EFFECT OF NICOTINE SMOKE ON LIVER AND KIDNEYS OF ADULT MALE ALBINO RATS: AN EXPERIMENTAL STUDY

Apart from heart and lungs, being cited as the main affected organs by nicotine smoke and hence, contributing for the morbidity and mortality, other organs like kidneys, gastrointestinal tract, liver, reproductive organs, endocrine glands, skin etc. are also affected. In the current study we planned to evaluate the effects of nicotine smoke on liver and kidneys. The study was conducted on 12 inbred adult Wistar albino rats; 6 animals acting as control and remaining 6 acting as test group. The animals of control group were given only sterile water where as animals of test group were exposed to smoke produced from the nicotine wrapped in a cotton wool in the dose of 6mg/day three times a day for each session of 5 minutes each for 5 days. Each rat was exposed to the smoke produced due to nicotine separately in a closed inhalational chamber and not in groups. The rats were sacrificed after the period of experimentation and testis were dissected out and subjected further to tissue processing for histological examination. The histological examination of tissue sections of liver of test group animals revealed distorted or normal lobular architecture of hepatic lobules with dilated and congested central vein, portal venule and hepatic sinusoids. Also, there was presence of focal inflammatory aggregates especially around bile canaliculi at portal triads. On the other hand, the tissue sections of liver of control group showed normal hepatic architecture with normal hepatocytes. The renal specimens of the control group also demonstrated normal renal architectural pattern; with glomeruli surrounded by urinary space and renal tubules present in cortex and medulla composed of collecting tubules, loop of henle and convoluted tubules. On the contrary, the renal sections of test group showed dilation of urinary space, shrunken and distorted glomeruli with some renal tubules showing solid cord like pattern and some showing eosinophilic material in lumen, focal inflammatory infiltrates and renal congestion. Keywords: Nicotine smoke, liver, kidney

SO021EFFECTS OF SODIUM-GLUCOSE COTRANSPORTER 2 INHIBITOR, CANAGLIFLOZIN ON GLOMERULAR HYPERFILTRATION AND OXIDATIVE STRESS IN MICE WITH TYPE 2 DIABETES

Background and Aims In most developed countries, diabetic kidney disease (DKD) is the most common cause of chronic kidney disease, which can lead to end-stage renal disease. In recent clinical trials, sodium–glucose cotransporter 2 inhibitors (SGLT2is) slowed the progression of kidney disease as compared with a placebo in patients with type 2 diabetes. One of the main mechanisms of the renoprotective effects of SCLT2is in DKD is considered the ability of these inhibitors to improve glomerular hyperfiltration. We previously demonstrated that the adenosine/adenosine A1 receptor pathway played a pivotal role in the tubuloglomerular feedback(TGF) system in a type 1 diabetic model, Akita mice (Circulation, 2019). We also reported that increased oxidative stress was involved in the pathogenesis of diabetic vascular complications. Uncoupling of endothelial nitric oxide (NO) synthase (eNOS) via oxidation of tetrahydrobiopterin (BH4), a cofactor required for NO production, played a major role in generation of oxidative stress (AJPRP, 2005; JASN, 2013). In the present study, we explored the renal protective effects of SGLT2 inhibition, with a focus on glomerular hemodynamics and glomerular oxidative stress. Method This study used type 2 diabetic db/db mice and db/m+ mice as a control (male, 8wk old). We developed a novel method to measure the glomerular filtration rate of single nephrons (SNGFRs) in mice using multiphoton laser microscopy. In the first experiment, we measured the SNGFRs in 12 wk-old db/db and db/m+ mice to confirm glomerular hyperfiltration. Next, we evaluated the SNGFRs change before and after the administration of a single dose of canagliflozin (CANA) (10 mg/kg). The SNGFRs, glomerular permeability of macromolecules, glomerular reactive oxygen species (ROS) and NO production, and tetrahydrobiopterin (BH4) level in serum and kidney were evaluated after the CANA treatment for 8 wk. Finally, human glomerular endothelial cells (hGECs) were exposed to normal glucose (5 mmol/L), high glucose (30 mmol/L of D-glucose), or a hyperosmotic control (5 mmol/L of D-glucose plus 25 mmol/L of L-glucose) in the presence or absence of CANA (10 μmol/L). Results The CANA treatment ameliorated glomerular hyperfiltration in the db/db mice. In the db/db mice, glomerulus ROS production increased, and NO production decreased as compared with the levels in the control mice. CANA improved the imbalance between ROS and NO production. The serum and kidney concentrations of BH4 declined in the non-treated db/db mice, whereas the CANA treatment preserved the BH4 level. Leakage of 70-kD FITC-labeled albumin into the urinary space was observed in the db/db mice. The CANA treatment reduced the amount of FITC-labeled albumin in the urinary space of the db/db mice. The CANA treatment also alleviated vascular endothelial damage in glomeruli. BH4 levels decreased in the hGECs exposed to high glucose. CANA did not improved BH4 level in the hGECs exposed to high glucose. Conclusion SGLT2i ameliorated glomerular hyperfiltration, preserving BH4 levels and improving the glomerular ROS/NO imbalance in type 2 diabetic mice.

Novel cell contact between podocyte microprojections and parietal epithelial cells analyzed by volume electron microscopy

Podocytes are highly specialized cells with a clear cell polarity. It is known that in health and disease, microvilli protrude from the apical surface of the podocytes into the urinary space. As a basis to better understand the podocyte microprojections/microvilli, the present study analyzed their spatial localization, extension, and contact site with parietal epithelial cells (PECs). Using different electron microscopic (EM) techniques, we analyzed renal corpuscles of healthy young adult male C57BL/6 mice fixed by vascular perfusion. Serial block-face scanning EM was used to visualize entire corpuscles, focused ion beam scanning EM was performed to characterize microprojection/microvilli-rich regions at higher magnification, and transmission EM of serial sections was used to analyze the contact zone between podocyte microprojections and PECs. Numerous microprojections originating from the primary processes of podocytes were present in the urinary space in all regions of the corpuscle. They often reached the apical surface of the PEC but did not make junctional contacts. At high resolution, it was observed that the glycocalyx of both cells was in contact. Depending on the distance between podocytes and PECs, these microprojections had a stretched or coiled state. The present study shows that microprojections/microvilli of podocytes are a physiological feature of healthy mouse kidneys and are frequently in contact with the apical surface of PECs, thus spanning the urinary space. It is proposed that podocyte microprojections serve mechanosensory or communicative functions between podocytes and PECs.

Induced sepsis by cecal ligation and puncture in a rat model: hepatic and renal histological features

Animal models have been developed in an attempt to test potential therapeutic agents. The study aims to determine the hepatic and renal histological features induced by sepsis following cecal ligation and puncture (CLP) in a rat model. Regarding the material, we used 20 adult-male Wistar rats (control group 1, n=10, and group 2, n=10, that underwent CLP protocol). The experimental protocol was approved by the National Sanitary Veterinary and Food Authority, Cluj (Romania), project number 116/11.05.2018. The endpoint of the experiment was pre-set to 10 hours post-surgery. A complete necropsy survey was performed. The main renal lesions detected histologically were: glomerular congestion and edema, hyalinization of glomerular mesangium, presence of hyaline in the urinary space with associated compression atrophy of vascular glomerular tuft, granules of hyaline in the lumen of cortical tubules, and reduction of the urinary space. The hepatic lesion identified histologically was represented by isolated miliary necrotic foci.

Effect of Neonatal Exposure of Monosodium Glutamate in Kidney of Albino Mice – A Histological Study

Monosodium Glutamate (MSG) is a commonly used food additive. Scientists have found that MSG has toxic effects in several tissues and organs like neurons, liver, testes, ovary, kidneys etc due to oxidative stress both after exposure in neonatal period as well as in adult animal models. Although various reports have suggested that MSG has damaging effect in kidneys only few histological studies are available. This study was done to observe any histological changes in kidneys of albino mice after neonatal exposure with MSG. Study showed significant changes in weight and volume of kidneys in gross morphology. Increased urinary space and dilatation of proximal convoluted tubules (PCT) and distal convoluted tubules (DCT) were constant finding in experimental animals. There were loss of luminal microvilli and reduced height of lining cells of both PCT and DCT.

Glomerular Hematuria: Cause or Consequence of Renal Inflammation?

Glomerular hematuria is a cardinal symptom of renal disease. Glomerular hematuria may be classified as microhematuria or macrohematuria according to the number of red blood cells in urine. Recent evidence suggests a pathological role of persistent glomerular microhematuria in the progression of renal disease. Moreover, gross hematuria, or macrohematuria, promotes acute kidney injury (AKI), with subsequent impairment of renal function in a high proportion of patients. In this pathological context, hemoglobin, heme, or iron released from red blood cells in the urinary space may cause direct tubular cell injury, oxidative stress, pro-inflammatory cytokine production, and further monocyte/macrophage recruitment. The aim of this manuscript is to review the role of glomerular hematuria in kidney injury, the role of inflammation as cause and consequence of glomerular hematuria, and to discuss novel therapies to combat hematuria.

Human podocytes perform polarized, caveolae-dependent albumin endocytosis

The renal glomerulus forms a selective filtration barrier that allows the passage of water, ions, and small solutes into the urinary space while restricting the passage of cells and macromolecules. The three layers of the glomerular filtration barrier include the vascular endothelium, glomerular basement membrane (GBM), and podocyte epithelium. Podocytes are capable of internalizing albumin and are hypothesized to clear proteins that traverse the GBM. The present study followed the fate of FITC-labeled albumin to establish the mechanisms of albumin endocytosis and processing by podocytes. Confocal imaging and total internal reflection fluorescence microscopy of immortalized human podocytes showed FITC-albumin endocytosis occurred preferentially across the basal membrane. Inhibition of clathrin-mediated endocytosis and caveolae-mediated endocytosis demonstrated that the majority of FITC-albumin entered podocytes through caveolae. Once internalized, FITC-albumin colocalized with EEA1 and LAMP1, endocytic markers, and with the neonatal Fc receptor, a marker for transcytosis. After preloading podocytes with FITC-albumin, the majority of loaded FITC-albumin was lost over the subsequent 60 min of incubation. A portion of the loss of albumin occurred via lysosomal degradation as pretreatment with leupeptin, a lysosomal protease inhibitor, partially inhibited the loss of FITC-albumin. Consistent with transcytosis of albumin, preloaded podocytes also progressively released FITC-albumin into the extracellular media. These studies confirm the ability of podocytes to endocytose albumin and provide mechanistic insight into cellular mechanisms and fates of albumin handling in podocytes.