Metabolic dysfunction-associated steatotic liver disease, or MASLD, is an umbrella term describing conditions related to a buildup of fat in the liver. Formerly known as nonalcoholic fatty liver disease, this condition affects 1 in 4 people worldwide. Among those with type 2 diabetes, insulin resistance, obesity or all three, the prevalence of MASLD increases to 3 in 4 people.

As a diabetologist, the possibility of liver disease is on my mind every time I see a patient. Understanding your risk of developing this common yet underrecognized condition is essential to treating it.

What is MASLD?

MASLD is a complex disorder with both environmental and genetic contributions. In its early stages, liver cells accumulate fat in a process called steatosis. Major sources of this fat include adipose tissue as well as fatty acids the liver makes in response to insulin resistance and excess caloric intake. This fat accumulation can enlarge the liver and interfere with its normal functioning.

Over time, fatty acids activate enzymes, which can produce toxic byproducts capable of causing liver cell injury, inflammation and scarring. This condition is better known as MASH, or metabolic dysfunction-associated steatohepatitis. Progression to MASH is more common in the presence of other risk factors such as type 2 diabetes, insulin resistance and metabolic syndrome.

Left unaddressed, MASLD and MASH can progress to liver scarring, failure and, in some cases, cancer. They also increase risk of death from cardiovascular disease and liver-related complications.

In the U.S., MASH is the leading cause of liver transplants due to hepatic cancer among women and in those 65 and older. It is also on track to overtake hepatitis B and C as the main reason people develop liver cancer and thus need a liver transplant.

Liver disease and type 2 diabetes

Three out of four people with type 2 diabetes have MASLD. Linking liver disease, type 2 diabetes and obesity is the key role insulin resistance plays in their genesis.

Obesity is associated with increased fat deposits around the internal organs and higher levels of fatty acids delivered to the liver. Accumulation of fat in the liver increases its resistance to insulin.

Normally, insulin suppresses glucose production in the liver when blood sugar is high. When the liver becomes resistant to insulin, it produces more glucose despite elevated blood sugar levels, which in turn contributes to the development of type 2 diabetes.

A 2015 meta-analysis found that people with MASLD have a nearly twofold greater risk of developing type 2 diabetes than those without the disease. MASLD is also more likely to progress to MASH in the presence of type 2 diabetes.

MASLD disproportionately affects certain ethnic groups. For instance, 1 in 5 people of Hispanic descent in the U.S. have MASLD, with or without diabetes. This is thought to be related to genetic mutations that affect how the liver cells process fat. One particular mutation more common in Hispanic people promotes steatosis by interfering with the cells’ ability to clear fat deposits.

Treating MASLD and MASH

The silver lining is that management of obesity and type 2 diabetes – such as through lifestyle changes – is very similar to management of MASLD. The most critical early interventions for type 2 diabetes can also help with MASLD, and this is not surprising given how closely interrelated these two conditions are.

The best way to reverse the early stages of MASLD is with weight loss through healthy eating habits and regular exercise. The aim is to shed at least 5% to 10% of initial body weight, maintain that weight loss through sustainable and realistic lifestyle choices, and avoid excess alcohol intake to limit additional liver injury.

New medications to treat diabetes, such as GLP-1 receptor agonists like Ozempic and Mounjaro, as well as SGLT2 inhibitors like Jardiance or Invokana, have also shown benefit in early stages of MASLD. These drugs promote weight loss, which in turn improves MASLD. In addition, studies have shown that Ozempic and Mounjaro could reverse MASH, even with inflammation and fibrosis.

Older medications used for diabetes, such as pioglitazone, typically can also help reduce the progression of MASH by reducing insulin resistance.

In people with severe obesity or who have not had success with lifestyle changes and weight loss drugs, bariatric surgery is another highly effective option to treat MASLD, as it is associated with significant and sustained weight loss.

New drugs are also in the pipeline. The Food and Drug Administration recently approved a new medication called resmetirom to treat MASH with advanced liver scarring.

However, a cure for this chronic disease remains elusive. This is why it is essential to diagnose MASLD as early as possible and use proven measures that can be maintained long term. Treatments and lifestyle changes need to be deployed as early as possible, before inflammation and scarring have firmly set in. MASH gets trickier to treat in more advanced stages when liver damage becomes irreversible. For instance, while Ozempic may help treat early MASH, it doesn’t benefit patients with more advanced stages of liver scarring.

Ignorance is not bliss

Very few people are aware of MASLD and its health implications, including those living with it. While roughly over 35% of U.S. adults have MASLD, less than 5% are aware they have liver disease.

MASH can be difficult to diagnose because it either causes no symptoms or can be mistaken for other conditions. Patients may have the condition for years and not be aware that it is slowly and meticulously causing damage. In that sense, MASH is strikingly similar to type 2 diabetes or high cholesterol.

Young people are increasingly being diagnosed with early-onset MASLD. Indeed, MASLD with MASH is the most common pediatric liver condition, affecting nearly 8% of children and adolescents and over 34% of children with obesity in the U.S. These children and adolescents are at high risk of developing type 2 diabetes and have a significantly increased lifetime risk of cardiovascular disease and cancer.

Health care costs for people with type 2 diabetes and MASH are estimated to reach US$55 billion over the next 20 years, accounting for 65,000 liver transplants, 1.37 million cardiovascular-related deaths and 812,000 liver-related deaths.

These grim statistics need not be if MASH is tackled early and aggressively.

If you are one of the millions of Americans with prediabetes or diabetes and are also overweight, you most likely have some degree of MASLD or MASH. Being aware of MASLD and getting checked is the first step to addressing it.

Promptly determining the best way to treat your MASLD or MASH is the next step. An early referral to a liver specialist will help you halt the progression of this challenging and common condition and take advantage of the treatment breakthroughs researchers have made in the past few years.

Madona Azar, Associate Professor of Medicine, UMass Chan Medical School

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The stars aren’t fixed and unchanging, unlike what many ancient people thought. Once in a while, a star appears where there wasn’t one before, and then it fades away in a matter of days or weeks.

The earliest record of such a “guest star,” named so by ancient Chinese astronomers, is a star that suddenly appeared in skies around the world on July 4, 1054. It quickly brightened, becoming visible even during the day for the next 23 days.

Astronomers in Japan, China and the Middle East observed this event, as did the Anasazi in what is now New Mexico.

In the second half of 2024, a nova explosion in the star system called T Coronae Borealis, or T CrB, will once again be visible to people on Earth. T CrB will appear 1,500 times brighter than usual, but it won’t be as spectacular as the event in 1054.

I am a space scientist with a passion for teaching physics and astronomy. I love photographing the night sky and astronomical events, including eclipses, meteor showers and once-in-a-lifetime astronomical events such as the T CrB nova. T CrB will become, at best, the 50th brightest star in the night sky – brighter than only half the stars in the Big Dipper. It might take some effort to find, but if you have the time, you’ll witness a rare event.

What is a nova?

In 1572, the famous Danish astronomer Tycho Brahe observed a new star in the constellation Cassiopeia. After reporting the event in his work “De Nova Stella,” or “On the New Star,” astronomers came to associate the word nova with stellar explosions.

Stars, regardless of size, spend 90% of their lives fusing hydrogen into helium in their cores. How a star’s life ends, though, depends on the mass of the star. Very massive stars – those more than eight times the mass of our Sun – explode in dramatic supernova explosions, like the ones people observed in 1054 and 1572.

In lower mass stars, including our Sun, once the hydrogen in the core is exhausted, the star expands into what astronomers call a red giant. The red giant is hundreds of times its original size and more unstable. Eventually, all that is left is a white dwarf – an Earth-sized remnant made up of carbon and oxygen. White dwarves are a hundred thousand times denser than diamond. Unless they’re part of a binary star system, where two stars orbit each other, they slowly fade in brightness over billions of years and eventually disappear from sight.

T CrB is a binary star system – it’s made up of a red giant and a white dwarf, which orbit each other every 228 days at about half the distance between Earth and the Sun. The red giant is nearing the end of its life, so it has expanded dramatically, and it’s feeding material into a rotating disk of matter called an accretion disk, which surrounds the white dwarf.

Matter from the accretion disk, which is made mostly of hydrogen, spirals in and slowly accumulates on the surface of the white dwarf. Over time, this blanket of hydrogen becomes thicker and denser, until its temperature exceeds 18 million degrees Fahrenheit (10 million degrees Celsius).

A nova is a runaway thermonuclear reaction similar to the detonation of a hydrogen bomb. Once the accretion disk gets hot enough, a nova occurs where the hydrogen ignites, gets blown outward and emits bright light.

When will it occur?

Astronomers know of 10 recurrent novae – stars that have undergone nova explosions more than once. T CrB is the most famous of these. It erupts on average every 80 years.

Because T CrB is 2,630 light-years from Earth, it takes light 2,630 years to travel the distance from T CrB to Earth. The nova we will see later this year occurred over 2,000 years ago, but its light will be just reaching us later this year.

The accretion of hydrogen on the surface of the white dwarf is like sand in an 80-year hourglass. Each time a nova occurs and the hydrogen ignites, the white dwarf itself is unaffected, but the surface of the white dwarf is wiped clean of hydrogen. Soon after, hydrogen begins accreting on the surface of the white dwarf again: The hourglass flips, and the 80-year countdown to the next nova begins anew.

Careful observations during its past two novae in 1866 and 1946 showed that T CrB became slightly brighter about 10 years before the nova was visible from Earth. Then, it briefly dimmed. Although scientists aren’t sure what causes these brightness changes, this pattern has repeated, with a brightening in 2015 and a dimming in March 2023.

Based on these observations, scientists predict the nova will be visible to us sometime in 2024.

How bright will it be?

Astronomers use a magnitude system first devised by Hipparchus of Nicaea more than 2,100 years ago to classify the brightness of stars. In this system, a difference of 5 in magnitude signifies a change by a factor of 100 in brightness. The smaller the magnitude, the brighter the star.

In dark skies, the human eye can see stars as dim as magnitude 6. Ordinarily, the visible light we receive from T CrB comes entirely from its red giant, a magnitude 10 star barely visible with binoculars.

During the nova event, the white dwarf’s exploding hydrogen envelope will brighten to a magnitude 2 or 3. It will briefly become the brightest star in its home constellation, Corona Borealis. This maximum brightness will last only several hours, and T CrB will fade from visibility with the naked eye in a matter of days.

Where to look

Corona Borealis is not a prominent constellation. It’s nestled above Bootes and to the west of Ursa Major, home to the Big Dipper, in northern skies.

To locate the constellation, look due west and find Arcturus, the brightest star in that region of the sky. Then look about halfway between the horizon and zenith – the point directly above you – at 10 p.m. local time in North America.

Corona Borealis is approximately 20 degrees above Arcturus. That’s about the span of one hand, from the tip of the thumb to the tip of the pinky, at arm’s length. At its brightest, T CrB will be brighter than all the stars in Corona Borealis, but not as bright as Arcturus.

You can also use an interactive star chart such as Stellarium, or one of the many apps available for smartphones, to locate the constellation. Familiarizing yourself with the stars in this region of the sky before the nova occurs will help identify the new star once T CrB brightens.

Although T CrB is too far from Earth for this event to rival the supernova of 1054, it is nevertheless an opportunity to observe a rare astronomical event with your own eyes. For many of us, this will be a once-in-a-lifetime event.

For children, however, this event could ignite a passion in astronomy. Eighty years in the future, they may look forward to observing it once again.

Vahe Peroomian, Professor of Physics and Astronomy, USC Dornsife College of Letters, Arts and Sciences

This article is republished from The Conversation under a Creative Commons license. Read the original article.