What Is Red Marrow?

It is a mesh between the bone marrow cavity of long bones (such as the humerus and femur) and the thin bones of flat bones (such as the sacrum). It is a spongy tissue. The bone marrow that can produce blood cells is slightly red and is called red. marrow.

It is a mesh between the bone marrow cavity of long bones (such as the humerus and femur) and the thin bones of flat bones (such as the sacrum). It is a spongy tissue. The bone marrow that can produce blood cells is slightly red and is called red. marrow.

Chinese name

Red bone marrow

Foreign name

Stem cell

Include

Humerus, femur

Nature

Human organs

Function

Physiological function

Purpose

Hematopoietic capacity

Histological changes of autologous red bone marrow transplantation

After autologous red bone marrow ectopic transplantation, hematopoietic cells degenerate, degenerate, and finally die and disappear at the same time: at the same time, bone marrow stromal cells proliferate and become differentiated into bone under the influence of transplant trauma and local environmental factors. Reticulated bone is formed first, and then transformed into laminar lamellar bone with plastic transformation. Stromal cells also constitute a hematopoietic microenvironment, allowing hematopoietic stem cells from the bloodstream to reside, differentiate, and mature here.

Clinical application of red bone marrow and its prospects

Autogenous bone grafting is superior to any other type of bone grafting, so autologous bone is used more clinically. However, in the case of spinal fusion, trauma filling and extensive bone resection, autogenous bone obviously cannot meet the needs, especially in children and elderly patients with osteoporosis. In addition, extra bone surgery is required to remove the autogenous bone, which increases the risk of infection and blood loss, and prolongs the operation time and length of hospital stay. So people have been looking for alternatives to autologous bone. Autologous red bone marrow has been used as a bone repair material in clinic. Salama first used a heterogeneous bone (Kiel bone) plus red bone marrow from an autologous sacrum for compound transplantation, and reported a total of 126 patients with nonunion and bone defect were treated twice, achieving satisfactory results. Graham reported that 10 patients with nonunion had a solid bone connection after "xenogeneic bone-autologous red bone marrow" composite bone grafting. In the field of oral surgery, Jackson et al. Used autologous red bone marrow transplantation to close children's sacral defects, and the effect was significantly better than cortical bone transplantation. At present, there are not many reports of autologous red bone marrow transplantation in orthopedic clinics. It is expected that in the future, autologous red bone marrow and (1) allogeneic or heterogeneous bone: (2) BMG or BMP: (3) porous biodegradable bone substitutes such as ceramic composite grafts will be widely used in clinical To make up for the lack of autologous bone grafting and replace it. If this goal can be achieved, it will undoubtedly be a major progress in the field of orthopedic surgery.

Origin and biological characteristics of red bone marrow hematopoietic stem cells

The classic doctrine is that during embryonic development, hematopoietic development occurs from the yolk sac, liver, and spleen to the bone marrow. In adults, hematopoiesis occurs mainly in the bone marrow, spleen, and thymus. The earliest stage of blood cell development occurs at the blood island of the yolk sac. The hematopoiesis was first seen in the yolk sac blood islands outside the embryos at 7.5 days in mouse embryos (16 days in human embryos). The cells in the middle of the blood islands differentiated into the earliest hematopoietic stem cells. ) Differentiated, the first identifiable hematopoietic cells in the blood island blood circulation appear in 8-9 days. After the embryonic body has established circulation, hematopoietic stem cells migrate into the embryonic liver through blood flow, and the liver replaces the yolk sac to become the main tissue of hematopoietic: after birth, this position moves to the spleen and bone marrow. Bone marrow is a life-long hematopoietic organ and the main place for producing hematopoietic cells. Hematopoietic stem cells mainly exist in red bone marrow. The bone marrow hematopoietic microenvironment is composed of bone marrow stromal cells, extracellular matrix, and various growth factors. It is a "niche" for hematopoietic stem cells to maintain optimal functional status. Hematopoietic stem cells reside in the hematopoietic microenvironment of the bone marrow. Proliferation and differentiation to maintain the function of hematopoietic tissue and the constant number of blood cells [1]. As the core component of hematopoietic tissue, hematopoietic stem cells have high self-renewal ability and the potential to differentiate into various lines of hematopoietic cells in multiple directions under appropriate conditions, and have the characteristic of being non-proliferative for a long time. Under normal circumstances. After hematopoietic stem cells undergo mitosis, about half of the daughter cells under normal steady state still retain all the characteristics of the stem cells, namely self-renewal. Self-renewal maintains the size (number of stem cells) and quality of the stem cell pool, so it is also called seIf-maintenance. Another half of the stem cells change their characteristics during the mitotic process towards a gradual differentiation pathway, leaving the stem cell pool and entering the proliferation and differentiation pool. This maintains the body's normal hematopoiesis and guarantees the body's need for various types of cells during life. The differentiation of hematopoietic stem cells is a process of gradually increasing the number of hematopoietic cells. These cells gradually differentiate and mature. They pass from hematopoietic progenitor cells to identifiable precursor cells, eventually mature and gradually die. Some experiments have shown that hematopoietic stem cells can also produce certain non-hematopoietic cells, such as osteoclasts, mast cells, and epidermal germinal stellate cells. In addition, another biological characteristic of hematopoietic stem cells is that they have a large proliferation potential. Under normal physiological conditions, about 1 × 1011 blood cells are produced from bone marrow hematopoietic stem cells every day and released into the blood to supplement blood cells that die every day during aging. The stem cells in the bone only account for 1/106 to 1/107 of the bone marrow mononuclear cells, and only a few (<5%) hematopoietic stem cells are in the cell cycle, which can ensure the body's constant hematopoietic. Stem cells enter the cell cycle from the G0 phase. The biological characteristics of hematopoietic stem cells also include their quiescence, heterogeneity, and some special surface signs.