Age-dependent Morphological Changes Research Articles

Probing the morphological and mechanical changes in a C. elegans model of Huntington's disease.

Huntington's Disease (HD) is a fatal neurodegenerative disease caused by a mutation in the huntingtin gene, in which CAG nucleotides are excessively repeated. In turn, translated huntingtin protein (htt) contains an expanded polyglutamine (polyQ) domain, which triggers toxic protein aggregation, the hallmark feature of this disease. Common symptoms of HD, such as chorea, muscle atrophy, and behavioral and neurological decline, continue to worsen as the disease progresses. This study aims to investigate the relationship between polyQ domain length and age-dependent morphological and mechanical changes in a Caenorhabditis elegans model of HD. C. elegans are an established model species to investigate aging, as morphological and mechanical changes—such as epidermal roughening and whole body decrease in Young's modulus, respectively—occur as a function of age. Moreover, worm mobility exhibits a deficit as a result of such changes. We expect to observe age-dependent morphological changes much earlier in the pathogenic C. elegans (Q128), as opposed to age-matched, non-pathogenic C. elegans (Q15). Morphological analysis was performed using tapping mode atomic force microscopy (AFM), and images were processed using custom MATLAB scripts to determine RMS roughness. Further studies will be conducted to investigate the role of age-dependent changes in mechanical properties, such as Young's modulus, as they relate to polyQ domain length. In-situ contact mode AFM will be used to achieve this. We expect to observe age-dependent mechanical changes much earlier in the Q128 worms, in comparison to the Q15 worms. Pending results, additional studies may be conducted to determine if these changes serve as a peripheral biomarker of HD, as well as the role of such a biomarker in diagnostic, prognostic, and therapeutic strategies.

Aging and Senescence in Canine Testes.

Senescent cells accumulate with age but tissue-based studies of senescent cells are limited to selected organs from humans, mice, and primates. Cell culture and xenograft studies have indicated that senescent cells in the microenvironment may play a role in tumor proliferation via paracrine activities. Dogs develop age-related conditions, including in the testis, but cellular senescence has not been confirmed. We hypothesized that senescent cells accumulate with age in canine testes and in the microenvironment of testicular tumors. We tested the expression of the established senescence markers γH2AX and p21 on normal formalin-fixed, paraffin-embedded testes from 15 young dogs (<18 months of age) and 15 old dogs (7-15 years of age) and correlated the findings with age-dependent morphological changes. A statistically significant age-dependent increase in the percentage of p21-expressing cells was observed for testicular fibroblasts (4-fold) and Leydig cells (8-fold). However, p21-expressing cells were still a rare event. In contrast, the percentage of γH2AX-positive cells did not increase with age. P21- and γH2AX-expressing cells were rare in the microenvironments of tumors. Age-dependent morphological changes included an increased mean number of Leydig cells per intertubular triangle (2.95-fold) and a decreased spermatogenesis score. To our surprise, no age-related changes were recorded for interstitial collagen content, mean tubular diameter, and epithelial area. Opposed to our expectations based on previous in vitro data, we did not identify evidence of a correlation between age-associated accumulation of senescent cells and testicular tumor development. Understanding the role of the microenvironment in senescence obviously remains a challenging task.

Changes in the Morphology of Hypoglossal Motor Neurons in the Brainstem of Developing Rats.

The autonomic brainstem generates breathing rhythm by integrating inputs from chemosensors and mechanosensors in the viscera and coordinating descending outputs from higher structures in the central nervous system. Hypoglossal motoneurons (XII MNs) receive inputs from respiratory premotor neurons, important for maintaining airway patency. Previous studies in rodents report significant changes in breathing control during the first 3 weeks of life, with a sensitive period at 10 to 13 days postbirth (P10-P13) characterized by pronounced changes in neurotransmitters, excitation-inhibition balance, and breathing physiology. However, age-dependent morphological changes of XII MNs during the first 3 weeks postbirth and especially this sensitive period are under-studied. Here, we comprehensively characterize and quantify the early morphological changes in rat XII MNs. We hypothesized that morphological changes in XII MNs correspond to the functionally defined sensitive period observed at postnatal day 10-13 (P10-P13). To test this hypothesis, we used an innovative contemporary statistical approach to analyze Golgi-Cox stained XII MNs at nine postnatal ages between P1 and P21. Our findings reveal two subpopulations of XII MNs, which are dependent on age and morphological features. Soma size increased approximately 40% from P1 to P21, without changing shape. However, dendritic arborization increased in extent/distance and complexity. Dendritic branching of developing neurons significantly increased from P1 through P13, with the greatest increase at P10-P13 based on the Sholl method. Our detailed characterization of XII MN morphological development establishes a foundation for the study and elucidation of morphological changes caused by maternal and perinatal conditions. Anat Rec, 302:869-892, 2019. © 2018 Wiley Periodicals, Inc.

Sex-Related Differences in the Developmental Morphology of the Atlas: A Computed Tomography Study.

A retrospective study. To elucidate sex-related differences in the age at synchondroses closure, the normative size of the atlas, and the ossification patterns of the atlas in Japanese children. The atlas develops from three ossification centers during childhood. The anterior and posterior synchondroses, which are separate ossification centers, mimic fracture lines on computed tomography (CT). Sex-related differences of age dependent morphological changes of the atlas in a large sample size have not been reported. This study analyzed data of 688 subjects (449 boys) between 0 and 18 years old who underwent CT examination of the head and/or neck between January 2010 and July 2016. The age at synchondroses closure, anteroposterior outer, inner, and spinal canal widths of the atlas, and variations of the ossification centers were examined. Anterior synchondroses closed by 10 years in boys and by 7 years in girls. Significant earlier closure of anterior synchondroses was observed in girls than in boys (P < 0.05 at 4 and 5 years old). Posterior synchondrosis closed by 6 years in boys and by 5 years in girls. The outer, inner, and spinal canal widths increased up to 10 to 15 years in both sexes, although all three parameters in girls peaked 3 years earlier than those in boys. All parameters in boys were significantly larger than those in girls, except in the 10- to 12-year-old age category. Two or more ossification centers in the anterior arch were observed in 18.3% subjects, and 6% had midline ossification centers in the posterior arch of the atlas. Distinct sex-related differences in the age at anterior synchondroses closure and the size of the atlas were observed in Japanese children. Knowledge of morphological features of the atlas could help distinguish fractures from synchondroses. 3.

Developmental changes in hypoglossal motoneuron morphology in neonatal rat

The autonomic brainstem generates and modifies breathing rhythm by integrating inputs from chemo‐ and mechanosensors in the viscera while coordinating descending outputs from higher CNS structures. Hypoglossal motoneurons (XII MNs) receive inputs from respiratory premotor neurons in the medulla. Previous studies in rodents have demonstrated significant changes in breathing control during the first three weeks of life, with a putative sensitive period at 10 to 13 days post‐birth (P10–P13) characterized by pronounced changes in neurotransmitters, receptors, excitation‐inhibition balance, and breathing physiology [Li et al., J Physiol, 577:957–770, 2006]. However, age‐dependent morphological changes of XII MNs during the first three weeks post‐birth and especially during this sensitive period, have not been thoroughly studied. In this study, we comprehensively characterize and quantify the postnatal morphological changes in rat XII MNs. We hypothesized that morphological changes occur in XII MN morphology and arbor complexity corresponding to the functionally‐defined sensitive period observed at P10–P13. To test this hypothesis, we used innovative statistical approaches to quantify and compare developmental changes in Golgi‐Cox stained XII MNs at nine postnatal ages between P1–P21. Soma size increased ~40% from P1 to P21, with no significant change in shape. However, dendritic arborization increased in extent and complexity. Dendritic branching of developing neurons significantly increased from P1 through P13, with the greatest increase at P10–P13 based on the Sholl method. For many parameters, three age groups 1) P1–P5, 2) P7–P12, and 3) P13–P21 were used as possible windows of development. We also found that at specific ages certain parameters such as soma size and dendrite distance were non‐normally distributed. Our detailed characterization of XII MN morphological development establishes a foundation for the study and elucidation of morphological changes caused by maternal and perinatal conditions using a rigorous statistical approach.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Clinical, neurophysiological and morphological study of dominant intermediate Charcot-Marie-Tooth type C neuropathy.

Dominant intermediate Charcot-Marie-Tooth neuropathy subtype C (DI-CMTC) was associated with mutations in the YARS gene, encoding tyrosyl-tRNA synthetase, in two large unrelated Bulgarian and US pedigrees and one sporadic case. Here for the first time we describe the clinical, neurophysiological and histopathological features, and phenotypic differences between these two DI-CMTC families. Twenty-one affected individuals from the US family and 27 from the Bulgarian family were evaluated. The mean age of onset in US subjects was 10.7 years in men and 7.3 years in women, while in the Bulgarian participants it was 18.2 years in men and 33.7 years in women. The course was slowly progressive. Extensor digitorum brevis atrophy was uniform. Atrophy and/or weakness of upper and lower limb muscles were found in over 50 % of the subjects. Nerve conduction studies (NCS) were abnormal in all US adults and five of six children and all Bulgarian patients except one asymptomatic 25-year-old man. Median motor NCS were in the range of 29.5-45.6 m/s in the US family and 24.7-57.8 m/s in the Bulgarian family. Sural sensory nerve action potentials were absent in 14/21 and 4/12 NCS from adult US and Bulgarian participants, respectively. Analysis of sural nerve biopsies from US patients revealed age-dependent morphological changes of axonal degeneration, absence of onion bulbs, and <10 % fibers with segmental remyelination. Our findings provide further insights into the diagnosis and pathology of intermediate CMT. They also extend the phenotypic spectrum of peripheral neuropathies associated with aminoacyl-tRNA synthetase mutations.

Rim and Wall of sternal rib ends, a specific approach to justify age

Study of age dependent morphological changes in varieties of bones is a distinguished way to justify age, especially for ages beyond thirties. This study was carried out to discover various changes at sternal rib ends of fourth ribs with special attention to the rim and wall, as well as to correlate them with the age of an individual. Special focus was given to ascertain any bilateral variability for the same. Total 170 ribs were collected from male dead bodies out of which 140 ribs belonged to 70 cases were included as study materials. Each rib was classified according to different stages of Rim and Wall morphology. The data derived were statistically analysed. It is concluded that changes of rim and wall at sternal end of fourth ribs are age dependent. With the advancing age, Rim changes from its smoothness towards the well-defined scallops formation to ill-defined scallops and Wall changes from its appearance to its increasing thickness and then towards its structural deterioration with bony projections. There is no any significant bilateral variation seen in changes of rim and wall according to age.

Three dimensional surface analyses of pubic symphyseal faces of contemporary Japanese reconstructed with 3D digitized scanner

Three dimensional pubic bone images were analyzed to quantify some age-dependent morphological changes of the symphyseal faces of contemporary Japanese residents. The images were synthesized from 145 bone specimens with 3D measuring device. Phases of Suchey-Brooks system were determined on the 3D pubic symphyseal images without discrepancy from those carried out on the real bones because of the high fidelity. Subsequently, mean curvatures of the pubic symphyseal faces to examine concavo-convex condition of the surfaces were analyzed on the 3D images. Average values of absolute mean curvatures of phase 1 and 2 groups were higher than those of phase 3-6 ones, whereas the values were approximately constant over phase 3 presumably reflecting the inactivation of pubic faces over phase 3. Ratio of the concave areas increased gradually with progressing phase or age classes, although convex areas were predominant in every phase.

Electromagnetic field therapy delays cellular senescence and death by enhancement of the heat shock response

Hormesis may result when mild repetitive stress increases cellular defense against diverse injuries. This process may also extend in vitro cellular proliferative life span as well as delay and reverse some of the age-dependent changes in both replicative and non-replicative cells. This study evaluated the potential hormetic effect of non-thermal repetitive electromagnetic field shock (REMFS) and its impact on cellular aging and mortality in primary human T lymphocytes and fibroblast cell lines. Unlike previous reports employing electromagnetic radiation, this study used a long wave length, low energy, and non-thermal REMFS (50 MHz/0.5 W) for various therapeutic regimens. The primary outcomes examined were age-dependent morphological changes in cells over time, cellular death prevention, and stimulation of the heat shock response. REMFS achieved several biological effects that modified the aging process. REMFS extended the total number of population doublings of mouse fibroblasts and contributed to youthful morphology of cells near their replicative lifespan. REMFS also enhanced cellular defenses of human T cells as reflected in lower cell mortality when compared to non-treated T cells. To determine the mechanism of REMFS-induced effects, analysis of the cellular heat shock response revealed Hsp90 release from the heat shock transcription factor (HSF1). Furthermore, REMFS increased HSF1 phosphorylation, enhanced HSF1–DNA binding, and improved Hsp70 expression relative to non-REMFS-treated cells. These results show that non-thermal REMFS activates an anti-aging hormetic effect as well as reduces cell mortality during lethal stress. Because the REMFS configuration employed in this study can potentially be applied to whole body therapy, prospects for translating these data into clinical interventions for Alzheimer’s disease and other degenerative conditions with aging are discussed.

Morphological skin ageing criteria by multiphoton laser scanning tomography: non‐invasive in vivo scoring of the dermal fibre network

Morphological changes in the dermal collagen and elastin fibre network are characteristic for skin ageing and for pathological skin conditions of the dermis. To characterize pathological and physiological conditions by multiphoton laser scanning tomography (MLT) in vivo, it is necessary to investigate and identify morphological alterations related to ageing. In vivo MLT was used to image two-photon excited autofluorescence (AF) and second harmonics generation (SHG) in human dermis of 18 volunteers of different ages. Criteria for the evaluation of age-dependent morphological changes in MLT images were fibre tension and morphology, network pattern, clot formation and image homogeneity. These criteria were weighted and a score was calculated. The resulting MLT-based Dermis Morphology Score is correlated with age (R2 = -0.90) and with the previously published SHG to AF Ageing Index of Dermis (R2 = 0.66). The two groups of young (age 21-38) and old (age 66-84) volunteers showed a significant difference in MLT score values (P < 0.001). We could demonstrate an in vivo relationship between morphological characteristics of human dermis assessed by MLT and age. The present score allows the semi-quantitative evaluation of specific morphological changes of the dermal fibre network in ageing skin by in vivo AF and SHG imaging. This method will be useful for diagnostics of pathological conditions and their differentiation from ageing effects.

Developmental changes in spinal motoneuron dendrites in neonatal mice

We examined the age-dependent morphological changes of lumbar spinal motoneurons (MNs) in neonatal Swiss-Webster mice during the first 2 weeks of postnatal life. Neurons labeled by intracellular injection of biocytin in hemisected lumbosacral spinal cords in vitro were reconstructed from serial sections. Digitized data were compared for young (P3; postnatal days 2-4; n = 9) and older animals (P11; postnatal days 10-13; n = 8). As expected, measures of dendritic size (e.g., stem branch diameter, total surface area, maximum distance to tips, and lateral tree spread) were all significantly greater for P11 than for P3 mice. In contrast, the number of dendrites per MN and parameters related to tree topology (e.g., terminations per tree and maximum branch order), although slightly greater for P11 animals, were not significantly different between the two ages. Dendrite growth appeared to be proportional throughout the tree because the ratios between average terminal and internal branch lengths were similar for the two groups. Furthermore, this elongation was proportional to enlargement of overall spinal cord dimensions. A variety of other morphometric measures showed no significant difference between age groups. The relative constancy of MN dendritic topology up to P13 was surprising, given the striking maturation in motor function during this time period.

Bladder weight in perimenopausal women aged 50-55

This study aimed to determine whether the preliminary factor for the manifestation of lower urinary tract symptoms (LUTS) in perimenopausal women is age-dependent morphological changes in the bladder or hypoestrogenism. The bladder weights and the effects of bladder weight changes on LUTS were evaluated in three groups of women within and age range of 50-55 years: premenopausal (n = 29), short-term menopausal (less than 5 years) (n = 38) and long-term menopausal (5 years and more) (n = 31). The comparison of LUTS among the groups was made using the International Prostate Symptom Score (IPSS) questionnaire; the ultrasonographically determined bladder weights of all the women and the duration of menopause were evaluated for the presence of any correlation for their ages. The relation between the bladder weights and the symptom scores was also tested. The bladder weight of women with longer duration of menopause was found to be significantly decreased compared with that of women with shorter-duration menopause within the same age group (p < 0.05). There was significant correlation between the increased duration of menopause and the decrease in the bladder weight (r = 0.2, p = 0.015). When all the women were taken into account, there was no correlation between the ages and bladder weights (r = 0.03; p = 0.76). There was no significant difference among the groups in terms of symptom scores evaluated as single scores, total symptom scores, total irritative and obstructive scores (p > 0.05 for each). The symptom scores had no correlation with the bladder weights or the ages of patients (p > 0.05 for each). In this age group of women the duration of hypoestrogenism does not seem to cause a difference in the symptom scores. To observe a possible significant difference, it is necessary to evaluate older women or women with a longer duration of hypoestrogenism. These findings suggest the cause for the decreased bladder weight to be the higher duration of hypoestrogenism rather than the older age.

Age-dependent morphological changes in the seminal colliculus in male mice. Light and scanning electron microscopic study.

The developmental changes in the seminal colliculus of male mice were studied by light and scanning electron microscopy. The epithelium of the mouse seminal colliculus is transformed to the mature epithelium between 20 and 25 days of age, while the transformation of the remaining urethral wall occurred from 5 to 10 days of age. During the process of this epithelial transformation at the seminal colliculus unusual structures, including prominent epithelial proliferations and protrusions, were observed in the area adjacent to the ejaculatory duct openings and the ventral area of the upper medial region of the seminal colliculus in 15-day-old mice. In these unusual structures, three types of cells were recognized by their surface characteristics: cells which had distinct borders and ruffled cell surfaces with microridges; cells which had distinct borders and flat or slightly ruffled cell surfaces with many short microvilli, and small cells which had rounded cell surfaces with many long microvilli. In the remaining area of the seminal colliculus, two types of cells were distinguished: those which had flat or slightly rounded cell surfaces with many short microvilli and those cells with many long microvilli similar to the ones in the previously described area. In 25-day-old mice, the unusual protruding structures were not observed, but some cells with ruffled surfaces were still seen.