Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bone is an active tissue constantly being remodeled and changing metabolically through the balanced activity of osteoclasts, osteoblasts and osteocytes. Recent data have revealed the role of immune system to regulate bone cells and participate in the pathogenesis of several bone disorders. The RANK/RANKL/OPG system and the Wnt signaling are crucial pathways for the differentiation and function of osteoclasts and osteoblasts. Osteopenia and osteoporosis represent painful complications of thalassemia. Several factors that are responsible for bone loss in thalassemia act through the activation of osteoclasts and/or the inhibition of osteoblasts. Alterations in the RANKL/OPG ratio and increased serum levels of Wnt antagonists are present in thalassemic patients with osteoporosis. This review summarizes all available data for the interactions between bone and immune cells and their possible implications for the pathogenesis of bone loss in thalassemia. Through the understanding of the molecular pathways that are responsible for bone destruction in these patients we will be able to produce novel agents targeting these pathways and thus improve the management of osteoporosis in thalassemia.
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PMID:Interactions between osteoclasts, osteoblasts and immune cells: implications for the pathogenesis of bone loss in thalassemia. 1933 62

Bone disease (BDT) represents a prominent cause of morbidity in patients of both sexes with thalassaemia major (TM). The exact pathogenesis of BDT in TM is multifactorial, still unclear and complicated. Peak bone mass is achieved shortly after completion of puberty and normally remains stable until the third decade of life. After the age of 30 years, age related bone loss begins. Growth hormone (GH) and sex steroids have a crucial role in bone remodelling and therefore are important in helping to establish and maintain peak bone mass for both sexes. The anabolic effects of GH and IGF-1 in bone are important not only for the acquisition of bone mass during adolescence but also for the maintenance of skeletal architecture during adult life. GH deficiency is not a rare finding in adult patients with TM, thus contributing to the development of BDT. Furthermore, patients with TM are often hypogonadal, and therefore the lack of sex steroids in critical periods, such as puberty, contributes to the failure to achieve optimal peak bone mass and to maintain bone mass later in life. Sex steroids probably act by increasing the expression of RANKL by osteoblastic cells, and alterations in the RANK/RANKL/OPG system in favour of osteoclasts are characteristic in TM, where the ratio of sRANKL/OPG is increased. It is still not clear whether DEXA scan is the gold standard for determination of bone density in thalassaemics and if so, whether the WHO criteria for defining osteopenia and osteoporosis are relevant to patients with TM. The question therefore arises whether other methods should be adopted, since DEXA may often overestimate BDT in these patients. BDT in thalassaemia represents a unique clinical entity with a multifactorial aetiology and of complex mechanisms which need to be clarified. It is essential for us to understand the underlying mechanisms of bone destruction and the bony defect at the ultrastructural level in order to be able to design not only preventive strategies but also therapeutic measures.
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PMID:Hormonal dysregulation and bones in thalassaemia--an overview. 1933 63

Osteoporosis in thalassaemia major (TM) represents a prominent cause of morbidity. The mechanism of pathogenesis of bone disease (BD) in TM is multifactorial and complicated. Peak bone mass is achieved shortly after completion of puberty and normally remains stable until the third decade of life when age-related bone mass begins. Growth hormone (GH) and sex steroids play a crucial role in bone remodeling and in the maintenance of skeletal architecture during adult life. GH and insulin growth factors (IGFs) have anabolic effect in bone formation. Sex steroids act probably by increasing the expression of RANKL by osteoblastic cells and alterations in the RANK/RANKL/OPG system in favor of osteoclasts. Impaired GH secretion and lack of sex steroids in thalassemic patients due to pituitary damage, contribute to failure of achieving optimal peak bone mass. Other endocrine complications such as hypoparathyroidism and vitamin D deficiency have also a detrimental role on bones in TM. It is still questionable whether the international criteria for defining osteopenia and osteoporosis are relevant to patients with TM; also a question arises for the diagnostic methods such as DEXA scan and management of osteoporosis with known treatment protocols, in the thalassaemic patient.
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PMID:Osteoporosis syndrome in thalassaemia major: an overview. 2097 89

Bone is a dynamic organ, constantly changing metabolically and being remodelled through the balanced activity of osteoclast and osteoblast on trabecular surfaces. Osteoporosis represents a continuum, in which multiple pathogenic mechanisms converge to cause loss of bone mass and deterioration of microarchitecture of skeletal structure. In thalassaemia major (TM), progressive 'aging' of bone starts in early childhood, through the gradual development of an imbalance between augmented osteoclastic resorption and insufficient osteoblastic bone formation. Chronic anemia, iron toxicity and endocrine complications, via a complex mechanism, lead to alterations in the RANK/RANKL/OPG system in favor of increased osteoclastic activity and enhanced osteoblastic dysfunction. Hypogonadotrophic hypogonadism and delayed puberty are the most common endocrine complications in patients with TM; they also contribute to osteopenia and osteoporosis, which is present in more than 50% of patients. There are gender differences not only in the prevalence but also in the severity of the osteoporosis syndrome. The anabolic effects of GH and IGF-1 on bone formation are important for the acquisition of bone mass, mainly during childhood and puberty. In TM, GH secretory dysfunction is common and contributes to osteopenia and osteoporosis, along with other endocrinopathies such as hypoparathyroidism and vitamin D deficiency, hypothyroidism and diabetes. Prevention is with no doubt the first step in the management of osteoporosis in TM, with the final goal of preventing bone loss and fractures. The management of patients with TM should start as early as birth in order to minimize the disease complications. Induction of puberty at a proper age with estrogens in girls and testosterone in boys and later treatment of hypogonadism with HRT are vital steps in the prevention of bone disease in TM. Biphosphonates, the well known medication for osteoporosis, have been tried in the treatment of TM-osteoporosis with promising outcomes. Since the origin of bone disease in TM is multifactorial and some of the underlying pathogenic mechanisms are still unclear, further research in this field is needed, which will allow the design of optimal therapeutic measures.
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PMID:Bone disease in thalassaemia major: recent advances in pathogenesis and clinical aspects. 2170 82

We report two cases of beta-thalassemia-induced osteoporosis. A man and a woman presented an osteoporosis at the densitometry and were treated with bisphoshonate iv. All the studies analysed the efficacity of bisphosphonate, in particular zoledronate seems to be effective. Concerning the pathogenesis, the RANK-RANK-Ligand and OPG play a major role in bone-resorption and seem to be the principal implicated mechanism for the development of osteoporosis in BTM. At the moment there is no study evaluating the efficacity of denosumab in the BTM.
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PMID:[Should we treat thalassemia-induced osteoporosis: two case reports]. 2303 99