neutrophils

Recovery from muscle loss injuries hindered by immune cell conflicts

/ Katie Sharify / Leave a comment

During a game in 2018, Alex Smith suffered a compound fracture that broke both the tibia and fibula in his right leg. The gruesome injury aside, the former 49ers quarterback soon developed life-threatening necrotizing fasciitis — a rare bacterial infection — that resulted in sepsis and required him to undergo 17 surgeries.

In a battle to save his life and avoid amputating his leg, doctors had to remove a great deal of his muscle tissue leading to volumetric muscle loss (VML). When Smith returned to the field after nearly two years of recovery, many called his comeback a “miracle”. 

Skeletal muscle is one of the most dynamic tissues of the human body. It defines how we move and can repair itself after injury using stem cells. However, when significant chunks of muscle are destroyed through severe injury (e.g. gunshot wound) or excessive surgery (like that of Smith’s), VML overwhelms the regenerative capacity of the muscle stem cells.

Despite the prevalence of these injuries, no standardized evaluation protocol exists for the characterization and quantification of VML and little is understood about why it consistently overwhelms the body’s natural regenerative processes. Current treatment options include functional free muscle transfer and the use of advanced bracing designs.

However, new research from the University of Michigan (U-M) may have just discovered why tissues often fail to regenerate from traumatic muscle loss injuries.

When researchers from U-M collaborated with partners at Georgia Tech, Emory University and the University of Oregon to study VML injuries in mice, they found that that sometimes post-injury immune cells become dysregulated and prevent stem cell repair. In VML injuries that don’t heal, neutrophils — a type of white blood cell — remain at the injured site longer than normal meaning that they’re not doing their job properly.

In addition, researchers found that intercellular communication between neutrophils and natural killers cells impacted muscle stem cell-mediated repair. When neutrophils communicated with natural killer cells, they were essentially prompted to self-destruct.

The findings suggest that by altering how the two cell types communicate, different healing outcomes may be possible and could offer new treatment strategies that eventually restore function and prevent limb loss. The team of researchers hope that better treatments could mean that recovery from VML injuries is no longer considered a “miracle”.

To read the source release, click here.

Gene therapy gives patient a cure and a new lease on life

/ Yimy Villa / 1 Comment
Brenden Whittaker (left), of Ohio, is a patient born with a rare genetic immune disease who was treated at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center in a CIRM funded gene therapy trial. Dr. David Williams (on right) is Brenden’s treating physician.
Photo courtesy of Rose Lincoln – Harvard Staff Photographer

Pursuing an education can be quite the challenge in itself without the added pressure of external factors. For Brenden Whittaker, a 25 year old from Ohio, the constant trips to the hospital and debilitating nature of an inherited genetic disease made this goal particularly challenging and, for most of his life, out of sight.

Brenden was born with chronic granulomatous disease (CGD), a rare genetic disorder that affects the proper function of neutrophils, a type of white blood cell that is an essential part of the body’s immune system. This leads to recurring bacterial and fungal infections and the formation of granulomas, which are clumps of infected tissue that arise as the body attempts to isolate infections it cannot combat. People with CGD are often hospitalized routinely and the granulomas themselves can obstruct digestive pathways and other pathways in the body. Antibiotics are used in an attempt to prevent infections from occurring, but eventually patients stop responding to them. One in two people with CGD do not live past the age of 40.

In Brenden’s case, when the antibiotics he relied on started failing, the doctors had to resort to surgery to cut out an infected lobe of his liver and half his right lung. Although the surgery was successful, it would only be a matter of time before a vital organ was infected and surgery would no longer be an option.

This ultimately lead to Brenden becoming the first patient in a CGD gene therapy trial at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.  The trial, lead by UCLA’s Dr. Don Kohn thanks to a CIRM grant, combats the disease by correcting the dysfunctional gene inside a patient’s blood stem cells. The patient’s corrected blood stem cells are then reintroduced, allowing the body to produce properly functioning neutrophils, rebooting the immune system.

It’s been a little over three years since Brenden received this treatment in late 2015, and the results have been remarkable. Dr. David Williams, Brenden’s treating physician, expected Brenden’s body to produce at least 10 percent of the functional neutrophils, enough so that Brenden’s immune system would provide protection similar to somebody without CGD. The results were over 50 percent, greatly exceeding expectations.

Brenden Whittaker mowing the lawn in the backyard of his home in Columbus, Ohio. He is able to do many more things without the fear of infection since participating in the trial. Photo courtesy of Colin McGuire

In an article published by The Harvard Gazette, Becky Whittaker, Brendan’s mother, is quoted as saying, ““Each day that he’s free of infection, he’s able to go to class, he’s able to work at his part-time job, he’s able to mess around playing with the dog or hanging out with friends…[this] is a day I truly don’t believe he would have had beyond 2015 had something not been done.”

In addition to the changes to his immune system, the gene therapy has reinvigorated Brenden’s drive for the future. Living with CGD had caused Brenden to miss out on much of his schooling throughout the years, having to take constant pauses from his academics at a community college. Now, Brenden aims to graduate with an associate’s degree in health sciences in the spring and transfer to Ohio State in the fall for a bachelor’s degree program. In addition to this, Brenden now has dreams of attending medical school.

In The Harvard Gazette article, Brenden elaborates on why he wants to go to medical school saying, ” Just being the patient for so long, I want to give back. There are so many people who’ve been there for me — doctors, nurses who’ve been there for me [and] helped me for so long.”

In a press release dated February 25, 2019, Orchard Therapeutics, a biopharmaceutical company that is continuing the aforementioned approach for CGD, announced that six patients treated have shown adequate neutrophil function 12 months post treatment. Furthermore, these six patients no longer receive antibiotics related to CGD. Orchard Therapeutics also announced that they are in the process of designing a registrational trial for CGD.

Breast Cancer Tumors Recruit Immune Cells to the Dark Side

/ cirmweb / Leave a comment

We rely on our immune system to stave off all classes of disease—but what happens when the very system responsible for keeping us healthy turns to the dark side? In new research published today, scientists uncover new evidence that reveals how breast cancer tumors can actually recruit immune cells to spur the spread of disease.

Some forms of breast cancer tumors can actually turn the body's own immune system against itself.

Some forms of breast cancer tumors can actually turn the body’s own immune system against itself.

Breast cancer is one of the most common cancers, and if caught early, is highly treatable. In fact, the majority of deaths from breast cancer occur because the disease has been caught too late, having already spread to other parts of the body, a process called ‘metastasis.’ Recently, scientists discovered that women who have a heightened number of a particular type of immune cells, called ‘neutrophils,’ in their blood stream have a higher chance of their breast cancer metastasizing to other tissues. But they couldn’t figure out why.

Enter Karin de Visser, and her team at the Netherlands Cancer Institute, who announce today in the journal Nature the precise link between neutrophil immune cells and breast cancer metastasis.

They found that some types of breast tumors are particularly nefarious, sending out signals to the person’s immune system to speed up their production of neutrophils. And then they instruct these newly activated neutrophils to go rogue.

Rather than attack the tumor, these neutrophils turn on the immune system. They especially focus their efforts at blocking T cells—the type of immune cells whose job is normally to target and attack cancer cells. Further examination in mouse models of breast cancer revealed a particular protein, called interleukin 17 (or IL17) played a key role in this process. As Visser explained in today’s news release:

“We saw in our experiments that IL17 is crucial for the increased production of neutrophils. And not only that, it turns out that this is also the molecule that changes the behavior of the neutrophils, causing them to become T cell inhibitory.”

The solution then, was clear: block the connection, or pathway, between IL17 and neutrophils, and you can thwart the tumor’s efforts. And when Visser and her team, including first author and postdoctoral researcher Seth Coffelt, did this they saw a significant improvement. When the IL17-neutrophil pathway was blocked in the mouse models, the tumors failed to spread at the same rate.

“What’s notable is that blocking the IL17-neutrophil route prevented the development of metastases, but did not affect the primary tumor,” Visser added. “So this could be a promising strategy to prevent the tumor from spreading.”

The researchers are cautious about focusing their efforts on blocking neutrophils, however, as these cells are in and of themselves important to stave off infections. A breast cancer patient with neutrophil levels that were too low would be at risk for developing a whole host of infections from dangerous pathogens. As such, the research team argues that focusing on ways to block IL17 is the best option.

Just last month, the FDA approved an anti-IL17 based therapy to treat psoriasis. This therapy, or others like it, could be harnessed to treat aggressive breast cancers. Says Visser:

“It would be very interesting to investigate whether these already existing drugs are beneficial for breast cancer patients. It may be possible to turn these traitors of the immune system back towards the good side and prevent their ability to promote breast cancer metastasis.”