Cystatin C, a blood marker of kidney function, proved significantly more accurate than the standard blood marker, creatinine, in predicting serious complications of kidney disease, in a study by researchers at the San Francisco VA Medical Center and the University of California, San Francisco. Among adults who were identified as having chronic kidney disease by high creatinine levels, the researchers found that only patients who also had abnormally high levels of cystatin C were at high risk for death, cardiovascular disease, heart failure, or kidney failure. People with high creatinine but normal cystatin C levels had risks similar to those with normal creatinine levels.
The researchers also found that a small but important segment of the study population was missed by creatinine but identified by cystatin C as being at significant risk of serious complications, according to lead author Carmen A. Peralta, MD, MAS, an SFVAMC researcher and an assistant professor of medicine in residence in the division of nephrology at UCSF.
The study of 11,909 participants appears online on December 16, 2010, in the JASN Express section of the Journal of the American Society of Nephrology. The authors analyzed patient data from two prospective studies: the Multi-Ethnic Study of Atherosclerosis and the Cardiovascular Health Study, both sponsored by the National Heart, Lung, and Blood Institute.
Principal investigator Michael G. Shlipak, MD, MPH, chief of general internal medicine at SFVAMC, said that the current study highlights a potential clinical use for cystatin C as a method for confirming a diagnosis of chronic kidney disease. Shlipak has been a leader among physicians in identifying cystatin C as an alternative, accurate, and reliable marker of kidney function.
Both cystatin C and creatinine are substances made in the body and filtered by the kidneys. High levels of the substances in the blood indicate that the kidneys are losing the ability to filter them, and thus are losing function. However, explained Peralta, creatinine is a byproduct made in muscles, so it is affected by what you eat and especially by how much muscle you have. Thus, a bodybuilder with healthy kidneys might have an elevated creatinine level because of high muscle mass, whereas a frail elderly person might have normal or even low levels of creatinine, but in fact this persons kidneys are not working well – its just that theres not much creatinine because theres not much muscle.
In contrast, cystatin C is a protein made in cells throughout the body. In studies so far, it does not seem to be that affected by age or muscle mass or diet, said Shlipak, who is also a professor in residence of medicine and epidemiology and biostatistics at UCSF.
Shlipak proposes that cystatin C, which can cost as little as $17 per test, be added as a method for confirming or staging chronic kidney disease in guidelines that are currently being formulated by nephrologists. Its vital that we have an accurate diagnostic test, because kidney disease does not show symptoms until its too late, when your kidneys have almost failed completely, he said. Being missed by creatinine is an important limitation in our current method of diagnosing kidney disease, said Peralta. Yet, she adds, being falsely identified with kidney disease through inaccurate test results can be disastrous as well. There is fear and psychological stress, particularly in communities of color, where people have a lot of friends and family members who are on dialysis, she noted. You can also be subjected to unnecessary and expensive tests and medications.
A dietary supplement of the synthetic derivative of vitamin B1 has the potential to prevent heart disease caused by diabetes, according to new research from the University of Bristol, funded by Diabetes UK. Vitamin B1 may help the body to dispose of toxins and therefore protect cells of the heart from becoming damaged.
Diabetes leaves the heart more vulnerable to stress as less oxygen and nutrients are delivered to the heart and other organs. Heart damage can be caused by high levels of glucose entering cardiovascular cells, which forms toxins that accelerate the ageing of the cell. Around 50 per cent of people with diabetes die from cardiovascular disease, and this complication is the leading cause of death among people with diabetes. Researchers warn that with increasing prevalence of diabetes ( around one in twenty people in the UK are now diagnosed with the condition ), diabetes will result in a new epidemic of heart failure unless new treatments are developed.
A team of researchers at the University of Bristol gave a synthetic derivative of vitamin B1 called benfotiamine to mice with and without diabetes. They found that treating mice with Type 1 or Type 2 diabetes with benfotiamine from the early stages of diabetes can delay progression to heart failure. They also found that the vitamin B1 derivative improved survival and healing after heart attacks in Type 1 mice ( and even in the mice without diabetes too ). Foods rich in vitamin B1 include Marmite, yeast and quorn, but it is not yet known whether changes to diet alone would provide enough of the vitamin to see the same effects as supplements achieved in mice.
Previous Diabetes UK-funded research at the University of Warwick was the first to show that people with Type 1 and Type 2 diabetes have around 75 per cent lower levels of vitamin B1 than people without diabetes. It is thought that this may not be due to diet, but due to the rate at which the vitamin is cleared from the body. Small scale clinical trials of people with Type 2 diabetes have also discovered a link between taking vitamin B1 supplements and a reduction in the signs of kidney disease.
The latest research has been published in the Journal of Molecular and Cellular Cardiology. Professor Paolo Madeddu who led this research at the University of Bristol said “Supplementation with benfotiamine from early stages of diabetes improved the survival and healing of the hearts of diabetic mice that have had heart attacks, and helped prevent cardiovascular disease in mice with both Type 1 and Type 2 diabetes. We conclude that benfotiamine could be a novel treatment for people with diabetes, and the next step in this research will be testing whether similar effects are seen in humans.”
Dr Victoria King, Head of Research at Diabetes UK said “Diabetes UK is pleased to have supported this research and is encouraged by these promising results which now need to be tested and confirmed in human trials. We would like to note that it’s still too early to draw any firm conclusions about the role of vitamin B1 in the prevention of complications and we would not advise that people look to vitamin supplements to reduce their risk of cardiovascular complications at this stage. Taking your prescribed medication, eating a healthy balanced diet and taking regular physical activity are key to good diabetes management and therefore reducing your risk of diabetes associated complications.”
Benfotiamine improves functional recovery of the infarcted heart via activation of pro-survival G6PD/Akt signaling pathway and modulation of neurohormonal response by Rajesh Katare, Andrea Caporali, Costanza Emanueli, Paolo Madeddu in the Journal of Molecular and Cellular Cardiology.