Armine Grigoryan

Osteoporosis is a multifactorial disease which affects the skeleton and is characterized by loss of bone mass, alterations of bone micro-architecture and increased fracture risk. The disease is prevalent among the adult population and in postmenopausal women. The causes of the development of osteoporosis are different. Overall estrogen deficiency is a major factor for the development of osteoporosis. Bone loss after ovariectomy or postmenopausal is associated with increased bone metabolism and rapid degradation of the bone matrix. In the pathogenesis of osteoporosis participate mainly 2 type proteolytic enzymes-cathepsin K and matrix metalloproteinases (MMPs). MMPs are a growing family of endopeptidases with similar functional domeins and mechanism of action related to the degradation of extracellular matrix components (ECM). MMPs are key mediators in the extracellular matrix remodeling, bone growth and osteoclastic bone resorption. Estrogen deficiency contributes to the imbalance i...

Estradiol is an estrogen steroid hormone and is produced basically within the follicles of the ovaries. The decrease in serum estrogens concentration at menopause disrupts the metabolic balance, changes the lipid profile leading to visceral obesity, which caused an increase in serum estradiol levels, through aromatase activity. Estrogen deficiency also is a reason for the development of osteoporosis.We investigated the serum estradiol levels and changes in bone alpha estrogen receptor expression in ovariectomized rats. For this purpose, we used 20 female Wistar rats at reproductive age - 2 months divided into 2 groups: group 1 (G1)-10 animals were ovariectomized and group 2 (G2)-10 of which were sham-operated. All animals of G1 showed weight gain compared to group G2. The results showed that the values of serum 17β-estradiol in rats of G1 statistically increased compared to G2 (p <0.05). Immunohistochemical analysis revealed no difference in estrogen receptor expression between t...

Introduction. Osteoporosis is a disease characterized by decreased bone density and destruction of the microarchitectonics of the bone structure. This leads to increased bone fragility and risk of fracture, particularly of the hip, spine, wrist and shoulder. Osteoporosis is known as "The Silent Epidemic of the Century" because bone loss occurs without symptoms. An altered ovarian function is one of the most common causes of osteoporosis. Indicators for altered bone homeostasis are the changes in serum levels of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Objective. The aim of current study was to determine the activity of alkaline phosphatase (ALP) and serum concentrations of MMP-9, MMP-13 and TIMP-1 in the ovariectomized rats. Materials and Methods. An experiment was performed on 35 female Wistar rats at reproductive age – 2 months divided into 2 groups: group 1 (G1)-20 animals were sham-operated (sham) and group 2 (G2)-15 were ovariectomized (ov...

SummaryOsteoporosis is a systemic skeletal disease characterized by decreased bone mass, destruction of the microarchitectonics of bone structure and a high risk for fracture. One of the criteria for altered bone homeostasis includes the changes in serum levels of alkaline phosphatase (ALP) and the activity of matrix metalloproteinases (MMPs). The purpose of this study was to determine the serum concentrations of calcium (Ca2+), phosphorus (P), magnesium (Mg2+), alkaline phosphatase (ALP) and MMP-9 in ovariectomized rats. We used 35 female Wistar rats at reproductive age (2 months) divided into 2 groups: a control group (G1-SHAM) – 20 animals subjected to “false” ovariectomy and placebo-operation, and an ovariectomized group (G2-OVX) – 15 animals subjected to bilateral ovariectomy. Blood was collected from the abdominal aorta for testing levels of Ca2 +, P, Mg2+, ALP and MMP-9. No statistically significant differences in serum concentrations of Ca2+, P and Mg2+were found between G2 ...