Targeting a master-regulator of inflammation with a monoclonal antibody potentially improves two unrelated conditions that currently have limited treatment options: preterm births and fatty liver disease, two new studies show.
Mounting research has made it clear that runaway inflammation drives the severity of a broad array of diseases and conditions, said Joe G.N. “Skip” Garcia, M.D., associate vice president for research at UF Health. In preterm birth related to uterine infection and in non-alcoholic fatty liver disease related to obesity, inflammatory signals go haywire, igniting significant disease and worsening outcomes, the studies show.
“Combined with our earlier studies, these results suggest that stopping the inflammatory cascade may prevent disease progression for a wide range of serious conditions with limited options, including the heartbreak of preterm birth and the difficult, protracted cascade of illnesses that flow from fatty liver disease including cirrhosis and liver cancer,” said Garcia, a physician-scientist and head of the Center for Inflammation Science and Systems Medicine at The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, based in Jupiter, Florida.
Garcia’s group has developed a monoclonal antibody, ALT-100, that reduces inflammation by neutralizing a master regulatory protein called eNAMPT, short for extracellular NAMPT. Garcia’s laboratory discovered eNAMPT 20 years ago and has led understanding about its role in the inflammatory cascade in a series of publications. His group found that eNAMPT is a master regulator of innate immunity, and affects many genes and proteins involved in inflammation.
Excessive eNAMPT in tissues leads to profound systemic inflammation, organ swelling and damage, and even cytokine storm. This hyperimmune reaction is responsible for many deaths from COVID-19 during the pandemic, Garcia said. The acronym NAMPT is short for “nicotinamide phosphoribosyltransferase.”
“The eNAMPT protein may be the most important factor in amplifying the innate immune response,” Garcia said. “When eNAMPT regulation is impaired, the results are potentially disastrous.”
Preterm birth delayed
In their latest publication, Garcia and colleagues documented high levels of eNAMPT in blood and tissues donated by women whose pregnancies ended prematurely, relative to those who delivered normally. They likewise saw its elevation in a mouse-based simulation of infection during late pregnancy.
The data showed that excess eNAMPT in the placenta and amniotic sac surrounding a fetus contributed to preterm birth, resulting in reduced survival in the offspring who later exhibited serious disabilities. Treatment of the pregnant mice with the ALT-100 antibody delayed pregnancy loss and reduced disability and death in their offspring. Their study was published June 20 in the journal Frontiers in Physiology.
“In these mice, 80% of the babies were dead on delivery. With our antibody, 80% were alive,” Garcia said. “We’re very excited by these results as they clearly demonstrate that eNAMPT is a highly druggable target that is involved in the complications of premature births.”
Doctors currently have limited options when a pregnant women goes into labor prematurely due to infection or inflammation. Antibiotics or anti-inflammatory drugs may be prescribed, but that doesn’t stop the premature delivery or prevent harm to the baby, the scientists noted.
The paper’s first author was Mohamed Ahmed, M.D, Ph.D., of the University of Arizona Health Sciences, in Tucson, Arizona.
“Complications due to premature births, before 37 weeks gestation, are a leading cause of death worldwide among children under 5, resulting in approximately 900,000 deaths each year,” Ahmed said. “This is a major unmet global medical need. Our results offer promise for this serious need.”
Obesity-related fatty liver disease
The Garcia group also recently studied the role of eNAMPT in fatty liver disease. Up to one quarter of adults have excess fat in their livers. It is an obesity-related condition that causes fatigue, abdominal pain, weakness and initiation of inflammatory processes. As metabolism becomes dysregulated, fat cells in the liver secrete excess eNAMPT, promoting a vicious spiral of illness.
“Inflammation plays a serious role in the transition from fatty liver to liver fibrosis, cirrhosis and liver cancer,” Garcia said. “We believe that the production of eNAMPT contributes to this transition, with the ALT-100 monoclonal antibody a potential therapeutic to mitigate this in a precision medicine fashion.”
Four in 10 people diagnosed with fatty liver disease may go on to develop a more serious condition, NASH, short for non-alcoholic steato-hepatitis. It’s a step on the road to liver fibrosis and cirrhosis, where scar tissue replaces healthy liver tissue. Fatty liver disease increases risk of heart disease, liver cancer, Type 2 diabetes and chronic kidney disease.
In mouse models of non-alcoholic fatty liver disease, mice treated with the monoclonal antibody ALT-100 experienced less liver injury and fibrosis than untreated mice.
Those fed a high-fat diet and treated with ALT-100 also had reduced glucose intolerance and insulin resistance, and were less likely to develop Type 2 diabetes. In human subjects with metabolic syndrome and Type 2 diabetes, eNAMPT was found to be significantly elevated in blood plasma. Belinda L. Sun, M.D., Ph.D., and Xiaoguang Sun, M.D., Ph.D., co-authored the study published in The FASEB Journal.
“Non-alcoholic fatty liver disease is a major public health issue worldwide, with approximately 40% of patients progressing to NASH and, subsequently, to liver fibrosis and cirrhosis,” said Xiaoguang Sun. “Our research indicates that eNAMPT inflammatory pathway activation is a key contributor to non-alcoholic fatty liver disease and progression to hepatic fibrosis.”
Many questions remain, Garcia said. With so many adults living with some degree of fatty liver disease, it becomes important to understand who would benefit from treatment with ALT-100.
“This is preventable disease with the right therapeutic. Given the global pandemic in people affected by NASH and metabolic syndrome, we need precision medicine approaches with useful biomarkers and genetic testing to identify folks who are most likely to benefit from treatment. The Center for Inflammation Science and Systems Medicine is working hard on developing these tools.” Garcia said.
How the antibody works
The eNAMPT protein participates in regulating the innate immune response, by binding to a gate-like structure, a protein that traverses cells’ membranes, called toll-like receptor 4, or TLR4. eNAMPT activates the TLR4 inflammatory cascade, which is designed to keep an infection from moving beyond a localized area. It is when this process becomes excessively exuberant that problems develop from unremitting inflammation.
Scientists have, in the past, tried blocking TL4 itself to stop inflammation, but that strategy failed in clinical trials because blocking the receptor suppressed patients’ ability to fight infection or sepsis, Garcia said. Garcia’s ALT-100 antibody is an indirect route to the same goal. It blocks a major activator of TLR4, rather than blocking the entire receptor, thus allowing the TLR4 to continue with its protective function against infection, he said.
The antibody has already passed a first safety clinical trial phase in healthy human volunteers, and is about to be tested in subjects with acute respiratory distress syndrome, or ARDS, a critical illness in patients with respiratory failure requiring mechanical ventilation. Phase 2 of that clinical trial is set to begin in a matter of months, Garcia said.
In addition to preterm births and fatty liver disease, in published studies, the Garcia lab has provided support for the eNAMPT-neutralizing antibody for other indications, including autoimmune disease such as systemic lupus and inflammatory bowel disease and even cancer.
As a former intensive care physician, Garcia remembers the struggle of having few therapeutic options other than steroids for patients whose health was failing due to runaway inflammation. For the memory of all of those patients, seeing the success the eNAMPT-targeting antibody ALT-100 has been rewarding, Garcia said.
“I believe that our antibody is a highly novel and potentially impactful tool to address multiple serious unmet needs around the world,” Garcia said. “It will be gratifying to validate this hope in our upcoming clinical trials.”
Mohamed Ahmed et al, The eNAMPT/TLR4 inflammatory cascade drives the severity of intra-amniotic inflammation in pregnancy and predicts infant outcomes, Frontiers in Physiology (2023). DOI: 10.3389/fphys.2023.1129413
Belinda L. Sun et al, Involvement of eNAMPT/TLR4 inflammatory signaling in progression of non‐alcoholic fatty liver disease, steatohepatitis, and fibrosis, The FASEB Journal (2023). DOI: 10.1096/fj.202201972RR
University of Florida
Inflammation-targeting antibody found to improve preterm birth outcomes, prevent obesity-linked liver disease (2023, June 22)
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