Diabetes distresses bone marrow stem cells by damaging their microenvironment

New research has shown the presence of a disease affecting small blood vessels, known as microangiopathy, in the bone marrow of diabetic patients. While it is well known that microangiopathy is the cause of renal damage, blindness and heart attacks in patients with diabetes, this is the first time that a reduction of the smallest blood vessels has been shown in bone marrow, the tissue contained inside the bones and the main source of stem cells.

These precious cells not only replace old blood cells but also exert an important reparative function after acute injuries and heart attacks. 

The starvation of bone marrow as a consequence of microangiopathy can lead to a less efficient healing in diabetic patients. Also, stem cells from a patient's bone marrow are the most used in regenerative medicine trials to mend hearts damaged by heart attacks.  Results from this study highlight an important deficit in stem cells and supporting microenvironment that can reduce stem cells' therapeutic potential in diabetic patients.

The research team, led by professor Paolo Madeddu, chair of experimental cardiovascular medicine in the School of Clinical Sciences and Bristol Heart Institute at the University of Bristol, investigated the effect of diabetes on bone marrow stem cells and the nurturing of small blood vessels in humans.

The new study, published in the American Heart Association journal Circulation Research, was funded by the British Heart Foundation (BHF).

The researchers have shown a profound remodelling of the marrow, which shows shortage of stem cells and surrounding vessels mainly replaced by fat, especially in patients with a critical lack of blood supply to a tissue (ischaemia).  This means that, as peripheral vascular complications progress, more damage occurs in the marrow. In a vicious cycle, depletion of bone marrow stem cells worsens the consequences of peripheral ischaemia.