Kidney failure linked to silent stroke in people with diabetes

Kidney failure is one of the major health problems that people with type 2 diabetes may face as their disease progresses. A study shows that so-called silent cerebral infarctions (SCIs), otherwise known as ‘silent strokes,’ could be an indicator of kidney failure among diabetics. The study, from researchers at Shiga University School of Medicine, Japan, involved 608 patients with type 2 diabetes who had no obvious symptoms of kidney failure like protein in the urine. Nor did they have complications like stroke or heart disease. They underwent magnetic resonance imaging of the brain which showed that about 29% had SCI.

In long term follow up, those with SCI had a higher risk of kidney failure. Compared to those with normal scans, those with SCI were two and a half times more likely to die or develop end-stage kidney disease. Their risk of declining kidney function or need for dialysis was five times greater. The researchers agree that protein in the urine is the most common marker of kidney failure in diabetes. But some patients get decreased kidney function without having protein in the urine. This study suggests that subtle brain damage, SCI, detectable on a magnetic resonance image scan can detect those at risk of kidney failure independent of protein in the urine. It may be that small vessel disease in the brain is indicative of a similar problem in the kidneys.

Even modest gain in weight increases the risk of kidney disease

Gaining weight is a risk factor for development of chronic kidney disease. And, according to a study, this is so even if the person is not actually overweight or obese.

Healthy individuals who gain weight are at risk of developing chronic kidney disease, even if they stay within the so-called normal weight range. The findings come from annual health exams carried out on men in Korea. They show how those whose weight fluctuated the least had the lowest risk of kidney disease.

Increasing numbers of people are developing end stage renal disease (ESRD) and it is preceded by a condition known as chronic kidney disease (CKD). If we could diagnose, and deal with, CKD at an early stage, then progression to ESRD could be slowed or even halted. We already know that obesity is a risk factor for both ESRD and CKD but not much is known of the risk, if any, associated with modest weight gain that still leaves the individual within a ‘healthy’ weight range. This study comes from Korea and refers to the World Health Organization’s definition of BMI (body mass index) ranges for Asians. A healthy weight is BMI between 18.5 and 23, overweight from 23 to 25, and BMI over 25 is considered obese. Since the healthy range is quite wide, people may think it’s OK to put on a bit of weight as they age, so long as their BMI doesn’t go over 23.

Researchers at the Kangbuk Samsung Hospital in Seoul, took data – including BMI – from 8,792 healthy men undergoing a worksite health check in 2002 and followed up for the next few years. During this time, there were 427 new cases of CKD.

In both the normal weight and overweight groups, a U-shaped curve was found between weight change and risk of CKD. That is, minimal weight change was associated with lowest risk. Those who either lost or gained weight had a higher risk of CKD.

This is the first study to show a link between weight gain within the normal range and the risk of CKD. Weight loss was linked with increased risk too, but the researchers believe this result needs to be treated with caution – the weight loss could be a symptom of ill health that itself contributes to CKD. They are not sure just why weight gain increases the risk of CKD – but it may be because of increases in body fat. We also know that weight gain increases the risk of hypertension (high blood pressure) and diabetes which can, in turn, increase the risk of kidney disease. But the current findings suggest that weight gain is an independent risk factor of kidney disease. The take-home message seems to be that it is important to keep your weight steady as you age if you want to avoid kidney disease and its complications.

Preventing kidney stones through a healthy diet

Kidney stones are from through accumulation of salts in the urinary system. Having a kidney stone can be extremely painful but new research now suggests that a healthy diet can help avoid developing one.

The dietary approaches to hypertension (DASH) diet has previously been investigated for preventing high blood pressure, diabetes, and heart disease but not, till now, for kidney stones. However, a team at Maine Medical Center has looked at the impact of DASH on kidney stones, using data from three well known clinical studies. The Health Professionals Follow-up Study, the Nurses’ Health Study I and the Nurses’ Health Study II have run for many years and look at the impact of factors such as diet on chronic health conditions.

Kidney stones have previously been linked to higher rates of high blood pressure, obesity, diabetes and other heart disease risk factors. So there was already speculation that the DASH diet could, perhaps, also prevent kidney stones. In the study, participants were given a score linked to the main components of the DASH diet: fruit, vegetables, nuts and legumes, low fat dairy, whole grains, and lower intakes of salt, sweetened drinks, red meat and processed meat, like bacon and sausages. The study participants were followed up for several years, during which time there were 5,646 cases of kidney stones.

Those with the highest DASH scores were around 40% less likely to develop a kidney stone compared to those with the lowest scores. Kidney stones can be extremely painful and the medications used to treat them are far from ideal. This study suggests an alternative approach – prevention with a healthy DASH style diet. And there are other good reasons for adopting a diet based on fresh produce, low fat dairy and whole grains – namely, prevention of heart disease. The study is interesting also because it highlights the link between kidney stones and other health conditions – with the DASH diet, you may be able to reduce your risk of any of these, is the take home message.

Male and female rats show different patterns of kidney gene expression throughout their lives

Male and female rats show different patterns of kidney gene expression throughout their lives, a study in the open access journal Biology of Sex Differences reveals. The finding could help explain some of the gender differences observed in human renal disease, and lead to improved biomarkers of kidney function. 

Our kidneys play many important physiological roles. They filter waste products from the blood, produce urine, regulate blood pressure and make hormones. It's accepted that men and women experience renal disease differently - sex differences have been spotted in acute, chronic and diabetic kidney disease and in response to renal toxins - but the mechanisms responsible for these differences are unclear.

James C. Fuscoe and colleagues at the National Center for Toxicological Research, USFDA, Jefferson, AR studied gene expression  in the kidneys of male and female rats from 2 weeks to 2 years old, and identified over 800 genes that were expressed at different levels between the sexes. The findings help to explain what's happening at the molecular level, inside the kidney, as the rats age. Many of the differentially expressed genes were involved in pathways linked to renal injury, drug metabolism, and immune cell and inflammatory responses.

Expression levels of many of these genes also varied across the lifecycle. 'Middle-aged' females expressed higher levels of genes involved in xenobiotic metabolism and endocrine function, whilst males of the same age expressed higher levels of genes related to oxidative stress and renal cell death. So together, the findings may help explain some of the gender differences seen in human patients.

There are currently half a dozen urinary biomarkers of kidney injury qualified by the FDA. Dramatic sex differences were also spotted in the expression of genes encoding thesebiomarker proteins, a finding that should be taken into account as current biomarkers are used, and new biomarkers are developed.

Study: Ultrasound treatments may prevent acute kidney injury

Ultrasound treatments may prevent acute kidney injury that commonly arises after major surgery, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). The findings suggest that this simple and noninvasive therapy may be an effective precaution for patients at risk.

Acute kidney injury, an abrupt decline in kidney function, is an increasingly prevalent and potentially serious condition in hospitalized patients. Sometimes acute kidney injury arises after major surgery because the kidneys can be deprived of normal blood flow during the procedure. Once the injury develops, patients have few established treatment options besides supportive care.

Mark Okusa, MD, Joseph Gigliotti, PhD (University of Virginia), and their colleagues found that a drug-free, noninvasive, ultrasound-based treatment could prevent acute kidney injury in mice. When they exposed anesthetized mice to ultrasound with a routine clinical imaging system 24 hours prior to blood disruption to the kidneys, the mice exhibited preserved kidney health after blood flow was restored. In contrast, sham-treated mice exhibited significant kidney injury. Further analyses revealed that the ultrasound treatment likely stimulated an anti-inflammatory response that originated from the spleen and was responsible for protecting the kidneys.

"Our studies using noninvasive ultrasound now provide us with an active treatment that appears to be simple, effective, and nontoxic for the prevention of acute kidney injury," said Dr. Okusa. "To our knowledge this has never been described for the prevention of tissue or organ injury. Interestingly, we suspect that similar mechanisms that lead to kidney injury may also lead to lung, heart, and liver damage and that this form of therapy might be effective for prevention of injury in other organs as well."

In an accompanying editorial, Alain Le Moine, MD, PhD (Erasme Hospital, in Belgium) and his colleagues noted that opportunities arising from the work are numerous and promising because many procedures that carry a very high risk of AKI are planned. "In searching for novel approaches to prevent and even cure AKI, we believe that splenicultrasound stimulation has a bright future ahead," they wrote.

Diet Choices May Help Diabetics Stave Off Kidney Disease

Fruit, protein and moderate alcohol intake tied to lower risk of chronic disease in study.A healthy diet and moderate alcohol consumption may help people with type 2 diabetes reduce their risk of chronic kidney disease or slow its progression, a new study indicates.
Researchers looked at more than 6,200 diabetes patients, and found that nearly 32 percent of them developed chronic kidney disease and about 8 percent died during 5.5 years of follow-up.
Patients with the healthiest diets had a lower risk of kidney disease and of dying than those with the least healthy diets. Patients who ate more than three servings of fruit per week were less likely to develop chronic kidney disease than those who ate less fruit.
The study was published online Aug. 12 in the journalJAMA Internal Medicine.
Patients with the lowest intake of total and animal protein were more likely to develop kidney disease than those with the highest intake, the researchers also found. Moderate alcohol intake was associated with a lower risk of kidney disease and death. Sodium intake was not associated with kidney disease risk, according to a journal news release.
"A healthy diet and moderate intake of alcohol may decrease the incidence or progression of [chronic kidney disease] among individuals with type 2 diabetes. Sodium intake, within a wide range, and normal protein intake are not associated with [chronic kidney disease]," concluded Daniela Dunkler, of McMaster University in Ontario, Canada, and colleagues.
Could the new findings place an added burden on people who already have to be careful of their food choices?
"Patients with both type 2 diabetes and kidney disease may be frustrated by the numerous dietary restrictions that are recommended by their health care team," Dr. Holly Kramer, of Loyola University, and Dr. Alex Chang, of Johns Hopkins University, wrote in an accompanying commentary.
"Patients may even ask 'What can I eat?'" they added. "Perhaps the best dietary advice we can give to patients with type 2 diabetes and kidney disease is the same as the advice for those who want to avoid chronic kidney disease, and the same advice for preventing and treating hypertension, and the same dietary advice for everyone: Eat a diet rich in fruits and vegetables, low-fat dairy products, and whole grains while minimizing saturated and total fat."

HEALTHY DIET, MODERATE ALCOHOL LOWERS RISK OF KIDNEY DISEASE

 healthy diet and moderate alcohol consumption is linked to a decreased risk or progression of chronic kidney disease (CKD) in patients with type 2 diabetes, according to a study published by JAMA Internal Medicine.

Type 2 diabetes-related CKD has become a major public health issue. Researchers at McMaster University in Ontario, Canada examined the association of a healthy diet, alcohol, protein and sodium intake with incident or progression of CKD in patients with type 2 diabetes. The observational study included 6,213 patients with type 2 diabetes in the ONTARGET trial.

Results showed that 31.7% of patients developed CKD and 8.3% of patients died after 5.5 years of follow-up. In comparison to patients in the least healthy scoring group on an index that assessed diet quality, patients in the healthiest group showed a lower risk of developing CKD as well as mortality. Those patients that ate more than three servings of fruits per week had a lower risk of CKD, compared to those who ate fruit less frequently. Patients in the lowest group of total and animal protein intake had an increased risk of CKD compared with patients in the highest group. Also, sodium intake was not associated with CKD, but moderate alcohol intake reduced the risk of developing CKD and mortality. Findings from the study showed that a healthy diet as well as moderate alcohol intake can decrease the risk or progression of CKD among those with type 2 diabetes.

How Does Acute Pain Become Chronic?

Chronic pain is a major medical problem, affecting as many as 100 million Americans, robbing them of a full sense of well-being, disrupting their ability to work and earn a living, and causing untold suffering for the patient and family. This condition costs the country an estimated $560-635 billion annually—a staggering economic burden [1]. Worst of all, chronic pain is often resistant to treatment. NIH launched the Grand Challenge on Chronic Pain [2] to investigate how acute pain (which is part of daily experience) evolves into a chronic condition and what biological factors contribute to this transition.

But you may wonder: what, exactly, is the difference between acute and chronic pain?

Acute pain is an intensely unpleasant sensation transmitted by the nervous system to alert you to a real or impending injury—like a bruise, cut, or burn—or an infection like a toothache. It’s a warning that something’s wrong with your body, and that you need to take action. It can trigger you to remove your hand from a hot stove or to get rid of that pair of shoes that make your feet hurt every time you wear them. Pain is a powerful protective mechanism: those who cannot feel it, whether from a genetic condition or from an acquired disease of peripheral nerves like leprosy, suffer very serious consequences. But normally, acute pain is short lived—when the injury has healed, the pain is gone.

But in some situations, this acute pain becomes chronic, persisting for months or even years. In many instances that happens because the physiological condition is ongoing and unresolved—as in cancer or arthritis. But in some instances, the pain doesn’t appear to be caused by any disease, injury, or detectable damage to the nervous system [3]. That pain is just as real to the person suffering from it, though it is referred to as psychogenic pain.

We currently treat chronic pain with a variety of therapies, including medications, electrical stimulation, and surgery. Medications range from relatively mild over-the-counter drugs like aspirin to more powerful prescription drugs like Vicodin™ or Percocet™, which act on the brain and spinal cord to relieve pain. But these powerful narcotic drugs can cause serious side effects. They also carry the risk of addiction.

We believe that one key to developing better treatments is to identify signs that acute pain is likely to become chronic. By discovering such markers, we can personalize the treatment of pain. We could provide more aggressive treatments for those at high risk for chronic pain and minimal treatment for those likely to bounce back quickly. This would also help to reduce the risk of abuse and addiction to painkillers.

Here’s one example. We’re funding efforts to understand how the brain perceives a very common problem: back pain. Are there are biological markers that signal which patients’ pain will evolve into a more chronic form? Already, promising new fMRI brain imaging studies can predict which people will suffer from chronic pain after the acute phase [4].

We’re also looking into whether acute pain causes brain changes in certain people that might enhance pain sensitivity and lead to chronic pain. People coping with chronic pain often suffer from several conditions simultaneously—fibromyalgia and temporomandibular joint disorders or irritable bowel syndrome, for example. Is there some common mechanism?

We know there’s a significant difference in the way children, adults, and the elderly react to pain. A paper cut, for example, might cause your 6 year old to erupt in a fountain of tears, whereas most adults would just brush the injury aside. Is that because our wiring changes as we age? It’s an intriguing question, and one that we hope to answer.

We’re also investigating the use of complementary and alternative methods—like massage, acupuncture, herbal remedies, meditation, and yoga—to treat pain separately, or in addition to traditional analgesic treatments [5, 6]. As part of the Grand Challenge on Chronic Pain, we hope to understand the causes of chronic pain better—and ultimately to alleviate the suffering of millions.

References:

[1] Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research

[2] Grand Challenge on Chronic Pain

[3] NINDS Chronic Pain Information Page

4] Corticostriatal functional connectivity predicts transition to chronic back pain. Baliki MN, Petre B, Torbey S, Herrmann KM, Huang L, Schnitzer TJ, Fields HL, Apkarian AV. Nat Neurosci. 2012 Jul 1;15(8):1117-9.

[5] NINDS Hope Through Research

[6] Chronic Pain and Complementary and Alternative Medicine

Watch and Wait Works for Small Kidney Tumors For tumors less than 4 cm, no increase in risk for kidney cancer death

“Surveillance of small kidney tumors did not increase the risk of dying of kidney cancer,” said William Huang, MD, a surgical oncologist at New York University Langone Medical Center in New York City. In contrast, “surgical treatment, particularly removal of the entire kidney, was associated with cardiovascular complications and poorer survival over time.” He presented the study at the 2013 Genitourinary Cancers Symposium (abstract 343).

Nearly two-thirds of newly diagnosed kidney tumors are small (<4 a="" adversely="" affect="" also="" although="" and="" be="" been="" cancers="" cm="" emerging="" evidence="" for="" group="" has="" heterogeneous="" ill="" in="" intervention="" malignant="" may="" morbidly="" non-oncologic="" of="" older="" or="" outcomes.="" p="" patients="" potential.="" represents="" standard="" suggests="" surgery="" surgical="" that="" the="" these="" this="" treatment="" tumors="" unnecessary="" varying="" with="">

In the current study, researchers set out to identify the effect of surveillance of small renal tumors on morbidity and mortality compared with surgery. They used the Surveillance, Epidemiology, and End Results cancer registry data linked to Medicare claims data, to capture patient comorbidities, for diagnoses between 2000 and 2007. The retrospective cohort study included 8,300 patients who were aged 66 years or older with kidney tumors less than 4 cm. Of these patients, 78% had surgery and 22% received surveillance.

During a median follow-up of five years, patients in the surveillance group had a 16% lower risk for death from any cause compared with the surgical group (hazard ratio [HR], 0.84; 95% confidence interval, 0.75-0.94). Kidney cancer–specific mortality did not differ significantly between the groups.

“Surveillance is a reasonable option, particularly for patients who are older or have a limited life expectancy,” said Dr. Huang. He added that a small number of small tumors can become lethal over a period of time, and therefore if a patient has a normal life expectancy, surgery should still remain the treatment of choice for these patients.

Bruce Roth, MD, a professor of medicine in the Oncology Division at Washington University in St. Louis, who was not involved in the study, said the findings were important in showing that surveillance does not have a negative influence on kidney cancer mortality. He pointed out that today, more small lesions are being identified. “In 2013, it is difficult to go to an emergency room with chest pain or abdominal pain and not come out with a CAT [computed axial tomography] scan,” he said. “The more CAT scans you do, the more kidney masses you are going to find.”