Biology subjects

Brunse, A.

Publications and source records attributed to Brunse, A..

5 recordsLinked to original sources

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↗