26 | New Scientist | 21/28 December 2019

I

N JANUARY, we broke the news that we

may finally know what causes Alzheimer’s

disease. For decades, it had been thought

that the condition is caused by a protein

called beta-amyloid going awry in the brain.

But in 2019, evidence pointed the finger

elsewhere: at Porphyromonas gingivalis,

a type of bacteria involved in gum disease.

Research conducted by labs around the

world, and led by the firm Cortexyme in

San Francisco, suggests that beta-amyloid

is a symptom, not a cause of the condition.

Instead, it may be the toxins released by

P. gingivalis, called gingipains, that result in

the brain damage that brings on the disease.

The hope is that blocking gingipains may

at last lead to effective treatments. I caught

up with Steve Dominy, head of science at

Cortexyme, to find out what has happened

since the findings were published.

What was the reaction to your study linking

Alzheimer’s to Porphyromonas gingivalis?

The response has been tremendous. A few

days after it came out, we’d been invited to

present the work at three big international

Alzheimer’s conferences. By the following

week, we’d been contacted by labs around

the world wanting to collaborate.

Some researchers have expressed doubts

about the work, including those who have

long thought beta-amyloid is to blame.

It’s never easy to challenge conventions

in science. But when we were able to show

our data, and the depth of the evidence,

to people at conferences, they became very

enthusiastic. Some of the leading figures

working in Alzheimer’s clinical trials have

now joined our clinical advisory board.

Are you conducting clinical trials now?

We are testing our experimental drug,

COR388, which blocks gingipains, to see

if it improves symptoms. We are enrolling

up to 570 people with mild to moderate

Alzheimer’s at 95 centres across the US

and Europe, and randomly assigning them

to get the drug or a placebo. The results

won’t be back until late 2021.

Review of the year

Q&A

Alzheimer’s

disease

breakthrough

Steve Dominy led a landmark study that

linked Alzheimer’s to gum disease bacteria.

He spoke to Debora MacKenzie

It has been

estimated that

for every bottle

of prosecco

that is made,

4.4 kilograms

of Italian hillside

is eroded away

Porphyromonas

gingivalis bacteria can

cause gum disease -

and maybe Alzheimer’s

01

Whether through overhype or simple

error, some of the most promising

developments of the 2010s didn’t deliver

The decade’s 5 biggest

disappointments

Self-driving cars

This was meant to be the decade of the

self-driving car, as governments began

permitting testing on public roads.

But you can’t hang up your steering

wheel just yet. Car firms and tech giants

have found it tricky to make self-driving

cars work, while a string of crashes

has dented public confidence.

The mako

shark can reach

speeds of

68 kilometres

an hour,

making it

the world’s

fastest shark

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