Erythropoiesis- Dr.E. Muralinath-C Kalyan

This presentation provides information on formation of RBC.

1. ERYTHROPOIESIS 2 GENERAL FACTORS ESSENTIAL FOR ERYTHROPOIESIS INCLUDE: 1) ERYTHROPOIETIN 2HEMOPOIETIC GROWTH FACTORS 3THYROXINE 4)VITAMINS

2. GENERAL FACTORS:-   ERYTHROPOIETIN:- The most important general factor for erythropoiesis is the hormone termed as erythropoietin. It is otherwise known as hemopoietin or erythrocyte stimulating factor.   CHJEMISTRY: It is a glycoprotein with 165 amino acids. SOURCE OF SECRERTION: The secretion of major quantity of erythropoietin takes place by capillaries of kidney. It is also secreted in brain and liver also. STIMULANT FOR SECRETION Hypoxia is the stimulant for the secretion of erythroietin. ACTIONS OF ERYTHROIPOITIN Erythroipoietin is helpful regarding formation and release of new RBCs into circulation. After secretion, it takes approximately 4-5 days to exhibit the action. Erythroipoietin enhances the following processes. Production of proerythroblasts from CFU-E of the bone marrow. Conversion of proerythroblasts into matured RBCs via various stages - early normoblast, intermediate normoblast, l;ate normoblast and reticulocyte. Release of matured erythrocytes into blood.. Even a very few reticulocytes ( immature erythrocytes) are released along with matured RBCs. The blood level of erythroipoietin enhances in anemia.

3. 2) HEMOPOIETIC GROWTH FACTORS:- Hemopoietic growth factors or growth inducers are interleukins and stem cell factor. Normally these factors initiate the proliferation of PHSCs. Interleukins ( IL ) are glyco proteins which are linked to the cytokines family. An involvement of the interleukins takes place in erythropoiesis and the names of interleukins include Interleukin - 3 (IL-3) produced by T cells Interleukin 6 (IL -6) produced by T cells, macrophages and endothelial cells. Interleukin 11 (IL-11) produced by osteoblast.

4. 3)THYROXINE:- Thyroxine enhances the process of erythropoiesis at various levels because thyroxine behaves as a general metabolic hormone. That is why, polycythemia is observed in hyper thyroidiam.

5. 4) VITAMINS:- A very few vitamins are essential for the process of erythropoiesis. The deficiencies of these vitamins lead to anemia associated with other types of disorders. The vitamins, which are responsible for the erythropoiesis include   Vitamin B: Its deficiency results in anemia and pellagra ( disease manifested by skin lesions, nervousness, weakness, diarrhea and dementia).   Vitamin C Its deficiency leads to anemia and scurvy ( ancient disease manifested by impaired collagen synthesis leading to rough skin, loosening o0f teeth, bleeding gum, bone pain, poor wound healing, lethargy and emotional changes) c) Vitamin D Its deficiency leads to anemia as well as rickets ( bone disease ) d) Vitamin E Its deficiency results in anemia as well as mal nutrition.

6. MATURATION FACTORS:- - Vitamin B12 , intrinsic factor and folic acid are responsible regarding maturtation of RBCs.   VITAMIN B12 (Cyano cobalamin):- Vitamin B12 is otherwise knon as extrinsic factor since it is derived mostly from diet. Its absorption from intestine needs the presence of intrinsic factor of castle . Vitamin B12 is preserved primarily in liver and in small quantity in muscle. If necessaity arises, the transpoortation of B12 takes place in bone marrow. to enhance maturation of RBCs. B12 is also produced in the large intestine particularly by the intestinal flora. ACTION:- a)Vitamin B12 plays an important role in regarding the synthesis of DNA in RBCs. Is deficiency results in failure regarding maturation of cell and decrement in the cell division. b) Besides, thje cells are larger with fragile and weak cell membrane leading to macro cytic anemia. The deficiency of vitamin B12 leads to pernicious anemia.

7. 2).INTRINSIC FACTOR OF CASTLE:- a)The production of an intrinsic factor of Castle takes place in gastric mucosa particularly by parietal cells. b) It is responsible for absorption of B12 from intestine C)An absorption of intrinsic factor does not happen particularly during the absence of intrinsic factor. This results in Pernicious anemia d)The deficiency of intrinsic factor takes place in Gastrectomy, Severe gastritis and Ulcer. e)The extrinsic and intrinsic factors are together termed as Hematinic Principle which is the maturation factor’

8. 3.)FOLIC ACID:-- Folic acid also plays an important role especially during maturation. It is needed for synthesis for the synthesis of DNA In the deficiency of folic acid , the synthesis of DNA reduces and leading to failure of maturation. This results in anemia in which, the cells are larger and appear in megaloblastic (proerythroblastic) stage. An anemia happens because of the folic acid deficiency abd this condition is termed as megaloblastic anemia.

9. FACTORS ESSENTIAL FOR HEMOGLOBIN FORMATION:- Various materials play an important role regarding the formation of hemoglobin especially in the RBCs. An absence of these materials reduces the production of hemoglobin and results in anemia. Such factors are First class proteins and amino acids:- Proteiins of high biological value are responsible for the formation of hemoglobin. Amino acids derived from these proteins are needed for the synthesis of protein part of hemoglobin, the globin. Cobalt and nickle : These materials are responsible for the utilization of iron especially during hemoglobin formation. Copper:- It plays an important role during the absorption of iron from the gastro intestinal tract (GIT). Iron:- It plays an important role during the formation of heme part of hemoglobin. Vitamins:- Vitamin C, Pyrridoxine and nicotinic acid play an important role during the formation of hemoglobin

10. References 1. Coad J, Pedley K. Iron deficiency and iron deficiency anemia in women. Scand J Clin Lab Invest Suppl. 2014;244:82-9; discussion 89. [ PubMed ] 2. Hunt JR, Zito CA, Johnson LK. Body iron excretion by healthy men and women. Am J Clin Nutr. 2009 Jun;89(6):1792-8. [ PubMed ] 3. Abbaspour N, Hurrell R, Kelishadi R. Review on iron and its importance for human health. J Res Med Sci. 2014 Feb;19(2):164-74. [ PMC free article ] [ PubMed ] 4. von Drygalski A, Adamson JW. Iron metabolism in man. JPEN J Parenter Enteral Nutr. 2013 Sep;37(5):599-606. [ PubMed ] 5. Han O. Molecular mechanism of intestinal iron absorption. Metallomics. 2011 Feb;3(2):103-9. [ PubMed ] 6. Hunt JR, Roughead ZK. Adaptation of iron absorption in men consuming diets with high or low iron bioavailability. Am J Clin Nutr. 2000 Jan;71(1):94-102. [ PubMed ] 7. Hurrell R, Egli I. Iron bioavailability and dietary reference values. Am J Clin Nutr. 2010 May;91(5):1461S-1467S. [ PubMed ]

11. . Carpenter CE, Mahoney AW. Contributions of heme and nonheme iron to human nutrition. Crit Rev Food Sci Nutr. 1992;31(4):333-67. [ PubMed ] 9. Lynch SR, Hurrell RF, Dassenko SA, Cook JD. The effect of dietary proteins on iron bioavailability in man. Adv Exp Med Biol. 1989;249:117-32. [ PubMed ] 10. Björn-Rasmussen E, Hallberg L. Effect of animal proteins on the absorption of food iron in man. Nutr Metab. 1979;23(3):192-202. [ PubMed ] 11. Taylor PG, Mart í nez-Torres C, Romano EL, Layrisse M. The effect of cysteine-containing peptides released during meat digestion on iron absorption in humans. Am J Clin Nutr. 1986 Jan;43(1):68-71. [ PubMed ] 12. Lynch SR, Cook JD. Interaction of vitamin C and iron. Ann N Y Acad Sci. 1980;355:32-44. [ PubMed ] 13. Conrad ME, Schade SG. Ascorbic acid chelates in iron absorption: a role for hydrochloric acid and bile. Gastroenterology. 1968 Jul;55(1):35-45. [ PubMed ] 14. Friel J, Qasem W, Cai C. Iron and the Breastfed Infant. Antioxidants (Basel). 2018 Apr 06;7(4) [ PMC free article ] [ PubMed ] 15. De la Cruz-G ó ngora V, Villalpando S, Shamah-Levy T. Prevalence of anemia and consumption of iron-rich food groups in Mexican children and adolescents: Ensanut MC 2016. Salud Publica Mex. 2018 May-Jun;60(3):291-300. [ PubMed ]