Dog kidney: anatomical relationships between intrarenal arteries and kidney collecting system

Gross morphological and ultrasonographic dimensions of normal feline kidney with reference to resistive index

Ultrasonography with color Doppler is the most quantitative analysis method for intra-renal parameters. There is a wide variation between authors in the measurement site and referencing the inter-lobar resistivity index (RI) in felines. Our objective is to morphometrically and ultrasonographically investigate the normal renal dimensions and vasculatures and draw up a normal reference value for the renal inter-lobar artery resistivity index (RI) using a Pulsed wave-Doppler ultrasonography. A total of twelve adult domestic cats were sedated and treated according to IACUC regulation guidelines to be examined using Doppler ultrasound. The same cats were used for morphometric investigation and divided into three groups regarding the used technique. The size difference between the right and left kidneys is slight, measuring 17 g (weight), 3.65 ± 0.06 cm (length), 2.54 ± 0.08 cm (width), and 2.21 ± 0.03 cm (thickness) for the right kidney, and about 15 g, 3.42 ± 0.06 cm, 2.32 ± 0.05 cm, and 2.13 ± 0.03 cm for the left one, respectively. There are three patterns of renal arteries' point of origin. The mean RI values of both kidneys were 0.57 ± 0.08 (0.50-0.67) in the right kidney and 0.60 ± 0.08 (0.51-0.69) in the left kidney. The gross examination and ultrasonography measurements did not have a statistically different effect on the actual renal dimensions. Moreover, 0.69 is considered the standard resistivity index (RI) threshold of the feline inter-lobar artery with no correlation to the animal's body weight.

Simple ectopic kidney with renal artery originating from internal iliac bifurcation in a dog

An ectopic left kidney together with an aberrant vascular structure were identified during a routine sterilization procedure in an eighteen-month-old female Akita Inu. Subsequently, ultrasound and computed tomography were performed to evaluate the clinical relevance. Based on these examinations' findings, a simple unilateral left-sided ectopic kidney with an abnormal course of the left renal artery as well as an earlier division of the right-sided renal artery were diagnosed. An ectopic kidney is clinically relevant differential diagnosis of secondary renal displacement or abdominal mass.

Use of contrast-enhanced computed tomography to detect kidney infarction in dogs

Background

Kidney infarction is a renovascular disease diagnosed by contrast‐enhanced computed tomography (CECT) in humans.

Objectives

To describe the frequency of kidney infarction and to determine the detection of kidney infarction with CECT in dogs.

Animals

Eight hundred and twenty‐six abdominal CECT studies of 826 dogs.

Methods

A cross‐sectional retrospective study. Dogs with abdominal CT scans including CECT were retrospectively retrieved. Kidney infarction was classified into 3 grades based on the extent of infarction relative to total kidney area. The location and number of kidney infarctions in each kidney were expressed as number and percentage. The ability of visualization of kidney infarction in each multiplanar reconstruction (MPR) image plane was evaluated by agreement of 2 observers.

Results

The frequency of kidney infarction in dogs was 3.15% (26/826 dogs; 95% CI = 2.05‐4.61). Most kidney infarctions were classified as grade 1, or the lesions were less than 25% of the kidney (47/56, 83.93%) and most were detected at the caudal pole of the kidney (31/56, 55.35%) on the sagittal plane. On MPR image planes, the sagittal plane had the highest proportion (34/56, 60.71%) of excellent visual category to detect kidney infarction.

Conclusions and Clinical Importance

The CECT, especially the sagittal plane, is a useful diagnostic tool for the detection of kidney infarction in dogs.

The bovine kidney as an experimental model: Simulated partial nephrectomy of the cranial pole and proportional analysis of the arterial segments

Previous studies have shown that the pig kidney is not a good model for some procedures. This study aimed to describe the relationship between the collecting system and the intrarenal arteries, the arterial segments, and to evaluate the bovine kidney as an experimental model for partial nephrectomy of the cranial pole. Polyester resin endocasts of the kidney collecting system together with the intrarenal arteries were prepared. Thirty-two kidneys were used to evaluate the relationship between the collecting system and the intrarenal arteries, while 25 kidneys were transversally sectioned at different points to simulate partial nephrectomy of the cranial pole. Polyester resin of different colors was injected into each segmental artery of the 24 kidneys to evaluate the arterial segments proportionally. The renal artery was divided into cranial and caudal primary branches in 75% of the cases. The cranioventral branch curved on the cranial pole and ran toward the ventral mid-zone in 56.3% of the cases, resembling the retropelvic artery of the human kidney. The kidney was divided into two (25%) or three (75%) arterial segments. The caudal arterial segment had the highest proportional volume (62%). The cranioventral branch was damaged in 28.6% of the kidneys sectioned 1 cm inside the hilum. The arterial branching pattern, the arterial segmentation, and the impairment of the arterial supply after the simulated partial nephrectomy of the cranial pole are quite different from those found in humans. Thus, all differences should be taken into account when using the bovine kidney as a model.

Anatomical background of ovine kidney for use as animal model: analysis of arterial segmentation, proportional volume of each segment and arterial injury after cranial pole partial nephrectomy

OBJECTIVE

To study the arterial segments of ovine kidney, present a proportional volume analysis of each kidney arterial segment, and analyze arterial injuries caused by simulated partial nephrectomy of cranial pole.

MATERIALS AND METHODS

Forty-eight ovine kidneys injected with polyester resin into the renal arteries and collecting system were used in this study. Eighteen kidneys were used to study the arterial segments and the proportional volume of each renal segment. Other 30 kidneys were submitted to superior pole resection at a distance of 1.0cm, 0.5cm, or exactly at the cranial hilar edge, just before the resin hardening. These endocasts were used to evaluate the arterial injuries caused by these different resection planes.

RESULTS

Ovine renal artery divided into two (ventral and dorsal) or three segmental arteries. Dorsal segment presented higher proportional volume than ventral segment. For kidneys with three segments, the third segment was on the caudal region (caudo-ventral or caudo-dorsal segment) and presented the lowest proportional volume. None of the resected kidneys (at 1.0, 0.5 or at the cranial hilar edge) presented injury of arterial branches that irrigate non-resected region.

CONCLUSION

The segmental distribution of renal artery, the proportional volume of each segment and arterial injuries after cranial pole resection in ovine kidneys are different from what is observed in human kidneys. Meanwhile, ovine kidneys show a primary segmental division on anterior and posterior, as in humans, but different from swine. These anatomical characteristics should be considered when using ovine as animal models for renal experimental and/or training procedures.

Distribution and microstructure of intrarenal arteries in Bactrian camels (Camelus Bactrianus)

Studies and reports focusing on the Bactrian camels' kidney structure from an anatomical perspective are scanty, therefore, this work aims to systemically investigate the anatomical structure of the kidney and examine the distribution and microstructure of intrarenal arteries. Ten pairs of healthy adult kidneys from male and female Bactrian camels were used in the study. The kidney of Bactrian camel appeared like a broad bean with a smooth surface. Using artery casting, we observed that the renal artery divided into dorsal and ventral branches; the dorsal branch continuously divided into a shorter anterior branch and a longer posterior branch, while the ventral branch directly divided into interlobar arteries. The number of interlobar arteries in the left and right kidneys were slightly different, 14 to 16 in left while 16 in the right kidney. No anastomosis was found between the dorsal and ventral branches or their sub-branches. To further study the microscopic structure, microanatomy and scanning microscope were used. Surprisingly, we observed two other ways afferent arteriole arose apart from the interlobular artery. They were the arcuate artery and conjoint afferent arteriole. Two afferent arterioles supplied one glomerulus and occasionally the absence of glomerulus was also observed, where the arteriole kept extending, and no typical glomerulus formed. Since branching of arteries and urologic function of kidneys are physiologically integrated, these features of Bactrian camel may help to further investigate their adaptations to desert climate.

Renal vasography in mink (Mustela vison)

This paper presents the results of the research on renal blood vessels of the mink. The main goal of this research is to provide a unique insight in renal vessel constellation and thereby contributes to the amount and quality of the available data on the cardiovascular system of the mink, since the data found in the available literature regarding this specific field is rather poorly documented. Blood vessels of the mink kidney were studied by dissection and corrosion injection technique. The renal artery and its branches, and the lobar, interlobar and interlobular arteries are terminal arteries and they do not anastomose between each other. The arterial system is characterized by two independent vascular areas, supplied by the dorsal and ventral lobar artery. Lobar arteries divide the kidney horizontally into a dorsal and ventral half, while lobar veins divide it vertically into the cranial and caudal half. The renal vein is formed from the cranial and caudal lobar vein. The obtained results are compared with relevant literature findings on renal blood supply of a dog and other sympatric carnivores.

Arrangement of Renal Arteries in Guinea Pig

The aim of this study was to describe origin, localization, and variations of renal arteries in guinea pig. The study was carried out on 26 adult guinea pigs. We prepared corrosion casts of the guinea pig arterial system. Batson's corrosion casting kit no. 17 was used as the casting medium. In 57.7% of specimens, a. renalis dextra was present as a single vessel with different level of its origin from aorta abdominalis. In 38.5% of specimens, two aa. renales dextrae were present with variable origin and arrangement. The presence of three aa. renales dextrae we found in one specimen. In 76.9% of specimens, a. renalis sinistra was present as a single vessel with different level of its origin from aorta abdominalis and variable arrangement. In 23.1% of specimens, we found two aa. renales sinistrae with variable origin and arrangement. The anatomical knowledge of the renal arteries, and its variations are of extreme importance for the surgeon that approaches the retroperitoneal region in several experiments, results of which are extrapolated in human. This is the first work dealing with the description of renal arteries arrangement in guinea pig. Anat Rec, 300:556-559, 2017. © 2016 Wiley Periodicals, Inc.

Vascular theory of the formation of Randall plaques

The relationship between calcium-based calculi and Randall plaques is well documented, but the role these plaques play in the early process of urinary stone formation remains unknown. The vascular hypothesis of Randall plaque formation has been proposed, and recent works support this concept. The renal papilla's vascular environment is subject to relative hypoxia, hyperosmolar surroundings, and turbulent blood flow. These factors together create an environment prone to vascular injury and may potentiate Randall plaque precipitation. Recent data support the similarity between the vascular calcification process itself and urinary stone formation. Furthermore, epidemiological studies have suggested an association between urinary stones, adverse cardiovascular events, and vascular calcification risk factors. The concept that an initial vascular insult precipitates a Randall plaque and subsequent urolithiasis is compelling and represents an area in need of continued research. This may lead to future novel treatment approaches to urolithiasis.

Morphological characteristics of renal artery and kidney in rats

The gross anatomy and morphometry of the kidney and renal arteries were studied in the strains of laboratory rat: Sprague-Dawley (Sp) and Wistar (W) rats. Total of 106 three-dimensional endocasts of the intrarenal arteries of kidney that were prepared using standard injection-corrosion techniques were examined. A single renal artery was observed in 100% of the cases. The renal arteries were divided into a dorsal and a ventral branch. The dorsal and ventral branches were divided into two branches, the cranial and caudal branch. Renal arteries were classified into types I and II, depending on the cranial and caudal branches and their made of branching. The present study also showed that the right kidney was slightly heavier than the left one and that the kidney of the male was generally larger than that of the female. The mean live weights of the Sprague-Dawley and Wistar rats were found to be 258.26 ± 5.9 and 182.4 ± 19.05 g, respectively. The kidney weights were significantly correlated (P < 0.01) with body weights. The kidney weights were not found significantly correlated (P > 0.01) with the length of renal arteries.

The morphometric development and arterial vascularization of bovine fetal kidneys in the prenatal period

This study presents a morphometric developmental analysis of bovine kidneys and a demonstration of intrarenal arterial vascularization in the prenatal period. A total of 40 Holstein bovine fetuses constituted the material of the study. The fetuses were divided into three groups, according to the gestational stages they belonged to early, mid- and late stages, such that each group comprised 10 fetuses. Sixty kidneys and their renal arteries were evaluated using morphometric measurements. Furthermore, 10 bovine fetuses were injected with cast solution to demonstrate the intrarenal arteries. Data obtained in the present study were statistically analyzed. Although the right and left kidneys did not significantly differ from each other, significant differences existed between the different gestational stages (P<0.05). The kidney parameters, including length, width and thickness, were positively correlated with both the right and left kidneys as well as with gestational age. Four types of intrarenal arterial segmentation were demonstrated. Type I was observed in 10 kidneys (50%), type II in four kidneys (20%) as well as type III, and type IV in only two kidneys (10%). In the most frequent arterial segmentation type (type I), the renal artery divided into three segmental arteries, which supplied the cranial polar, medial and caudal polar regions of the kidney, after stemming from the abdominal aorta. Furthermore, cases of double and multiple renal arteries were also observed.

Anatomical relationship between the collecting system and the intrarenal arteries in the rabbit: contribution for an experimental model

Intrarenal anatomy was studied in detail to evaluate how useful rabbits could be as a urologic model. Only one renal artery was observed, which was divided into dorsal and ventral branches in all cases. Three segmental arteries (cranial, mesorenal and caudal) was the most frequent branching pattern found in both the dorsal and ventral division. There was an important artery related to the ureteropelvic junction in both dorsal and ventral surfaces in all specimens. The cranial pole was supplied by both dorsal and ventral divisions of the renal artery in 23 of 41 casts (56%). Although the cranial pole of the rabbit kidney could be useful as a model because of the resemblances with human kidney, the different relationship between the intrarenal arteries and the kidney collecting system in other regions of the kidney must be taken into consideration by the urologists, when using rabbit kidney in urological research.