scholarly journals Expression of Kisspeptin, Neurokinin B, and Dynorphin During Pubertal Development in Female Sheep

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A539-A539
Author(s):  
Eliana G Aerts ◽  
KaLynn E Harlow ◽  
Max J Griesgraber ◽  
Elizabeth C Bowdridge ◽  
Steven L Hardy ◽  
...  

Abstract Puberty onset depends upon an increase in pulsatile GnRH/LH secretion, which in sheep is the result of reduced sensitivity to estrogen negative feedback. Neurons within the arcuate nucleus of the hypothalamus (ARC) expressing kisspeptin, neurokinin B (NKB), and dynorphin (i.e. KNDy neurons) express estrogen receptors and are believed to play a key role in mediating the effects of estrogen on GnRH/LH secretion. Therefore, the purpose of this study was to assess changes in kisspeptin, NKB, and dynorphin within the ARC across pubertal development in female sheep. Blood samples were collected at 12-minute intervals for 4 hours and assessed for LH secretion in five age groups of ewes: 5 months (n=6), 6 months (n=6), 7 months (n=5), 8 months (n=5), and 10 months (n=6) of age. Following each bleed, ewes were sacrificed, hypothalamic tissue containing the ARC was collected, and then processed for use in dual immunofluorescence and RNAscope. Mean LH and LH pulse frequencies followed the expected patterns: concentrations and frequencies were low during the prepubertal ages (5-7 months of age), intermediate during the peripubertal age (8 months of age), and elevated in the postpubertal age group (10 months of age). Using immunofluorescence, kisspeptin and NKB immuno-positive cell numbers did not change significantly (P > 0.50) over time with cell numbers averaging 235.3±16.8 and 231.3±16.8, respectively. Colocalization of kisspeptin and NKB was greater than 90% for all age groups. Using RNAscope, the total number of cells expressing mRNA for kisspeptin and dynorphin did not change significantly (P > 0.05) over time with cell numbers averaging 46.7±12.0 and 28.3±10.0 cells/hemisection, respectively. Taken together, our data suggest that the increase in LH secretion that drives puberty onset is not limited by changes in kisspeptin, NKB, or dynorphin expression, but may instead depend on other factors such as changes in receptor expression or changes in KNDy neuron activity via a reduction in inhibitory and/or an increase in stimulatory afferent inputs.

Endocrinology ◽  
2012 ◽  
Vol 153 (6) ◽  
pp. 2756-2765 ◽  
Author(s):  
Casey C Nestor ◽  
Amanda M.S. Briscoe ◽  
Shay M. Davis ◽  
Miro Valent ◽  
Robert L. Goodman ◽  
...  

Puberty onset in female sheep is marked by a decrease in estradiol-negative feedback, allowing for the increase in GnRH and LH pulses that heralds the first ovulation. Based on recent genetic studies in humans, two possible neuropeptides that could promote puberty onset are kisspeptin and neurokinin B (NKB). Our first experiment determined whether the NKB agonist, senktide, could stimulate LH secretion in prepubertal ewes. A second study used prepubertal and postpubertal ewes that were intact or ovariectomized (OVX) to test the hypothesis that expression of kisspeptin and NKB in the arcuate nucleus increased postpubertally. For comparison, kisspeptin and NKB expression in age-matched intact, and castrated males were also examined. In experiment 1, the percentage of ewes showing an LH pulse immediately after injection of senktide (100 μg, 60%; 500 μg, 100%) was greater than that for water-injected controls (experiment 1a, 25%; experiment 1b, 20%). In experiment 2, kisspeptin-positive cell numbers in the arcuate nucleus increased after puberty in intact females and were increased by OVX in prepubertal but not postpubertal ewes. Changes in kisspeptin cell numbers were paralleled by changes in kisspeptin-close contacts onto GnRH neurons in the medial preoptic area. NKB cell numbers did not differ significantly between intact prepubertal and postpubertal ewes but increased with OVX in both age groups. NKB fiber immunoreactivity was greater in postpubertal than in prepubertal intact ewes. In age-matched males, kisspeptin and NKB cell numbers increased with castration, but decreased with age. These results support the hypothesis that kisspeptin is a gatekeeper to female ovine puberty and raise the possibility that NKB may also play a role, albeit through different means.


Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 988
Author(s):  
Eliana G. Aerts ◽  
KaLynn Harlow ◽  
Max J. Griesgraber ◽  
Elizabeth C. Bowdridge ◽  
Steven L. Hardy ◽  
...  

The neural mechanisms underlying increases in gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion that drive puberty onset are unknown. Neurons coexpressing kisspeptin, neurokinin B (NKB), and dynorphin, i.e., KNDy neurons, are important as kisspeptin and NKB are stimulatory, and dynorphin inhibitory, to GnRH secretion. Given this, we hypothesized that kisspeptin and NKB expression would increase, but that dynorphin expression would decrease, with puberty. We collected blood and hypothalamic tissue from ovariectomized lambs implanted with estradiol at five, six, seven, eight (puberty), and ten months of age. Mean LH values and LH pulse frequency were the lowest at five to seven months, intermediate at eight months, and highest at ten months. Kisspeptin and NKB immunopositive cell numbers did not change with age. Numbers of cells expressing mRNA for kisspeptin, NKB, or dynorphin were similar at five, eight, and ten months of age. Age did not affect mRNA expression per cell for kisspeptin or NKB, but dynorphin mRNA expression per cell was elevated at ten months versus five months. Thus, neither KNDy protein nor mRNA expression changed in a predictable manner during pubertal development. These data raise the possibility that KNDy neurons, while critical, may await other inputs for the initiation of puberty.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 127-128
Author(s):  
KaLynn Harlow ◽  
Allison Renwick ◽  
Sydney Shuping ◽  
Jeff Sommer ◽  
Mark Knauer ◽  
...  

Abstract Advancing gilt puberty onset is financially desirable for swine production. Neurons in the hypothalamic arcuate nucleus (ARC) that co-express kisspeptin, neurokinin B (NKB), and dynorphin (i.e. KNDy cells) are believed to control gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion, but their role in gilt pubertal development is unknown. We hypothesized that puberty onset in gilts would coincide with greater expression of mRNA for kisspeptin and NKB, and less expression of dynorphin. Using fluorescent in situ hybridization (RNAscope), we examined expression of kisspeptin, NKB, and dynorphin in pre- and postpubertal gilts from two genetic lines divergently selected for age at puberty. Prepubertal (n = 6/line) and postpubertal (n = 6/line) gilts were used, and postpubertal animals all received Matrix (0.22% altrenogest) orally for 14 days with tissue collection two days after the final dose. Gilts were euthanized and heads were perfused with 8 L of 4% paraformaldehyde (PFA). Hypothalamic brain tissue was removed, placed in 4% PFA for 24 hrs, and then in 20% sucrose until sectioning (50 µm). Sectioned tissue was stored in cryopreservative at -20°C until RNAscope. Data were analyzed using SAS software (Version 9.4, SAS Institute, Cary NC) with significance declared at P < 0.05. We determined mRNA expression for kisspeptin was not different between groups (P > 0.05). In addition, we found that mRNA expression for NKB was higher in prepubertal gilts compared to postpubertal gilts (P < 0.05) but was not different between lines; mRNA expression was lowest in postpubertal late puberty gilts. Furthermore, total number of dynorphin cells were higher in prepubertal gilts compared to postpubertal gilts (P < 0.05), while individual cell mRNA expression for dynorphin was greatest in postpubertal early puberty gilts (P < 0.05). Taken together, we suggest puberty onset in gilts is more dependent on NKB and dynorphin than kisspeptin.


2020 ◽  
Vol 33 (11) ◽  
pp. 1449-1455
Author(s):  
Suzana Nesi-França ◽  
Rodrigo B. Silveira ◽  
Juliana Cristina R. Rojas Ramos ◽  
Adriane A. Cardoso-Demartini ◽  
Monica N. Lima Cat ◽  
...  

AbstractObjectivesAdequate treatment of congenital hypothyroidism (CH) is required for normal growth and sexual development. To evaluate pubertal development in patients with permanent CH detected by a statewide Neonatal Screening Program of Paraná and, secondly, to evaluate adult height (AH) in a subgroup of patients.MethodsClinical, laboratory, and auxological data obtained from medical records of 174 patients (123 girls).ResultsMedian chronological age (CA) at treatment initiation was 24 days, and mean initial levothyroxine dose was 11.7 ± 1.9 μg/kg/day; mean CA at puberty onset was 11.5 ± 1.3 years (boys) and 9.7 ± 1.2 years (girls); mean CA in girls who underwent menarche (n=81) was 12.1 ± 1.1 years. Thyroid-stimulating hormone (TSH) values above the normal range were observed in 36.4% of the boys and 32.7% of the girls on puberty onset, and in 44.6% around menarche. Among 15 boys and 66 girls who had reached the AH, the median height z-score value was significantly greater than the target height (TH) z-score value in boys (p=0.01) and in girls (p<0.001). Boys with normal TSH values at puberty onset had greater mean AH z-score compared with boys with TSH values above the normal range (p=0.04).ConclusionsIn this group, pubertal development in girls with CH was not different from that reported in healthy girls in the general Brazilian population. Boys with higher TSH at puberty onset may have an increased risk of not reaching their potential height compared with those with normal TSH during this period. In a subgroup who attained AH, the median AH z-score was greater than the median TH z-score.


2021 ◽  
pp. 1-10
Author(s):  
Lea Oelkers ◽  
Mandy Vogel ◽  
Agnes Kalenda ◽  
Hans Christian Surup ◽  
Antje Körner ◽  
...  

Introduction: Current health literature suggests that there has been a decline in the age of pubertal onset and that pubertal onset/duration of puberty may, besides weight status, be influenced by socioeconomic context. Objective: The goal of this study was to determine whether pubertal onset/duration and puberty-triggering hormones luteinizing hormone (LH) and follicle-stimulating hormone (FSH) vary according to socioeconomic status (SES). Moreover, we aimed to propose cutoff values of serum LH and FSH for predicting gonadarche in boys. Methods: 2,657 apparently healthy children and adolescents between 5.5 and 18 years from the area of Leipzig were recruited from the LIFE Child study. Age at pubertal onset/end of puberty was given in 738/573 children, respectively. Anthropometric parameters of puberty, blood measurements of LH and FSH, and questionnaires assessing SES were evaluated. Results: Lower SES was associated with earlier thelarche and longer duration of puberty in overweight/obese girls, whereas age of menarche was not affected. In boys with low SES, a trend versus earlier puberty onset can be seen. Lower SES was significantly associated with boys’ age at mutation. No significant differences in boys’ and girls’ serum levels of LH and FSH during puberty according to SES were observed. Serum LH levels of 0.56 IU/L and serum FSH levels of 1.74 IU/L showed the best prediction of gonadarche in boys. Conclusion: Puberty onset/duration and boys’ age at mutation is affected by SES. The proposed cutoff levels for serum LH and FSH could provide a serological tool to determine gonadarche in boys.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 410-410
Author(s):  
Vineet Raichur ◽  
Lindsay Ryan ◽  
Richard Gonzalez ◽  
Jacqui Smith

Abstract Cross-sectional analyses of internet use patterns among older adults find that the rate of internet use is less with greater physical and memory difficulties. It is not clear, however, how age-cohorts differ in their internet use as physical and memory difficulties increase over time. In addition to factors such as increasing accessibility (cost) and social influences, the expansion and cognitive complexity of functions performed by the internet-enabled devices over time could influence internet use patterns. In this study, we investigate how the association between internet use and episodic memory difficulties over time varies between cohorts. We analyzed longitudinal data from the Health and Retirement Study (N = 15,703 in 2002; Aged 51 and older) between years 2002-2016 using mixed effects logistic regression models. Immediate and delayed word recall measures were used to assess episodic memory. Rate of internet use in the sample increased from 30% in 2002 to 53% in 2016. Rate of internet use among younger age groups was significantly higher in the baseline year. Younger age groups also showed a significantly higher rate of increase in internet use over time. In general, internet use decreased with episodic memory impairment. In addition to these effects, the effect of episodic memory on the rate of increase in internet use over time is lower in younger cohorts. These results indicate that younger cohorts of older adults are more likely to maintain internet use as they continue to age and therefore could better utilize technology for communication, social interactions and health interventions.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 156.1-156
Author(s):  
E. Yen ◽  
D. Singh ◽  
M. Wu ◽  
R. Singh

Background:Premature mortality is an important way to quantify disease burden. Patients with systemic sclerosis (SSc) can die prematurely of disease, however, the premature mortality burden of SSc is unknown. The years of potential life lost (YPLL), in addition to age-standardized mortality rate (ASMR) in younger ages, can be used as measures of premature death.Objectives:To evaluate the premature mortality burden of SSc by calculating: 1) the proportions of SSc deaths as compared to deaths from all other causes (non-SSc) by age groups over time, 2) ASMR for SSc relative to non-SSc-ASMR by age groups over time, and 3) the YPLL for SSc relative to other autoimmune diseases.Methods:This is a population-based study using a national mortality database of all United States residents from 1968 through 2015, with SSc recorded as the underlying cause of death in 46,798 deaths. First, we calculated the proportions of deaths for SSc and non-SSc by age groups for each of 48 years and performed joinpoint regression trend analysis1to estimate annual percent change (APC) and average APC (AAPC) in the proportion of deaths by age. Second, we calculated ASMR for SSc and non-SSc causes and ratio of SSc-ASMR to non-SSc-ASMR by age groups for each of 48 years, and performed joinpoint analysis to estimate APC and AAPC for these measures (SSc-ASMR, non-SSc-ASMR, and SSc-ASMR/non-SSc-ASMR ratio) by age. Third, to calculate YPLL, each decedent’s age at death from a specific disease was subtracted from an arbitrary age limit of 75 years for years 2000 to 2015. The years of life lost were then added together to yield the total YPLL for each of 13 preselected autoimmune diseases.Results:23.4% of all SSc deaths as compared to 13.5% of non-SSc deaths occurred at <45 years age in 1968 (p<0.001, Chi-square test). In this age group, the proportion of annual deaths decreased more for SSc than for non-SSc causes: from 23.4% in 1968 to 5.7% in 2015 at an AAPC of -2.2% (95% CI, -2.4% to -2.0%) for SSc, and from 13.5% to 6.9% at an AAPC of -1.5% (95% CI, -1.9% to -1.1%) for non-SSc. Thus, in 2015, the proportion of SSc and non-SSc deaths at <45 year age was no longer significantly different. Consistently, SSc-ASMR decreased from 1.0 (95% CI, 0.8 to 1.2) in 1968 to 0.4 (95% CI, 0.3 to 0.5) per million persons in 2015, a cumulative decrease of 60% at an AAPC of -1.9% (95% CI, -2.5% to -1.2%) in <45 years old. The ratio of SSc-ASMR to non-SSc-ASMR also decreased in this age group (cumulative -20%, AAPC -0.3%). In <45 years old, the YPLL for SSc was 65.2 thousand years as compared to 43.2 thousand years for rheumatoid arthritis, 18.1 thousand years for dermatomyositis,146.8 thousand years for myocarditis, and 241 thousand years for type 1 diabetes.Conclusion:Mortality at younger ages (<45 years) has decreased at a higher pace for SSc than from all other causes in the United States over a 48-year period. However, SSc accounted for more years of potential life lost than rheumatoid arthritis and dermatomyositis combined. These data warrant further studies on SSc disease burden, which can be used to develop and prioritize public health programs, assess performance of changes in treatment, identify high-risk populations, and set research priorities and funding.References:[1]Yen EY….Singh RR. Ann Int Med 2017;167:777-785.Disclosure of Interests:None declared


2016 ◽  
Vol 130 (8) ◽  
pp. 706-711 ◽  
Author(s):  
O Hilly ◽  
E Hwang ◽  
L Smith ◽  
D Shipp ◽  
J M Nedzelski ◽  
...  

AbstractBackground:Cochlear implantation is the standard of care for treating severe to profound hearing loss in all age groups. There is limited data on long-term results in elderly implantees and the effect of ageing on outcomes. This study compared the stability of cochlear implantation outcome in elderly and younger patients.Methods:A retrospective chart review of cochlear implant patients with a minimum follow up of five years was conducted.Results:The study included 87 patients with a mean follow up of 6.8 years. Of these, 22 patients were older than 70 years at the time of implantation. Hearing in Noise Test scores at one year after implantation were worse in the elderly: 85.3 (aged under 61 years), 80.5 (61–70 years) and 73.6 (aged over 70 years;p= 0.039). The respective scores at the last follow up were 84.8, 85.1 and 76.5 (p= 0.054). Most patients had a stable outcome during follow up. Of the elderly patients, 13.6 per cent improved and none had a reduction in score of more than 20 per cent. Similar to younger patients, elderly patients had improved Short Form 36 Health Survey scores during follow up.Conclusion:Cochlear implantation improves both audiometric outcome and quality of life in elderly patients. These benefits are stable over time.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Abhinav J Appukutty ◽  
Lesli E Skolarus ◽  
Mellanie V Springer ◽  
William J Meurer ◽  
James F Burke

Introduction: Stroke incidence is reportedly increasing in younger adults. While increasing vascular risk factor prevalence has been suggested as a cause, the reasons for rising stroke incidence in the young are not clear. We explored several alternate explanations: trends in neurologically-focused emergency department (ED) visits, differential diagnostic classification of stroke and TIA over time, and changes in the use of advanced imaging in young and older adults. Methods: We performed a retrospective, serial, cross-sectional study on a nationally representative sample of all ED visits in the United States to quantify changes in patterns of neurologically-focused ED visits, stroke and TIA diagnoses, and rates of MRI utilization for young (18 – 44 years) and older (65+ years) adults over a 17-year period (1995 – 2000; 2005 – 2015) using National Hospital Ambulatory Medical Care Survey (NHAMCS) data. Results: In young adults, 0.4% (95% CI 0.3% – 0.5%) of neurologically-focused ED visits resulted in a primary diagnosis of stroke vs. 6.8% (95% CI 6.2% – 7.5%) for older adults. In both populations, the incidence of neurologically-focused ED visits has increased over time (+111/100,000 population/year, 95% CI +94 – +130 in the young vs. +70/100,000 population/year, 95% CI +34 – +108 in older adults). There was no evidence of differential classification of TIA to stroke over time (OR 1.001 per year, 95% CI 0.926 – 1.083 in the young; OR 1.003 per year, 95% CI 0.982 – 1.026 in older adults) and no evidence of disproportionate rise in MRI utilization for neurologically-focused ED visits in the young (OR 1.057 per year, 95% CI 1.028 – 1.086 in the young; OR 1.095 per year, 95% CI 1.066 – 1.125 in older adults). Conclusions: If the specificity of stroke diagnosis amongst ED visits is similar amongst young and older populations, then the combination of data observed here, including (1) a lower prior probability of stroke diagnoses in the young and (2) an increasing trend in neurologically-focused ED visits in both age groups, suggests that false positive diagnoses will increase over time, with a faster rise in the young compared to older adults. These data suggest a potential explanation that may contribute to higher stroke incidence in the young and merits further scrutiny.


2021 ◽  
Author(s):  
Zeyu Lyu ◽  
Hiroki Takikawa

BACKGROUND The availability of large-scale and fine-grained aggregated mobility data has allowed researchers to observe the dynamic of social distancing behaviors at high spatial and temporal resolutions. Despite the increasing attentions paid to this research agenda, limited studies have focused on the demographic factors related to mobility and the dynamics of social distancing behaviors has not been fully investigated. OBJECTIVE This study aims to assist in the design and implementation of public health policies by exploring the social distancing behaviors among various demographic groups over time. METHODS We combined several data sources, including mobile tracking data and geographical statistics, to estimate visiting population of entertainment venues across demographic groups, which can be considered as the proxy of social distancing behaviors. Then, we employed time series analyze methods to investigate how voluntary and policy-induced social distancing behaviors shift over time across demographic groups. RESULTS Our findings demonstrate distinct patterns of social distancing behaviors and their dynamics across age groups. The population in the entertainment venues comprised mainly of individuals aged 20–40 years, while according to the dynamics of the mobility index and the policy-induced behavior, among the age groups, the extent of reduction of the frequency of visiting entertainment venues during the pandemic was generally the highest among younger individuals. Also, our results indicate the importance of implementing the social distancing policy promptly to limit the spread of the COVID-19 infection. However, it should be noticed that although the policy intervention during the second wave in Japan appeared to increase the awareness of the severity of the pandemic and concerns regarding COVID-19, its direct impact has been largely decreased could only last for a short time. CONCLUSIONS At the time we wrote this paper, in Japan, the number of daily confirmed cases was continuously increasing. Thus, this study provides a timely reference for decision makers about the current situation of policy-induced compliance behaviors. On the one hand, age-dependent disparity requires target mitigation strategies to increase the intention of elderly individuals to adopt mobility restriction behaviors. On the other hand, considering the decreasing impact of self-restriction recommendations, the government should employ policy interventions that limit the resurgence of cases, especially by imposing stronger, stricter social distancing interventions, as they are necessary to promote social distancing behaviors and mitigate the transmission of COVID-19. CLINICALTRIAL None


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