Marrow Hyperplasia and Hemoglobin Reserve in Experimental Anemia Due to Bleeding

Abstract

In long continued severe anemia due to bleeding in dogs we may observe all degrees of red marrow spread. The maximal red marrow spread takes in the total marrow area in ribs, vertebrae and long bones. The minimal red marrow spread may involve but 10 to 20 per cent of this maximal area. All gradations between these extremes are observed in this series. The extent of the red marrow spread is not dependent upon the length of the anemia period nor is it related to the capacity of the dog to produce new hemoglobin and red cells on standard diets. Evidence points to the liver as concerned with this hemoglobin production and liver function may set the limits for hemoglobin production on these standard diets. This in turn may determine the needful red marrow spread. During favorable diet periods there is a storage of hemoglobin or hemoglobin precursors which come out later in the control periods as finished red cells. This reserve of hemoglobin producing material is not stored as mature red cells in the marrow or elsewhere but as intermediates stored probably in the liver and red marrow but also perhaps in the kidney and spleen. Red marrow very rarely gives evidence of exhaustion even after many years of continuous severe anemia (Dog 18-114). This would seem to consist of a shrinkage of the red marrow area rather than a degenerative change of the red marrow cells. The spleen shows some evidence of erythrogenesis in these dogs. Megakaryocytes in some instances are conspicuous (Fig. 6) and nests of nucleated red cells are found in the spleen pulp but it is unlikely that the spleen contributes any large amount of red cells to the anemic circulation in these experiments. There is no evidence that erythrogenesis occurs in the liver or lymphatic tissue in these dogs.

Studies on Hypochromic Anemia in Dogs. I. The Evaluation of a Standard Bread Diet and of a Meat Diet on Formation of Hemoglobin Before and After Gastrectomy 1

“…This individual variation showed the importance of controlled preoperative observations in order to interpret accurately similar studies after gastrectomy. This reaction is comparable to that observed following the use of one of the less potent iron preparations (18), namely, ferric chloride (25 mgm. iron as metal), with a maximal weekly output of 14 grams of hemoglobin.…”

“…In some of the intercellular spaces a few clumps of normoblasts and leukopoietic cells were present. Usually a marked hyperplasia of erythropoietic tissue is to be found in the marrow of dogs with anemia after bleeding (18).…”

What's the matter with MAT? Marrow adipose tissue, metabolism, and skeletal health

“…Induction of anemia in dogs by weekly bleeding resulted in a variable conversion of MAT to red marrow (from 0% to 100%). 138 Anemia-induced lipemia in rabbits is more consistent and, in one study, was prevented by transaction of the spinal cord at the 4th thoracic vertebrae. 139 In light of this finding, one potential common theme between anemia, cardiac failure, and calorie restriction is the regulation of sympathetic tone.…”

Development, regulation, metabolism and function of bone marrow adipose tissues

“…Furthermore, cBMA number is modestly depleted by a prostaglandin E 2 receptor type 4 agonist in ovariectomized rats 25 . Although not measured in rodents, it appears likely that both rBMAT and cBMAT are reduced in response to profound starvation 54 , blood-letting 55 , leukemia 34 , and infection 56 . Thus, whilst the term “constitutive” as a descriptor of some BMAT depots has merit, there are also caveats that diminish its dogmatic applicability.…”