Acute myocarditis, a sudden inflammation of the heart, typically causes mild symptoms. However, in about 10% of cases, the condition becomes severe—leading to dangerous complications such as cardiac arrhythmias, heart failure, or even death. Unfortunately, existing treatments rely on limited data and often fail to address the disease’s root causes. In critical cases, patients may even need mechanical circulatory support to survive.
Targeting Inflammation at Its Source
A team at UC San Francisco (UCSF) has pioneered a novel approach to treat acute fulminant myocarditis by targeting the inflammation that drives the condition. Their findings, published in the journal Circulation, detail how immune-modulating drugs can offer new hope to patients facing life-threatening heart inflammation.
As per the Medical Xpress, the team focused on a class of immune-regulating enzymes known as Janus kinases (JAKs). These enzymes serve as key communication hubs for immune cells. During acute heart inflammation, JAK activity spikes, further escalating the immune response.
“We developed several animal models of myocarditis and observed that JAKs become hyperactive during inflammation,” explained Dr. Javid Moslehi, William Grossman Distinguished Professor in Cardiology and Chief of Cardio-Oncology and Immunology at UCSF. “We hypothesized that JAK inhibitors could effectively block this process.”
Promising Results in Preclinical Models
Over recent years, Moslehi’s team has studied the effects of JAK inhibitors on immune cell behavior at the RNA and protein levels. Their preclinical work showed that these inhibitors can quickly and significantly reduce inflammation in laboratory models of myocarditis.
Rapid Recovery in a Critical Case
This research led to a breakthrough case at UCSF. A 20-year-old woman arrived at the hospital with acute fulminant myocarditis—her heart function was deteriorating rapidly.
“This patient’s heart was effectively falling apart, and we had no time to spare,” said Dr. Connor O’Brien, UCSF cardiologist and critical care specialist. The team placed her on extracorporeal membrane oxygenation (ECMO) to sustain blood flow and began preparing her for a heart transplant.
When corticosteroid treatment failed to improve her condition, O’Brien consulted with Moslehi and introduced ruxolitinib, a JAK inhibitor, into the treatment regimen. The patient’s arrhythmias slowed, cardiac enzyme levels dropped, and within days her heart function showed remarkable improvement. She no longer needed ECMO and was discharged from the hospital just one week later.
Looking Ahead: Hope with Caution
Since this successful outcome, UCSF Health has treated additional patients with JAK inhibitors for acute myocarditis, achieving encouraging results. However, Moslehi urges restraint.
“The gold standard for validating any treatment is a clinical trial,” he emphasized. “While our early experience is promising, we must confirm these findings through formal studies.”