Authors: Herbert B. Allen
Biofilms are made by microbes and are exceedingly common in nature. On examination of pathological specimens from the hippocampi in Alzheimer’s disease (AD) brains, biofilms have been observed both intra and extra-cellularly. It is highly probable that the microbes that create the biofilms in AD are spirochetes of either Lyme or dental origin. Borrelia burgdorferi of Lyme disease and T. denticola (representative of the dental organisms) have been found by PCR analysis, and Borrelia burgdorferi has been cultured from AD brains. Simultaneously with making biofilms in vitro, these cultivated Borrelia have been shown to make beta amyloid precursor protein (ABPP) and amyloid beta (Aβ) in pure culture. Comparatively, in the intracellular location in vivo, the Aβ (formed by the spirochetes while making biofilm), when meshing with tau protein, causes tau to be phosphorylated by a known interaction. When tau is hyperphosphorylated tau (p-tau), it no longer functions to stabilize neuronal dendrites, and those dendrites disintegrate. Extracellular biofilms are coated with Aβ (which is antimicrobial). Further, those biofilms attract Toll-like receptor 2 from the innate immune system; this molecule attempts to kill the spirochetes, but is ineffective, because it is unable to penetrate the biofilm. NFkB, one of the intermediates in the MyD88 pathway generated by TLR2, catalyzes beta amyloid converting enzyme which, in turn, catalyzes beta and gamma secretase that cleave ABPP to Aβ. Consequently, in the formation of biofilm, Aβ is created; and, in the TLR2/MyD88 response to the “spirochete-coated” biofilm, Aβ is also created. Finally, p-tau, the other major element of the pathology, is directly related to the creation of the biofilms. Biofilms are thus integral to the pathology of AD.
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