Children with idiopathic short stature have significantly different gut microbiota than their normal height siblings: a case-control study.

Objectives: To investigate the role of gut microbiota (GM) in pathogenesis of idiopathic short stature (ISS) by comparing GM of ISS children to their normal-height siblings. Methods: This case-control study, conducted at the Schneider Children's Medical Center's Institute for Endocrinology and Diabetes between 4/2018-11/2020, involved 30 pairs of healthy pre-pubertal siblings aged 3-10 years, each comprising one sibling with ISS and one with normal height. Outcome measures from fecal analysis of both siblings included GM composition analyzed by 16S rRNA sequencing, fecal metabolomics, and monitoring the growth of germ-free (GF) mice after fecal transplantation. Results: Fecal analysis of ISS children identified higher predicted levels of genes encoding enzymes for pyrimidine, purine, flavin, coenzyme B, and thiamine biosynthesis, lower levels of several amino acids, and a significantly higher prevalence of the phylum Euryarchaeota compared to their normal-height siblings (p<0.001). ISS children with higher levels of Methanobrevibacter, the dominant species in the archaeal gut community, were significantly shorter in stature than those with lower levels (p=0.022). Mice receiving fecal transplants from ISS children did not experience stunted growth, probably due to the eradication of Methanobrevibacter caused by exposure to oxygen during fecal collection. Discussion: Our findings suggest that different characteristics in the GM may explain variations in linear growth. The varying levels of Methanobrevibacter demonstrated within the ISS group reflect the multifactorial nature of ISS and the potential ability of the GM to partially explain growth variations. The targeting of specific microbiota could provide personalized therapies to improve growth in children with ISS.

A Whey-Based Diet Can Ameliorate the Effects of LPS-Induced Growth Attenuation in Young Rats.

Chronic inflammation in childhood is associated with impaired growth. In the current study, a lipopolysaccharide (LPS) model of inflammation in young rats was used to study the efficacy of whey-based as compared to soy-based diets to ameliorate growth attenuation. Young rats were injected with LPS and fed normal chow or diets containing whey or soy as the sole protein source during treatment, or during the recovery period in a separate set of experiments. The body and spleen weight, food consumption, humerus length, and EGP height and structure were evaluated. Inflammatory markers in the spleen and markers of differentiation in the EGP were assessed using qPCR. The LPS led to a significant increase in the spleen weight and a decrease in the EGP height. Whey, but not soy, protected the animals from both effects. In the recovery model, whey led to increased EGP height at both 3 and 16 d post treatment. The most affected region in the EGP was the hypertrophic zone (HZ), which was significantly shortened by the LPS treatment but enlarged by whey. In conclusion, LPS affected the spleen weight and EGP height and had a specific effect on the HZ. Nutrition with whey protein appeared to protect the rats from the LPS-induced growth attenuation.

Different Effects of Soy and Whey on Linear Bone Growth and Growth Pattern in Young Male Sprague-Dawley Rats.

The aim of this investigation was to determine the better protein for supporting optimal linear growth, as the exact composition and benefits of specific dietary proteins in supporting linear growth is unknown. In the current study, we compared the effect of soy and whey proteins, both proteins contain all essential amino acids and are considered the best proteins in their categories. Young male rats were subjected to multiple feeding protocols using iso-energetic diets containing soy or whey as the sole protein source. The rats were allowed to eat ad libitum for 11, 24, or 74 days in the first set of experiments, and the soy group was pair-fed to the whey group in the second set. The differences in weight gain, food consumption, and humeri length of the soy group that were greater at the beginning of the ad libitum experiments lessened over time. Pair-fed experiments revealed that the increased weight and humeri length resulted from the differences in food consumption. However, other parameters were protein specific. Bone quality, which was better in the soy group at 24 days, was matched by the whey group and even surpassed that of the soy group in the long-term experiment, with a significantly greater bone mineral density, cortical thickness, and growth plate. Although in the short term the levels of insulin like growth factor (IGF)-I were similar between the groups, IGF-I increased with age in the whey group, and the levels at the long-term experiment were significantly higher compared to the soy group. Furthermore, using the pair fed setup made it clear that when the difference in food consumption were no longer playing part, whey was more efficient in increasing IGF-I. There were no indications of metabolic sequelae. Although the use of soy is gaining in popularity as a sustainable protein, our findings indicate a better effect of whey on linear growth by leading to slower growth with better-organized epiphyseal growth plates and bone quality.

Cartilage -specific knockout of Sirt1 significantly reduces bone quality and catch-up growth efficiency.

BACKGROUND: Spontaneous catch-up (CU) growth occurs when a growth-restricting factor is resolved. However, its efficiency is sometimes inadequate and growth deficits remain permanent. The therapeutic toolbox for short stature is currently very limited, thus, finding new regulatory pathways is important for the development of novel means of treatment. Our previous studies using a nutrition-induced CU growth model showed that the level of sirtuin-1 (Sirt1) was significantly increased in food-restricted animals and decreased during CU growth. AIM: This study sought to investigate the role of Sirt1 in modulating the response of the epiphyseal growth plate (EGP) to nutritional manipulation. METHOD: Collagen type II-specific Sirt1 knockout (CKO) mice were tested for response to our CU growth model consisting of a period of food restriction followed by re-feeding. RESULTS: The transgenic CKO mice weighed more than the control (CTL) mice, their EGP was higher and less organized, specifically at the resting and proliferative zones, leading to shorter bones. Ablation of Sirt1 in the chondrocytes was found to have a dramatic effect on bone mineralization on micro-CT analysis. The CKO mice were less responsive to the nutritional manipulation, and their CU growth was less efficient. They remained shorter than the CTL mice who corrected the food restriction-induced growth deficit during the re-feeding period. CONCLUSIONS: Sirt1 appears to be important for normal regulation of the EGP. In its absence, the EGP is less organized and CU growth is less efficient. These results suggest that SIRT1 may serve as a novel therapeutic target for short stature.

Beta Palmitate Improves Bone Length and Quality during Catch-Up Growth in Young Rats.

Palmitic acid (PA) is the most abundant saturated fatty acid in human milk, where it is heavily concentrated in the sn-2-position (termed beta palmitate, BPA) and as such is conserved in all women, regardless of their diet or ethnicity, indicating its physiological and metabolic importance. We hypothesized that BPA improves the efficiency of nutrition-induced catch up growth as compared to sn-1,3 PA, which is present in vegetable oil. Pre-pubertal male rats were subjected to a 17 days food restriction followed by re-feeding for nine days with 1,3 PA or BPA-containing diets. We measured bone length, epiphyseal growth plate height (EGP, histology), bone quality (micro-CT and 3-point bending assay), and gene expression (Affymetrix). The BPA-containing diet improved most growth parameters: humeri length and EGP height were greater in the BPA-fed animals. Further analysis of the EGP revealed that the hypertrophic zone was significantly higher in the BPA group. In addition, Affymetrix analysis revealed that the diet affected the expression of several genes in the liver and EGP. Despite the very subtle difference between the diets and the short re-feeding period, we found a small but significant improvement in most growth parameters in the BPA-fed rats. This pre-clinical study may have important implications, especially for children with growth disorders and children with special nutritional needs.

The reliability, concurrent validity and association with salivary oxytocin of the self-report version of the Inventory of Callous-Unemotional Traits in adolescents with conduct disorder.

The present study evaluated the self-report version of the Inventory of Callous-Unemotional Traits (ICU-SR) in terms of reliability, concurrent validity, and correlation with salivary oxytocin levels, a potential biomarker of CU traits. 67 socially at-risk male adolescents (mean 16.2 years) completed the ICU-SR, ICU teacher-version (ICU-TR), Strengths and Difficulties Questionnaire, and their medical files were coded for previous antisocial acts using Brown-Goodwin Lifetime Aggression Scale. Salivary samples were assayed for oxytocin. The reliability of ICU-SR was lower (α = 0.71) than ICU-TR (α = 0.86). ICU-SR mean score was significantly lower than ICU-TR (M = 25.29, SD = 8.02; M = 33.14, SD = 9.47). ICU-TR but not ICU-SR, significantly correlated with history of antisocial acts (r = 0.40). Two-way analysis of variance showed a significant effect of conduct disorder and oxytocin on ICU-TR but not ICU-SR [F(1,59) = 6.53; F(1,59) = 6.08], and a significant interaction only for ICU-TR [F(1,59) = 2.89]. Subjective self-reports of CU traits may be less reliable and valid than teachers' reports.

Salivary oxytocin in adolescents with conduct problems and callous-unemotional traits.

Callous-unemotional (CU) traits correlate with the severity and prognosis of conduct disorder in youth. The neuropeptide oxytocin (OT) has been linked to prosocial behaviors, including empathy and collaboration with others. This study discusses a possible role for OT in the biology of delinquent behavior. We hypothesized that in delinquent youth OT secretion will correlate with the severity of conduct problems and specifically with the level of CU traits. The study group included 67 male adolescents (mean age 16.2 years) undergoing residential treatment, previously assessed by an open clinical interview and history for the psychiatric diagnosis. Staff based Inventory of Callous-Unemotional traits for psychopathy and Strength and Difficulties Questionnaire were administered, and patients' medical and social personal files were systematically coded for previous history of antisocial acts using the Brown-Goodwin Questionnaire. Salivary OT was assayed by ELISA. Salivary OT levels were inversely correlated with conduct problems severity on Strength and Difficulties Questionnaire (r = -0.27; p ≤ 0.01). Recorded history of antisocial acts did not correlate with current OT levels. Odds ratio (OR) for significant CU traits among subjects with conduct problems was increased in low-OT (OR = 14, p ≤ 0.05) but not in high-OT subjects (OR = 6, p ≥ 0.05). Children with conduct problems and low levels of salivary OT are at risk for significant CU traits. These results suggest a possible role for salivary OT as a biomarker for CU traits and conduct problems severity.

Growth without growth hormone: can growth and differentiation factor 5 be the mediator?

Growth without growth hormone (GH) is often observed in the setup of obesity; however, the missing link between adipocytes and linear growth was until now not identified. 3T3L1 cells were induced to differentiate into adipocytes and their conditioned medium (CM) (adipocytes CM, CMA) was added to metatarsals bone culture and compared to CM derived from undifferentiated cells. CMA significantly increased metatarsals bone elongation. Adipogenic differentiation increased the expression of growth and differentiation factor (GDF)-5, also found to be secreted into the CMA. GDF-5 significantly increased metatarsal length in culture; treatment of the CMA with anti-GDF-5 antibody significantly reduced the stimulatory effect on bone length. The presence of GDF-5 receptor (bone morphogenetic protein receptor; BMPR1) in metatarsal bone was confirmed by immunohistochemistry. Animal studies in rodents subjected to food restriction followed by re-feeding showed an increase in GDF-5 serum levels concomitant with nutritional induced catch up growth. These results show that adipocytes may stimulate bone growth and suggest an additional explanation to the growth without GH phenomenon.