SummaryDietary restriction (DR) is well known as a nongenetic intervention that robustly extends lifespan in a variety of species; however, its underlying mechanisms remain unclear. We have found in Caenorhabditis elegans that dietary deprivation (DD) during adulthood, defined as removal of their food source Escherichia coli after the completion of larval development, increased lifespan and enhanced thermotolerance and resistance to oxidative stress. DD-induced longevity was independent of one C. elegans SIRTUIN, sir-2.1 , which is required for the effects of DR, and was independent of the daf-2 /insulin-like signaling pathway that independently regulates longevity and larval diapause in C. elegans . DD did not significantly alter lifespan of fem-1(hc17) ; eat-2(ad465) worms, a genetic model of DR. These findings suggest that DD and DR share some downstream effectors. In addition, DD was detrimental for longevity when imposed on reproductively active young adults, suggesting that DD may only be beneficial in the absence of competing metabolic demands, such as fertility. Adult-onset DD offers a new paradigm for investigating dietary regulation of longevity in C. elegans . This study presents the first evidence that long-term DD, instead of being detrimental, can extend lifespan of a multicellular adult organism.
We believe that LM is the strongest predictor of BMD at all ages for Chinese men and women, even though positive correlations between FM and BMD existed in old people.
Background. 3β-HSD deficiency is a rare type of congenital adrenal hyperplasia (CAH), which is caused by HSD3B2 gene mutations.Objectives. In order to improve the understanding and diagnosis of the disease, we analyzed and summarized the clinical characteristics, genetic variants and treatment for 3 children with 3β-HSD deficiency in this study. Materials and methods.A summary of the clinical data, hormone levels (17-hydroxyprogesterone, adrenocorticotropic hormone, cortisol, testosterone, dehydroepiandrosterone, androstenedione, renin, and aldosterone), therapeutic drugs, and gene sequencing results from 3 3β-HSD deficiency patients was created.Results. The 3 patients developed external genital abnormalities and adrenal insufficiency in infancy. Steroid hormone levels were consistent with 3β-hydroxysteroid dehydrogenase deficiency. Gene sequencing for the 3 patients detected complex heterozygous mutations in the HSD3B2 gene, which confirmed the diagnosis of 3β-HSD deficiency type II. Among the mutation types, c. 154_162delinsTCCTGTT and c.674T>A have not been reported in the literature. The 3 children were treated with glucocorticoid and mineralocorticoid replacement, which controlled the adrenal insufficiency satisfactorily. In 2 male patients, external genital dysplasia manifested as hypospadias and small penis. After long-acting testosterone intramuscular injection to increase the penis size, the hypospadias were repaired. Mild masculinization in the female patient resulted in skin pigmentation and clitoral hypertrophy; however, no surgical intervention was required. Conclusions.The main clinical manifestations of 3β-HSD deficiency were adrenal insufficiency and sex hormone synthesis dysfunction. There was a strong phenotype correlation between the observed clinical manifestations in conjunction with steroid hormone levels and HSD3B2 mutations. The novel mutations c. 154_162delinsTCCTGTT and c.674T>A were classified as pathogenic variants. Adrenal cortical function control was satisfactory after hormone replacement therapy, and hypospadias and small penis were attenuated using testosterone replacement therapy during mini-puberty for optimal surgical outcome.
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