https://www.sciencedirect.com/science/article/pii/S0889159119303010

Comment; Activated & inactivated spore types decreased neurogenesis and caused striking memory deficits in young mice, while decreasing pain thresholds and enhancing auditory-cued memory in older mice. Nontoxic spores also increased anxiety-like behavior. Levels of hippocampal immune activation correlated with decreased neurogenesis, contextual memory deficits, and/or enhanced auditory-cued fear memory. Innate-immune activation may explain how both toxic mold and nontoxic mold skeletal elements caused cognitive and emotional dysfunction.

Author links open overlay panelCheryl F.HardingabCarolyn L.PyttebcKimberly G.PagebKelly J.RybergaEdnaNormanddeGregory J.RemigioaRichard A.DeStefanoefDavid B.MorrisdJuliaVoroninafArielLopezcLauren A.StalbowceErin P.WilliamsceohelyAbreucShow morehttps://doi.org/10.1016/j.bbi.2019.11.006Get rights and content

Highlights

Inhalation of quantified mold stimuli caused hippocampal immune activation, decreased neurogenesis, impaired contextual memory in younger mice, while increasing pain sensitivity and anxiety-like behavior and enhancing auditory-cued memory in older mice.•

Skeletal elements of mold spores, with toxins and other metabolites removed, were sufficient to cause many problems, though their precise effects differed from those of intact toxic spores.•

Measures of immune activation correlated with neural and behavioral problems.•

These data support our hypothesis that innate immune activation is one mechanism through which both toxic and nontoxic mold stimuli can affect brain and behavior.

Abstract

Individuals living or working in moldy buildings complain of a variety of health problems including pain, fatigue, increased anxiety, depression, and cognitive deficits. The ability of mold to cause such symptoms is controversial since no published research has examined the effects of controlled mold exposure on brain function or proposed a plausible mechanism of action. Patient symptoms following mold exposure are indistinguishable from those caused by innate immune activation following bacterial or viral exposure. We tested the hypothesis that repeated, quantified doses of both toxic and nontoxic mold stimuli would cause innate immune activation with concomitant neural effects and cognitive, emotional, and behavioral symptoms. We intranasally administered either 1) intact, toxic Stachybotrys spores; 2) extracted, nontoxic Stachybotrys spores; or 3) saline vehicle to mice. As predicted, intact spores increased interleukin-1β immunoreactivity in the hippocampus. Both spore types decreased neurogenesis and caused striking memory deficits in young mice, while decreasing pain thresholds and enhancing auditory-cued memory in older mice. Nontoxic spores also increased anxiety-like behavior. Levels of hippocampal immune activation correlated with decreased neurogenesis, contextual memory deficits, and/or enhanced auditory-cued fear memory. Innate-immune activation may explain how both toxic mold and nontoxic mold skeletal elements caused cognitive and emotional dysfunction.

Dr. Raymond Oenbrink