Several individuals in Nebraska developed severe infections after receiving unapproved cell-based therapies said to include , .
These patients -- fewer than five -- became seriously ill, with some developing sepsis, Leah Bucco-White, a spokesperson with the Nebraska Department of Health and Human Services, told 鶹ý via email.
All were given an exosome product that was , according to a sent by the state to clinicians. 鶹ý has previously reported on a growing trend of hospitals implementing placenta donation programs and potential links to unapproved stem cell products.
"We continue to carefully and actively assess this situation with our federal partners," including the CDC and the FDA, Bucco-White said. She added that she couldn't share further details at this time, including the name of the product used, the source of the C-sectioned placentas it came from, the clinics where it was administered, or the bacteria that caused the infections.
While exosomes are being evaluated in legitimate research studies, some clinics -- often those peddling unapproved stem cell therapies -- are offering exosome therapy for all kinds of conditions. One site for a clinic in San Diego describes the treatment as "" and even offers . Delaware Integrative Medicine advertises exosome therapy as being "chronic inflammation, autoimmune disease, Lyme disease, and other chronic degenerative diseases."
But stem cell researchers say exosomes -- packages of proteins and RNAs that can be transferred from cell to cell -- are nowhere near ready for prime time.
Until 2007, researchers thought exosomes were just a way for cells to get rid of trash. But that year, showed that some cells use them to transfer genetic material. Chemical & Engineering News reported that companies are looking at exosomes in , and a PubMed search reveals scores of experiments with these compounds.
But what's in them, and their actual function, remains up for debate.
"A lot more evidence is required to understand what they are, and it may be that a lot of claims about what they do in the end go by the wayside," Sean Morrison, PhD, a stem cell biologist and director of the Children's Medical Research Institute at UT Southwestern, told 鶹ý. Disagreement continues as to whether exosomes even have a physiologic function, "or if they're just some cellular waste product," he said.
Even the methods for purifying exosomes grown from culture are controversial within the scientific community, he added -- raising questions about what's in the vials being used in treatment.
"What these snake oil salesmen do is they pick a word out of the scientific literature that gets people excited, and they start to sell it," Morrison told 鶹ý.
The same companies that are willing to ignore FDA requirements for safety and efficacy testing are the same ones willing to ignore regulations for good manufacturing practices and cut corners to sell things that are contaminated with bacteria, he added.
The FDA has long been trying to get a handle on unapproved stem cell therapies. Last week, the agency sent a warning letter to Liveyon, the company involved in a spate of infections tied to stem cell products last year. It has warned several other stem cell companies as well. In 2017, the agency issued guidance on regenerative medicine products, with a November 2020 deadline for full compliance.
Morrison suspects the companies not yet in compliance have no intention of doing so: "They're going to keep doing what they do as long as they possibly can."
One of the "unfortunate facts" is that FDA resources for enforcement are limited and many of these companies are "betting on the fact that FDA is not going to have the resources to shut them down," he said.