Gamaleldin I. Harisa

Low density lipoprotein bionanoparticles: From cholesterol transport to delivery of anti-cancer drugs

In this review article, we highlight the importance of low-density lipoprotein (LDL) and its implications in the field of drug delivery to cancer cells. LDL is naturally occurring bionanoparticles (BNP) with a size of 18–25 nm. These BNPs specifically transport cholesterol to cells expressing the LDL receptors (LDLRs). Several tumors overexpress LDLRs, presumably to provide cholesterol for sustaining a high rate of membrane synthesis. LDL BNPs are biocompatible and biodegradable, favorably bind hydrophobic and amphiphilic drugs, are taken up by a receptor-mediated mechanism, have a half-life of 2–4 days, and can be rerouted. Drugs can be loaded onto LDL BNPs by surface loading, core loading, and apoprotein interaction. LDL may be used as a drug carrier for treatment of atherosclerosis, cancer, and in photodynamic therapies.

Quercetin protects against acetaminophen-induced hepatorenal toxicity by reducing reactive oxygen and nitrogen species

High or toxic doses of acetaminophen (APAP), a mild analgesic and antipyretic drug, can cause life-threatening hepatic and renal dysfunction. This study is designed to investigate the potential protective role of quercetin to attenuate the hepatorenal toxicity induced by a high single oral dose (3g/kg) of APAP in rats. Three main groups of Sprague-Dawley rats were used: quercetin, APAP and quercetin plus APAP-receiving animals. Corresponding control animals were also used. Interestingly, oral supplementation of quercetin (15mg/kg/day) prior to APAP intoxication dramatically reduced APAP-induced hepatorenal toxicity as evidenced by measuring serum lipid profile, total protein, urea, creatinine, ALT, AST, ALP, G-GT and liver tissue content of TC and TG. Quercetin treatment markedly prevented the generation of TBARS and PCC with substantial improvement in terms of GSH and activities of antioxidant enzymes in both liver and kidney homogenates. The relationship between quercetin and NO levels which is still a matter of debate, was also investigated. NO levels in serum, liver and kidney tissues were significantly inhibited in quercetin pre-treated animals. Furthermore, quercetin administration significantly inhibited the reduction of liver and kidney contents of ATP parcels associated with this hepatorenal toxicity. These results suggest that the protective role of quercetin in the prevention of APAP-induced hepatorenal toxicity in rats was associated with the decrease of oxidative and nitrosative stress in hepatic and renal tissues as well as its capacity to improve the mitochondrial energy production. However, clinical studies are warranted to investigate such an effect in human subjects.

Wogonin attenuates etoposide-induced oxidative DNA damage and apoptosis via suppression of oxidative DNA stress and modulation of OGG1 expression.

Damage to DNA can lead to many different acute and chronic pathophysiological conditions, ranging from cancer to endothelial damage. The current study has been initiated to determine whether the flavonoid wogonin can attenuate etoposide-induced oxidative DNA damage and apoptosis in mouse bone marrow cells. We found that oral administration of wogonin before etoposide injection significantly attenuates etoposide-induced oxidative DNA damage and apoptosis in a dose dependent manner. Etoposide induced a significant down-regulation of mRNA expression of the OGG1 repair gene and marked biochemical alterations characteristic of oxidative DNA stress, including increased 8-OHdG, enhanced lipid peroxidation and reduction in reduced glutathione. Prior administration of wogonin ahead of etoposide challenge restored these altered parameters. Importantly, wogonin had no antagonizing effect on etoposide-induce topoisomerase-II inhibition. Conclusively, our study indicates that wogonin has a protective role in the abatement of etoposide-induced oxidative DNA damage and apoptosis in the bone marrow cells of mice via suppression of oxidative DNA stress and enhancing DNA repair through modulation of OGG1 repair gene expression. Therefore, wogonin can be a promising chemoprotective agent and might be useful to avert secondary leukemia and other drug-related cancers in cured cancer patients and medical personnel exposing to the potent carcinogen etoposide.

Curcumin Ameliorates Streptozotocin-Induced Heart Injury in Rats

Heart failure (HF) is one of diabetic complications. This work was designed to investigate the possible modulatory effect of curcumin against streptozotocin‐induced diabetes and consequently HF in rats. Rats were divided into control, vehicle‐treated, curcumin‐treated, diabetic‐untreated, diabetic curcumin–treated, and diabetic glibenclamide–treated groups. Animal treatment was started 5 days after induction of diabetes and extended for 6 weeks. Diabetic rats showed significant increase in serum glucose, triglycerides, total cholesterol, low‐density lipoprotein‐cholesterol, very low density lipoprotein‐cholesterol, nitric oxide, lactate dehydrogenase, cardiac malondialdehyde, plasma levels of interleukin‐6, and tumor necrosis factor‐alpha, and also showed marked decrease in serum high‐density lipoprotein‐cholesterol, cardiac reduced glutathione, and cardiac antioxidant enzymes (catalase, superoxide dismutase, and glutathione‐S‐transferase). However, curcumin or glibenclamide treatment significantly mitigated such changes. In conclusion, curcumin has a beneficial therapeutic effect in diabetes‐induced HF, an effect that might be attributable to its antioxidant and suppressive activity on cytokines.

Protective effect of pravastatin against mercury induced vascular cells damage: erythrocytes as surrogate markers.

In the present study we investigated the protective effect of pravastatin (PRV) against mercury-induced cellular damage. Human erythrocytes were incubated with PRV, HgCl(2) and HgCl(2) pretreated with PRV. Our results revealed that incubation of erythrocytes with HgCl(2) induces a significant increase the ratios of superoxide dismutase/glutathione peroxidase (SOD/GPx), superoxide dismutase/catalase (SOD/CAT), oxidized/reduced glutathione (GSSG/GSH), malondialdehyde(MDA) and protein carbonyl(PCO) by 60%, 50%, 333%, 400% and 208% respectively. Whereas, prior incubation of erythrocytes with PRV maintains these parameters at values similar to control cells. Furthermore, the level of nitrite in erythrocytes decreases significantly on treatment with HgCl(2), whereas it remains similar to the control when pretreated with PRV. Also, there was an increase in erythrocytes hemolysis when treated with HgCl(2), whereas it remained the like to the control when pretreated with PRV. In conclusion, PRV pretreatment maintained the erythrocytes oxidant/antioxidant balance and nitrite level during mercury exposure. Consequently, PRV pretreatment is worthy of further investigation in the reduction of the cardiovascular risk of mercury.

Erythrocyte nitric oxide synthase as a surrogate marker for mercury-induced vascular damage: The modulatory effects of naringin

In this study, endothelial nitric oxide synthase activity and nitric oxide (NO) production by human erythrocytes in the presence and absence of mercuric chloride (HgCl2), L‐arginine (L‐ARG), N ω ‐ nitro‐L‐arginine methyl ester (L‐NAME), and naringin (NAR) were investigated. In addition, the levels of reduced glutathione (GSH) and related enzymes were estimated in erythrocytes hemolysate. The protein carbonyl content (PCC) and thiobarbituric acid‐reactive substances (TBARS) levels were also determined. The results of this study revealed that the treatment of erythrocytes with either HgCl2 or L‐NAME induced a significant decrease in NOS activity and nitrite levels compared with control cells. Furthermore, mercury exposure significantly increased the levels of PCC and TBARS but reduced the GSH level. The activities of glucose‐6‐phosphate dehydrogenase, glutathione reductase, glutathione peroxidase, and glutathione‐S‐transferase (GST) were inhibited. The exposure of erythrocytes to HgCl2 in combination with L‐ARG, NAR, or both ameliorated the investigated parameters compared with erythrocytes incubated with HgCl2 alone. These results indicate that mercury exposure decreased both erythrocyte NOS activity and nitrite production, and that these parameters might be indicative of mercury exposure. The data also suggest that concomitant treatment with NAR can restore NO bioavailability through either its metal‐chelating properties or its antioxidant activity.

Erythrocyte-mediated Delivery of Pravastatin: In Vitro Study of Effect of Hypotonic Lysis on Biochemical Parameters and Loading Efficiency

Exposure of erythrocytes to hypotonic lysis creates pores in the cell membrane, through which pravastatin can enter and become trapped, after resealing them with a suitable buffer. We investigated the effects of tonicity, incubation time and drug concentration on drug loading into erythrocytes. Furthermore, we investigate the effects of pravastatin on erythrocyte oxidative stress markers and osmotic fragility behavior. Encapsulation was achieved using buffer solutions of different tonicities (0.5, 0.6 and 0.7% NaCl) and different drug concentrations (2, 4, 8 and 10 mg/mL) for a range of incubation times (15, 30, 60 and 120 min). The results demonstrated that controlled hypotonic lysis could entrap pravastatin in human erythrocytes, with acceptable loading parameters. The highest loading (34%) was achieved at 0.6% NaCl and 10 mg/mL pravastatin for 60 min incubation. At this pravastatin concentration, oxidative stress markers were similar to those seen in controls, and fragility and hematological parameters were unaffected in drug-loaded erythrocytes. These results indicate that the loading process and pravastatin concentration had no deleterious effects on the structure of pravastatin-loaded erythrocytes, suggesting that they may therefore have a similar life span to normal cells. Pravastatin-loaded erythrocytes may thus provide an effective extended-release-delivery system for pravastatin.

Pravastatin chitosan nanogels-loaded erythrocytes as a new delivery strategy for targeting liver cancer

Chitosan nanogels (CNG) are developed as one of the most promising carriers for cancer targeting. However, these carriers are rapidly eliminated from circulation by reticuloendothelial system (RES), which limits their application. Therefore, erythrocytes (ER) loaded CNG as multifunctional carrier may overcome the massive elimination of nanocarriers by RES. In this study, erythrocytes loaded pravastatin–chitosan nanogels (PR–CNG–ER) were utilized as a novel drug carrier to target liver cancer. Thus, PR–CNG formula was developed in nanosize, with good entrapment efficiency, drug loading and sustained release over 48 h. Then, PR–CNG loaded into ER were prepared by hypotonic preswelling technique. The resulting PR–CNG–ER showed 36.85% of entrapment efficiency, 66.82% of cell recovery and release consistent to that of hemoglobin over 48 h. Moreover, PR–CNG–ER exhibited negative zeta potential, increasing of hemolysis percent, marked phosphatidylserine exposure and stomatocytes shape compared to control unloaded erythrocytes. PR–CNG–ER reduced cells viability of HepG2 cells line by 28% compared to unloaded erythrocytes (UER). These results concluded that PR–CNG–ER are promising drug carriers to target liver cancer.

Beryllium chloride-induced oxidative DNA damage and alteration in the expression patterns of DNA repair-related genes

Beryllium metal has physical properties that make its use essential for very specific applications, such as medical diagnostics, nuclear/fusion reactors and aerospace applications. Because of the widespread human exposure to beryllium metals and the discrepancy of the genotoxic results in the reported literature, detail assessments of the genetic damage of beryllium are warranted. Mice exposed to beryllium chloride at an oral dose of 23mg/kg for seven consecutive days exhibited a significant increase in the level of DNA-strand breaking and micronuclei formation as detected by a bone marrow standard comet assay and micronucleus test. Whereas slight beryllium chloride-induced oxidative DNA damage was detected following formamidopyrimidine DNA glycosylase digestion, digestion with endonuclease III resulted in considerable increases in oxidative DNA damage after the 11.5 and 23mg/kg/day treatment as detected by enzyme-modified comet assays. Increased 8-hydroxydeoxyguanosine was also directly correlated with increased bone marrow micronuclei formation and DNA strand breaks, which further confirm the involvement of oxidative stress in the induction of bone marrow genetic damage after exposure to beryllium chloride. Gene expression analysis on the bone marrow cells from beryllium chloride-exposed mice showed significant alterations in genes associated with DNA damage repair. Therefore, beryllium chloride may cause genetic damage to bone marrow cells due to the oxidative stress and the induced unrepaired DNA damage is probably due to the down-regulation in the expression of DNA repair genes, which may lead to genotoxicity and eventually cause carcinogenicity.

The Influence of Lentinan on the Capacity of Repair of DNA Damage and Apoptosis Induced by Paclitaxel in Mouse Bone Marrow Cells

The ability of the flavonoid lentinan (LAN) to enhance the repair of paclitaxel (PAC)‐induced DNA damage and apoptosis in mouse bone marrow cells was investigated. Moreover, the possible mechanism underlying this modulation was determined. LAN was neither genotoxic nor apoptogenic at doses equivalent to 1 or 2 mg/kg/day. Pretreatment of mice with LAN significantly enhances the repair of PAC‐induced DNA damage and bone marrow suppression in a dose dependent manner. Moreover, LAN affords significant protection against PAC‐induced apoptosis. A significant increase of reactive oxygen species and a decrease in reduced glutathione levels were observed after PAC treatment and prior administration of LAN before PAC challenge ameliorated these oxidative stress markers. Conclusively, our study provides, for the first time, that LAN enhances the repair of PAC‐induced DNA damage and apoptosis that resides, at least in part, on its ability to modulate the cellular antioxidant levels and consequently protect bone marrow cells from PAC genotoxicity.