Current smokers and those who quit smoking less than 10 years before radical prostatectomy for prostate cancer (PCa) are twice as likely as patients who never smoked to experience biochemical recurrence, according to study findings presented at the European Association of Urology 2015 congress in Madrid.

The study included 7,191 men who underwent radical prostatectomy. Of these, 2,513 (34.9%) had never smoked, 2,269 31.6%) were former smokers, and 3,409 (33.5%) currently smoked. After a median follow-up of 28 months, current smokers and those who had quit smoking within the last 10 years had a 2.2 times and 2.0 times increased risk of biochemical recurrence of PCa, respectively, compared with never-smokers. Men who quit smoking 10 or more years had a non-significant 20% increased risk.

“This is a new analysis,” said lead researcher Malte Rieken, MD, of University Hospital in Basel, Switzerland, “but it seems to confirm results we have seen in many other types of cancer: basically, smoking increases the risk of cancer recurrence after initial treatment. … It's just another reason not to smoke at all, but the fact that the risk drops after 10 years means that anyone who has prostate cancer would be well advised to quit immediately.”

Commenting on the new study, former EAU Secretary General Per-Anders Abrahamsson, MD, PhD, chairman and professor in the Department of Urology at Skåne University Hospital in Malmo, Sweden, observed: “This is the first report that clarifies that smoking increases the risk of prostate cancer recurring after surgery, and, therefore, a major step forward to advise our patients to stop smoking when diagnosed with prostate cancer.”

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New research in mice at Washington University School of Medicine in St. Louis suggests vitamin D plays a major role in preventing the inflammation that leads to type 2 diabetes and atherosclerosis. The way key immune cells behave without adequate vitamin D may provide scientists with new therapeutic targets for patients with those disorders, the researchers said. The study appears March 19 in the journal Cell Reports.

Studying mice that lacked the ability to process vitamin D in immune cells involved in inflammation, the researchers found that the animals made excess glucose, became resistant to insulin action and accumulated plaques in their blood vessels.

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Study suggests vitamin D deficiency more closely linked to diabetes than obesity

“The finding that vitamin D helps regulate glucose metabolism may explain previous epidemiological studies identifying an increased risk of diabetes in patients with vitamin D deficiency,” said senior investigator Carlos Bernal-Mizrachi, MD, associate professor of medicine and of cell biology and physiology. “In our study, inactivation of the vitamin D receptor induced diabetes and atherosclerosis, so normalizing vitamin D levels may have the opposite effect.”

In addition, he said inadequate vitamin D turned immune cells into transporters of fat. That may help researchers better understand how diabetes and atherosclerosis are linked and provide new possibilities for therapy.

For years, researchers have been studying vitamin D’s possible roles in inflammation and inflammatory diseases, such as type 2 diabetes and atherosclerosis. By engineering mice without the vitamin D receptor on important immune cells called monocytes and macrophages, the researchers were able to learn how those conditions are linked, according to Bernal-Mizrachi.

Monocytes are white blood cells made in the bone marrow that circulate in the bloodstream. After a few days, they typically move into the body’s tissues where they mature into cells called macrophages.

“Inactivating the vitamin D receptor on monocytes and macrophages promotes inflammation of the liver and in artery walls,” he said. “It also increases the ability of monocytes in the blood to adhere and migrate into blood vessel walls, where they deposit cholesterol and secrete inflammatory substances that lead to diabetes and heart disease.”

He said the findings suggest that getting enough vitamin D may reduce those properties in immune cells, decreasing inflammation and reducing the onset of a combination of heart disease and diabetes. In addition, the researchers found that without vitamin D, monocytes carried fat to the walls of blood vessels, which is something that hadn’t been observed previously.

“We knew that when monocytes matured and became macrophages, they would eat cholesterol deposited inside the blood vessel wall,” said co-first author Amy E. Riek, MD, assistant professor of medicine. “But in these experiments, we found that when they don’t have vitamin D, the monocytes, while they’re still in circulation, also eat up cholesterol and carry it in the bloodstream.”

That’s an important discovery, Riek said, because it’s much easier to find treatments that target something in the blood than it is to target the same cells after they move into the wall of a blood vessel.

“So that provides us, potentially, with a new target for therapy,” she said.

It also changes the way that scientists think about how lipids are carried into the blood vessel wall to cause plaques. Scientists already knew that LDL, the so-called bad cholesterol, carried fat deposits to the vessel wall. Now this study suggests that when monocytes don’t have enough vitamin D, they can do it, too.

“The monocytes were laden with fat in the absence of vitamin D receptor,” Bernal-Mizrachi said. “And they carried that fat into the artery, so that’s a new understanding of another way fat may get into blood-vessel walls in patients who are vitamin D deficient.”

The problem was reversible in the mice. When the animals that had developed type 2 diabetes and atherosclerosis received bone marrow transplants from mice with healthy vitamin D receptors on their monocytes and macrophages, their inflammation levels decreased, and the animals had lower blood glucose and became more sensitive to insulin.

Currently, Bernal-Mizrachi and Riek are conducting clinical studies in people who have type 2 diabetes, treating them with vitamin D to see whether it can prevent some of the complications of diabetes and inflammation in humans, too.

“As part of that study, we’re actually isolating monocytes from the blood of patients before and after vitamin D therapy,” Riek said. “So we can look at the inflammatory properties of those cells to see whether vitamin D is causing any changes.”

Citation
Oh J, Riek AE, Darwech I, Funai K, Shao JS, Chin K, Sierra OL, Carmelier G, Ostlund RE, Bernal-Mizrachi C. Deletion of macrophage vitamin D receptor promotes insulin resistance and monocyte cholesterol transport to accelerate atherosclerosis in mice. Cell Reports, published online March 19, 2015.

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