Biology subjects

Yamaleyeva, L. M.

Publications and source records attributed to Yamaleyeva, L. M..

3 recordsLinked to original sources

bioRxiv2024

Sex-Specific Cardiovascular Adaptations to Simulated Microgravity in Sprague-Dawley Rats

Men and women have different cardiovascular responses to spaceflight; however few studies have focused on direct comparisons between sexes. Therefore, we investigated cardiovascular system differences, including arterial stiffness between socially and sexually mature 20-week-old male and female Sprague Dawley (SD) rats exposed to hindlimb unloading (HLU) - an analogue for spaceflight-induced microgravity. Two weeks of HLU had no effect on body weight in either male or female rats. The index of arterial stiffness determined by ultrasound, pulse wave velocity (PWV), was greater in the aortic arch and carotid artery of females after HLU versus control females. HLU had no effect on arterial PWV in males. smooth muscle actin, myosin, collagen, elastin, and collagen-to-elastin ratio were not different in rats of either sex in response to HLU. HLU exposure did not alter individual collagen fiber characteristics in studied groups. The levels of G protein-coupled estrogen receptor (GPER) were lower in the aorta of SD females exposed to HLU compared with female controls but not in males. These changes were associated with lower PPAR {gamma} and increased oxidative stress markers (8-hydroxy-2-deoxyguanosine and p47phox) in the females. Diastolic cardiac function was altered in females after HLU versus control females. GPER agonist, G1 prevented the increase in pulse wave velocity and 8-hydroxy-2-deoxyguanosine, without altering PPAR {gamma} or p47phox. Our data revealed that lower GPER in the HLU females contributes to the development of arterial stiffness, and that the SD rat is a suitable model to study the cardiovascular response of females to HLU.

physiology↗

bioRxiv2023

Photoacoustic Imaging for Non-Invasive Assessment of Physiological Biomarkers of Intestinal Injury in Experimental Necrotizing Enterocolitis

BackgroundNecrotizing enterocolitis (NEC) is an often-lethal disease of the premature infants intestinal tract that is exacerbated by significant difficulties in early and accurate diagnosis. In NEC disease, the intestine often exhibits hypoperfusion and dysmotility, which contributes to advanced disease pathogenesis. However, these physiological features cannot be accurately and quantitively assessed within the current constraints of imaging modalities frequently used in the clinic (plain film X-ray and ultrasound). We have previously demonstrated the ability of photoacoustic imaging (PAI) to non-invasively and quantitively assess intestinal tissue oxygenation and motility in a healthy neonatal rat model. As a first-in-disease application, we evaluated NEC pathogenesis using PAI to assess intestinal health biomarkers in a preclinical neonatal rat experimental model of NEC. MethodsNEC was induced in neonatal rat pups from birth to 4 days old via hypertonic formula feeding, full-body hypoxic stress, and lipopolysaccharide administration to mimic bacterial colonization. Healthy breastfed (BF) controls and NEC rat pups were imaged at 2- and 4-days old. Intestinal tissue oxygen saturation was measured with PAI imaging for oxy- and deoxyhemoglobin levels. To measure intestinal motility, ultrasound and co-registered PAI cine recordings were used to capture intestinal peristalsis motion and contrast agent (indocyanine green) transit within the intestinal lumen. Additionally, both midplane two-dimensional and volumetric three-dimensional imaging acquisitions were assessed for oxygenation and motility. ResultsNEC pups showed a significant decrease of intestinal tissue oxygenation as compared to healthy BF controls at both ages (2-days old: 55.90% +/-3.77% vs 44.12% +/-7.18%; 4-days old: 56.13% +/-3.52% vs 38.86% +/-8.33%). Intestinal motility, assessed using a computational intestinal deformation analysis, demonstrated a significant reduction in the intestinal motility index in both early (2-day) and established (4-day) NEC. Extensive NEC damage was confirmed with histology and dysmotility was confirmed by small intestinal transit assay. ConclusionsThis study presents PAI as a successful emerging diagnostic imaging modality for both intestinal tissue oxygenation and intestinal motility disease hallmarks in a rat NEC model. PAI presents enormous significance and potential for fundamentally changing current clinical paradigms for detecting and monitoring intestinal pathologies in the premature infant.

bioengineering↗

bioRxiv2023

Photoacoustic Imaging as a Novel Non-Invasive Biomarker to Assess Intestinal Tissue Oxygenation and Motility in Neonatal Rats

BackgroundWithin the premature infant intestine, oxygenation and motility play key physiological roles in healthy development and disease such as necrotizing enterocolitis. To date, there are limited techniques to reliably assess these physiological functions that are also clinically feasible for critically ill infants. To address this clinical need, we hypothesized that photoacoustic imaging (PAI) can provide non-invasive assessment of intestinal tissue oxygenation and motility to characterize intestinal physiology and health. MethodsUltrasound and photoacoustic images were acquired in 2-day and 4-day old neonatal rats. For PAI assessment of intestinal tissue oxygenation, an inspired gas challenge was performed using hypoxic, normoxic, and hyperoxic inspired oxygen (FiO2). For intestinal motility, oral administration of ICG contrast agent was used to compare control animals to an experimental model of loperamide-induced intestinal motility inhibition. ResultsPAI demonstrated progressive increases in oxygen saturation (sO2) as FiO2 increased, while the pattern of oxygen localization remained relatively consistent in both 2-day and 4-day old neonatal rats. Analysis of intraluminal ICG contrast enhanced PAI images yielded a map of the motility index in control and loperamide treated rats. From PAI analysis, loperamide significantly inhibited intestinal motility, with a 32.6% decrease in intestinal motility index scores in 4-day old rats. ConclusionThese data establish the feasibility and application of PAI to non-invasively and quantitatively measure intestinal tissue oxygenation and motility. This proof-of-concept study is an important first step in developing and optimizing photoacoustic imaging to provide valuable insight into intestinal health and disease to improve the care of premature infants. HighlightsO_LIIntestinal tissue oxygenation and intestinal motility are important biomarkers of intestinal physiology in health and disease of premature infants. C_LIO_LIThis proof-of-concept preclinical rat study is the first to report application of photoacoustic imaging for the neonatal intestine. C_LIO_LIPhotoacoustic imaging is demonstrated as a promising non-invasive diagnostic imaging method for quantifying intestinal tissue oxygenation and intestinal motility in premature infants. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=145 HEIGHT=200 SRC="FIGDIR/small/545971v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@585d0forg.highwire.dtl.DTLVardef@145a2bcorg.highwire.dtl.DTLVardef@bf0c46org.highwire.dtl.DTLVardef@bed354_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗