Bear in mind that Secretin may only be truly effective in a percentage of autistic children, somewhere between 15-40% and can have adverse reactions in those who do not have the medical need for it…
Repligen Discovers Site of Brain Activation by Secretin in Animal Studies Repligen and McLean Hospital to Extend Discovery Through Clinical Trial
NEEDHAM, MA - November 12, 2001 - Repligen Corporation (Nasdaq: RGEN) reported today that studies in animals demonstrate that secretin specifically activates neurons in the amygdala, a part of the brain known to be important in social interactions.
Several studies in other laboratories have previously established that people with autism do not show normal activation of the amygdala when engaged in social interactions such as recognizing emotions from facial expressions. Secretin is currently being evaluated by the Company for the improvement of reciprocal social interaction in children with autism; however, to date there has been no biological model for how secretin, a gastrointestinal hormone, may affect the brain. Results from two animal studies provide, for the first time, evidence of a biological mechanism for the action of secretin in autism. The findings were presented at the annual meeting of the Society for Neuroscience and the International Meeting for Autism Research on November 9-11.
Separately, Repligen announced that it would collaborate with McLean Hospital, a teaching facility for Harvard Medical School, to conduct a clinical trial using functional Magnetic Resonance Imaging (fMRI) to extend this research to humans.
The first study establishing the activation of the amygdala by secretin was performed in collaboration with researchers at the VA Medical Center in Boston and Harvard Medical School. In this study, neuronal activation in rats was evaluated 1-2 hours following administration of a single intravenous injection of secretin or a placebo. The brain tissue was fixed and stained for Fos, a readily measured and well-established marker of the activation of neurons. Prominent activation of the amygdala was observed only in secretin-treated animals. Additional analysis revealed a significant decrease in the level of the neurotransmitter serotonin in the amygdala of secretin-treated rats which was not observed in rats treated with a control injection.
A second study, performed in collaboration with the VA Medical Center in Saint Louis and Saint Louis University School of Medicine, established the ability of a biologically active, radioactive secretin analog to transfer out of the blood and enter the brain. The rate of entry of secretin into the brain was similar to other peptides with known neurological activity.
Repligen also presented data from its Phase 2 clinical trial which demonstrated that a subset of the autistic patients showed a clinical response to secretin. Symptom improvements were most evident in reciprocal social interaction as measured with the Autism Diagnostic Observation Schedule (ADOS), a standardized method for quantifying the severity of the symptoms of autism.
“Taken together, these studies show that secretin can activate a part of the brain involved in social interaction and known to have reduced activity in autism,” stated Walter C. Herlihy, Ph.D., President and Chief Executive Officer of Repligen Corporation. “We look forward to extending these results through our collaboration with the Brain Imaging Center at McLean Hospital.”
The Amygdala and Autism The amygdala is part of a complex neural system that is critical for ascribing emotional value to stimuli and influencing affective responsiveness and emotional learning. One of the core deficits of autism is impaired reciprocal social interaction including eye contact, joint attention and an inability to deduce the mental states of others from facial expressions. Although neuropathological and imaging studies have revealed abnormalities in several regions of the brain in autism, a lack of activation of the amygdala is recognized as an important correlate of the social deficits of autism.
The role of the amygdala in social interaction has been studied in both normal and autistic patients using various neuroimaging tools. Studies using fMRI, have established an activation of the amygdala when processing and responding to social stimuli. Reduced activation of the amygdala in patients with autism has been documented using fMRI with particular impairment noted in their ability to respond to facial expressions of fear, to perceive eye-gaze direction and to establish recall memory for faces. Other studies indicate that patients with either surgical or congenital amygdala damage show similar symptoms. These data suggest that reduced activity of the amygdala is important in autism.
About McLean Hospital McLean Hospital maintains the largest research program of any private, U.S. psychiatric hospital. It is the largest psychiatric teaching facility of Harvard Medical School, an affiliate of Massachusetts General Hospital and a member of Partners HealthCare System. The Brain Imaging Center at McLean employs one of the largest MRI instruments in the country in studies of brain function. Researchers at McLean were part of the team that first identified regional abnormalities in brain activation in patients with schizophrenia and in normal aging, as well as regional changes in blood flow and metabolism in patients with Alzheimer’s disease.
About Repligen Corporation Repligen Corporation develops new drugs for debilitating pediatric disorders including autism, cancer, and immune and metabolic disorders. Repligen also manufactures and markets a set of patented products based on Protein A, which are used by the pharmaceutical industry to produce therapeutic antibodies. Its corporate headquarters are located at 117 Fourth Avenue, Needham MA, 02494.
Additional information may be requested from www.repligen.com.