Collagen and Microvascularization in Placentas From Young and Older Mares

In older mares, increasing collagen fibers (fibrosis) in the endometrium and oviduct predisposes to sub-fertility and infertility. In this study, (i) gene transcription of collagen (qPCR: COL1A1, COL1A2, COL3A1, COL5A1); (ii) total collagen protein (hydroxyproline); (iii) collagen distribution (Picrosirius red staining; polarized light microscopy); and (iv) microvascular density (Periodic acid-Schiff staining), were evaluated in mares' placenta, and related to mares age, and placenta and neonate weights. Samples were collected from the gravid horn, non-gravid horn, and body of the placenta from younger (n = 7), and older mares (n = 9) of different breeds. Transcripts of COL1A1, COL3A1 and COL5A1, total collagen protein, chorionic plate connective tissue thickness, and microvascularization increased in the gravid horn of older mares' placentas, compared to the youngest (P < 0.05). Although in other species placenta fibrosis may indicate placental insufficiency and reduced neonate weight, this was not observed here. It appears that older fertile mares, with more parities, may develop a heavier, more vascularized functional placenta with more collagen, throughout a longer gestation, which enables the delivery of heavier foals. Thus, these features might represent morphological and physiological adaptations of older fertile mares' placentas to provide the appropriate nutrition to the equine fetus.

Psychrophiles

Life on the Earth has evolved in the cold environments. Such cold habitats pose special challenges to the microbes in cold ecosystems, such as minimum metabolic activities, very limited nutrient availability, and often extreme conditions such as pH and salinity apart from temperature. Microbial communities surviving under these extreme conditions must have evolved complex structural and functional adaptations. Prokaryotic adaptations to cold environments are through physiological adaptations by increasing membrane fluidity through large amount of unsaturated fatty acids. These microbes also possess some cold adapted proteins whose steady state levels are maintained. They also produce certain compounds such as polyamines, sugars, polyols, amino acids, and some antifreeze proteins to protect themselves under freezing conditions. They also produce exopolymeric substances that promote adhesion of microbes to moist surfaces to induce biofilm formation which helps getting nutrients and protect the cells from harsh conditions. Antioxidants help destroying toxic reactive oxygen species.

Neurobiology of phenotypic plasticity in the light of climate change

Phenotypic plasticity describes the ability of an organism with a given genotype to respond to changing environmental conditions through the adaptation of the phenotype. Phenotypic plasticity is a widespread means of adaptation, allowing organisms to optimize fitness levels in changing environments. A core prerequisite for adaptive predictive plasticity is the existence of reliable cues, i.e. accurate environmental information about future selection on the expressed plastic phenotype. Furthermore, organisms need the capacity to detect and interpret such cues, relying on specific sensory signalling and neuronal cascades. Subsequent neurohormonal changes lead to the transformation of phenotype A into phenotype B. Each of these activities is critical for survival. Consequently, anything that could impair an animal’s ability to perceive important chemical information could have significant ecological ramifications. Climate change and other human stressors can act on individual or all of the components of this signalling cascade. In consequence, organisms could lose their adaptive potential, or in the worst case, even become maladapted. Therefore, it is key to understand the sensory systems, the neurobiology and the physiological adaptations that mediate organisms’ interactions with their environment. It is, thus, pivotal to predict the ecosystem-wide effects of global human forcing. This review summarizes current insights on how climate change affects phenotypic plasticity, focussing on how associated stressors change the signalling agents, the sensory systems, receptor responses and neuronal signalling cascades, thereby, impairing phenotypic adaptations.

Knowledge Gaps in the Fetal to Neonatal Transition of Infants With a Congenital Diaphragmatic Hernia

Clinical research for infants born with a congenital diaphragmatic hernia (CDH) has until recently mainly focused on advances in prenatal and postnatal treatment. However, during the early perinatal transition period there are major physiological adaptations. For most infants these changes will happen uneventfully, but for CDH infants this marks the beginning of serious respiratory complications. In recent years, there is emerging evidence that the clinical management during the perinatal stabilization period in the delivery room may influence postnatal outcomes. Herein, we discuss major knowledge gaps and novel concepts that aim to optimize fetal to neonatal transition for infants with CDH. One such novel and interesting approach is performing resuscitation with an intact umbilical cord, the efficacy of this procedure is currently being investigated in several clinical trials. Furthermore, close evaluation of neonatal physiological parameters in the first 24 h of life might provide early clues concerning the severity of lung hypoplasia and the risk of adverse outcomes. We will provide an overview of trending concepts and discuss potential areas for future research.

Different patterns of chronic hypoxia lead to hierarchical adaptative mechanisms in goldfish metabolism

Some hypoxia-tolerant species, such as goldfish, experience intermittent and severe hypoxia in their natural habitat causing them to develop multiple physiological adaptations. However, in fish, the metabolic impact of regular hypoxic exposure on swimming performance in normoxia is less well understood. Therefore, we experimentally tested whether chronic exposure to constant (30 days at 10% air saturation) or intermittent hypoxia (3hrs in normoxia and 21hrs in hypoxia, 5 days a week) would result in similar metabolic and swimming performance benefits after reoxygenation. Moreover, half of the normoxic and intermittent hypoxic fish were put on a 20-day normoxic training regime. After these treatments, metabolic rate (standard and maximum metabolic rates: SMR and MMR) and swimming performance (critical swimming speed [Ucrit] and cost of transport [COT]) were assessed. In addition, enzyme activities (citrate synthase CS, cytochrome c oxidase COX and lactate dehydrogenase LDH) and mitochondrial respiration were examined in red muscle fibres. We found that acclimation to constant hypoxia resulted in (1) metabolic suppression (-45% SMR, and -27% MMR), (2) increased anaerobic capacity (+117% LDH), (3) improved swimming performance (+80% Ucrit, -71% COT) and (4) no changes at the mitochondrial level. Conversely, the enhancement of swimming performance was reduced following acclimation to intermittent hypoxia (+45% Ucrit, -41% COT), with a 55% decrease in aerobic scope, despite a significant increase in oxidative metabolism (+201% COX, +49% CS). This study demonstrates that constant hypoxia leads to the greatest benefit in swimming performance and that mitochondrial metabolic adjustments only provide minor help in coping with hypoxia.

Electrocardiographic (ECG) Characteristics among Malaysian Athletes

The electrocardiogram (ECG) is a graphic representation of the heart's electrical activity. Although it has some limitations as a diagnostic or prognostic tool, it contains a wealth of information necessary for the proper care of a patient with a potential cardiovascular disease. Understanding the ECG changes among athletes would allow medical practitioners to distinguish between normal physiological adaptations and abnormal changes. However, there is limited data on the ECG characteristics among multi-ethnic athletes such as in Malaysia. This study aimed to determine the ECG characteristics and its associated factors among Malaysian national athletes. Malaysian national athletes annual pre-participation medical records were retrieved. Information on sociodemographic, sports and medical history including the 12-lead resting ECG tracings were extracted. ECG were assessed and categorised into normal, physiological adaptation changes, and abnormal ECG using the standardised ‘Seattle criteria’. Differences in ECG characteristics between genders, ethnic background, and type of sports was investigated. Additionally, factors associated with the ECG characteristics were assessed using multiple logistic regression. Majority of Malaysian national athletes had physiological adaptation ECG changes (61%). The most frequent changes were early repolarization, sinus bradycardia and isolated left ventricular hypertrophy. We found significantly higher prevalence of physiological adaptation changes among men (÷2(2,371) = 18.9; p = 0.001) and athletes of Chinese ethnicity (both genders) (÷2(2,356) = 13.8; p = 0.002). Factors associated with physiological ECG changes were men (OR=2.67; 95% CI= 1.68, 4.27; p<0.001) and Chinese ethnicity (OR=2.92; 95% CI=1.68, 4.27; p=0.039). Most athletes had physiological adaptation ECG changes which were significantly associated with male gender and Chinese ethnicity. This information would facilitate the development of a specific guideline in interpreting ECG among Malaysian athletes.