lipopolysaccharides (LPS), either alone or in combination, have indicated that when compared, bacterial LPSs exhibit the strongest induction of pro-inflammatory signaling in human neuronal–glial cells in primary coculture of any single inducer, and different LPS extracts from different gastrointestinal (GI)-tract resident Gram-negative bacteria appeared to have different pro-inflammatory potential
powerful inducer of the NF-κB
In both neocortex and hippocampus, LPS has been detected to range from a ~7- to ~21-fold increase abundance in AD brain
Major Gram-negative bacilli of the human GI-tract, such as the abundant B. fragilis and Escherichia coli (E. coli), are capable of discharging a remarkably complex assortment of pro-inflammatory neurotoxins
(i) bacterial amyloids (10, 21); (ii) endotoxins and exotoxins (5, 12); (iii) LPS (12, 18); and (iv) small non-coding RNAs (sncRNAs)
integral components of the outer leaflet of the outer membrane of Gram-negative bacteria, LPS
LPS, the major molecular component of the outer membrane of Gram-negative bacteria normally serves as a physical barrier providing the bacteria protection from its surroundings
LPS is also recognized by the immune system as a marker for the detection of bacterial pathogen invasion and responsible for the development of inflammatory response is perhaps the most potent stimulator and trigger of inflammation known
AD-affected brains have remarkably large loads of bacterial-derived toxins compared to controls. The transfer of noxious, pro-inflammatory molecules from the GI-tract microbiome to the CNS may be increasingly important during the course of aging when both the GI-tract and blood–brain barriers become significantly more permeable
first evidence of a perinuclear association of LPS with AD brain cell nuclei
LPS-mediated stimulation of chronic inflammation, beta-amyloid accumulation, and episodic memory decline in murine models of AD (39, 40) and a biophysical association of LPS with amyloid deposits and blood vessels in human AD patients
Strong adherence of LPS to the nuclear periphery has recently been shown to inhibit nuclear maturation and function that may impair or block export of mRNA signals from brain cell nuclei, a highly active organelle with extremely high rates of transcription, mRNA processing, and export into the cytoplasm
LPS may be further injurious to the nuclear membrane just as LPS contributes to cerebrovascular endothelial cell membrane injury
high intake of dietary fiber is a strong inhibitor of B. fragilis abundance and proliferation in the intact human GI-tract and as such is a potent inhibitor of the neurotoxic B. fragilis-derived amyloids, LPS, enterotoxins, and sncRNAs.
GI-tract microbiome-derived LPS may be an important initiator and/or significant contributor to inflammatory degeneration in the AD CNS
LPS has been recently localized to the same anatomical regions involved in AD-type neuropathology
a known pro-inflammatory transcription factor complex that triggers the expression of pathogenic pathways involved in neurodegenerative inflammation
pro-inflammatory amyloids, endo- and exotoxins, LPSs, and sncRNAs but also serve as potent sources of membrane-disrupting agents
The levels of LH in the ibuprofen group had increased by 23% after 14 d of administration
This increase was even more pronounced at 44 d, at 33%
We found an 18% decrease (P = 0.056) in the ibuprofen group compared with the placebo group after 14 d (Fig. 1A) and a 23% decrease (P = 0.02) after 44 d (Fig. 1C). Taken together, these in vivo data suggest that ibuprofen induced a state of compensated hypogonadism during the trial,
which occurred as early as 14 d and was maintained until the end of the trial at 44 d
We first investigated testosterone production after 24 and 48 h of ibuprofen
exposure to assess its effects on Leydig cell steroidogenesis. Inhibition of testosterone levels was significant and dose-dependent
(β = −0.405, P = 0.01 at 24 h and β = −0.664, P < 0.0001 at 48 h) (Fig. 2A) and was augmented over time
The AMH data show that the hypogonadism affected not only Leydig cells but also Sertoli cells and also occurred as early
as 14 d of administration
Sertoli cell activity showed that AMH levels decreased significantly with ibuprofen
administration, by 9% (P = 0.02) after 14 d (Fig. 1B) and by 7% (P = 0.05) after 44 d compared with the placebo group
Examination of the effect of ibuprofen exposure on both the ∆4 and ∆5 steroid pathways (Fig. 2B) showed that it generally inhibited all steroids from pregnenolone down to testosterone and 17β-estradiol; the production
of each steroid measured decreased at doses of 10−5–10−4 M. Under control conditions, production of androstenediol and dehydroepiandrosterone (DHEA) was below the limit of detection
except in one experiment with DHEA
Measuring the mRNA expression of genes involved in steroidogenesis in vitro showed that ibuprofen had a profound inhibitory
effect on the expression of these genes (Fig. 3 B–D), consistent with that seen above in our ex vivo organ model. Taken together, these data examining effects on the endocrine
cells confirm that ibuprofen-induced changes in the transcriptional machinery were the likely reason for the inhibition of
steroidogenesis.
Suppression of gene expression concerned the initial conversion of cholesterol to the final testosterone synthesis. Hence,
expression of genes involved in cholesterol transport to the Leydig cell mitochondria was impaired
A previous study reported
androsterone levels decreased by 63% among men receiving 400 mg of ibuprofen every 6 h for 4 wk
We next examined the gene expression involved in testicular steroidogenesis ex vivo and found that levels of expression of
every gene that we studied except CYP19A1 decreased after exposure for 48 h compared with controls
the changes in gene expression indicate that the transcriptional machinery behind the endocrine action
of Leydig cells was most likely impaired by ibuprofen exposure.
Together, these data show that ibuprofen also directly impairs Sertoli cell function ex vivo by inhibiting transcription
ibuprofen use in men led to (i) elevation of LH; (ii) a decreased testosterone/LH ratio and, to a lesser degree, a decreased inhibin B/FSH ratio; and (iii) a reduction in the levels of the Sertoli cell hormone AMH
The decrease in the free testosterone/LH ratio resulted primarily
from the increased LH levels, revealing that testicular responsiveness to gonadotropins likely declined during the ibuprofen
exposure. Our data from the ex vivo experiments support this notion, indicating that the observed elevation in LH resulted
from ibuprofen’s direct antiandrogenic action
AMH levels were consistently suppressed by ibuprofen both in vivo and ex vivo, indicating that this hormone is uncoupled from
gonadotropins in adult men. The ibuprofen suppression of AMH further demonstrated that the analgesic targeted not only the
Leydig cells but also the Sertoli cells, a feature encountered not only in the human adult testis but also in the fetal testis
a chemical compound, through its effects on the signaling
compounds, can result in changes in the testis at gene level, resulting in perturbations at higher physiological levels in
the adult human
The analgesics acetaminophen/paracetamol and ibuprofen have previously been shown to inhibit the postexercise
response in muscles by repressing transcription
Previous ex vivo studies on adult testis have indeed pointed to an antiandrogenicity, only on Leydig cells, of phthalates
(41), aspirin, indomethacin (42), and bisphenol A (BPA) and its analogs
ibuprofen’s effects were not restricted to Leydig and Sertoli cells, as data showed that the expression of genes
in peritubular cells was also affected
short-term
exposure
In the clinical setting, compromised Leydig cell function resulting in increased insensitivity to LH is defined as compensated
hypogonadism (4), an entity associated with all-cause mortality
compensated hypogonadic men present with an increased likelihood of reproductive, cognitive, and physical symptoms
an inverse relationship was recently reported between endurance exercise training and male sexual libido
AMH concentrations are lower in seminal plasma from patients with azoospermia than
from men with normal sperm levels
inhibin B is a key clinical marker of reproductive health (32). The function of AMH, also secreted by Sertoli cells, and its regulation through FSH remain unclear in men
the striking dual effect of ibuprofen observed here on both Leydig and Sertoli cells makes this NSAID the chemical
compound, of all the chemical classes considered, with the broadest endocrine-disturbing properties identified so far in men.
after administration of 600 mg of ibuprofen to healthy
volunteers