Khaled Radad

Recent advances in autophagy-based neuroprotection

Macroautophagy is a highly regulated intracellular process that, under certain circumstances, delivers cytoplasmic components to the lysosomes for degradation. It consists of several sequential steps including initiation and nucleation, double membrane formation and elongation, formation and maturation of autophagosomes and finally autophagosomes/lysosomes fusion and degradation of intra-autophagosomal contents by lysosomal enzymes. After decades of considering autophagy as a cell death pathway, it has recently been shown to have a survival function through clearing of protein aggregates and damaged cytoplasmic organelles in response to a variety of stress conditions. Most recently, there is increasing evidence from literature revealing that autophagy induction may combat neurodegeneration. In the light of this, our current review tried to address the recent advances in the role of induced autophagy in neuroprotection with a particular focus on its contribution in the most common neurodegenerative disorders like Alzheimer’s disease, Parkinson’s disease and Huntington’s disease.

Ultrastructural Changes of Smooth Muscles in Varicocele Veins

Background: Varicocele is a dilatation of the pampiniform venous plexus and internal spermatic veins. It affects about 15–20% of male population and can cause infertility. Objective: To describe the most significant ultrastructural changes of the smooth muscle cells in grade 3 varicocele veins. Methods: The authors analyzed 2- to 3-cm tracts of pampiniform venous plexus from 20 patients who underwent varicocelectomy for left varicocele. Light microscopic examination was performed with Van Gieson’s stain. Ultrastructural examination was done using scanning and transmission electron microscopy. Results: Light microscopic examination revealed irregularity and separation of medial smooth muscle cells by abundant collagen fibers in varicocele veins. On scanning electron microscopy, the medial layer of varicocele veins showed hypertrophy, irregularity, and separation of the outer longitudinal smooth muscle cells and deposition of numerous fatty globules in between muscle fibers. Transmission electron microscopy showed marked indentation and chromatin condensation of the nucleus, presence of clear vacuoles and myelin figures in the cytoplasm and plasmalemmal projections and formation of ghost bodies. Furthermore, smooth muscle cells were found to have pseudopodia-like projections around adjacent elastic and collagen fibers. Conclusions: The degenerative changes observed in smooth muscle cells and presence of abundant collagen fibers in the medial layer may contribute to the development of the varicocele of pampiniform venous plexus. Further molecular studies are required to shed more light for the underlying mechanism.

Ultrastructural Changes of the Smooth Muscle in Esophageal Atresia

Abstract Esophageal atresia (EA) with or without tracheo-esophageal fistula (TEF) is a relatively rare congenital anomaly. Despite the advances in the management techniques and neonatal intensive care, esophageal dysmotility remains a very common problem following EA/TEF repair. Our current study aimed to describe the most significant ultrastructural changes of the smooth muscle cells (SMCs) trying to highlight some of the underlying mechanisms of esophageal dysmotility following EA/TEF repair. Twenty-three biopsies were obtained from the tip of the lower esophageal pouch (LEP) of 23 patients during primary repair of EA/TEF. Light microscopic examination was performed with hematoxylin and eosin (HE), and Van Gieson’s stains. Ultrastructural examination was done using transmission electron microscopy (TEM). Histopathological examination showed distortion of smooth muscle layer and deposition of an abundant amount of fibrous tissue in-between smooth muscles. Using TEM, SMCs exhibited loss of the cell-to-cell adhesion, mitochondrial vacuolation, formation of myelin figures, and apoptotic fragmentation. There were also plasmalemmal projections and formation of ghost bodies. Interestingly, SMCs were found extending pseudopodia-like projections around adjacent collagen fibers. Engulfed collagen fibers by SMCs underwent degradation within autophagic vacuoles. Degeneration of SMCs and deposition of abundant extracellular collagen fibers are prominent pathological changes in LEP of EA/TEF. These changes might contribute to the pathogenesis of esophageal dysmotility in patients who have survived EA/TEF.

Ultrastructural changes of kidney in Schistosoma mansoni-infected mice

ABSTRACT Schistosomiasis is the second threatening parasitic disease after malaria and among Schistosoma spp., Schistosoma mansoni (S. mansoni) affects about 100 million people in tropic regions in Africa and South America. The current study was carried out to investigate ultrastructural changes of the kidney in mice infected with cercariae of S. mansoni, in which 20 Swiss albino mice of 60-day-old were assigned into two groups (10 each). Control group received 1 ml normal saline by intraperitoneal route. Model group were intraperitoneally infected with 1 ml normal saline containing 40 cercariae of S. mansoni/mouse. After 60 days of infection, specimens from the kidneys of both control and infected mice were obtained and processed for transmission electron microscopy (TEM) examination. The main ultrastructural changes were observed in both glomeruli and tubules. Glomerular findings included irregular thickening and splitting of the glomerular basement membrane (GBM), flattening and effacement of the foot processes of podocytes, and proliferation of mesangial cells. Tubular changes were in the form of swelling, atrophy and vacuolation of tubular epithelial cells, and presence of autophagic vacuoles. In conclusion, adopting TEM shows a number of ultrastructural changes in the kidneys of mice infected with cercariae of S. mansoni, most notably thickening and splitting of GBM and flattening and effacement of foot processes of podocytes and tubular autophagic vacuoles. These changes are still unraveled well in the literature.

Ultrastructural changes induced by Solanum incanum aqueous extract on HCT 116 colon cancer cells

ABSTRACT Medicinal plants have recently gained increasing scientific interest as an important source of molecules with different therapeutic potentials. Accordingly, the present study was carried out to investigate ultrastructural changes induced by the aqueous extract of Solanum incanum (SI) fruit on human colorectal carcinoma cell line (HCT 116 cells). Examination of SI-treated HCT 116 cells with transmission electron microscopy (TEM) demonstrated numerous ultrastructural changes in the form of loss of the surface microvilli, mitochondrial damage and dilatation of cristae, and formation of autophagic vacuoles and increasing numbers of lipid droplets. Also, majority of the treated cells showed nuclear shrinkage with chromatin condensation and nucleolar changes. Moreover, some cells showed focal areas of cytoplasmic degeneration associating with formation of myelin figures and fatty globules. In conclusion, TEM was able to verify cytotoxicity of SI aqueous extract against HCT 116 colon cancer cells.

Radiation-induced damage to lacrimal glands: an ultrastructural study in Sprague Dawley rats

ABSTRACT Injury to lacrimal glands represents a major health problem after radiation therapy of the head and neck malignancies. Accordingly, this study aimed to investigate significant ultrastructural changes of lacrimal glands and some of their underlying mechanisms following the exposure to different fractionated doses of irradiation. In this study, 28 Sprague Dawley (SD) rats were assigned to four groups (seven rats each): Group I acted as control and received no irradiation. Groups II–IV received fractionated irradiation of 5 Gy (100 cGy/fraction daily for 5 days), 9 Gy (300 cGy/fraction daily for 3 days), and 20 Gy (one fraction), respectively. One month after the experiment, examination of lacrimal glands with transmission electron microscopy (TEM) demonstrated dose-dependent ultrastructural changes in the lacrimal acinar and intralobular ductal epithelial cells. In the acinar cells, there were swollen rough endoplasmic reticulum, irregularly shaped nuclei with chromatin condensation, mitochondrial damage, and retention of secretory granules. Intaralobular ductal epithelial cells showed loss of surface microvilli and damage to mitochondria. In addition to the potential direct effects of irradiation on lacrimal acinar and intralobular ductal epithelial cells, damage to blood vessels and nerve endings seemed to mediate some of the underlying mechanisms of these irradiation-induced ultrastructural changes. In conclusion, using TEM reveals that lacrimal gland is highly sensitive to even small doses of irradiation therapy; in addition, swelling of rough endoplasmic reticulum and aberrant nuclei are the most encountered structural changes. Damage to blood vessels and nerve endings might mediate some of the underlying mechanisms of irradiation-induced secondary injury in lacrimal glands.

Long-term neurotoxic effects of domoic acid on primary dopaminergic neurons

Domoic acid, an excitatory neurotoxin produced by certain algae, reaches the food chain through accumulation in some sea organisms. To investigate its long-term neurotoxicity on dopaminergic neurons, prepared primary mesencephalic cell cultures were exposed to different concentrations of domoic acid (0.1, 1, 10, 100 μM) on the 8th day in vitro (DIV) for 4 days. On the 12th DIV, culture media were collected for measurement of lactate dehydrogenase and cultured cells were subjected to immunohistochemistry against tyrosine hydroxylase, neuronal nuclear antigen and glial fibrillary acidic protein, and fluorescence staining using H2DCFDA, JC-1 and Hoechst 33342 dyes. Moreover, roles of AMPA/KA and NMDA receptors in domoic acid neurotoxicity were also investigated. Domoic acid significantly decreased the number of dopaminergic neurons and adversely affected their morphology, and slightly reduced the expression of neuronal nuclear antigen and glial fibrillary acidic protein. Co-treatment of cultures with domoic acid and the AMPA/KA or NMDA receptor antagonists NBQX and MK-801 rescued significant number of dopaminergic neurons. Domoic acid significantly decreased red:green fluorescence ratio of JC-1 and did not affect production of reactive oxygen species and apoptotic cell death. In conclusions, the present study reveals that long-term treatment of primary mesencephalic cell culture with domoic acid significantly destroyed dopaminergic neurons. This effect appears to be attributed to activation of AMPA/KA and NMDA receptors and mitochondrial damage.

Ultrastructural pathology of human liver in Rift Valley fever

Rift Valley fever (RVF) is a zoonotic disease that primarily affects ruminant animals and can also cause fatal disease in humans. In the current report, we present the ultrastructural changes in the liver of a man aged 60 years who died from RVF in the Aseer Central Hospital, Abha, Saudi Arabia. The main hepatic changes by transmission electron microscopy included the presence of 95–115 nm electron-dense particles consistent with RVF virions, nuclear condensation, vacuolar degeneration, lipid droplet accumulation and mitochondrial damage and dilation. There were also viral inclusion bodies with electron-dense aggregates, dilation of intercellular spaces, damage of sinusoidal microvilli with widening of space of Disse, dilation of bile canaliculi and increasing number of phagolysosomes.