Automatic Identification of Glomerular in Whole-Slide Images Using a Modified UNet Model

Glomeruli are interconnected capillaries in the renal cortex that are responsible for blood filtration. Damage to these glomeruli often signifies the presence of kidney disorders like glomerulonephritis and glomerulosclerosis, which can ultimately lead to chronic kidney disease and kidney failure. The timely detection of such conditions is essential for effective treatment. This paper proposes a modified UNet model to accurately detect glomeruli in whole-slide images of kidney tissue. The UNet model was modified by changing the number of filters and feature map dimensions from the first to the last layer to enhance the model's capacity for feature extraction. Moreover, the depth of the UNet model was also improved by adding one more convolution block to both the encoder and decoder sections. The dataset used in the study comprised 20 large whole-side images. Due to their large size, the images were cropped into 512 × 512-pixel patches, resulting in a dataset comprising 50,486 images. The proposed model performed well, with 95.7% accuracy, 97.2% precision, 96.4% recall, and 96.7% F1-score. These results demonstrate the proposed model's superior performance compared to the original UNet model, the UNet model with EfficientNetb3, and the current state-of-the-art. Based on these experimental findings, it has been determined that the proposed model accurately identifies glomeruli in extracted kidney patches.

Effects of dexmedetomidine on new oxidative stress markers on renal ischaemia-reperfusion injury in rats: thiol/disulphide homeostasis and the ischaemia-modified albumin

OBJECTIVES

This study investigated the effect of dexmedetomidine on the oxidant-antioxidant (thiol/disulphide) balance.

METHODS

A total of 24 rats were divided into four groups. The renal arteries in groups IR (ischaemia/reperfusion) and IR + D (ischaemia/reperfusion + dexmedetomidine) were clamped for 45 min and reperfused for 180 min. Groups D (Dexmedetomidine) and IR + D were administered 100 μg/kg dexmedetomidine. Oxidant-antioxidant (thiol/disulphide) levels were measured. Kidney tissue was examined histopathologically.

RESULTS

No statistically difference was found between the groups in terms of thiol-disulphide averages, while IMA, TOS and thiol-disulphide results showed a minimal decrease in Group IR + D compared to Group IR (p > 0.05). Tubular lesions and necrosis were found in 26-50% of tubules in Group IR. Tubular damage and necrosis in Group IR + D declined to 5-25% .

CONCLUSIONS

No statistically difference was found in the study where OSI index, thiol/disulphide balance and IMA were measured together as biochemical values.

A Novel Fluorogenic Assay for the Detection of Nephrotoxin-Induced Oxidative Stress in Live Cells and Renal Tissue

Drug-induced kidney injury frequently leads to aborted clinical trials and drug withdrawals. Sufficiently sensitive sensors capable of detecting mild signs of chemical insult in cell-based screening assays are critical to identifying and eliminating potential toxins in the preclinical stage. Oxidative stress is a common early manifestation of chemical toxicity, and biomolecule carbonylation is an irreversible repercussion of oxidative stress. Here, we present a novel fluorogenic assay using a sensor, TFCH, that responds to biomolecule carbonylation and efficiently detects modest forms of renal injury with much greater sensitivity than standard assays for nephrotoxins. We demonstrate that this sensor can be deployed in live kidney cells and in renal tissue. Our robust assay may help inform preclinical decisions to recall unsafe drug candidates. The application of this sensor in identifying and analyzing diverse pathologies is envisioned.

Protein Extraction From FFPE Kidney Tissue Samples: A Review of the Literature and Characterization of Techniques

Most tissue biopsies from patients in hospital environments are formalin-fixed and paraffin-embedded (FFPE) for long-term storage. This fixation process produces a modification in the proteins called “crosslinks”, which improves protein stability necessary for their conservation. Currently, these samples are mainly used in clinical practice for performing immunohistochemical analysis, since these modifications do not suppose a drawback for this technique; however, crosslinks difficult the protein extraction process. Accordingly, these modifications make the development of a good protein extraction protocol necessary. Due to the specific characteristics of each tissue, the same extraction buffers or deparaffinization protocols are not equally effective in all cases. Therefore, it is necessary to obtain a specific protocol for each tissue. The present work aims to establish a deparaffinization and protein extraction protocol from FFPE kidney samples to obtain protein enough of high quality for the subsequent proteomic analysis. Different deparaffination, protocols and protein extraction buffers will be tested in FFPE kidney samples. The optimized conditions will be applied in the identification by LC-MS/MS analysis of proteins extracted from 5, 10, and 15 glomeruli obtained through the microdissection of FFPE renal samples.

Renal reabsorption in 3D vascularized proximal tubule models

Current kidney-on-chip models lack the 3D geometry, complexity, and functionality vital for recapitulating in vivo renal tissue. We report the fabrication and perfusion of 3D vascularized proximal tubules embedded within an engineered ECM that exhibit active reabsorption of solutes via tubular–vascular exchange. Using this model, we quantified albumin and glucose reabsorption over time. We also studied hyperglycemic effects in the absence and presence of a glucose transport inhibitor. Our 3D kidney tissue provides a platform for in vitro studies of kidney function, disease modeling, and pharmacology.

Three-dimensional renal tissues that emulate the cellular composition, geometry, and function of native kidney tissue would enable fundamental studies of filtration and reabsorption. Here, we have created 3D vascularized proximal tubule models composed of adjacent conduits that are lined with confluent epithelium and endothelium, embedded in a permeable ECM, and independently addressed using a closed-loop perfusion system to investigate renal reabsorption. Our 3D kidney tissue allows for coculture of proximal tubule epithelium and vascular endothelium that exhibits active reabsorption via tubular–vascular exchange of solutes akin to native kidney tissue. Using this model, both albumin uptake and glucose reabsorption are quantified as a function of time. Epithelium–endothelium cross-talk is further studied by exposing proximal tubule cells to hyperglycemic conditions and monitoring endothelial cell dysfunction. This diseased state can be rescued by administering a glucose transport inhibitor. Our 3D kidney tissue provides a platform for in vitro studies of kidney function, disease modeling, and pharmacology.

Recombinant human erythropoietin prevents etoposide- and methotrexate-induced toxicity in kidney and liver tissues via the regulation of oxidative damage and genotoxicity in Wistar rats

Etoposide (ETO) and methotrexate (MTX) are two effective chemotherapeutic drugs. However, the clinical use of these drugs is limited by its toxicity in normal tissues, especially in kidney and in liver tissues. Recombinant human erythropoietin (rhEPO), erythropoietin hormone, has also been shown to exert tissue protective effects. The purpose of this study was to explore the protective effect of rhEPO against oxidative stress and genotoxicity induced by ETO and MTX in vivo. Adult male Wistar rats were divided into 10 groups (6 animals each): control group, rhEPO alone group, ETO alone group, MTX alone group and rhEPO + ETO/MTX groups. In rhEPO + ETO/MTX groups, three doses of pretreatment with rhEPO were performed: 1000, 3000 and 6000 IU/kg. Our results showed that rhEPO pretreatment protects liver and kidney tissues against oxidative stress induced by the anticancer drugs. The glycoprotein decreased malondialdehyde (MDA) levels, reduced catalase activity and ameliorated glutathione depletion. Furthermore, we showed that rhEPO administration prevented drug-induced DNA damage accessed by comet test. Altogether, our results suggested a protective role of rhEPO, especially at 3000 IU/kg, against ETO- and MTX-induced oxidative stress and genotoxicity in vivo.

Antitumor activity with nontoxic doses of protein A

This report confirms our previous observation that IV inoculation of purified protein A causes regression of rat mammary adenocarcinomas. In treated tumors, we have obtained histological evidence of changes indicating tumor cell destruction. Protein A treatment does not cause reduction in the body weight or organ weights of rats; nor does it cause any decrease in activity of the enzymes of the microsomal mixed function oxidase system in the liver. Protein A stimulates peripheral white cell counts in normal rats, but not in tumor-bearing rats. We found that protein A infusion reduced (P less than 0.0005) the level of circulating plasma immune complex concentration. A homing study with 125I-labeled protein A indicated that liver, spleen, and kidney tissues are the major sites of protein A accumulation. Therefore, protein A seemed to exert its antitumor effects without causing any generalized toxicity to the system. It is postulated that the action of protein A may be related to its ability to cause a drastic reduction in circulating plasma immune complex concentration, thus potentiating the immune reactivity of the host observed earlier.