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    Measuring the intrarenal distribution of glomerular volumes from histological sections
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    Abstract:
    Glomerular volume is an important metric reflecting glomerular filtration surface area within the kidney. Glomerular hypertrophy, or increased glomerular volume, may be an important marker for renal stress. Current stereological techniques report the average glomerular volume (AVglom) within the kidney. These techniques cannot assess the spatial or regional heterogeneity common in developing renal pathology. Here, we report a novel "unfolding" technique to measure the actual distribution of individual glomerular volumes in a kidney from the two-dimensional glomerulus profiles observed by optical microscopy. The unfolding technique was first developed and tested for accuracy with simulations and then applied to measure the number of glomeruli (Nglom), AVglom, and intrarenal distribution of individual glomerular volume (IVglom) in the oligosyndactyl (Os/(+)) mouse model compared with wild-type (WT) controls. The Os/(+) mice had fewer and larger glomeruli than WT mice: Nglom was 12,126 ± 1,658 (glomeruli/kidney) in the WT mice and 5,516 ± 899 in the Os/(+) mice; AVglom was 2.01 ± 0.28 × 10(-4) mm(3) for the WT mice and 3.47 ± 0.35 × 10(-4) mm(3) for the Os/(+) mice. Comparing the glomerular volume distributions in Os/(+) and WT kidneys, we observed that the Os/(+) distribution peaked at a higher value of IVglom than the WT distribution peak, and glomeruli with a radius greater than 55 μm were more prevalent in the Os/(+) mice (3.4 ± 1.6% of total glomeruli vs. 0.6 ± 1.2% in WT). Finally, the largest profiles were more commonly found in the juxtamedullary region. Unfolding is a novel stereological technique that provides a new quantitative view of glomerular volume distribution in the individual kidney.
    Keywords:
    Glomerulus
    Renal glomerulus
    Stereology
    Kidney Glomerulus
    Abstract Background and aims: The cortical glomerulus shows many developmental changes during fetogenesis. Nonnalhistologyofthe fetal glomerulus at various stages of development was studied to get insight into the morphology of fetal glomerulus. Fetal glomerular study is a necessity for correlation with increase in gestational age and pathological changes which may affect the normal functioning of kidneys in fetal life. Method: Dissection of 70 normal human fetuses was carried out and histological findings of glomerulus were noted with respect to the age of fetus. The histology of fetal kidney was studied using H & E stain. Important developmental stages of glomerulus were observed. Results: Fetal kidney glomerulus histology is different from adult. Unlike in adult kidney, foetal kidney glomerulus shows many developmental stages as v, c, s, cresentric in starting phase. Multiple rows arrangement in between mednllary rays with well developed mature glomeruli at juxtamednllary junction. Capillary invagination with developed Juxta glomerular apparatus was appreciated. Nephrogenic zone which was found as hroad band in early gestational weeks disappeared near term. Conclusion: The present study will be helpful in understanding the normal histological architecture of foetal kidney glomerulus and add to the existing knowledge regarding development of foetal kidney, its relation with gestational age and pathogenesis.
    Glomerulus
    Kidney Glomerulus
    Renal glomerulus
    Citations (0)
    Summary A method for unbiased capillary number estimation based on the estimation of the Euler–Poincaré characteristic or Euler number with the disector is evaluated. The generation of a new capillary creates a new loop in the capillary network corresponding to a change of exactly one unit in the Euler number of the network. In this way the Euler number has a one‐to‐one relationship to the number of capillaries in a network. In this report rat glomerular capillaries are counted. Three tissue blocks from each of 14 perfusion‐fixed rat kidneys, aged between 5 days and 18 months, were uniformly sampled and embedded in Epon. Two complete glomerular profiles were sampled per block. Three consecutive sections were studied per glomerulus using the middle one to evaluate the topological events of the capillaries in the sampled glomerulus. The use of complete glomerular profiles eliminated problems with the edges, whereas the disector ensured unbiased sampling in the third dimension. Estimates per animal were weighted averages over blocks, the weights being half the number of glomerular profiles in a section from a block. The number of capillaries in a glomerulus is the mean Euler number per disector volume multiplied by the mean volume of glomeruli obtained by the fractionator. The observed coefficient of variation between animals was 18.3% for the estimated number of capillaries per glomerulus, and the observed coefficient of error at the level of blocks within animals was 14.7%. The exact capillary number from the node‐branch network of two reconstructed glomeruli equalled the capillary number obtained by the total Euler number from the same glomeruli. This shows in an applied example, as would be expected, that the estimation of capillary number using the Euler number is unbiased and independent of the direction of sectioning.
    Stereology
    Glomerulus
    Renal glomerulus
    Coefficient of variation
    It has been postulated that morphological changes of podocytes might be related to glomerular sclerotic lesions in experimental models and patients with glomerular diseases. To estimate the absolute number of podocytes in mammalian normal glomerulus, we analyzed normal glomeruli in four rats and six humans. In PAS stained light microscopic sections, at least 25 midsections of open glomeruli were photographed. Stereologic estimation was performed to obtain the following values: absolute values of glomerular volume (V), glomerular surface area (S), podocyte and intraglomerular cell number per glomerulus (P and IGC), glomerular surface area covered by one podocyte (S/P) and glomerular volume occupied by one intraglomerular cell (V/IGC). The glomerular volume, glomerular surface area and podocyte and intraglomerular cell numbers per glomerulus of human were significantly increased compared with those of the rat (V: 2.70 +/- 0.86 > 0.89 +/- 0.19, S: 4.84 +/- 1.26 > 1.88 +/- 0.26, P: 407.7 +/- 88.2 > 153.8 +/- 84.0, p < 0.01 vs rat). On the other hand, there were no significant differences in glomerular surface area covered by one podocyte and glomerular volume occupied by one intraglomerular cell between the humans and rats (S/P: 1.25 +/- 0.20, 1.29 +/- 0.05, V/IGC: 2,471 +/- 487, 2,227 +/- 201, p < 0.01 vs rat). These data were almost the same as previously reported values. It appears that these values can be considered as standards for rats and humans in morphometric analysis of the glomerulus.
    Glomerulus
    Kidney Glomerulus
    Renal glomerulus
    Stereology
    Citations (1)
    Glomerulus
    Mesangium
    Glomerular mesangium
    Renal glomerulus
    Kidney Glomerulus
    Stereology
    Mesangial cell
    Citations (28)
    Background and aims: The cortical glomerulus shows many developmental changes during fetogenesis. Normal histology of the fetal glomerulus at various stages of development was studied to get insight into the morphology of fetal glomerulus. Fetal glomerular study is a necessity for correlation with increase in gestational age and pathological changes which may affect the normal functioning of kidneys in fetal life. Method: Dissection of 70 normal human fetuses was carried out and histological findings of glomerulus were noted with respect to the age of fetus. The histology of fetal kidney was studied using H & E stain. Important developmental stages of glomerulus were observed. Results: Fetal kidney glomerulus histology is different from adult. Unlike in adult kidney, foetal kidney glomerulus shows many developmental stages as v, c, s, cresentric in starting phase. Multiple rows arrangement in between medullary rays with well developed mature glomeruli at juxtamedullary junction. Capillary invagination with developed Juxta glomerular apparatus was appreciated. Nephrogenic zone which was found as broad band in early gestational weeks disappeared near term. Conclusion: The present study will be helpful in understanding the normal histological architecture of foetal kidney glomerulus and add to the existing knowledge regarding development of foetal kidney, its relation with gestational age and pathogenesis.
    Glomerulus
    Kidney Glomerulus
    Renal glomerulus
    Histology
    Citations (0)