Males and females are known to have gender-specific differences in their immune system and gut microbiota composition. Whether these differences in gut microbiota composition are a cause or ...consequence of differences in the immune system is not known. To investigate this issue, gut microbiota from conventional males or females was transferred to germ-free (GF) animals of the same or opposing gender. We demonstrate that microbiota-independent gender differences in immunity are already present in GF mice. In particular, type I interferon signaling was enhanced in the intestine of GF females. Presumably, due to these immune differences bacterial groups, such as
, and Porphyromonadaceae, known to expand in the absence of innate immune defense mechanism were overrepresented in the male microbiota. The presence of these bacterial groups was associated with induction of weight loss, inflammation, and DNA damage upon transfer of the male microbiota to female GF recipients. In summary, our data suggest that microbiota-independent gender differences in the immune system select a gender-specific gut microbiota composition, which in turn further contributes to gender differences in the immune system.
Ageing is associated with a changing immune system, leading to inflammageing (increased levels of inflammation markers in serum) and immunosenescence (reduced immune cells and reduced responses ...towards pathogens). This results in reduced vaccination responses and increased infections in elderly. Much is known about the adaptive immune system upon ageing, but less is known about the innate immune system. Therefore, the aim of this study was to compare innate immune function of Toll like receptor (TLR)-mediated responses between elderly and young adult women. To this end, elderly and young adult women were compared to study the effect of ageing on the relative prevalence and reactivity to TLR-mediated responses of myeloid- and plasmacytoid dendritic cells (mDC, pDC). In addition, TLR expression and inflammatory markers in serum were investigated. Elderly women had reduced numbers of circulating pDCs. In addition, pDCs and mDCs of elderly women responded differently towards TLR stimulation, especially TLR7/8 mediated stimulation was reduced, compared to young adults. In serum, markers involved in inflammation were generally increased in elderly. In conclusion, this study confirms and extends the knowledge about immunosenescence and inflammageing on innate immunity in elderly women.
Abstract
The human milk oligosaccharide 3′-sialyllactose (3′SL) has previously been shown to activate murine dendritic cells (DC) in a Toll-like receptor (TLR) 4-mediated manner ex vivo. In this ...study we aimed to investigate whether 3′SL has similar immunomodulatory properties on human DC. 3′SL was shown to induce NF-κB activation via human TLR4. However, LPS was detected in the commercially obtained 3′SL from different suppliers. After the removal of LPS from 3′SL, we studied its ability to modify DC differentiation in vitro. In contrast to LPS and 3′SL, LPS-free 3′SL did not induce functional and phenotypical changes on immature DC (iDC). iDC that were differentiated in the presence of LPS or 3′SL showed a semi-mature phenotype (i.e., fewer CD83+CD86+ DC), produced IL-10 and abrogated IL-12p70 and tumor necrosis factor-alpha levels upon stimulation with several TLR ligands. Differentiation into these tolerogenic DC was completely abrogated by LPS removal from 3′SL. In contrast to previous reports in mice, we found that LPS-free 3′SL does not activate NF-κB via human TLR4. In conclusion, removing LPS from (oligo)saccharide preparations is necessary to study their potential immunomodulatory function.
During aging the immune system is dysregulated. Especially plasmacytoid dendritic cells (pDCs) and myeloid DCs (mDCs) have reduced Toll like receptor (TLR)-mediated responses resulting in increased ...susceptibility to infections. Consumption of bovine lactoferrin (bLF) has been shown to reduce infections with viruses. Galacto-oligosacharides (GOS) and vitamin D are associated with reduced pro-inflammatory cytokine levels in serum, and increased TLR7/8 responses, respectively. A double-blind placebo-controlled nutritional intervention study in elderly women was performed, to investigate the potential of bLF, GOS, and vitamin D to restore TLR responsiveness of pDCs and mDCs and to reduce inflammatory markers in serum. The nutritional intervention group (
= 15) received bLF for 3 weeks, followed by 3 weeks of bLF + GOS, and subsequently 3 weeks of bLF + GOS + vitamin D. The placebo group (
= 15) received maltodextrin for 9 weeks. Every 3 weeks, blood was collected and TLR responses of pDCs and mDCs, and inflammation-related markers in serum were measured. After 3 weeks of bLF supplementation, increased TLR7/8 and TLR1/2 responses were observed in pDCs of the nutritional intervention group compared to the placebo group. When the effects of the entire nutritional intervention were investigated, increased TLR1/2 mediated responses in mDCs were observed, and in serum sVCAM tended to decrease. Finally, based on the RAND-36 questionnaire physical function tended to improve in the intervention group. Since especially TLR7-mediated responses in pDCs were enhanced after bLF supplementation compared to placebo, this suggests that bLF may contribute to antiviral responses mediated by pDC in elderly women.Clinical trial registry number: NCT03026244, clinicaltrials.gov.
Pycnogenol
(PYC), an extract of French maritime pine bark, is widely used as a dietary supplement. PYC has been shown to exert anti-inflammatory actions via inhibiting the Toll-like receptor 4 (TLR4) ...pathway. However, the role of the other receptors from the TLR family in the immunomodulatory activity of PYC has not been described so far.
The aim of this study was to investigate whether PYC might exert its immunomodulatory properties through cell membrane TLRs (TLR1/2, TLR5, and TLR2/6) other than TLR4. Moreover, the effect of gastrointestinal metabolism on the immunomodulatory effects of PYC was investigated.
We showed that intact non-metabolized PYC dose-dependently acts as an agonist of TLR1/2 and TLR2/6 and as a partial agonist of TLR5. PYC on its own does not agonize or antagonize TLR4. However, after the formation of complexes with lipopolysaccharides (LPS), it is a potent activator of TLR4 signaling. Gastrointestinal metabolism of PYC revealed the immunosuppressive potential of the retentate fraction against TLR1/2 and TLR2/6 when compared to the control fraction containing microbiota and enzymes only. The dialyzed fraction containing PYC metabolites revealed the capacity to induce anti-inflammatory IL-10 secretion. Finally, microbially metabolized PYC affected the colonic microbiota composition during in vitro gastrointestinal digestion.
This study showed that gastrointestinal metabolism of PYC reveals its biological activity as a potential inhibitor of TLRs signaling. The results suggest that metabolized PYC acts as a partial agonist of TLR1/2 and TLR2/6 in the presence of the microbiota-derived TLR agonists (retentate fraction) and that it possesses anti-inflammatory potential reflected by the induction of IL-10 from THP-1 macrophages (dialysate fraction).
The influence of age on basophils is poorly understood, as well as the effect of aging-associated microbiota on basophils. Therefore, we studied the influence of aging and aging-associated microbiota ...on basophil frequency and phenotype, and differentiation from basophil precursors.
Basophils became more abundant in bone marrow (BM) and spleens of 19-month-old mice compared with 4-month-old mice. Aged basophils tended to express less CD200R3 and more CD123, both in BM and spleen. Differences in microbiota composition with aging were confirmed by 16S sequencing. Microbiota transfers from young and old mice to germ-free recipients revealed that CD11b tended to be lowered on splenic basophils by aging-associated microbiota. Furthermore, abundance of
,
,
, and
family positively correlated and CD123 expression, whereas
abundance negatively correlated with basophils numbers.Subsequently, we purified FcεRIα
CD11c
CD117
BM-derived basophils and found that those from aged mice expressed lower levels of CD11b upon stimulation. Higher frequencies of IL-4
basophils were generated from basophil precursors of aged mice, which could be reproduced in basophils derived from germ-free recipients of aging-associated microbiota.
Collectively, these results show the influence of aging on basophils. Furthermore, this study shows that aging-associated microbiota altered activation of BM-derived basophils in a similar fashion as observed in BM-derived basophils from aged mice.
Background In situ hypothermic perfusion during liver resection performed under vascular inflow occlusion decreases hepatic ischemia-reperfusion injury, but technical limitations have restricted its ...widespread use. In situ hypothermic perfusion with retrograde outflow circumvents these impediments and thus could extend the applicability of in situ hypothermic perfusion. The safety and feasibility of in situ hypothermic perfusion with retrograde outflow were analyzed in selected patients undergoing right (extended) hepatectomy and compared to intermittent vascular inflow occlusion, the gold standard method, in this randomized pilot study. Methods Patients were first screened for parenchymal liver disease (exclusion criteria: steatosis ≥30%, cirrhosis, or cholestasis). Study participants were randomized intraoperatively to undergo in situ hypothermic perfusion with retrograde outflow ( n = 9) or intermittent vascular inflow occlusion ( n = 9). The target liver core temperature during in situ hypothermic perfusion with retrograde outflow was 28°C. The primary end point was ischemia-reperfusion injury (expressed by peak postoperative transaminase levels). Secondary outcomes included functional liver regeneration (assessed by hepatobiliary scintigraphy) and clinical outcomes. Results Peak transaminase levels, total bilirubin, and the international normalized ratio were similar between both groups, although a trend toward more rapid normalization of bilirubin levels was noted for the in situ hypothermic perfusion with retrograde outflow group. Functional liver regeneration as evaluated by hepatobiliary scintigraphy was improved on postoperative day 3 following in situ hypothermic perfusion with retrograde outflow but not after intermittent vascular inflow occlusion. Furthermore, in situ hypothermic perfusion with retrograde outflow (requiring continuous ischemia) was comparable to intermittent vascular inflow occlusion for all clinical outcomes, including postoperative complications and hospital stay. Conclusion The use of in situ hypothermic perfusion with retrograde outflow appears to be safe and feasible in selected patients with healthy liver parenchyma and may benefit early functional liver regeneration. Future applications of in situ hypothermic perfusion with retrograde outflow include patients with damaged liver parenchyma who would require major hepatic resection with a prolonged vascular inflow occlusion duration.
The use of
as potential therapeutic intervention is receiving increasing attention. Health benefits attributed to this bacterium include an improvement of metabolic disorders and exerting ...anti-inflammatory effects. The abundance of
is associated with a healthy gut in early mid- and later life. However, the effects of
on a decline in intestinal health during the aging process are not investigated yet. We supplemented accelerated aging
mice with
for 10 weeks and investigated histological, transcriptional and immunological aspects of intestinal health.
The thickness of the colonic mucus layer increased about 3-fold after long-term
supplementation and was even significantly thicker compared to mice supplemented with
WCFS1. Colonic gene expression profiles pointed towards a decreased expression of genes and pathways related to inflammation and immune function, and suggested a decreased presence of B cells in colon. Total B cell frequencies in spleen and mesenteric lymph nodes were not altered after
supplementation. Mature and immature B cell frequencies in bone marrow were increased, whereas B cell precursors were unaffected. These findings implicate that B cell migration rather than production was affected by
supplementation. Gene expression profiles in ileum pointed toward a decrease in metabolic- and immune-related processes and antimicrobial peptide production after
supplementation. Besides,
decreased the frequency of activated CD80
CD273
B cells in Peyer's patches. Additionally, the increased numbers of peritoneal resident macrophages and a decrease in Ly6C
monocyte frequencies in spleen and mesenteric lymph nodes add evidence for the potentially anti-inflammatory properties of
.
Altogether, we show that supplementation with
prevented the age-related decline in thickness of the colonic mucus layer and attenuated inflammation and immune-related processes at old age. This study implies that
supplementation can contribute to a promotion of healthy aging.
Although it is clear that probiotics improve intestinal barrier function, little is known about the effects of probiotics on the aging intestine. We investigated effects of 10-week bacterial ...supplementation of
WCFS1,
BL23, or
DSM20213 on gut barrier and immunity in 16-week-old accelerated aging
mice, which have a median lifespan of ~20 weeks, and their wild-type littermates. The colonic barrier in
mice was characterized by a thin (< 10 μm) mucus layer.
prevented this decline in mucus integrity in
mice, whereas
exacerbated it. Bacterial supplementations affected the expression of immune-related genes, including Toll-like receptor 4. Regulatory T cell frequencies were increased in the mesenteric lymph nodes of
- and
-treated
mice.
- and
-treated
mice showed increased specific antibody production in a T cell-dependent immune response
. By contrast, the effects of bacterial supplementation on wild-type control mice were negligible. Thus, supplementation with
- but not with
and
prevented the decline in the mucus barrier in
mice. Our data indicate that age is an important factor influencing beneficial or detrimental effects of candidate probiotics. These findings also highlight the need for caution in translating beneficial effects of probiotics observed in young animals or humans to the elderly.
Hepatic ischemia/reperfusion (I/R) injury is characterized by hepatocellular damage, sterile inflammation, and compromised postoperative liver function. Generally used mouse I/R models are too severe ...and poorly reflect the clinical injury profile. The aim was to establish a mouse I/R model with better translatability using hepatocellular injury, liver function, and innate immune parameters as endpoints.
Mice (C57Bl/6J) were subjected to sham surgery, 30min, or 60min of partial hepatic ischemia. Liver function was measured after 24h using intravital microscopy and spectroscopy. Innate immune activity was assessed at 6 and 24h of reperfusion using mRNA and cytokine arrays. Liver inflammation and function were profiled in two patient cohorts subjected to I/R during liver resection to validate the preclinical results.
In mice, plasma ALT levels and the degree of hepatic necrosis were strongly correlated. Liver function was bound by a narrow damage threshold and was severely impaired following 60min of ischemia. Severe ischemia (60min) evoked a neutrophil-dominant immune response, whereas mild ischemia (30min) triggered a monocyte-driven response. Clinical liver I/R did not compromise liver function and displayed a cytokine profile similar to the mild I/R injury model.
Mouse models using ≤30min of ischemia best reflect the clinical liver I/R injury profile in terms of liver function dynamics and type of immune response.
This short duration of ischemia therefore has most translational value and should be used to increase the prospects of developing effective interventions for hepatic I/R.
•Plasma ALT level and the degree of hepatic necrosis correlate in murine models of hepatic I/R.•Immune signaling differs with the degree of hepatocellular damage.•Liver function is bound by a liver damage threshold in mice.•Mouse models of I/R might not adequately represent clinical hepatic I/R following liver resection.
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