Biology subjects

Brunse, A.

Publications and source records attributed to Brunse, A..

12 recordsLinked to original sources

bioRxiv2025

Ketone and glycolytic metabolism are key modulators of inflammation during neonatal sepsis

Neonatal sepsis is a life-threatening condition in preterm infants, primarily due to a dysregulated immunometabolic response to infection. Sepsis and infection mortality are associated with excessive glycolysis-induced inflammation, impaired mitochondrial oxidative phosphorylation (OXPHOS) and loss of disease tolerance. Reduced glucose intake can reverse these dysregulations, but it is unclear how the mechanistic control of glycolysis-OXPHOS balance drives defense strategies and infection outcomes. Here, in a preterm piglet model of neonatal sepsis, glycolysis inhibition with 2-deoxyglucose (2-DG) completely prevents acute infection mortality, reduces systemic inflammation and markers of liver injury, accompanied by enhanced mitochondrial metabolism and disease tolerance. Strikingly, this protection by 2-DG is conferred despite elevated blood glucose levels and higher bacterial burdens than the infected controls. Alternatively, partial replacement of glucose intake with the ketone beta-hydroxybutyrate (BHB) abolishes sepsis-related mortality via improving disease tolerance and clinical parameters. This intervention also shifts the hepatic transcriptome away from inflammatory signaling and towards mitochondrial metabolism. In macrophages in vitro, BHB also exerts anti-inflammatory effects independently of metabolic modulation via the HCAR2 receptor. Finally, data from a cohort of 700 infants confirm an association of plasma BHB levels and anti-inflammatory state. These findings demonstrate that metabolic reprogramming through glycolysis inhibition or ketone supplementation is a promising therapeutic strategy to enhance disease tolerance and improve sepsis outcomes in neonates.

immunology↗

bioRxiv2025

Harnessing systemic glycolysis-TCA cycle axis to boost the host defense against newborn infection

Energy metabolism and immune response are tightly connected, but it is poorly understood how this interplay is regulated in early life to dictate host defense strategy, infection risks and severity. This interplay is particularly relevant for preterm, low birthweight or otherwise immunocompromised infants, who have poor metabolic control and increased risks of sepsis. Here, we utilized data from the COPSAC2010 cohort with 700 mother-child pairs and showed that plasma levels of TCA cycle metabolites in early life were associated with reduced childhood risk of bacterial infection and an attenuated systemic inflammatory response. Next, we explored how two distinct nutritional strategies, which were aimed at boosting TCA cycle activity instead of glycolysis, impacted neonatal host defense against a serious bloodstream infection in preterm piglets. Substituting galactose for glucose in parenteral nutrition enhanced disease tolerance in early phase of infection and overall glucose homeostasis, improving survival. Further, combining glucose restriction with supplementation of glucogenic amino acids conferred glycemic control and completely prevented sepsis and abnormal changes of organ injury markers. Mechanistically, this intervention enhanced both disease resistance and tolerance, accompanied by metabolic rewiring from glycolysis towards gluconeogenesis, TCA cycle activity and oxidative phosphorylation. Thus, optimized nutritional strategies controlling the interplay of energy metabolism and host defense may be lifesaving for infected infants. In briefNewborns rely on two distinct defense strategies to combat infections in early life. Disease resistance, fueled by aerobic glycolysis, seeks to actively eliminate microorganisms while disease tolerance, fueled by mitochondrial oxidative phosphorylation, seeks to reduce collateral tissue damage during infections. We found that in healthy human newborns, increased plasma levels of metabolites from the tricarboxylic acid (TCA) cycle were associated with lower burden of childhood infections and reduced pro-inflammatory status. In a newborn animal model of bloodstream infection, nutritional strategies boosting systemic TCA cycle activity, while reducing aerobic glycolysis, enhanced both host disease tolerance and resistance, thereby improving survival. These findings could pave a path for improved infection management in human newborns. HighlightsO_LIIn healthy children, higher plasma levels of TCA cycle metabolites are associated with lower infection risks and systemic inflammation. C_LIO_LIIn a neonatal infection model, the supply of galactose, instead of glucose, improves host glucose homeostasis and TCA cycle activity, improving disease tolerance and survival. C_LIO_LIA combination of glucose restriction and glucogenic amino acid supply also improves TCA cycle activity, enhancing both disease resistance and tolerance and completely preventing lethal sepsis. C_LI

immunology↗

bioRxiv2025

Characterization of a virulent bacteriophage consortium targeting Enterobacteriaceae from inflamed preterm gut mucosa

Preterm infants have a high risk of intestinal inflammation which can progress to necrotizing enterocolitis (NEC). The gut microbial colonization commencing at birth is essential for proper intestinal maturation, but this process is often disrupted in preterm infants, leading to dysbiosis and increased risk of developing NEC. Bacteriophages (phages), viruses that specifically infect bacteria, are an important constituent of the gut microbiome and protects the gut epithelium against invading bacteria. This study aimed to isolate and characterize phages for use as a preventive measure against NEC-associated bacteria. We initially cultured Enterobacteriaceae from ileal mucosa of preterm piglets that exhibited severe NEC-like pathology. We then screened 23 donor fecal samples for inhibition of bacterial growth and isolated a collection of unique phages to use further. The phages were characterized by whole genome sequencing, host receptor binding determination, and immune cell activation in vitro. The final phage collection consisted of ten virulent phages within five genera, representing myovirus, podovirus and siphovirus morphologies. All phages in the collection induced expression of both pro-and anti-inflammatory genes in co-culture with macrophage-like THP-1 cells, but to different extents than Escherichia coli. Ultimately, we selected one phage for a high-dose oral administration to newborn piglets and assessed its infectivity and presence in different gut segments. This intervention did not result in any direct side effects, while both infective phages and signatures of phage DNA were detected in the intestinal content and mucosa. Having characterized a set of rationally selected virulent phages, we support the advancement of phage therapy as a potential protection against NEC.

microbiology↗

bioRxiv2024

Chemostat culturing reduces fecal eukaryotic virus load and delays diarrhea after virome transplantation

Fecal virome transfer (FVT) shows promise in reducing necrotizing enterocolitis (NEC), likely due to donor bacteriophages preventing the gut dysbiosis preceding disease. However, concurrent transfer of eukaryotic viruses may carry a risk of infection for the recipient. To increase safety, we investigated chemostat propagation as a method to eliminate eukaryotic viruses from donor feces while maintaining a diverse and reproducible bacteriophage community. Donor feces was collected from healthy suckling piglets and inoculated into a fermenter containing growth media supplemented with lactose and milk oligosaccharides (MOs). During continuous medium exchange (20% volume/h), dilution significantly reduced eukaryotic viruses. Viral richness was concurrently reduced although still preserving a stable community of 200-250 bacteriophages. Inclusion of MOs in the medium ensured higher bacterial richness and a bacterial community closer resembling donor feces. Fecal Lactobacillaceae bacteria were lost during cultivation but partially replaced by members of the Bacteroidota phylum in MO-supplemented cultures, accompanied by phages predicted to have Parabacteroides as host. After cultivation, virus-like particles (VLPs) were isolated, and their ability to reduce NEC incidence tested in vivo. Preterm piglets were delivered by cesarean section and received either the lactose- or MO-propagated viromes by oral route (n = 14-15/group). These were compared with groups receiving the same dose of donor fecal virome (1010 VLPs/kg) or vehicle control. The piglets were subsequently fed infant formula for 96 hours followed by euthanasia and tissue sampling. Both chemostat-propagated viromes effectively mitigated diarrhea compared to the donor virome. The donor virome partially engrafted in recipients and led to higher levels of Lactobacillaceae bacteria and Lactobacillaceae targeting phages. However, these signatures were lost in recipients of chemostat-propagated viromes, and only minor microbiome effects and no NEC prevention were observed. To conclude, we provide in vivo proof-of-concept for chemostat propagation of fecal viruses as a means to deplete eukaryotic viruses and in turn reduce side effects in newborn virome recipients. However, chemostat culture conditions need further optimization to preserve the donor phageome.

microbiology↗

bioRxiv2024

Protection against necrotizing enterocolitis by fecal filtrate transfer requires an active donor virome

Necrotizing enterocolitis (NEC) remains a frequent catastrophic disease in preterm infants, but fecal filtrate transfer (FFT) has been identified as a promising prophylactic therapy in preclinical studies. This study examined the importance of the FFT virome viability on gut colonization and NEC occurrence. We established an ultraviolet irradiation-based viral inactivation protocol and demonstrated total loss of infectivity of a viral mock community. Using this protocol, we inactivated an aliquot of sterile-filtered donor feces and compared the response in preterm piglets subjected to experimental NEC induction. Gut pathology and barrier properties were assessed, and bacterial and viral compositions were determined by 16S rRNA amplicon and viral metagenomics sequencing, respectively. Native FFT decreased NEC severity and proinflammatory cytokines, but inactivated FFT (iFFT) completely abolished these effects. Mild side effects in the form of diarrhea manifested earlier in recipients of native FFT than iFFT or controls. A distinct gut colonization pattern of increased viral heterogeneity increased bacterial homogeneity and reduction in pathobionts like Clostridium perfringens and Escherichia was observed in the group receiving native FFT, but not in the iFFT group. The present study uncovered a clear distinction between active and inactivated transferred viromes in the ability to modulate gut colonization after preterm birth and decrease NEC. FFT efficacy is potentially driven by active bacteriophages targeting pathogenic bacteria.

microbiology↗

bioRxiv2024

Reduced glucose supply during neonatal infection attenuates neurological and renal pathology via modulation of innate and Th1 immunity

BackgroundPremature infants are highly susceptible to infections that can lead to sepsis with life-threatening organ dysfunctions. The clinical practice of high parenteral glucose supply in preterm infants can exacerbate infection outcomes through excessive glycolysis-induced inflammatory response. This in turn can affect the health of vital preterm organs, including the brain and kidneys. We hypothesized that reducing glucose supply in infected preterm newborns may help protect against pathology in these two key organs. MethodsCaesarean-delivered preterm pigs were nourished with high or low parenteral glucose levels, infected with Staphylococcus epidermidis or saline, and cared for until 22h. Blood, brain, and kidney samples were collected at the end of the study for analyses. ResultsInfection led to multiple pathological changes, increased inflammation and tissue injury and dysfunction in both brain and kidneys of preterm piglets. Reduced glucose supply in infected animals alleviated neurological degradation, hyperemia and enhanced M2 microglial phenotype in the brain. This intervention also reduced plasma creatinine, renal edema, tubular vacuolization and dilatation. Multiple genes related to innate and Th1 immunity in both organs were highly correlated and dampened by reduced glucose supply, but there were clear signs that renal inflammation was closely connected to systemic inflammation while neuroinflammation was likely driven by immune response to the bacteria translocated into the brain. ConclusionReduced glucose supply can protect brain and kidney health in infected preterm neonates.

immunology↗

bioRxiv2024

A weighted and cumulative point system for accurate scoring of intestinal pathology in a piglet model of necrotizing enterocolitis

BackgroundNecrotizing enterocolitis (NEC) is a serious condition, primarily affecting premature infants, in which a portion of the gut undergoes inflammation and necrosis. Symptoms of NEC are unspecific, and together with a rapid progression, the disease remains a significant concern. The preterm pig develops NEC spontaneously, making it a suitable model for exploring novel treatments. During piglet necropsy, NEC-lesions closely resemble the pathologies found during surgery or autopsy of preterm infants. As such, the systematic gross inspection enables direct evaluation of gut lesions, which is not possible in the medical preterm patient. Here, we introduce a revised intestinal scoring system with an expanded score range and more detailed descriptive features to accurately describe the diversity of NEC-lesions in the preterm piglet model. MethodsWe included 333 preterm piglets from four separate experiments, each delivered via cesarian section at 90% gestation. The pigs were fed either a gently processed (GP) or harshly processed (HP) milk formula for 96 hours and were subsequently euthanized. At necropsy, the gastrointestinal tract was assessed with 1) an established 6-grade scoring system and 2) a systematic and descriptive approach focusing on the distribution and severity of hyperemia, hemorrhage, pneumatosis intestinalis (intramural gas), and necrosis. Lesion biopsies were sampled for cytokine measurement and a subset (n = 62) was sampled for histopathological assessment. ResultsThe systematic and descriptive registrations were evaluated and converted into a weighted and cumulative point (WCP) score. Compared to the 6-grade score, the WCP score enabled a higher discrepancy in severity levels, especially among organs with more prominent NEC lesions. IL-1{beta} in small intestinal lesions and both IL-8 and IL-1{beta} in colon lesions correlated positively with the WCP scale. A histopathological grade system (0-8) was established and revealed mucosal lesions not recognized macroscopically. Finally, the WCP score showed a higher NEC-promoting effect of the HP formula compared to the GP formula. ConclusionThe validation of the weighted and cumulative scoring system demonstrated an expanded score range, enhancing the accuracy in describing NEC-lesions in gastrointestinal segments of preterm pigs. This approach may increase the efficiency of preclinical NEC experiments.

pathology↗

bioRxiv2023

Altered hepatic metabolism mediates sepsis preventive effects of reduced glucose supply in infected preterm newborns

Preterm infants are susceptible to neonatal sepsis, a syndrome of pro-inflammatory activity, organ damage and altered metabolism following infection. Given the unique metabolic challenges and poor glucose regulatory capacity of preterm infants, their glucose intake during infection may have a high impact on the degree metabolism dysregulation and organ damage. Using a preterm pig model of neonatal sepsis, we previously showed that a drastic restriction in glucose supply during infection protects against sepsis via suppression of glycolysis-induced inflammation, but results in severe hypoglycemia. Now we explored clinically relevant options of reducing glucose intake to decrease sepsis risk, without causing hypoglycemia and further explore the involvement of the liver in these protective effects. We found that a reduced glucose regime during infection increased survival via reduced pro-inflammatory response, while maintaining normoglycemia. Mechanistically, this intervention enhanced hepatic oxidative phosphorylation and possibly gluconeogenesis, and dampened both circulating and hepatic inflammation. However, switching from a high to a reduced glucose supply after debut of clinical symptoms did not prevent sepsis, suggesting metabolic conditions at the start of infection are key in driving the outcome. Finally, an early therapy with purified human inter-alpha inhibitor protein, a liver derived anti-inflammatory protein, partially reversed the effects of low parenteral glucose provision, likely by inhibiting neutrophil functions that mediate pathogen clearance. Our findings suggest a clinically relevant regime of reduced glucose supply for infected preterm infants could prevent or delay the development of sepsis in vulnerable neonates.

immunology↗

bioRxiv2023

A reproducible enteric phage community improves blood glucose regulation in an obesity mouse model

Metabolic syndrome encompasses amongst other conditions like obesity, type-2 diabetes, and metabolic dysfunction associated fatty liver disease (MAFLD), which are all associated with gut microbiome (GM) dysbiosis. Fecal microbiota transplantation (FMT) has been explored to treat metabolic syndrome by restoring the GM. FMT is generally safe, but motivated by case reports, accidental transfer of pathogenic bacteria remains a concern. As a safer alternative, fecal virome transplantation (FVT, sterile-filtrated feces) has the advantage over FMT in that mainly bacteriophages are transferred and FVT from lean male donors has shown promise in alleviating the metabolic effects of a high-fat diet in a preclinical mouse study. However, FVT still carries the risk of eukaryotic viral infections. To address this, we here apply recently developed modification methodologies to inactivate or remove the eukaryotic viral component of FVT while maintaining an active enteric bacteriophage community. Modified FVTs were compared with unmodified FVT and saline in an animal model of diet-induced obesity using male C57BL/6N mice. In contrast to the obese control group, mice administered a modified FVT, nearly depleted from eukaryotic viruses (0.1%), exhibited enhanced blood glucose clearance, although without a concurrent reduction in weight gain. The unmodified FVT improved liver pathology and reduced the proportions of immune cells in the adipose tissue with a non-uniform response. GM analysis suggested that bacteriophage-mediated GM modulation had influenced these outcomes. When optimized, this may pave the way for developing safe bacteriophage-based therapies targeting metabolic syndrome through GM restoration.

microbiology↗

bioRxiv2023

Development of safe and effective bacteriophage-mediated therapies against C. difficile infections a proof-of-concept preclinical study

BackgroundFecal microbiota transplantation (FMT) and fecal virome transplantation (FVT, sterile filtrated donor feces) have been effective in treating recurrent Clostridioides difficile infections, possibly through bacteriophage-mediated modulation of the gut microbiome. However, challenges like donor variability, costly screening, coupled with concerns over pathogen transfer (incl. eukaryotic viruses) with FMT or FVT hinders their wider clinical application in treating less acute diseases. MethodsTo overcome these challenges, we developed methods to broaden FVTs clinical application while maintaining efficacy and increasing safety. Specifically, we employed the following approaches: 1) Chemostat-fermentation to reproduce the bacteriophage FVT donor component and remove eukaryotic viruses (FVT-ChP), 2) solvent-detergent treatment to inactivate enveloped viruses (FVT-SDT), and 3) pyronin-Y treatment to inhibit RNA-virus replication (FVT-PyT). We assessed the efficacy of these processed FVTs in a C. difficile infection mouse model and compared them with untreated FVT (FVT-UnT), FMT, and saline. ResultsFVT-SDT, FVT-UnT, and FVT-ChP reduced the incidence of mice reaching the humane endpoint (0/8, 2/7, and 3/8, respectively) compared to the FMT, FVT-PyT, and saline control (5/8, 7/8, and 5/7, respectively) and significantly reduced the load of colonizing C. difficile cells and toxin A/B levels. There was a potential elimination of C. difficile colonization, with 7 out of 8 mice treated with FVT-SDT testing negative with qPCR. In contrast, all other treatments exhibited the continued presence of C. difficile. Moreover, the results were supported by changes in the gut microbiome profiles, cecal cytokine levels and histopathological findings. Assessment of viral engraftment following FMT/FVT treatment and host-phage correlations analysis suggested that transfer of phages likely were an important contributing factor associated with treatment efficacy. ConclusionsThis proof-of-concept study show that specific modifications to FVT hold promise in addressing challenges related to donor variability and infection risks. Two strategies lead to treatments significantly limiting C. difficile colonization in mice, with solvent/detergent treatment and chemostat-propagation emerging as promising approaches.

microbiology↗

bioRxiv2021

Parenteral glucose supply and pharmacological glycolysis inhibition determine the clinical fate of infected preterm newborns

Preterm infants are susceptible to bloodstream infection that can lead to sepsis. High parenteral glucose supplement is commonly used to support their growth and energy expenditure, but may exceed endogenous regulation during infection, causing dysregulated immune response and clinical deterioration. Using a preterm piglet model of neonatal sepsis induced by Staphylococcus epidermidis infection, we demonstrate the delicate interplay between immunity and energy metabolism to regulate the host infection response. Circulating glucose levels, glycolysis and inflammatory response to infection are closely connected across the states of tolerance, resistance and immunoparalysis. Further, high parenteral glucose provision during infection induces hyperglycemia, elevated glycolysis and inflammation, leading to lactate acidosis and sepsis, whereas glucose restricted individuals are clinically unaffected with increased gluconeogenesis to maintain moderate hypoglycemia. Finally, pharmacological glycolysis inhibition during normoglycemia enhances bacterial clearance and dampens inflammation but fails to prevent sepsis. Our results uncover how blood glucose controls immune cell metabolism and function, in turn determining the clinical fate of infected preterm neonates. This also questions the current practice of parenteral glucose supply for infected preterm infants.

pathology↗

bioRxiv2020

Fecal filtrate transfer protects against necrotizing enterocolitis in preterm pigs

Background and aimsNecrotizing enterocolitis (NEC) is an acute and life-threatening gastrointestinal disorder afflicting preterm infants, which is currently unpreventable. Fecal microbiota transplantation (FMT) is a promising preventative therapy, but potential side effects raise concern. Removal of bacteria from donor fecal water may reduce side effects while maintaining wanted effects. We aimed to assess preclinical efficacy and safety of bacteria-free fecal filtrate transfer (FFT). MethodsUsing fecal material from healthy suckling piglets, we administered rectal FMT or cognate FFT by either rectal or oro-gastric administration to formula-fed preterm, cesarean piglets, and compared gut pathology and related safety parameters with saline controls. We then analyzed mucosa and luminal bacterial and viral composition using 16S rRNA gene amplicon and metavirome sequencing, respectively. Finally, we used isolated ileal mucosa, coupled with RNA-Seq, to gauge the host response to the different treatments. ResultsOro-gastric FFT eliminated NEC, which was confirmed by microscopy, whereas FMT did not perform better than control. Moreover, FFT but not FMT reduced intestinal permeability, whereas FMT animals had reduced body weight increase and intestinal growth. Oro-gastric FFT increased viral diversity and reduced Proteobacteria abundance in ileal mucosa relative to control. Global gene expression of host mucosa responded to FMT but not FFT with increased and decreased bacterial and viral defense mechanisms, respectively. ConclusionsAs preterm infants are extremely vulnerable, rational therapies need incontestable safety profiles. Here we show in a clinically relevant animal model that FFT, as opposed to FMT, efficiently prevents NEC without any recognizable side effects. If translatable to preterm infants, this could lead to a change of practice and in turn a reduction in NEC burden.

microbiology↗