UNO’s Dr. Harshaw Studies Tylenol

University of New Orleans psychology professor Dr. Christopher Harshaw is uncovering the  possible link between a common pain reliever and developmental disorders. His findings have  been published in the October issue of Pharmacology, Biochemistry and Behavior, as reported  by UNO Campus news.

Dr. Harshaw was awarded a oneyear grant from the Louisiana Board of Regents for the  research, which focused on the developmental reaction that mice have to acetaminophen, best known by its popular brand name version, Tylenol.

In the UNO article, Harshaw said, “Several epidemiological studies have linked the use of acetaminophen in infants and young children to attention deficit and autism spectrum disorder  in humans. Studies in animals have also shown long-term changes in brain in behavior after  exposure to acetaminophen early in life. Most had nevertheless neglected the question of how acetaminophen interacts with inflammation early in life. We emphasize that, though  provocative, our results do not support a simple conclusion regarding the relative danger vs.  safety of (acetaminophen exposure) early in life.”

What are the most important applications of his findings?

“Though our results are provocative, we emphasize the need for caution. That is, the results of  our initial study do not support a simple conclusion regarding the relative danger of APAP  [acetaminophen] early in life for humans. First, our study has a number of limitations. We thus  plan to replicate these results and refine our methods in future experiments. Critically, we also  documented a significantly protective effect of APAP against a novel inflammation-induced morphological change in these same mice (see Harshaw & Warner, 2021). Given that a number  of prior studies have reported neuroprotective effects of APAP in specific contexts and brain cell types,” he explained, “future studies must investigate potential beneficial effects of APAP  against changes in the developing brain induced by early-life inflammation.”

As stated at the conclusion of the paper, “A key implication of our findings is that no simple  conclusion regarding the relative safety vs. danger of APAP early in life is yet possible. In fact, it  may be that inflammation and APAP constitute a developmental Scylla and Charybdis. Further  research is needed, however, to ascertain the veracity and boundaries of this claim, including  the conditions—genetic, epigenetic, and experiential—that may interact to canalize atypical  developmental trajectories in response to these common early life exposures” (Harshaw &  Warner, 2022).”

What are some more of his recent publications?

“My lab’s recent papers have focused on the effects of early life exposures on behaviors relevant to Autism Spectrum Disorders (ASDs) in mice. In particular, we’ve focused on exposure  of the mother to antibiotics (during pregnancy and nursing) and exposure of the pups to  acetaminophen early in development. Our paper on antibiotic (ABx) exposure found significant  differences in microbiome diversity following perinatal ABx that were far more pronounced in  male than in female offspring. We also found a number of subtle differences in behavior in these pups during the early postnatal period. However, we also showed that some of these  behavioral differences were, in fact, the result of significant deficits in temperature regulation in these animals, induced by ABx,” said Dr. Harshaw.

“Our paper on acetaminophen (APAP) examined how APAP interacts with inflammation early in ife to influence ASDrelevant behavior. This is an important question given that confound by  undication is a significant issue in the human epidemiological literature and early life sickness  and infection are also risk factors for neurodevelopmental disorders. We found distinct effects  of inflammation and APAP, with APAP increasing social caution in males but not females. We  also found significant interaction between inflammation and APAP, with ‘two hit’ inflammation +APAP females showing significantly greater levels of anxiety and ‘two hit’ males showing  levated levels of social avoidance.”

Can he tell us about his laboratory?

“My laboratory is called the Mechanisms Underlying Sociality (MUS) Lab and is located in the  Department of Psychology at the University of New Orleans (UNO).  It consists of a ‘wet lab’,  rooms in the animal facility, and office space. I currently have three Ph.D. students and a  number of undergraduate RAs in my lab. Two of the Ph.D. students are conducting their own  experiments in rodent models, and one is conducting a study examining the thermal correlates of social anxiety in human participants.”

What is his agenda for the coming years?

“In the coming years I plan to continue to focus on exploring the mechanisms underlying effects of early-life APAP on behavior. Using funds from the Louisiana Board of Regents (BoR), for  example, we recently purchased an Agilent ‘Seahorse’ mitochondrial analyzer and a vibratome  for slicing unfixed brain tissue. We will soon begin examining whether APAP induces long-term  mitochondrial damage in specific populations of neurons early in life.”

What is it like at UNO and how are things with the new chair?

“UNO is a great place to teach and conduct research–I am excited about continuing my career  here! The new chair, Dr. Refinetti, has also done a great deal to stabilize and grow the  department. Under his leadership the Department is in a far better position to adapt and meet  the changing needs of our students and community.”

Dr. Harshaw earned his Ph.D. in Developmental Science, with a specialization in Developmental  Psychobiology, at Florida International University in Miami. Since the Fall of 2017 he has been  an Assistant Professor in the Department of Psychology at the University of New Orleans.

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