One of the major complications of diabetes is diabetic nephropathy, a loss of kidney function that may lead to renal failure. As kidney disease progresses, the barrier that keeps large molecules out of the urine, called the glomerular barrier, begins to break down. With the barrier failing, certain large molecules begin to migrate into the urine. One of those hefty molecules is immunoglobulin M, or IgM.
Now Swedish researchers have found that type 1 patients with higher urine IgM levels are three times more likely to eventually die of a cardiovascular event or reach end-stage renal disease than patients with normal IgM levels.
(Although that sounds like pretty bad news, there is a silver lining to this dark cloud.)
The research team, led by Omran Bakoush, MD, PhD, studied a group of 139 patients with type 1 diabetes. Their urine was sampled and their IgM levels were measured when they were recruited into the study in 1984. By the study’s end in 2007, 32 of them had died of a cardiovascular event and 20 had reached end-stage renal disease. The analysis revealed that the patients with higher initial IgM levels in their urine were approximately three times more likely to die of a cardiovascular event or reach end-stage renal disease than those with lower levels.
(That’s still a pretty dark cloud we have here. No sign of a silver lining yet, but just be patient.)
The patients with increased IgM who died of cardiovascular disease may have been victims of atherosclerosis. Atherosclerosis is the thickening and narrowing of blood vessels, caused by the accumulation of fatty material such as cholesterol. The thickened artery walls slow the flow of blood and may eventually close completely, blocking vital blood flow to areas of the body. When the system tries to compensate by forcing other arteries to carry more blood, a dangerous bubble, called an aneurysm, may develop in an artery and eventually burst.
(It all still sounds pretty depressing. But here, finally, is the good news.)
Atherosclerosis is treatable.
In addition to a healthy diet and exercise, drugs called statins may be able to reverse the thickening of blood vessel walls. If we know that high IgM levels indicate a patient who already has atherosclerosis, then we have a valuable tool to prevent, or at least reduce, the condition before symptoms appear. Such patients, forewarned, could start a diet and exercise regimen and even consider taking statins.
And that’s the silver lining.
Provisional abstract from BMC Medicine, published August 4, 2009
BioMed Central (2009, August 6). IgM In Urine Acts As Prognostic Indicator In Diabetes.