Lopinavir and Nelfinavir Induce the Accumulation of Crystalloid Lipid Inclusions within the Reservosomes of Trypanosoma cruzi and Inhibit Both Aspartyl-Type Peptidase and Cruzipain Activities Detected in These Crucial Organelles

Several research groups have explored the repositioning of human immunodeficiency virus aspartyl peptidase inhibitors (HIV-PIs) on opportunistic infections caused by bacteria, fungi and protozoa. In Trypanosoma cruzi, HIV-PIs have a high impact on parasite viability, and one of the main alterations promoted by this treatment is the imbalance in the parasite’s lipid metabolism. However, the reasons behind this phenomenon are unknown. In the present work, we observed by transmission electron microscopy (TEM) that the treatment of T. cruzi epimastigotes with the HIV-PIs lopinavir and nelfinavir induced a huge accumulation of crystalloid-shaped lipids within the reservosomes, most of them deforming these key organelles. As previously reported, those structures are characteristic of lipid inclusions formed mostly of cholesterol and cholesterol-esters. The fractionation of nontreated epimastigotes generated two distinct fractions enriched in reservosomes: one mostly composed of lipid inclusion-containing reservosomes (Fraction B1) and one where lipid inclusions were much less abundant (Fraction B2). Interestingly, the extract of Fraction B2 presented enzymatic activity related to aspartyl-type peptidases 3.5 times higher than that found in the extract obtained from Fraction B1. The cleavage of cathepsin D substrate by this class of peptidases was strongly impaired by pepstatin A, a prototypical aspartyl PI, and the HIV-PIs lopinavir and nelfinavir. In addition, both HIV-PIs also inhibited (to a lesser extent) the cruzipain activity present in reservosomes. Finally, our work provides new evidence concerning the presence and supposed participation of aspartyl peptidases in T. cruzi, even as it adds new information about the mechanisms behind the alterations promoted by lopinavir and nelfinavir in the protozoan.

Toxic Effect of Lead on the Red Marrow Cells of Birds

The purpose of this study was to determine the main patterns of the toxic effect of lead on the red marrow cells of birds in the first three days after exposure. The electro-microscopic study revealed that the toxic effect of lead nitrate on bone marrow cells begins even at a slight MAL excess after 1 day of intoxication. Hematopoietic and stromal marrow cells mainly show the signs of dystrophic changes, which increase as the term after exposure to lead nitrate increases. In the cytoplasm of many cells, heterogeneous lipid inclusions are formed, which are likely the lipid products of cell membrane destruction. In lead intoxication of chickens, the structure of the cell nuclei in the bone marrow is changed, and the morphological characteristics reveal a decrease in the transcription of ribosomal RNA genes and the preparation of many cells for apoptosis. Keywords: lead toxic effect, birds, marrow cells

Elevated myocardial fructose and sorbitol levels are associated with diastolic dysfunction in diabetic patients, and cardiomyocyte lipid inclusions in vitro

Diabetes is associated with cardiac metabolic disturbances and increased heart failure risk. Plasma fructose levels are elevated in diabetic patients. A direct role for fructose involvement in diabetic heart pathology has not been investigated. The goals of this study were to clinically evaluate links between myocardial fructose and sorbitol (a polyol pathway fructose precursor) levels with evidence of cardiac dysfunction, and to experimentally assess the cardiomyocyte mechanisms involved in mediating the metabolic effects of elevated fructose. Fructose and sorbitol levels were increased in right atrial appendage tissues of type 2 diabetic patients (2.8- and 1.5-fold increase respectively). Elevated cardiac fructose levels were confirmed in type 2 diabetic rats. Diastolic dysfunction (increased E/e’, echocardiography) was significantly correlated with cardiac sorbitol levels. Elevated myocardial mRNA expression of the fructose-specific transporter, Glut5 (43% increase), and the key fructose-metabolizing enzyme, Fructokinase-A (50% increase) was observed in type 2 diabetic rats (Zucker diabetic fatty rat). In neonatal rat ventricular myocytes, fructose increased glycolytic capacity and cytosolic lipid inclusions (28% increase in lipid droplets/cell). This study provides the first evidence that elevated myocardial fructose and sorbitol are associated with diastolic dysfunction in diabetic patients. Experimental evidence suggests that fructose promotes the formation of cardiomyocyte cytosolic lipid inclusions, and may contribute to lipotoxicity in the diabetic heart.

Mapping Sub-Cellular Protein Aggregates and Lipid Inclusions Using Synchrotron Radiation ATR-FTIR Microscopy

Visualising direct biochemical markers of cell physiology and disease pathology at the sub-cellular level is an ongoing challenge in the biological sciences. A suite of microscopies exists to either visualise...

Lipid inclusions in cardiac myocytes – a rare case of cardiolipotoxicity

The heart oxidizes fatty acids for its energy production. The physiological balance between fatty acid uptake and its oxidation prevents lipid accumulation in cardiac myocytes. However, accumulation of lipids due to various processes such as obesity, diabetes, heart failure, myocardial ischemia or infarction can result in damage to the heart tissue, also known as cardiolipotoxicity. We present a unique case of a 69-year-old gentleman with a history of heart failure and ventricular tachycardia. Endomyocardial biopsy to assess for restrictive cardiomyopathy/amyloid showed no evidence of amyloid, significant inflammation or fibrosis, but did show intracellular accumulation of significant amorphous material in most cardiac myocytes. We review the literature regarding the pathogenesis of cardiolipotoxicity, which has no definite cause or treatment yet identified.

THE CONTENT OF RETINOL AND α-TOCOPHEROL IN EXPERIMENTAL LIVER FIBROSIS IN RATS

Background. The content of retinol and α-tocopherol in the human body affects the development and progression of chronic liver diseases and is associated with the functioning of perisinusoidal lipocytes (HSC) and the state of biological membranes. Objective – to evaluate the content of retinol and α-tocopherol in blood plasma and liver tissue in the dynamics of experimental liver fbrosis in rats. Material and methods. Modeling of liver fbrosis / cirrhosis was carried out on sexually mature male rats by intraperitoneal administration of thioacetamide (TAA) solution at a dose of 200 mg / kg every other day for 4 and 12 weeks. The control group of animals received an equal volume of saline. The concentration of α-tocopherol and retinol was determined by S.L. Taylor’s method. Results. In rat liver preparations, 4 weeks after administration of TAA solution to animals, signs of FII-III stage of fbrosis were observed. According to electron microscopy, HSCs were in a transitional state and acquired a more elongated shape; the number of lipid inclusions in their cytoplasm decreased. The administration of TAA for 12 weeks led to the formation of liver cirrhosis in rats, with characteristic macro- and microscopic changes. On light microscopy, the number of HSCs decreased in rat liver preparations 3 months after administration of TAA; activated HSCs were encountered, which acquired an elongated shape and lost lipid inclusions. The content of retinol in the 2nd group of animals (with liver fbrosis stage II-III) was 2.2 times higher than in the control group, and 1.8 times higher than in the 3rd group with liver cirrhosis (p < 0.05). The content of retinol in the liver tissue after 4 weeks of TAA administration decreased by 11.7%, after 12 weeks - by 1.5 times. The level of α-tocopherol in the liver at the stage of fbrosis FII-III decreased by 21% compared with the control group, at the stage of cirrhosis - by 2 times. Conclusion. The use of thioacetamide in rats for 1 and 3 months leads to the development of liver fbrosis and cirrhosis. A decrease in the content of retinol and α-tocopherol in the liver occurs with the progression of liver fbrosis /cirrhosis. The high content of retinol and α-tocopherol in plasma at the stage of liver fbrosis FII-III is due to degranulation (activation) of HSC.

ULTRASTRUCTURAL FEATURES OF HERPESVIRUS-INDUCED AORTIC INTIMA DAMAGE IN MICE FED THE HIGH-FAT DIET

The aim: To study the effect of a high-fat diet (HFD) on the structural changes in the aortic intima in intact and HSV-1-infected mice using Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Materials and methods: In experiments Balb/c mice were infected with the HVS-1 and fed high-fat diet and 12 weeks later aortic ultrastructure was examined by SEM and TEM methods. The animals were subdivided into four experimental groups: 1st group – HSV-1-infected animals; 2nd – animals consuming high-fat diet (HFD); 3rd – infected animals that were subsequently consuming a high-fat diet (HSV / HFD); 4th – animals consuming a high-fat diet that were subsequently infected with HSV-1 (HFD / HSV) (n = 6); and control group – intact animals. Results: HVS-1 impaired ultrastructural changes in aorta greater than high-fat diet and HVS-1 alone (higher density of lipid inclusions in the subendothelial space, necrosis of endothelial cells), and infection of mice after high-fat diet ended 100% mortality. The formation of atheroma in the aortic wall during HFD was not detected, but the initiative manifestations of atherogenesis have been identified and restricted in the aortic intima. These structural changes included lipid inclusions in the subendothelial space, cell damage and destruction, which lead to an increase cellular detritus in the 3rd (HSV / HFD) group. Conclusions: HSV infection potentiates the accumulation of lipid inclusions in the aortic intima during a HFD, facilitates infection and contributes to the development of acute infection.

Special features of ultrastructural organization steroid-secretory cells in the gonads of juveniles of cyclostomes and fishes

The comparative ultrastructural analysis of steroid-secretory cells (SC) in gonads of youngs lamprey Lampetra fluviatilis (Linnaeus 1758), Siberian sturgeon Acipenser baerii Brandt 1869, sterlet A. ruthenus Linnaeus, 1758, rainbow trout Oncorhynchus mykiss (Walbaum 1792) and pink salmon Oncorhynchus gorbuscha (Walbaum 1792) at similar stages of gametogenesis was carried out. The SC localization and size, the diameters of mitochondria, tubules of agranular reticulum, lipid inclusions and also the relative volume density of these structures were determined and calculated. It is concluded that localization of SC in gonads and their activity changes are closely related to the processes of sex differentiation and the growth of oocytes. Thus, in females of all studied species there was a change in SC localization in the direction of stroma→theca→granulosa of previtellogenic oocytes with a simultaneous increase of their secretory activity (increase in SC size, size and volume density of mitochondria and of agranular endoplasmic reticulum tubules). In males, during gametogenesis, the SC localization also changed in the direction of epithelium→stroma testicular with an increase of their secretory activity. In this case, the largest and most active SC were found in the stroma of pink salmon testicular during the natural sex inversion. At the same time, however, were revealed differences in SC ultrastructural organization, appeared to be of species-specific nature. The highest average diameter of the agranular endoplasmic reticulum tubules was observed in sturgeon SC and they are characterized by a large number of lipid inclusions in early stages of gametogenesis. This should be taken into account when comparatively analysing of quantitative data in fish of different systematic groups.