The most common pathology affecting the pancreas is excess intra-pancreatic fat deposition (IPFD), often called fatty pancreas disease (FPD) — a disorder experienced by roughly one fifth of the world’s population. Although it is more common than type 2 diabetes, pancreatitis, and pancreatic cancer combined, it has remained relatively obscure.

By contrast, fatty liver — once called nonalcoholic fatty liver disease and recently renamed metabolic dysfunction–associated steatotic liver disease (MASLD) — is well-known.

 

 

Max Petrov, MD, MPH, PhD

“When it comes to diseases of the liver and pancreas, the liver is the big brother that has gotten all the attention, while the pancreas is the neglected little stepbrother that’s not sufficiently profiled in most medical textbooks and gets very little attention,” Max Petrov, MD, MPH, PhD, professor of pancreatology, The University of Auckland, Auckland, New Zealand, told Medscape Medical News. “The phenomenon of fatty pancreas has been observed for decades, but it is underappreciated and underrecognized.”

As early as 1926, fat depositions were identified during autopsies, but the condition remained relatively unknown, Mohammad Bilal, MD, associate professor of medicine-gastroenterology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, told Medscape Medical News. “Fortunately, FPD has recently been receiving more focus.”

 

 

Generally, healthy individuals have small amounts of fat in their pancreas. IPFD is defined as “the diffuse presence of fat in the pancreas, measured on a continuous scale,” and FPD refers to IPFD above the upper limit of normal. While there is no clear consensus as to what the normal range is, studies suggest it’s a pancreatic fat content ranging from 1.8% to 10.4%.

FPD’s “most important implication is that it can be a precursor for more challenging and burdensome diseases of the pancreas,” Petrov said.

Fatty changes in the pancreas affect both its endocrine and exocrine systems. FPD is associated with type 2 diabetes, the most common disease of the endocrine pancreas, as well as pancreatitis and pancreatic cancer, the most common diseases of the exocrine pancreas. It’s also implicated in the development of carotid atherosclerosis, pancreatic fistula following surgery, and exocrine pancreatic insufficiency (EPI).

 

 

• A ‘Pandora’s Box’

Up to half of people with fatty pancreas are lean. The condition isn’t merely caused by an overflow of fat from the liver into the pancreas in people who consume more calories than they burn, Petrov said. Neither robust postmortem nor biopsy studies have found a statistically significant association between fatty deposition in the pancreas and liver fat.

Compared with the way people accumulate liver fat, the development of FPD is more complex, Petrov said.

 

 

“Hepatic fat is a relatively simple process: Lipid droplets accumulate in the hepatocytes; but, in the pancreas, there are several ways by which fat may accumulate,” he said.

One relates to the location of the pancreas within visceral, retroperitoneal fat, Petrov said. That fat can migrate and build up between pancreatic lobules.

 

 

Fat also can accumulate inside the lobes. This process can involve a buildup of fat droplets in acinar and stellate cells on the exocrine side and in the islets of Langerhans on the endocrine side. Additionally, when functional pancreatic cells die, particularly acinar cells, adult stem cells may replace them with adipocytes. Transformation of acinar cells into fat cells — a process called acinar-to-adipocyte transdifferentiation — also

may be a way fat accumulates inside the lobes, Petrov said.

 

 

The accumulation of fat is a response to a wide array of insults to the pancreas over time. For example, obesity and metabolic syndrome lead to the accumulation of adipocytes and fat infiltration, whereas alcohol abuse and viral infections may lead to the death of acinar cells, which produce digestive enzymes.

 

Ultimately, the negative changes produced by excess fat in the pancreas are the origin of all common noninherited pancreatic diseases, bringing them under one umbrella, Petrov maintained. He dubbed this hypothesis PANcreatic Diseases Originating from intRapancreatic fAt (PANDORA).

 

 

The type of cells involved has implications for which disease may arise. For example, fat infiltration in stellate cells may promote pancreatic cancer, whereas its accumulation in the islets of Langerhans, which produce insulin and glucagon, is associated with type 2 diabetes.

 

The PANDORA hypothesis has eight foundational principles:

• Fatty pancreas is a key driver of pancreatic diseases in most people.
• Inflammation within the pancreatic microenvironment results from overwhelming lipotoxicity fueled by fatty pancreas.
• Aberrant communication between acinar cells involving lipid droplets drives acute pancreatitis.
• The pancreas responds to lipotoxicity with fibrosis and calcification — the hallmarks of chronic pancreatitis.
• Fat deposition affects signaling between stellate cells and other components of the microenvironment in ways that raise the risk for pancreatic cancer.
• The development of diabetes of the exocrine pancreas and EPI is affected by the presence of fatty pancreas.
• The higher risk for pancreatic disease in older adults is influenced by fatty pancreas.
• The multipronged nature of intrapancreatic fat deposition accounts for the common development of one pancreatic disease after another.

The idea that all common pancreatic diseases are the result of pathways emanating from FPD could “explain the bidirectional relationship between diabetes and pancreatitis or pancreatic cancer,” Petrov said.

 

• Risk Factors, Symptoms, and Diagnosis

A variety of risk factors are involved in the accumulation of fat that may lead to pancreatic diseases including:

• Aging
• Cholelithiasis
• Dyslipidemia
• Drugs/toxins (eg, steroids)
• Genetic predisposition
• Iron overload
• Diet (eg, fatty foods, ultraprocessed foods)
• Heavy alcohol use
• Overweight/obesity
• Pancreatic duct obstruction
• Tobacco use
• Viral infection (eg, hepatitis B, COVID-19)
• Severe malnutrition
• Prediabetes
• Dysglycemia

Petrov described FPD as a “silent disease” that’s often asymptomatic, with its presence emerging as an incidental finding during abdominal ultrasonography for other reasons. However, patients may sometimes experience stomach pain or nausea if they have concurrent diseases of the pancreas, he said.

 

There are no currently available lab tests that can definitively detect the presence of FPD. Rather, the gold standard for a noninvasive diagnosis of FPD is MRI, with CT as the second-best choice, Petrov said.

 

In countries where advanced imaging is not available, a low-cost alternative might be a simple abdominal ultrasound, but it is not definitive, he said. “It’s operator-dependent and can be subjective.”

 

Some risk factors, such as derangements of glucose and lipid metabolism, especially in the presence of heavy alcohol use and a high-fat diet, can “be detected on lab tests,” Petrov said. “This, in combination with the abdominal ultrasound, might suggest the patients will benefit from deeper investigation, including MRI.”

 

Because the exocrine pancreas helps with digestion of fatty food, intralobular fatty deposits or replacement of pancreatic exocrine cells with adipose cells can lead to steatorrhea, Bilal said.

“Fat within the stool or oily diarrhea is a clue to the presence of FPD,” Bilal said.

Although this symptom isn’t unique to FPD and is found in other types of pancreatic conditions, its presence suggests that further investigation for FPD is warranted, he added.

 

• Common-Sense Treatment Approaches

At present, there are no US Food and Drug Administration–approved treatments for FPD, Petrov said.

“What might be recommended is something along the lines of treatment of MASLD — appropriate diet and physical activity,” he said. Petrov hopes that as the disease entity garners more research attention, more clinical drug trials will be initiated, and new medications are found and approved.

Petrov suggested that there could be a “theoretical rationale” for the use of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) as a treatment, given their effectiveness in multiple conditions, including MASLD, but no human trials have robustly shown specific benefits of these drugs for FPD.

Petrov added that, to date, 12 classes of drugs have been investigated for reducing IPFD:

• Biguanides
• Sulfonylureas
• GLP-1 RAs
• Thiazolidinediones
• Dipeptidyl peptidase-4 (DPP-4) inhibitors
• Sodium-glucose cotransporter 2 inhibitors
• Statins
• Fibrates
• Pancreatic lipase inhibitors
• Angiotensin II receptor blockers
• Somatostatin receptor agonists
• Antioxidants

Of these, most have shown promise in preclinical animal models. But only thiazolidinediones, GLP-1 RAs, DPP-4 inhibitors, and somatostatin receptor agonists have been investigated in randomized controlled trials in humans. The findings have been inconsistent, with the active treatment often not achieving statistically significant improvements.

 

 

“At this stage of our knowledge, we can’t recommend a specific pharmacotherapy,” Petrov said. But we can suggest dietary changes, such as saturated fat reduction, alcohol reduction, smoking cessation, reduction in consumption of ultraprocessed food, physical exercise, and addressing obesity and other drivers of metabolic disease.

 

Mohammad Bilal, MD

Bilal, who is also a spokesperson for the American Gastroenterological Association, suggested that pancreatic enzyme replacement therapy, often used to treat pancreatic EPI, may treat some symptoms of FPD such as diarrhea.

Bariatric surgery has shown promise for FPD, in that it can decrease the patient’s body mass and potentially reduce the fat in the pancreas as well as it can improve metabolic diseases and hyperlipidemia. One study showed that it significantly decreased IPFD, fatty acid uptake, and blood flow, and these improvements were associated with more favorable glucose homeostasis and beta-cell function.

However, bariatric surgery is only appropriate for certain patients; is associated with potentially adverse sequelae including malnutrition, anemia, and digestive tract stenosis; and is currently not indicated for FPD.

Bilal advises clinicians to “keep an eye on FPD” if it’s detected incidentally and to screen patients more carefully for MASLD, metabolic disease, and diabetes.

 

“Although there are no consensus guidelines and recommendations for managing FPD at present, these common-sense approaches will benefit the patient’s overall health and hopefully will have a beneficial impact on pancreatic health as well,” he said.

 

From www. medscape.com

 

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