Developmental Characteristics of the Glomerular and Tubular Portion of the Nephron in the Human Foetal Kidney Cortex: Morphometrical and Immunohistochemical Analysis.

This study aimed to morphometrically examine the development of glomeruli and tubules in the kidney cortex of human foetuses at different gestational ages (GAs). We also investigated the expression of the proliferation marker Ki-67 and apoptosis-related markers Bcl-2 and Bax during nephrogenesis using immunohistochemistry. Kidney samples from 38 human foetuses of both sexes with GA ranging from 13 to 40 weeks were analysed. The samples were divided into 7 groups based on GA, each corresponding to 1 lunar month. Foetal kidneys showed a spatiotemporal gradient of nephron differentiation with the transient stages of nephron anlage located in the nephrogenic zone and immature nephrons located in the subjacent maturation zone. In the inner cortex, nephrons establish the morphological characteristics of definitive nephrons. The average area, perimeter, and Feret's diameter of the glomeruli formed within the kidney cortex gradually decreased up to a period of 29-32 weeks of gestation and subsequently increased until a period of 37-40 weeks. There was a weak negative correlation with GA. In contrast, the areal density of glomeruli increased up to a period of 21-24 weeks and then gradually decreased until a period of 37-40 weeks, showing a moderate negative correlation with GA. The average area of renal tubules slightly decreased until a period of 21-24 weeks of gestation and then gradually increased until a period of 36-40 weeks, showing a moderate positive correlation with GA. The average areal density of renal tubules increased significantly until a period of 21-24 weeks of gestation, remained relatively constant until a period of 33-36 weeks, and then increased significantly at 36-40 weeks. There was a strong positive correlation with GA. Our results showed that Ki-67 was expressed in numerous cells of the metanephric mesenchyme, pretubular aggregates, renal vesicles, comma-shaped bodies, and early S-shaped bodies. During subsequent development and the spatial expansion of nephrons towards the mature zone, the expression of Ki-67 was markedly reduced. Similarly, Bcl-2 was strongly expressed in induced nephrogenic progenitor cells, pretubular aggregates, renal vesicles, and comma-shaped bodies. As vascularisation and maturation of the nephron proceeded, Bcl-2 staining became less intense and limited to the parietal layer of the Bowman's capsule and renal tubules. Weak Bax expression was observed in individual scattered cells within segments of the nephrons at all developmental stages. In the mature zone, more intense Bax staining was observed in the renal tubules.

Human anterior pituitary's ACTH cells during the aging process: immunohistochemic and morphometric study.

Corticotrophs produce a hormone that stimulates the adrenal gland cortex to secrete glucocorticoids, which in turn have effects on carbohydrate and protein metabolism. Quantification, morphological characteristics, and distribution of corticotrophs in the anterior pituitary and changes in the number and shape of the cells during aging have been examined using immunohistochemical and morphometric methods. The material consisted of 14 anterior pituitaries taken from cadavers at routine autopsy. The tissue was processed by standard histological procedure and the obtained slices were stained by the monoclonal anti-ACTH antibody for corticotrophs identification. Digital images of stained histological sections were analyzed using the morphometric method with the Image J system. The volume density of ACTH positive cells was determined. The cases were classified into three age groups. One-way ANOVA showed that the volume density of the corticotrophs was significantly higher in the second and third group in relation to the first group. The difference in the volume densities of the corticotrophs between the genders was not significant. Morphometric and statistical analyses demonstrated a significant positive correlation between the corticotrophs volume densities and the age of the evaluated cases. Linear regression showed that age significantly predicts corticotrophs volume density. Corticotrophs significantly increase during the life span.

Stereological study of developing glomerular forms during human fetal kidney development.

BACKGROUND: Human fetal kidney development is a complex and stepwise process. The number, shape, size and distribution of glomeruli provide important information on kidney organization. The aim of this study was to quantify glomerular developing forms during human fetal kidney development using stereological methods. METHODS: Kidney tissue specimens of 40 human fetuses with gestational ages ranging from 9 to 40 weeks were analyzed. Specimens were divided into eight groups based on gestational age, each corresponding to 1 lunar month. Stereological methods were used at the light microscopy level to estimate volume, surface and numerical density of the glomerular developing forms. RESULTS: During gestation, nephrogenesis continually advanced, and the number of nephrons increased. Volume, surface and numerical densities of vesicular forms and S-shaped bodies decreased gradually in parallel with gradual increases in estimated stereological parameters for vascularized glomeruli. Volume density and surface density of vascularized glomeruli increased gradually during fetal kidney development, and numerical density increased until the seventh lunar month. A relative decrease in vascularized glomeruli per unit volume of cortex occurred during the last 3 lunar months. Nephrogenesis began to taper off by 32 weeks and was completed by 36 weeks of gestation. The last sample in which we observed vesicles was from a fetus aged 32 weeks, and the last sample with S-shaped bodies was from a fetus aged 36 weeks. CONCLUSIONS: The present study is one of few quantitative studies conducted on human kidney development. Knowledge of normal human kidney morphogenesis during development could be important for future medical practice. Events occurring during fetal life may have significant consequences later in life.

Morphometric analysis of somatotropic cells of the adenohypophysis and muscle fibers of the psoas muscle in the process of aging in humans.

The aim of this research was to quantify changes of the adenohypophyseal somatotropes and types 1 and 2 muscle fibers with aging, as well as to establish mutual interactions and correlations with age. Material was samples of hypophysis and psoas major muscle of 27 cadavers of both genders, aged from 30 to 90 years. Adenohypophyseal and psoas major tissue sections were immunohistochemically processed and stained by anti-human growth hormone and anti-fast myosin antibodies, respectively. Morphometric analysis was performed by ImageJ. Results of morphometric analysis showed a significant increase in the somatotrope area, and significant decrease in somatotrope volume density and nucleocytoplasmic ratio with age. Cross-sectional areas of types 1 and 2, and volume density of type 2 muscle fibers decreased significantly with age. One Way ANOVA showed that the latter cited changes in the somatotropes and types 1 and 2 muscle fibers mostly become significant after the age of 70. Significant positive correlation was observed between the area of the somatotropes and volume density of type 2 muscle fibers. A significant negative correlation was detected between the nucleocytoplasmic ratio of the somatotropes and cross-sectional areas of types 1 and 2 muscle fibers. So, it can be concluded that after the age of 70, there is significant loss of the anterior pituitary's somatotropes associated with hypertrophy and possible functional decline of the remained cells. Age-related changes in the somatotropes are correlated with the simultaneous atrophy of type 1, as well as with the atrophy and loss of type 2 muscle fibers.