Atrazine-Induced Hepato-Renal Toxicity in Adult Male Xenopus laevis Frogs

Atrazine (ATZ) is an herbicide commonly detected in groundwater. Several studies have focused on its immunological and endocrine effects on adult Xenopus laevis species. However, we investigated the impact of atrazine on the renal and hepatic biochemistry and histomorphology in adult male frogs. Forty adult male frogs were allocated to four treatment groups (control, one ATZ (0.01 µg/L), two ATZ (200 µg/L) and three ATZ (500 µg/L), 10 animals per group, for 90 days. Alanine aminotransferase (ALT) and creatinine levels increased significantly (p < 0.05) in the 200 and 500 μg/L groups but malondialdehyde only in the 500 μg/L group (p < 0.05). Histopathological observations of derangement, hypertrophy, vascular congestion and dilation, infiltration of inflammatory cells incursion, apoptosis and hepatocytes cell death were observed with atrazine exposure, mostly in the 500 μg/L group. Additionally, histochemical labelling of caspase-3 in the sinusoidal endothelium was observed in all the treated groups, indicating vascular compromise. Evaluation of renal histopathology revealed degradation and atrophy of the glomerulus, vacuolization, thick loop of Henle tubule epithelial cells devolution and dilation of the tubular lumen. Furthermore, expression of caspase-3 indicates glomerular and tubular apoptosis in atrazine-exposed animals. These findings infer that environmentally relevant atrazine doses (low or high) could induce hepatotoxicity and nephrotoxicity in adult male Xenopus laevis frogs and potentially related aquatic organisms.

Anisotropic expansion of hepatocyte lumina enforced by apical bulkheads

Lumen morphogenesis results from the interplay between molecular pathways and mechanical forces. In several organs, epithelial cells share their apical surfaces to form a tubular lumen. In the liver, however, hepatocytes share the apical surface only between adjacent cells and form narrow lumina that grow anisotropically, generating a 3D network of bile canaliculi (BC). Here, by studying lumenogenesis in differentiating mouse hepatoblasts in vitro, we discovered that adjacent hepatocytes assemble a pattern of specific extensions of the apical membrane traversing the lumen and ensuring its anisotropic expansion. These previously unrecognized structures form a pattern, reminiscent of the bulkheads of boats, also present in the developing and adult liver. Silencing of Rab35 resulted in loss of apical bulkheads and lumen anisotropy, leading to cyst formation. Strikingly, we could reengineer hepatocyte polarity in embryonic liver tissue, converting BC into epithelial tubes. Our results suggest that apical bulkheads are cell-intrinsic anisotropic mechanical elements that determine the elongation of BC during liver tissue morphogenesis.

Testicle histomorphometry in senescence/senility under use of homeopathy

Aging is an extremely complex and multifactorial process. Over time, the elderly begin exhibiting signs of function reduction. The aim of the present study was to assess the effects of homeopathic medicines on testicle histomorphometry in senescence/senility. The study was approved by the animal experimentation ethics committee of Santo Amaro University (07/2015). The rats (Wistar, all male, with 22-23 months of age were used) were caged with access to food and water ad libitum and 12-hour light cycle (7:00 am to 7:00 pm). The homeopathic medicines were prepared following the Brazilian Homeopathic Pharmacopoeia. The animals were randomly distributed in 4 groups (n= 6): control; hydroalcoholic solution; Calcarea carbonica 30cH (Calc) and Baryta muriatica 30cH (Bar-m). 5 globules of the medicines were added to each water dispenser; the containers were changed twice per week along 40 days. All investigators were blinded to the allocation groups. After 40 days all the animals were euthanized and the testicles collected. Based on their width and length, the testicles’ volume was calculated by means of the ellipsoid formula. Slides were prepared and stained with PAS. Photographs were taken of the slides with 40x magnification under microscope; software Image J was used to measure the diameter of 50 seminiferous tubules per slide (animal), diameter of the parenchyma and lumen of each tubule. Statistical analysis was performed by means of ANOVA followed by Tukey’s test; the significance level was set to p≤ 0.05. Increase of the testicles’ volume, increased parenchymal diameter and decrease of the tubular lumen was found in groups Calc and Bar-m compared to controls and the group treated with hydroalcoholic solution (p ≤ 0.05). We conclude that the tested homeopathic medicines changed the testicle histomorphometry of animals in senescence/senility. Keywords: Testicular histomorphometry, homeopathy, Calcarea carbonica, Baryta muriatica, Senescence/Senility

The Mechanism of Drug Nephrotoxicity and the Methods for Preventing Kidney Damage

Acute kidney injury (AKI) is a global health challenge of vast proportions, as approx. 13.3% of people worldwide are affected annually. The pathophysiology of AKI is very complex, but its main causes are sepsis, ischemia, and nephrotoxicity. Nephrotoxicity is mainly associated with the use of drugs. Drug-induced AKI accounts for 19–26% of all hospitalized cases. Drug-induced nephrotoxicity develops according to one of the three mechanisms: (1) proximal tubular injury and acute tubular necrosis (ATN) (a dose-dependent mechanism), where the cause is related to apical contact with drugs or their metabolites, the transport of drugs and their metabolites from the apical surface, and the secretion of drugs from the basolateral surface into the tubular lumen; (2) tubular obstruction by crystals or casts containing drugs and their metabolites (a dose-dependent mechanism); (3) interstitial nephritis induced by drugs and their metabolites (a dose-independent mechanism). In this article, the mechanisms of the individual types of injury will be described. Specific groups of drugs will be linked to specific injuries. Additionally, the risk factors for the development of AKI and the methods for preventing and/or treating the condition will be discussed.

Renal Handling of Albumin—From Early Findings to Current Concepts

Albumin is the main protein of blood plasma, lymph, cerebrospinal and interstitial fluid. The protein participates in a variety of important biological functions, such as maintenance of proper colloidal osmotic pressure, transport of important metabolites and antioxidant action. Synthesis of albumin takes place mainly in the liver, and its catabolism occurs mostly in vascular endothelium of muscle, skin and liver, as well as in the kidney tubular epithelium. Long-lasting investigation in this area has delineated the principal route of its catabolism involving glomerular filtration, tubular endocytic uptake via the multiligand scavenger receptor tandem—megalin and cubilin-amnionless complex, as well as lysosomal degradation to amino acids. However, the research of the last few decades indicates that also additional mechanisms may operate in this process to some extent. Direct uptake of albumin in glomerular podocytes via receptor for crystallizable region of immunoglobulins (neonatal FC receptor) was demonstrated. Additionally, luminal recycling of short peptides into the bloodstream and/or back into tubular lumen or transcytosis of whole molecules was suggested. The article discusses the molecular aspects of these processes and presents the major findings and controversies arising in the light of the research concerning the last decade. Their better characterization is essential for further research into pathophysiology of proteinuric renal failure and development of effective therapeutic strategies.

Sheep urinary tract architecture is not affected by acute urethral obstruction

Urolithiasis affects the urinary tract of small ruminants, thereby requiring the animal to prematurely terminate breeding. Morphometric study of organs can be used as a diagnostic method. Thus, this study aimed to describe the macroscopic, histopathological, and histomorphometric changes in the urinary tract of sheep with urolithiasis. For this purpose, 14 healthy male Santa Inês sheep, approximately 90 days old, were studied and fed an experimental diet. After the development of urolithiasis, the animals were reorganized into two groups, D1 (without urolithiasis) and D2 (with urolithiasis) for comparative data analysis. Sheep were necropsied to evaluate the pathological changes, followed by macroscopic morphometric analysis, and the histopathological and histomorphometric characteristics were described. Urethral necrosis and a full urinary bladder were observed in all animals that developed the disease. The comparison between sheep with and without urolithiasis showed no significant difference (P < 0.05) in the evaluated macroscopic morphometric variables, except for the right ureter width. Regarding the histopathological evaluation, multifocal areas of mild to moderate congestion within the glomerular tufts and protein in the tubular lumen of the kidneys were observed. In the liver, mild to moderate fatty degeneration was noted in the centrolobular regions, and an ulcerated focal area in the bladder mucosa was observed in only one animal. The present study demonstrated that the formulated diet was effective in inducing clinical disease. In acute obstructive urolithiasis in sheep tissue, lesions in the liver and urinary tract were observed, although there were no significant histomorphometric changes.

Sex Differences in Population Dynamics during Formation of Kidney Bacterial Communities by Uropathogenic Escherichia coli

ABSTRACT Uropathogenic Escherichia coli (UPEC), the primary etiologic agent of urinary tract infections (UTIs), encounters a restrictive population bottleneck within the female mammalian bladder. Its genetic diversity is restricted during establishment of cystitis because successful UPEC must invade superficial bladder epithelial cells prior to forming clonal intracellular bacterial communities (IBCs). In this study, we aimed to understand UPEC population dynamics during ascending pyelonephritis, namely, formation of kidney bacterial communities (KBCs) in the renal tubular lumen and nucleation of renal abscesses. We inoculated the bladders of both male and female C3H/HeN mice, a background which features vesicoureteral reflux; we have previously shown that in this model, males develop severe, high-titer pyelonephritis and renal abscesses much more frequently than females. Mice were infected with 40 isogenic, PCR-tagged (“barcoded”) UPEC strains, and tags remaining in bladder and kidneys were ascertained at intervals following infection. In contrast to females, males maintained a majority of strains within both the bladder and kidneys throughout the course of infection, indicating only a modest host-imposed bottleneck on overall population diversity during successful renal infection. Moreover, the diverse population in the infected male kidneys obscured any restrictive bottleneck in the male bladder. Finally, using RNA in situ hybridization following mixed infections with isogenic UPEC bearing distinct markers, we found that despite their extracellular location (in the urinary space), KBCs are clonal in origin. This finding indicates that even with bulk reflux of infected bladder urine into the renal pelvis, successful ascension of UPEC to establish the tubular niche is an uncommon event.

Comparing Nephrolithiasis with Nephrocalcinosis in Children; A Study From Two Tertiary Centers in Saudi Arabia

Background: Nephrolithiasis and nephrocalcinosis is uncommon in children; however, its incidence is increasing. Patients and Methods: A multicenter retrospective study of the clinical presentation, etiology, and outcome of childhood nephrolithiasis and compare it with nephrocalcinosis.Results: The study included 144 children; 93 with nephrolithiasis (formation of stones within renal pelvis or tubular lumen) and 51 with nephrocalcinosis. (deposition of calcium in the renal parenchyma) Mean age at presentation were 72 months and 54 months for nephrolithiasis and nephrocalcinosis, respectively. In 64.8% of the nephrolithiasis and 76% of nephrocalcinosis cases, a history of consanguinity was found. Congenital anomalies of the kidneys and urinary tract were present in 28% and 9.8% of those with nephrolithiasis and nephrocalcinosis, respectively. The most common symptoms of nephrolithiasis were flank pain (29%), hematuria (15%), and dysuria (11%). Urinary tract infection was the primary presentation in the nephrocalcinosis group (18%) followed by failure to thrive (16%), polyuria (12%), and dehydration (12%).The majority of nephrolithiasis cases were caused by metabolic disorders. In contrast, the most common underlying disorders for nephrocalcinosis were familial hypomagnesemia hypercalciuria nephrocalcinosis (35%), distal renal tubular acidosis (23%), and Bartter syndrome (6%).Clinical outcomes were significantly better in children with nephrolithiasis than those with nephrocalcinosis who had radiological evidence of worsening/persistent calcinosis and progressed more frequently to chronic kidney disease (stage II-IV) and end stage kidney disease.Conclusion: The etiology of nephrolithiasis can be identified in many children. Nephrocalcinosis is associated with worse clinical outcomes related to kidney function and disease resolution as compared to nephrolithiasis.

Clinical and anatomopathological study of urolithiasis in feedlot lambs subjected to diets with different phosphorus concentrations

Obstructive urolithiasis is common in farmed sheep and has a multifactorial etiology, but inadequate nutritional management is considered the most relevant condition for its occurrence. The objectives of this study were to verify the influence of two diets with different concentrations of calcium (Ca) and phosphorus (P) on the development of obstructive urolithiasis, and to describe the clinical and anatomopathological findings of the urinary system in sheep. Thirty male crossbred Santa Inês and Ile de France lambs were randomly distributed into two groups: Group 1 (G1, n = 15) - Ca: 1.9:1 P and 0.42% P; Group 2 (G2, n = 15) - Ca: P 1.5:1 and 0.65% P. The diets consisting of Coast-cross hay, soybean meal, wheat, and corn were provided for 90 consecutive days with water ad libitum. After the diagnosis of the disease, the lambs were subjected to clinical and surgical treatment, when necessary. Urolithiasis was detected in 36.7% (11/30) of lambs, 26.7% were asymptomatic and 10% (3/30) had urethral obstruction. A lamb was unobstructed after amputation of the urethral process and urethral catheterization, one died of bladder and uroperitoneum rupture, and another was sacrificed after the failure of perineal urethrostomy and cystostomy. The most frequent renal histopathological changes were vascular congestion, dilation, and tubular degeneration. Proteins in the tubular lumen were more pronounced in G2. The diets were rich in concentrate and had adequate Ca:P ratios, but caused calculogenesis, showing that excess minerals and a small amount of roughage can cause disease in the herd.

Bulkhead-like apical membrane structures between hepatocytes are required for anisotropic lumen expansion and liver tissue morphogenesis

SummaryCell polarity is key to epithelial organization. Whereas polarized epithelial cells have a single apico-basal axis, hepatocytes exhibit a complex multi-axial polarity. During development, the apical surfaces of hepatocytes elongate anisotropically, generating a 3D tubular network of bile canaliculi (BC). Here, to elucidate the mechanisms of hepatocyte polarity and re-engineer it into simple epithelial polarity, we optimised a culture system of primary mouse hepatoblasts that recapitulates hepatocyte differentiation and BC morphogenesis. Remarkably, we discovered a pattern of specific extensions of the apical membrane sealed by tight junctions traversing the lumen between two adjacent hepatocytes that remind the bulkheads of boats. These apical bulkheads were observed also in the developing liver. Screening for molecular factors required for hepatocyte polarity revealed that silencing of Rab35 caused loss of the bulkheads, conversion into simple polarity, formation of cyst-like structures and change in cell fate. By exploiting Rab35 depletion in the developing liver we could re-engineer hepatocyte polarity and trigger formation of epithelial tubes. Our results suggest a new model of BC morphogenesis based on mechanical stabilization of the tubular lumen.