الفهرس 
Hematopoietic Growth FactorsOnly 14 pages are availabe for public view
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Abstract
HGFs are a group of acidic glycoproteins that could be classified into three main groups: HGFs that support specific lineage e.g. EPO that stimulates clonal growth of CFU-E which explains that disorders affecting EPO production or signaling leading to either increase or decrease in red blood cell production, HGFs with an effect on multipotential hematopoietic cells e.g. IL-3 that stimulates growth of primitive hematopoietic cell lines with multilineage potential thereby, recombinant IL-3 has been used in various clinical trials to speed hematopoietic recovery following cytotoxic chemotherapy and HGFs that regulate hematopoiesis indirectly by inducing expression of direct-acting growth factor genes in auxiliary cells, e.g. IL-1 that induces expression of GM-CSF and G-CSF.
HGFs bind to specific cell surface receptors that trigger receptor conformational changes which in turn transmit biochemical signals via signal transduction cascade for cell survival, proliferation, differentiation and/or activation.
Signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another, most often involving ordered sequences of biochemical reactions inside the cell, that are carried out by enzymes and activated by second messengers.
HGFs act via different types of receptors including hematopoietic cytokine receptors, TNF receptor superfamily, RTKs, GPCR and TGF-β receptors and start transduction cascade.
A transduction cascade generates precise and appropriate responses. These responses may include alterations in cell motility or division, induction of the expression of specific genes, and the regulation of apoptosis.
Several mechanisms have been identified to extinguishing stimuli, including; receptor down-modulation, phosphatases, SOCS, inhibitory signals.
There are four general hematological indications for the administration of a HGF; including correction of cytopenia due to deficiency in the growth factor e.g. EPO in anemia of chronic renal failure, IL-3 in neutropenia, TPO mimics in immune thrombocytopenic purpra, stimulation of the recovery of hematopoietic stem and progenitor cells e.g. G-CSF for bone marrow transplantation, augmentation of hematopoiesis to compensate for pathologically rapid blood cell destruction, and activation of mature hematopoietic cells.
Moreover, most of HGFs exhibit extrahematopoietic functions that direct studies upon them for further clinical applications e.g. use of EPO in reduction of renal dysfunction, G-CSF in myocardial regeneration following cardiac infarction, most of interleukines or their monoclonal antibodies act as antiinflammatory agents e.g IL-4 antagonist, monoclonal antibodies against IL-5, anti-IL-9 and monoclonal antibodies against TNFα in treatment of asthma. Furthermore, IL-11 is considered to be a promising drug candidate for treatment of IBD together with IL-12 proved an antitumor activity.
Finally , we concluded from this essay that EPO , G-CSF , TPO mimics , IL-3 , IL-11 and TNF-α are approved to be used clinically while others till under trial .