Development of 24-hour rhythms in cortisol secretion across infancy: a systematic review and meta-analysis of individual participant data.

BACKGROUND: In adults, cortisol levels show a pronounced 24-hour rhythm with a peak in the early morning. It is unknown at what age this early-morning peak in cortisol emerges during infancy, hampering the establishment of optimal dosing regimens for hydrocortisone replacement therapy in infants with an inborn form of adrenal insufficiency. Therefore, we aimed to characterize daily variation in salivary cortisol concentration across the first year of life. METHODS: We conducted a systematic review followed by an individual participant data meta-analysis of studies reporting on spontaneous (i.e., not stress induced) salivary cortisol concentrations in healthy infants aged 0-1 year. A one-stage approach using linear mixed-effects modelling was used to determine the interaction between age and time of day on cortisol concentrations. FINDINGS: Through the systematic review, 54 eligible publications were identified, reporting on 29,177 cortisol observations. Individual participant data were obtained from 15 study cohorts, combining 17,079 cortisol measurements from 1,904 infants. The morning/evening cortisol ratio increased significantly from 1.7 (95% CI: 1.3-2.1) at birth to 3.7 (95% CI: 3.0-4.5) at 6-9 months (p < 0.0001). Cosinor analysis using all available data revealed the gradual emergence of a 24-hour rhythm during infancy. INTERPRETATION: The early-morning peak in cortisol secretion gradually emerges from birth onwards to form a stable morning/evening ratio from age 6-9 months. This might have implications for hydrocortisone replacement therapy in infants with an inborn form of adrenal insufficiency.

Inclusion body myositis, viral infections, and TDP-43: a narrative review.

The ubiquitous RNA-processing molecule TDP-43 is involved in neuromuscular diseases such as inclusion body myositis, a late-onset acquired inflammatory myopathy. TDP-43 solubility and function are disrupted in certain viral infections. Certain viruses, high viremia, co-infections, reactivation of latent viruses, and post-acute expansion of cytotoxic T cells may all contribute to inclusion body myositis, mainly in an age-shaped immune landscape. The virally induced senescent, interferon gamma-producing cytotoxic CD8+ T cells with increased inflammatory, and cytotoxic features are involved in the occurrence of inclusion body myositis in most such cases, in a genetically predisposed host. We discuss the putative mechanisms linking inclusion body myositis, TDP-43, and viral infections untangling the links between viruses, interferon, and neuromuscular degeneration could shed a light on the pathogenesis of the inclusion body myositis and other TDP-43-related neuromuscular diseases, with possible therapeutic implications.

Anemia in Sports: A Narrative Review.

Recent years have brought about new understandings regarding the pathogenesis of anemia in sports. From hemodilution and redistribution considered to contribute to the so-called "sports anemia" to iron deficiency caused by increased demands, dietary restrictions, decreased absorption, increased losses, hemolysis, and sequestration, to genetic determinants of different types of anemia (some related to sport), the anemia in athletes deserves a careful and multifactorial approach. Dietary factors that reduce iron absorption (e.g., phytate, polyphenols) and that augment iron's bioavailability (e.g., ascorbic acid) should be considered. Celiac disease, more prevalent in female athletes, may underlie an unexplained iron deficiency anemia. Iron loss during exercise occurs in several ways: sweating, hematuria, gastrointestinal bleeding, inflammation, and intravascular and extravascular hemolysis. From a practical point of view, assessing iron status, especially in the athletes at risk for iron deficiency (females, adolescents, in sports with dietary restrictions, etc.), may improve the iron balance and possibly the performance. Hemoglobin and serum ferritin are measures that are easily employable for the evaluation of patients' iron status. Cutoff values should probably be further assessed with respect to the sex, age, and type of sport. A healthy gut microbiome influences the iron status. Athletes at risk of iron deficiency should perform non-weight-bearing, low-intensity sports to avoid inducing hemolysis.

Interleukin-1A and interleukin-1B gene polymorphisms in gastroesophageal reflux disease.

Inflammation may play contradictory roles in the pathogenesis of gastroesophageal reflux disease (GERD): gastritis decreases gastric output and reduces the risk of esophagitis, while interleukins may favor mucosal inflammation. The inflammation may cause esogastric motility changes and thus increase the risk of esophagitis. Considering the genetic influence of inflammatory response, we looked for the genetic polymorphisms of IL-1 in GERD manifested as reflux esophagitis. This is a prospective study carried out in GERD and healthy controls. We assessed in these groups the following single nucleotide polymorphisms (SNPs): IL-1A (rs1800587), IL-1B (rs16944), IL-1B (rs1143634) and the VNTR for IL-1RN. Both groups were similar according to biographical data. Reflux esophagitis was confirmed by endoscopy and where necessary by pH-impedance monitoring. Reflux esophagitis was associated only with the polymorphism rs16944. No other correlations with the other three genetic polymorphisms were detected. These data suggest that the diverging effects of proinflammatory factors on the upper digestive tract may have deleterious effect on GERD. The IL-1B (rs16944) SNP correlates with reflux esophagitis.

Insights on Health and Food Applications of Equus asinus (Donkey) Milk Bioactive Proteins and Peptides-An Overview.

Due to its similarity with human milk and its low allergenic properties, donkey milk has long been used as an alternative for infants and patients with cow's milk protein allergy (CMPA). In addition, this milk is attracting growing interest in human nutrition because of presumed health benefits. It has antioxidant, antimicrobial, antitumoral, antiproliferative and antidiabetic activity. In addition, it stimulates the immune system, regulates the gastrointestinal flora, and prevents inflammatory diseases. Although all donkey milk components can contribute to functional and nutritional effects, it is generally accepted that the whey protein fraction plays a significant role. This review aims to highlight the active proteins and peptides of donkey milk in comparison with other types of milk, emphasizing their properties and their roles in different fields of health and food applications.

Allelic distribution of BDNF Val66Met polymorphism in healthy Romanian volunteers.

Population stratification of functional gene polymorphisms is a potential confounding factor in genetic association studies. The Val66Met (rs6265) single-nucleotide polymorphism in the brain-derived neurotrophic factor gene (BDNF) exhibits one of the highest variabilities in terms of allelic distribution between populations. The present study reports the distribution of BDNF Val66Met alleles in a sample of healthy volunteers (N = 1124) selected from the Romanian population. Frequencies were 80.74% for the Val allele and 19.26% for the Met allele. The data from this study extends efforts to map the allelic distribution of BDNF Val66Met in populations around the world and emphasizes that population stratification should be controlled for in future studies that report phenotypic associations in samples from different populations.

Reappraisal as a mediator in the link between 5-HTTLPR and social anxiety symptoms.

Social anxiety symptoms have been related to (a) polymorphisms in the serotonin-transporter gene-promoter region (also, serotonin-transporter-linked polymorphic region; 5-HTTLPR) and (b) reduced use of adaptive forms of emotion regulation such as reappraisal. It is not known, however, whether reappraisal functions as a mediator in the link between 5-HTTLPR and social anxiety. To address this issue, 182 unselected community volunteers were tested for 5-HTTLPR status, and self-report measures of social anxiety symptoms and reappraisal use were obtained. Relative to other participants, those with two low-expressing alleles displayed increased social anxiety and decreased reappraisal. As predicted, the influence of 5-HTTLPR on social anxiety symptoms was transmitted via reappraisal, and this effect of 5-HTTLPR was observed using two different measures of reappraisal. These findings suggest that cognitive reappraisal may be an intermediate phenotype of the social anxiety spectrum, and that individuals with low-expressing 5-HTTLPR genotypes may benefit the most from cognitive-behavioral psychotherapy because they do not appear to engage as frequently as others in reappraisal.

Respiratory sinus arrhythmia and serotonin transporter promoter gene polymorphisms: taking a triallelic approach makes a difference.

It has been recently reported in Psychophysiology that carriers of the short allele of an insertion/deletion (ins/del) functional polymorphism in the promoter region (5-HTTLPR) of the serotonin transporter gene may display decreased resting respiratory sinus arrhythmia (RSA). However, this region hosts another functionally connected single-nucleotide polymorphism (rs25531), which should also be genotyped in order to correctly categorize the low- and high-expressing alleles of 5-HTTLPR. The present study investigated resting RSA in an ethnically homogenous sample (N = 143) of participants genotyped for both the ins/del and rs25531 polymorphisms in 5-HTTLPR. In contrast with the biallelic genotypes, based only on the ins/del alleles, the triallelic 5-HTTLPR genotypes (i.e., including rs25531) showed no association with resting RSA. Taking a triallelic approach to 5-HTTLPR is thus necessary in order to avoid false positive results.