The Tangled Neuron

Cholesterol, Statins and Alzheimer’s, Part 2 of 3

Summary: In a small pilot trial, Lipitor (a statin), seemed to improve scores on neuropsychological tests, especially for patients with mild Alzheimer’s, high cholesterol and the APOE4 genetic variation. The results of two large trials of statins for treatment of Alzheimer’s should be published in 2008. Whether or not statins prove to be effective against Alzheimer’s, this research adds to the evidence of a connection between heart disease and some dementias.

In my last post, I wrote how recent research has dampened hopes that the cholesterol-lowering drugs called statins can reduce the risk of dementia. But what about people who’ve already been diagnosed with dementia?

Two large trials of statins to treat Alzheimer’s are underway. Dr. Larry Sparks, Head of the Ralph & Muriel Roberts Laboratory For Neurodegenerative Research at the Sun Health Research Institute in Arizona, is a lead investigator for one of these trials. He’s enthusiastic about exploring the connection between cholesterol and Alzheimer’s.

“Think about it,” Dr. Sparks says. “APOE4 [the genetic variation linked to increased risk of Alzheimer’s] leads to elevated cholesterol. I don’t think cholesterol causes Alzheimer’s, but I believe it negatively influences it, or causes it to progress faster. There’s definitely a vascular influence.”

Earlier in his career, Dr. Sparks was a Medical Examiner in Kentucky. While performing autopsies of non-demented people with coronary artery disease, he noticed they had amyloid plaques similar to those in people who had been diagnosed with Alzheimer’s. Later, working at the Sun Health Research Institute, he found that rabbits fed high cholesterol diets developed amyloid plaques in their brains. This plaque build-up was reversed when the cholesterol was removed from the rabbits’ diet.

Now, in a small pilot trial, Dr. Sparks and his colleagues have shown that a statin called Lipitor may actually improve scores on neuropsychological tests for some people with Alzheimer’s. In an article published last year, they wrote that Lipitor seemed to help the most in patients with mild Alzheimer’s, high cholesterol and the APOE4 genetic variation.

So reducing cholesterol to treat Alzheimer’s seems logical, right? Nothing is that simple with Alzheimer’s and dementia.

First, some scientists think statins might work by reducing inflammation in the brain, rather than by reducing cholesterol. Second, brain cells produce cholesterol because they need it to function. While bringing down cholesterol levels in the blood might prove helpful for Alzheimer’s, decreasing cholesterol in the brain may harm neurons. Three statins, Mevacor (Lovastatin), Zocor (Simvastatin) and Baycol (Cerivastatin – now off the market in the US) appear to work in the brain as well as in the blood. Two trials at the University of Pittsburgh testing the effects of Mevacor and Zocor on cognitive functioning in people with high cholesterol showed the drugs may have caused a small decrease in performance on some neuropsychological tests. While the effect of these statins on the brain is unknown, Dr. Sparks thinks a safer approach is to influence the brain indirectly by using statins that reduce cholesterol in the blood rather than in the brain.

Finally, a new study shows a late-life drop in cholesterol may actually be associated with an increased risk of Alzheimer’s. I’ll talk about that in my next post.

The results of the two large trials of statins for treatment of Alzheimer’s [CLASP (testing simvastatin or Zocor) and LEADe (testing atorvastatin or Lipitor)] should be published in 2008. Whether or not statins prove to be effective against Alzheimer’s, this research adds to the evidence of a connection between heart disease and some dementias. Dr. Sparks puts it this way: “if you’re sufficiently resilient that you don’t succumb to cardiovascular disease, then you’re looking down the barrel of dementia.”

Cholesterol, Statins and Alzheimer's: Part 1 of 3

Summary: Cholesterol is the Anna Nicole Smith of the Alzheimer’s world – it’s always in the news, and its relationships are hard to understand. High cholesterol in mid-life may be a risk factor for developing dementia. Studies on whether cholesterol-lowering drugs called statins can reduce that risk have had mixed results, with more recent research finding no effect. As with the men claiming to be the father of Ms. Smith’s baby, further tests will determine the role cholesterol-lowering drugs will play.

Going through my father’s medical records, I found a 2004 notation from his first neurologist: The recent total cholesterol (on Mevacor) was only 139 (LDL 81). Therefore, the Mevacor will be decreased to 10 mg. daily beginning today.

Mevacor is a statin, prescribed to lower cholesterol levels. But as far as I know, Dad’s cholesterol was always low – why was he taking Mevacor?

In the last few years, headlines on the use of statins to prevent dementia have swung from wild optimism to flat-out skepticism, and it seems Dad was dragged along for the ride.

In early 2000, when Dad started calling himself “stupid,” Loyola University researchers announced their analysis of hospital records showed patients taking statin drugs had a lower prevalence of probable Alzheimer’s. A paper by Boston University scientists that same year showed that British patients taking statins seemed to have a reduced risk of developing dementia. Dad probably saw the headlines: “Cholesterol drug may prevent Alzheimer’s” and “Statins Take On the Brain: Cholesterol-lowering drugs may also treat or prevent Alzheimer's disease.”

By 2001, he was combing through newsletters from Mayo Clinic and Harvard Medical School looking for ways to improve his memory. That year, Finnish researchers at the University of Kuopio published an article in BMJ that seemed to confirm the Alzheimer’s/cholesterol link. In their study of 1449 Finns followed over 21 years, high cholesterol levels at midlife were a risk factor for Alzheimer’s disease later in life. Shortly after that, studies in several labs showed a relationship between cholesterol and beta amyloid plaques and suggested that, at least in a test tube, high cholesterol leads to increased beta amyloid production. Surely the newsletters Dad subscribed to carried stories about these studies.

In 2003 or 2004, his family doctor must have prescribed Mevacor, but none of us know why. Maybe both Dad and his doctor had read about these studies, and agreed to give a statin a try.

By early 2005, Dad wasn’t reading much at all. But when I called to say hi one day, he was exasperated by a headline he’d seen in the local paper. “Did you see that?” he asked. “Now they say those drugs don’t help your brain.” The story was about a study by Johns Hopkins University researchers. After following approximately 5000 people over a period of five years, they found “no association between statin use and subsequent onset of dementia or AD”. Later that year, University of Washington scientists said that their analysis of statin use and dementia prevalence among 2798 participants in the Cardiovascular Health Study showed the use of statins was not associated with decreased risk of dementia. They wrote that the results of their investigation and similar studies depended on how they looked at the data, and that more research is needed.

After these negative results were published, the excitement about using statins to prevent Alzheimer’s had died down. Dad had stopped taking Mevacor anyway, and had definitely developed dementia.

Although statins may not prevent Alzheimer’s, studies are underway to see if they can be used to treat the disease after onset. I’ll write more about that in my next post.

Change of Shift

CHANGE OF SHIFT, Vol. 1, No. 18 is up at Protect The Airway. Every time I participate in Change of Shift, my appreciation for nurses grows.

Alzheimer's, Ulcerative Colitis and the Poetry of Donald Rumsfeld

My brother James called from his hospital bed in New Mexico to ask me to research cyclosporine, a potential treatment for his ulcerative colitis. He is weak and has lost more than thirty pounds. The beeping in the background means his IV system needs attention. I hold on while the nurses add steroids, morphine and the solution he gets his nourishment from.

James at Dripping Springs, Las Cruces, New Mexico

As with Alzheimer’s, no one is sure what triggers ulcerative colitis. And although medicines for ulcerative colitis are more effective than those for Alzheimer’s, there are not a lot of studies about treating an acute case like my brother’s. This is probably due to the fact that most people in the midst of painful, severe, life-threatening ulcerative colitis attacks don’t volunteer for clinical trials.

I pulled up the prescribing information for cyclosporine, and sorted through the few articles I could find. I looked up terms I didn’t understand (“parathesia” is a tingling or numbness, “renal insufficiency” is a fancy term for kidney failure). I checked the size of the studies on cyclosporine for ulcerative colitis (small, with around 50 participants). I marked some pages, and made some notes.

Then I called my brother back. “Did I wake you up?”

“That’s OK.”

“Cyclosporine is an immunosuppressant.” I was looking at Mayo Clinic’s site.

“Mmmmm,” he said. I think he already knew this.

“This potent drug is normally reserved for people who don't respond well to other medications or who face surgery because of severe ulcerative colitis,” I read to him. I flipped to a list of side effects I found in a study published in 2003. “Irreversible liver damage, kidney damage in 23% of patients, infections in 20%, seizures in 3%.”

“I don’t want that drug.” By then, he was wide awake. His doctor planned to start the cyclosporine within a couple of days if James didn’t get better.

The rush to research is a reflex action for me. But I don’t think all my compulsive research helped my father deal with his dementia, and I worry it won’t help my brother. I can only evaluate information from a layperson’s point of view. Am I influencing James and his wife Katya to refuse a treatment he needs? I’m getting an uncomfortable sense of déjà vu.

This is the way it goes when doctors and patients have to deal with a lot of unknowns. I was still thinking about this when the Alzheimer’s Research Forum posted a table called “What We Know, What We Don’t Know” for discussion and comment. Under the What We Know column, the editors listed research findings and achievements. There are 41 entries in the What We Know Column. But for every entry in the What We Know column, there is a corresponding entry in the What We Don’t Know column.

This makes me wonder if I should keep blogging about Alzheimer’s research, when there is so much “unknown.” But I think many of us want to understand what’s in the What We Know and What We Don’t Know columns when we’re weighing treatment options for various diseases. And who knows what we’ll find out about Alzheimer’s in the next few years? Maybe there will be a “breakthrough” discovery that really improves prevention or treatment.

Maybe this is what Donald Rumsfeld meant during a February 12, 2002 news briefing when he said:

As we know,
There are known knowns.
There are things we know we know.
We also know
There are known unknowns.
That is to say
We know there are some things
We do not know.
But there are also unknown unknowns,
The ones we don't know
We don't know.

I’ll update you on my brother’s progress. In the meantime, maybe we need to add a third column to our tables: What We Don’t Know We Don’t Know. It’s that Rumsfeld column that keeps me blogging about Alzheimer’s.