Morphometry: assessing direct and indirect methods of measuring the diameters of tubular structures / Morfometría: evaluación de métodos directos e indirectos para medir los diámetros de las estructuras tubulares

SUMMARY: Knowledge of the diameter of a structure or particle is required for stereological calculations. However, there is no consensus on the methodology for its measurement. This study aims to assess the differences between direct and indirect methods of measuring diameter. It is hypothesised that kidneys were removed, fixed, processed, sectioned, and stained. The stained slides were imaged using a digital microscope. The images were processed using the ImageJ software. The diameters of the renal glomeruli and collecting tubules were measured using direct and indirect methods. The measured diameters were analysed using the SPSS software v20. The differences between the measurements were assessed using a Z-test and test of association, and P < 0.05 was considered significant. No significant differences were observed between the diameters of the glomeruli (P = 0.82) and proximal (P = 0.86) and distal (P = 0.55) convoluted tubules as measured via direct and indirect methods. There was a strong positive correlation between the diameters of glomeruli (P = 0.97) and proximal (P = 0.82) and distal (P = 0.93) convoluted tubules measured using the two methods, both of which are convenient, accurate and suitable. The P-values based on these measurements were more than 0.05. Therefore, the study hypothesis was rejected. There was no significant difference between the direct and indirect methods of measuring diameter, and the null hypothesis was rejected; thus, both methods can be applied either independently or jointly.

RESUMEN: Se requiere el conocimiento del diámetro de una estructura o partícula para los cálculos estereológicos. Sin embargo, no existe consenso sobre la metodología para su medición. Este estudio tuvo como objetivo evaluar las diferencias entre los métodos directos e indirectos de medición del diámetro de una estructura. Riñones de ratas Wistar fueron extirpados, fijados, procesados y seccionados, y luego se tiñeron con HE. Se tomaron imágenes de las muestras teñidas usando un microscopio digital. Las imágenes fueron procesadas utilizando el software ImageJ. Los diámetros de los glomérulos renales y túbulos colectores se midieron por métodos directos e indirectos. Los diámetros medidos se analizaron utilizando el software SPSS v20. Las diferencias entre las medidas se evaluaron mediante una prueba Z y una prueba de asociación, y se consideró significativa P < 0,05. No se observaron diferencias significativas entre los diámetros de los glomérulos (P = 0,82) y túbulos contorneados proximales (P = 0,86) y distales (P = 0,55) medidos mediante métodos directos e indirectos. Hubo una fuerte correlación positiva entre los diámetros de los glomérulos (P = 0,97) y los túbulos contorneados proximales (P = 0,82) y distales (P = 0,93) medidos con los dos métodos, ambos convenientes, precisos y adecuados. Los valores P basados en estas mediciones fueron superiores a 0,05. Por lo tanto, se rechazó la hipótesis del estudio. No hubo diferencia significativa entre los métodos directo e indirecto de medición del diámetro, y se rechazó la hipótesis nula; por lo tanto, ambos métodos se pueden aplicar de forma independiente o conjunta.

Glomerular loss after arteriovenous and arterial clamping for renal warm ischemia in a swine model

ABSTRACT PURPOSE: To evaluate the glomerular loss after arteriovenous or arterial warm ischemia in a swine model. METHODS: Twenty four pigs were divided into Group Sham (submitted to all surgical steps except the renal ischemia), Group AV (submitted to 30 minutes of warm ischemia by arteriovenous clamping of left kidney vessels), and Group A (submitted to 30 minutes of ischemia by arterial clamping). Right kidneys were used as controls. Weigh, volume, cortical volume, glomerular volumetric density (Vv[Glom]), volume-weighted glomerular volume (VWGV), and the total number of glomeruli were measured for each organ. RESULTS: Group AV showed a 24.5% reduction in its left kidney Vv[Glom] and a 25.4% reduction in the VWGV, when compared to the right kidney. Reductions were also observed when compared to kidneys of sham group. There was a reduction of 19.2% in the total number of glomeruli in AV kidneys. No difference was observed in any parameters analyzed on the left kidneys from group A. CONCLUSIONS: Renal warm ischemia of 30 minutes by arterial clamping did not caused significant glomerular damage, but arteriovenous clamping caused significant glomerular loss in a swine model. Clamping only the renal artery should be considered to minimize renal injury after partial nephrectomies.

Estudo morfométrico de rins em felinos domésticos (Felis catus) / Morphometric study on the kidneys of domestic cats (Felis catus)

A saúde renal tem ao longo dos últimos anos chamado atenção dos médicos veterinários, pois o comprometimento deste órgão na insuficiência renal crônica se apresenta como a maior causa de morbidade e mortalidade em felinos. O presente estudo propõe a caracterização biométrica dos rins de gatos, Felis catus, sob os aspectos macroscópicos (comprimento, altura, largura, peso e volume), mesoscópico (altura do córtex e da medula, e a sua inter-relação) e microscópica (volume glomerular), a fim de se estabelecer possíveis diferenças decorrentes de idade, sexo e simetria bilateral. Foram utilizados, rins de 30 animais da espécie Felis catus (gato deméstico), sendo 15 machos e 15 fêmeas com idade variando entre 3 meses a 15 anos, divididos em três grupos: grupo 1 (3-9 meses), grupo 2 (3-5 anos) e grupo 3 (acima de 10 anos)...

Renal health has over the last few years called attention of veterinarians, because the chronic failure of the kidneyu is a major cause of morbidity and mortality in cats. This paper proposes biometric characterization of the kidneys from cats, Felis catus, on the macroscopic aspects (length, height, width, weight and volume), mesoscopic (height of the cortex and medulla, and their inter-relationship) and microscopic (glomerular volume) in order to establish possible differences arising from age, gender and bilateral symmetry. It where used 30 kidneys of animals from specie Felis catus (cat), 15 males and 15 females with ages between 3 months to 15 years, divided into three groups: group 1 (3-9 months), group 2 (3 - 5 years) and group 3 (above 10 years)...

Comparative study of the kidneys from dystrophic mice

The Duchenne Muscular Dystrophy (DMD) is a recessive genetic disease linked to chromosome X. Thisdisease is characterized by an absence or dysfunction in the expression of dystrophin. Experimental modelsmdxare widely used for the development of research addressing the DMD. The objective of this research is tocontribute to a detailed study of possible renal morphological changes resulting from DMD. We used five pairsof kidneys frommdxmice and five from normal mice, which were subjected to measurement, light microscopy,and scanning electron microscopy. The morphological findings of kidneys frommdxmice are within thepatterns described in animal studies with severe dehydration, which exhibit signs of diffuse hemorrhage inthe cortical and medullary area, while the glomeruli in the cortical region showed a decrease in urinary space,located between the Bowman’s capsule and the inner cell mass of the glomeruli. However, future experimentswith animals in different ages can assist in the proving of the morphological changes found here.

Genetics of idiopathic nephrotic syndrome.

Nephrotic syndrome (NS) is a pathological entity characterized by massive proteinuria and has diverse etiology. Although it is one of the most common renal diseases in children, the etiological factors responsible for idiopathic NS/FSGS remain largely unknown. Previous studies had implicated a variety of factors including genetic factors, although NS is generally regarded as a sporadic disease. Familial cases of NS have however been reported periodically, and both autosomal dominant and recessive forms have been identified. Studies of familial NS/FSGS have led to the discovery of several genes that are expressed in podocytes and are associated with proteinuria. These discoveries have shifted the focus from glomerular basement membrane (GBM) to recognition of the central role of podocytes in maintaining glomerular perm selectivity and pathogenesis of NS/FSGS. Associations with various genes (NPHS1, ACTN4, NPHS2, WT-1) and linkage to several chromosomal regions (such as 19q13, 11q21, 11q24) have been reported in patients with familial NS/FSGS.

Efeitos renais da haploinsuficiência do gene Pkd1 (Polycystic kidney disease 1) em camundongos / Renal effects of Pkd1 gene haploinsufficiency in mice

Vários estudos mostram que na doença renal policística autossômica dominante os cistos surgem a partir de um mecanismo de "dois-golpes". A patogênese das manifestações não-císticas, contudo, é pouco compreendida. Neste estudo usamos uma linhagem de camundongos endogâmica com uma mutação nula em Pkd1, onde animais heterozigotos apresentam formação cística renal mínima até 40 semanas de idade. O clearance de inulina e o número de glomérulos foram menores em machos Pkd1+/- que Pkd1+/+, enquanto o volume glomerular médio foi maior em heterozigotos. A excreção urinária de NO2/NO3 não diferiu significantemente entre os dois grupos. Avaliamos a osmolalidade urinária máxima em machos e fêmeas Pkd1+/- and Pkd1+/+, porém não foi detectada diferença significante entre os grupos heterozigoto e selvagem. Nossos resultados oferecem evidência direta de que a haploinsuficiência de Pkd1 resulta em anormalidades anatômicas e funcionais renais e sugerem que o estado haploinsuficiente de Pkd1 possa resultar na redução do número de néfrons por diminuir a ramificação tubular renal durante a nefrogênese.

Several studies show that in autosomal dominant polycystic kidney disease cysts arise through a "two-hit" mechanism. The pathogenesis of non-cystic features, however, is poorly understood. In this study we used an inbred mouse line with a null mutation of Pkd1, where heterozygotes had minimal renal cyst formation up to 40 weeks of age. Inulin clearance and the number of glomeruli were lower in Pkd1+/- than in Pkd1+/+ males, while a higher average glomerular volume was observed in heterozygotes. The urinary excretion of NO2/NO3 did not significantly differ between the two groups. Maximal urinary osmolality was evaluated in Pkd1+/- and Pkd1+/+ males and females, but no significant difference was detected between the heterozygous and the wild type groups. Our results provide direct evidence that haploinsufficiency for Pkd1 results in anatomic and functional abnormalities of the kidney and suggest that Pkd1 haploinsufficiency may result in a reduced number of nephrons by diminishing renal tubule branching during nephrogenesis.

Effects of sodium cyclamate in kidneys of rats fetuses: a morphometric study

El ciclamato es usado como edulcorante no calórico en muchos alimentos y bebidas y es 30 veces mas dulce que la sacarosa, sin el gusto amargo de la sacarina. Aparecen en su composición, los productos como ciclamato de sodio, ciclamato de calcio y acido ciclamico. El objetivo del trabajo fue evaluar los efectos del ciclamato de sodio en ri¤ones de fetos de ratas, considerandose las alteraciones morfometricas en glomerulo, túbulos contornados proximal y distal y conducto coletor. Fueron utilizadas 10 ratas adultas (Rattus norvegicus) variedad Wistar, con peso medio de 238 g, 5 ratas para el grupo control y 5 ratas tratadas con ciclamato de sodio. Entre el 10 y 14 dia de la pre¤ez, 5 ratas recibieron una inyección diaria intraperitoneal de 60mg/Kg/dia de ciclamato de sodio durante 5 dias. En el 20 dia, los animales fueron sacrificados y los fetos fijados en solución de Alfac, incluidos en parafina, cortados y te¤idos com H-E. El método utilizado fue la morfometría por la técnica cariométrica. Hubo disminución significativa en los pesos de los fetos y de la placenta en el grupo tratado con ciclamato de sodio (p= 0,004) comparado con el grupo control. En el volumen glomerular y tama¤o nuclear de las celulas de los túbulos contornados proximal, distal y conducto colector del ri¤ón fetal de las ratas tratadas con ciclamato de sodio, hubo aumento estadisticamente significativo. Los resultados mostraron que el uso del ciclamato de sodio produjo la reducción del peso de los fetos, placenta y longitud del cordón umbilical. Hubo aumento significativo en el volumen glomerular y en el tama¤o nuclear de las células de los túbulos contornados proximal, distal y conducto colector, sugerente de nefrotoxicidad.

Envejecimiento renal: conceptos actuales / Renal aging: current concepts

El proceso de envejecimiento genera una serie de cambios tanto estructurales como funcionales a nivel renal. Entre los primeros se hallan la instalación de la glomeruloesclerosis, el surgimiento de la circulación aglomerular, la membrana podocitaria y la tubulización de la capa parietal de la cápsula de Bowman, así como la formación de los divertículos tubulares. La reducción de los proteoglicanos en el parénquima renal podría vincularse con la aparición de la fibrosis intersticial y los microtrombos arteriolares que se observan en este grupo etario. Con respecto a los cambios funcionales, existe una reducción del filtrado glomerular, la tolerancia a las sobrecargas ácidas y la autorregulación de la perfusión renal, así como del Tm tubular para la glucosa y los fosfatos. Por otra parte, en los ancianos se suelen hallar alteraciones en el manejo hidroelectrolítico. El conocimiento de todos estos cambios se torna necesario para una mejor comprensión de las diferencias que las entidades nosológicas del anciano presentan respecto de las del adulto, así como para permitir una mejor y más racional terapéutica en los gerontes

Histologia glomerular normal / Normal glomerular histology

Se describen las caracteristicas morfologias del glomerulo normal con sus tres estructuras: el mesangio, compuesto de celulas y matriz; la pared capilar, conformada por las celulas endoteliales, la membrana basal y los podocitos, y la capsula de Bowman, formada por una gruesa membrana basal y un epitelio plano que la recubre en su interior. Se expone que estas estructuras, delimitando dos espacios (la luz capilar y el espacio urinario) estan en relacion con el resto del parenquima renal a traves de dos polos: el polo urinario, que relaciona el espacio urinario con la luz del tubulo contorneado proximal, y el polo vascular, que relaciona el capilar glomerular con la red vascular del riñon, a traves de las arteriolas aferente y eferente. Se señala que a nivel del polo vascular el mesangio se relaciona con las celulas del aparato yuxtaglomerular. Se definen las lesiones elementales de la patologia glomerular y la terminologia histopatologica correspondientes

The effects of sodium orthovanadate, noradrenaline and angiotensin II on isolated perfused rat kidney glomerular-tuft diameter.

The effects of sodium orthovanadate, angiotensin II (A II) and noradrenaline (NA) were studied on the isolated perfused rat kidney (IPRK) and on the diameter of the glomerular capsule and tuft. Vanadate (4.5 microM), A II (20 nM) and NA (17.3 microM) increased the total resistance of the IPRK. There was a simultaneous increase in glomerular filtration rate with vanadate and A II, but a decrease with NA. The glomerular tuft/capsule diameter ratio decreased significantly from 0.85 (control) to 0.81, 0.81 and 0.78 for vanadate, A II, and NE treated kidneys, respectively. The decrease in ratio was associated with an increase in diameter of the glomerular capsule for A II and NE. This finding accompanied with simultaneous rise in TPR and GFR in the case of vanadate and A II, indicates that the post capillary efferent arteriolar vasoconstriction is a component in the mechanism of action with A II and vanadate. Evidence for such a component is less clear for NA because GFR decreases and TPR increases. Vanadate may affect both with a predominance on the efferent arteriole. The data indicate that histological measurements of glomerular size lead to a better understanding of the mechanisms of vasoactive drugs acting on the kidney.