Background
Short-chain fatty acids (SCFAs) produced by the gut microbiota have beneficial anti-inflammatory and gut homeostasis effects and prevent type 1 diabetes (T1D) in mice. Reduced SCFA production indicates a loss of beneficial bacteria, commonly associated with chronic autoimmune and inflammatory diseases, including T1D and type 2 diabetes. Here, we addressed whether a metabolite-based dietary supplement has an impact on humans with T1D. We conducted a single-arm pilot-and-feasibility trial with high-amylose maize-resistant starch modified with acetate and butyrate (HAMSAB) to assess safety, while monitoring changes in the gut microbiota in alignment with modulation of the immune system status.
Results
HAMSAB supplement was administered for 6 weeks with follow-up at 12 weeks in adults with long-standing T1D. Increased concentrations of SCFA acetate, propionate, and butyrate in stools and plasma were in concert with a shift in the composition and function of the gut microbiota. While glucose control and insulin requirements did not change, subjects with the highest SCFA concentrations exhibited the best glycemic control. Bifidobacterium longum, Bifidobacterium adolescentis, and vitamin B7 production correlated with lower HbA1c and basal insulin requirements. Circulating B and T cells developed a more regulatory phenotype post-intervention.
Conclusion
Changes in gut microbiota composition, function, and immune profile following 6 weeks of HAMSAB supplementation were associated with increased SCFAs in stools and plasma. The persistence of these effects suggests that targeting dietary SCFAs may be a mechanism to alter immune profiles, promote immune tolerance, and improve glycemic control for the treatment of T1D.
Trial registration
ACTRN12618001391268. Registered 20 August 2018,https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375792
Human milk and a typical formula elicit similar postprandial glycaemic and insulinaemic responses, but there is a wide range of responses to other formulas.
Background
Cerebrospinal fluid (CSF) circulation in the brain has garnered considerable attention in recent times. In contrast, there have been fewer studies focused on the spine, despite the expected importance of CSF circulation in disorders specific to the spine, including syringomyelia. The driving forces that regulate spinal CSF flow are not well defined and are likely to be different to the brain given the anatomical differences and proximity to the heart and lungs. The aims of this study were to determine the effects of heart rate, blood pressure and respiration on the distribution of CSF tracers in the spinal subarachnoid space, as well as into the spinal cord interstitium.
Methods
In Sprague Dawley rats, physiological parameters were manipulated such that the effects of spontaneous breathing (generating alternating positive and negative intrathoracic pressures), mechanical ventilation (positive intrathoracic pressure only), tachy/bradycardia, as well as hyper/hypotension were separately studied. To investigate spinal CSF hydrodynamics, in vivo near-infrared imaging of intracisternally infused indocyanine green was performed. CSF tracer transport was further characterised with in vivo two-photon intravital imaging. Tracer influx at a microscopic level was quantitatively characterised by ex vivo epifluorescence imaging of fluorescent ovalbumin.
Results
Compared to mechanically ventilated controls, spontaneous breathing animals had significantly greater movement of tracer in the subarachnoid space. There was also greater influx into the spinal cord interstitium. Hypertension and tachycardia had no significant effect on spinal subarachnoid spinal CSF tracer flux and exerted less effect than respiration on tracer influx into the spinal cord.
Conclusions
Intrathoracic pressure changes that occur over the respiratory cycle, particularly decreased intrathoracic pressures generated during inspiration, have a profound effect on tracer movement after injection into spinal CSF and increase cord parenchymal tracer influx. Arterial pulsations likely drive fluid transport from perivascular spaces into the surrounding interstitium, but their overall impact is less than that of the respiratory cycle on net tracer influx.
Changes in labile soil phosphorus pools, together with changes in organic matter and total organic soil phosphorus levels, were measured following rhododendron harvest and hurricane windthrow events at the Coweeta Long Term Ecological Research (LTER) site. Seasonal soil samples were 1 taken every 3 months from June 1996 to September 1997. Soil cores were taken along four transects within each study area at distances approximately 1, 5, and 15 m upslope from the stream channel. Levels of resin P were low for all sites and sampling dates (<5 [jug PO 4 -P g soil" 1 ). Levels of bicarbonate inorganic P were <8 (jig PO 4 -P g soil" 1 for all sites and sampling dates, whereas bicarbonate organic P levels were somewhat higher and ranged from 6.5 to 26.6 jjig PO 4 -P g soil"
1. Microbial P levels were the most variable and ranged from 4.5 to 25.8 |xg PO 4 -P g soil"
1. In contrast, total organic P levels were high, 149 to 348 (jug PO 4 -P g soil"
1. For the 3 years after the disturbance events, there were no significant changes in labile phosphorus pools or in total organic phosphorus levels in the soil. This lack of significant differences is likely attributable to the low phosphorus, high P-sorbing status of the soils at Coweeta and the lack of erosion that followed these disturbance events. (Soil Science 1999;164:391-402)
Existing conceptualizations and measures of good sex are varied and inconclusive. Additionally, few studies have defined good sex from the margins, thus definitions are primarily informed from privileged perspectives. People with marginalized racial, gender, and sexual identities can offer culturally informed definitions of good sex that may expand current definitions. This study fills that gap by identifying factors that constitute good sex among Black people with diverse sexual and gender identities. Data were collected from 448 Black individuals who participated in an online Qualtrics survey with demographic, open-ended, and scaled questions. Results indicate a range of descriptors that align with existing sexual wellness literature and include the top 20 words to describe good sex as well as the top 10 words for demographics of interest. Differences in most frequent descriptors based on gender and sexual identities are reported. These results provide a foundation for sexual health practitioners, educators, and therapists to improve societal knowledge about what constitutes good sex among Black people.
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