποθέσεις που είναι α) τα οστεοπρογονικά κύτταρα, β) οι κατάλληλοι επαγωγικοί παράγοντες και γ) το ευνοϊκό οστεοεπαγωγικό περιβάλλον. Στην παρούσα εργασία με την χρήση κυτταρομετρίας ροής, δοκιμασιών με ηλεκτροχημειοφωταύγεια, Elisa και ανοσοπροσδιορισμού με χρήση Cytometric Bead Array προσδιορίσαμε τις συγκεντρώσεις των total procollagen type 1 amino-terminal propeptide (TP1NP), osteoprotegerin (OPG), β-isomerized C-terminal telopeptides (β- Crosslaps), soluble receptor activator of nuclear factor kappa-B ligand (sRANKL), N-MID osteocalcin, S100 και των κυτταροκινών IL-2, IL-4, IL-6, IL-10, INF-γ και TNF-a στον ορό ασθενών και υγιών μαρτύρων. Επιπλέον, στο ολικό αίμα προσδιορίσαμε τον πληθυσμό των θετικών στην οστεοκαλσίνη κυττάρων. Όλα τα προς μελέτη μόρια είχαν άμεση ή έμμεση σχέση με την οστική ανακατασκευή και τις φλεγμονώδεις αντιδράσεις. Συνολικά μελετήθηκαν 55 ασθενείς από τους οποίους ελήφθησαν δείγματα καθόλη την διάρκεια νοσηλείας τους. Οι ασθενείς μελετήθηκαν με βάση το είδος του τραύματος, την εμφάνιση ή όχι έκτοπης οστεοποίησης και την έκβαση της κατάστασης τους. Επιπλέον, οι επιμέρους ομάδες ασθενών μελετήθηκαν συναρτήσει του χρόνου. Τα αποτελέσματα μας έδειξαν ότι στο σύνολο των ασθενών παρατηρήθηκαν στατιστικά μειωμένα επίπεδα β- crosslaps, N-MID osteocalcin, sRANKL και S100 συγκριτικά με τους υγιείς μάρτυρες. Αντίθετα, τα επίπεδα των TP1NP, των θετικών στην οστεοκαλσίνη κυττάρων, της OPG, της INF-γ και της IL-6 ήταν στατιστικά σημαντικά αυξημένα. Επιπλέον, στατιστικά σημαντικά αυξημένα παρατηρήθηκαν τα επίπεδα του S100 στους ασθενείς που είχαν υποστεί κρανιοεγκεφαλικές κακώσεις κατά το πρώτο εικοσιτετράωρο μετά την επαγωγή της κάκωσης. Στατιστικά σημαντικά αυξημένο επίσης παρατηρήθηκε και στην ομάδα των ασθενών με κακή έκβαση συγκριτικά με τους υγιείς δότες. Στην ίδια ομάδα ασθενών παρατηρήθηκε μια γενικευμένη αύξηση των επιπέδων των κυτταροκινών που φαίνεται να σχετίζεται άμεσα με την κακή έκβαση της κατάστασης τους. Πιο συγκεκριμένα η αύξηση αυτή ήταν στατιστικώς σημαντική για τις IL-4, INF-γ και TNF-α. / Heterotopic ossification (HO) is the presence of bone in soft tissue where normally does not exist. The acquired form, which is also the most common, develops after musculoskeletal trauma, spinal cord injury or central nervous system injury and severe burns. Pathophysiology of OH still remains unclear, what we know is that the formation of ectopic bone requires three entities which are a) osteogenic precursor cells, b) inducing agents and c) an appropriate environment. In the present study using either flow cytometry, Elisa, electrochemiluminescence immunoassays or cytometric bead array assays we determined the concentrations of the osteoblast progenitors: osteocalcin positive cells in peripheral blood and the serum concentrations of total procollagen type 1 amino-terminal propeptide (TP1NP), osteoprotegerin (OPG), β-isomerized C-terminal telopeptides (β- Crosslaps), soluble receptor activator of nuclear factor kappa-B ligand (sRANKL), N-MID osteocalcin, S100 and the cytokines IL-2, IL-4, IL-6, IL-10, INF-γ and TNF-a. All measured molecules participate directly or indirectly in bone formation and metabolism and in inflammation. Our 55 patients were divided and studied in 3 different ways, regarding the kind of their injury, their outcome and the formation of HO. They were also monitored in course of time. Among our most interesting results is that patients had significantly lower levels of β- crosslaps, N-MID osteocalcin, sRANKL and S100 compared to healthy donors. On the other hand, levels of TP1NP, osteocalcin positive cells, OPG, INF-γ and IL-6 were significantly higher. S100 is significantly increased during the first 24 hours in patients who have sustained traumatic brain injury. In addition, S100 was significantly increased in patients with poor outcome compared to healthy donors. Furthermore, patients with poor outcome seem to develop a cytokine storm which is of great importance for their outcome. All measured cytokine levels were increased compared to patients with good outcome. Especially for IL-4, INF-γ, TNF-α this increase was statistically significant.