Lipopolysaccharide-induced platinum accumulation in the cerebral cortex after cisplatin administration in mice: Involvement of free radicals

Increased brain penetration of diphenhydramine and memantine in rats with adjuvant-induced arthritis

Brain penetration of cationic drugs is an important determinant of their efficacy and side effects. However, the effects of alterations in the activity of uptake transporters in the brain under inflammatory conditions on the brain penetration of cationic drugs are not fully understood. The aim of this study was to examine changes in brain penetration of cationic drugs, including diphenhydramine (DPHM), memantine (MMT), and cimetidine (CMD), and changes in the expression of uptake transporters such as organic cation transporter (Oct) in brain microvascular endothelial cells (BMECs) under inflammatory conditions. To clarify the effects of inflammation on the brain penetration of DPHM, MMT, and CMD, we performed brain microdialysis studies in a rat model of adjuvant-induced arthritis (AA). Further, differences in transporter mRNA expression levels between BMECs from control and AA rats were evaluated. Brain microdialysis showed that the unbound brain-to-plasma partition coefficient (K_p,uu,brain) for DPHM and MMT was significantly lower in AA rats compared with control rats. OCT mRNA levels were increased and proton-coupled organic cation (H⁺/OC) antiporter mRNA levels were decreased in AA rats compared with control rats. Taken together, our findings suggest that inflammation decreases the brain penetration of H⁺/OC antiporter substrates such as DPHM and MMT.

Review of the Role of the Brain in Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, debilitating, and dose-limiting side effect of many chemotherapy regimens yet has limited treatments due to incomplete knowledge of its pathophysiology. Research on the pathophysiology of CIPN has focused on peripheral nerves because CIPN symptoms are felt in the hands and feet. However, better understanding the role of the brain in CIPN may accelerate understanding, diagnosing, and treating CIPN. The goals of this review are to (1) investigate the role of the brain in CIPN, and (2) use this knowledge to inform future research and treatment of CIPN. We identified 16 papers using brain interventions in animal models of CIPN and five papers using brain imaging in humans or monkeys with CIPN. These studies suggest that CIPN is partly caused by (1) brain hyperactivity, (2) reduced GABAergic inhibition, (3) neuroinflammation, and (4) overactivation of GPCR/MAPK pathways. These four features were observed in several brain regions including the thalamus, periaqueductal gray, anterior cingulate cortex, somatosensory cortex, and insula. We discuss how to leverage this knowledge for future preclinical research, clinical research, and brain-based treatments for CIPN.

Nano Ellagic Acid Counteracts Cisplatin-Induced Upregulation in OAT1 and OAT3: A Possible Nephroprotection Mechanism

Cisplatin is an anticancer drug commonly used for solid tumors. However, it causes nephrotoxicity. OAT1 and OAT3 are organic anion transporters known to contribute to the uptake of cisplatin into renal tubular cells. The present study was designed to examine the protective role of ellagic acid nanoformulation (ellagic acid nano) on cisplatin-induced nephrotoxicity in rats, and the role of OAT1/OAT3 in this effect. Four groups of male Wistar rats were used (n = 6): (1) control, (2) cisplatin (7.5 mg/kg single dose, intraperitoneal), (3) cisplatin + ellagic acid nano (1 mg/kg), and (4) cisplatin + ellagic acid nano (2 mg/kg). Nephrotoxic rats treated with ellagic acid nano exhibited a significant reduction in elevated serum creatinine, urea, and oxidative stress marker, malondialdehyde (MDA). Additionally, ellagic acid nano restored renal glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Ellagic acid nano improved the histopathological changes induced by cisplatin, such as tubular dilatation, necrosis, and degeneration. Interestingly, OAT1 and OAT3 showed significantly lower expression at both mRNA and protein levels following ellagic acid nano treatment relative to the cisplatin-exposed group. These findings reveal a potential inhibitory role of ellagic acid antioxidant on OAT1 and OAT3 expression and thus explains its nephroprotective effect against cisplatin nephrotoxicity.

Honey protects against cisplatin-induced hepatic and renal toxicity through inhibition of NF-κB-mediated COX-2 expression and the oxidative stress dependent BAX/Bcl-2/caspase-3 apoptotic pathway

The protective effects of both manuka and talh honeys were assessed using a rat model of cisplatin (CISP)-induced hepatotoxicity and nephrotoxicity. The results revealed that both honeys exerted a protective effect against CISP-induced hepatotoxicity and nephrotoxicity as demonstrated by decreasing liver and kidney function. Manuka honey also prevented CISP-induced histopathological changes observed in the liver and decreased the changes seen in the kidneys. Talh honey decreased CISP-induced liver histopathological changes but had no effect on CISP-induced kidney histopathological changes. Both honeys reduced the oxidative stress in the liver. Conversely, they have no effect on kidney oxidative stress, except that manuka honey increased CAT activity. GC-MS analysis showed the presence of the antioxidant octadecanoic acid in talh honey while heneicosane and hydrocinnamic acid were present at a higher content in manuka honey. The molecular mechanism was to limit the expression of inflammatory signals, including COX-2 and NF-κB, and the expression of the apoptotic signal, BAX and caspase-3 while inducing Bcl-2 expression.

D-pinitol attenuates cisplatin-induced nephrotoxicity in rats: Impact on pro-inflammatory cytokines

Cisplatin has been widely used as a first-line agent against various forms of solid cancers. However, nephrotoxicity is the major limiting factor for its clinical use. Several clinical and pre-clinical studies have suggested different strategies for the reduction of cisplatin-induced nephrotoxicity. The present study was conducted to investigate the efficacy of D-Pinitol, against cisplatin-induced nephrotoxicity in Swiss albino mice. A single intraperitoneal injection of cisplatin (20 mg/kg) was used to induce nephrotoxicity in mice. Administration of cisplatin in mice is linked with elevated oxidative stress, imbalanced biochemical parameters, apoptosis and stimulation of mitogen-activated protein kinase (MAPK) pathway. D-Pinitol is a member of the flavonoid family and a chief constituent of Sutherlandia fruitesecnce. It was administered with saline water (10, 20, 40 mg/kg, p.o.) for seven consecutive days after a single dose of cisplatin. At the end of experiment, animals were sacrificed and biochemical parameters in serum and urine were recorded. Kidneys were isolated for the estimation of tumor necrosis factor-alpha, interleukin-1β, interlukin-6 levels and histopathological evaluations. It was noted that D-Pinitol significantly ameliorated biochemical levels of serum and urinary creatinine and blood urea nitrogen. Tissue homogenate levels of TNF-α, IL-6, IL-1β and the renal expression of tissue nitrites were also significantly decreased in D-Pinitol treated mice. These results were supplemented by histopathological findings. This study highlights the potential role of D-Pinitol against cisplatin-induced toxicity, exhibited through favorable alterations in biochemical and histological changes as well as reduction in oxidative stress and cytokine levels.

Cisplatin-induced neurotoxicity in vivo can be alleviated by riboflavin under photoillumination

Cisplatin (CP)-induced neurotoxicity is one of the major clinical problems in CP-based chemoradiotherapy, leading to its discontinuation depending upon their severity. In the present investigation, the photosensitizing property of riboflavin (RF) has been used to ameliorate the CP-induced neurotoxicity. According to dosing plan, the healthy mice were given RF, CP, and their combinations under photoillumination with their controls without any light exposure. After the treatment, antioxidant enzymes, cellular reductants, glutathione-S-transferase, brain markers, and oxidation products were assessed besides histopathology in their brain samples. These parameters revealed that RF ameliorates CP-induced neurotoxicity in a dose-dependent manner under photoillumination. Hence, inclusion of RF in CP-based chemoradiotherapy can be an effective strategy to counter CP-induced neurotoxicity.

Effects of lipopolysaccharide and chelator on mercury content in the cerebrum of thimerosal-administered mice

Thimerosal is one of the best-known preservative agents for vaccines in the world but a relationship between its use and autism has long been suspected so that its effects on the brain need more detailed research. We here examined the influence of lipopolysaccharide injury to the blood-brain barrier on the penetration of mercury from thimerosal into mouse cerebrums, as well as the effect of chelator of heavy metals on cerebrum mercury content. Mercury can be expected to be detected in the cerebrum of normal mice, because the metal is present in standard mouse chow. When 60μg/kg of thimerosal was subcutaneously injected into the mouse, the mercury content in the cerebrum was significantly higher 48h after the thimerosal injection with a maximum peak after 72h. In addition, mercury content in the cerebrum was still higher on day 7 than in the control group. When lipopolysaccharide was pre-injected into mice to induce damage on blood-brain barrier, the mercury content in the cerebrum was significantly higher at 24 and 72h after the injection of 12μg/kg of thimerosal compared to the control group, this dose alone does not cause any increase. The mercury content in the cerebrums of mice was decreased to the control group level on day 7 when a chelator, dimercaprol, was administered once a day from days 3 to 6 after a 60μg/kg, s.c. injection. In addition, d-penicillamine as a chelator decreased the mercury contents in the cerebrum after the high dose administration. In conclusion, a physiological dose of thimerosal did not increase the content of mercury in the cerebrum, but levels were increased when damage to the blood-brain barrier occurred in mice injected with thimerosal. In addition, a chelator of heavy metals may be useful to remove mercury from the cerebrum.

Penetration of cisplatin into mouse brain by lipopolysaccharide

We investigated the penetration of cisplatin into the mouse cerebral cortex-rich region (CCR) induced by lipopolysaccharide (LPS). With the injection of cisplatin into mice 3 h after the LPS treatment, platinum was detected in the CCR during the 7 days after the injection, while platinum was not detected in the CCR of cisplatin-injected mice without LPS pretreatment and of mice simultaneous treated with cisplatin and LPS. The N(G)-nitro-L-arginine methyl ester dose-dependently lowered the platinum level. A dose of 5 mg/kg of aminoguanidine reduced the increase in the platinum level of the LPS-treated mouse, and platinum was no longer detected at doses of 20 mg/kg in the aminoguanidine-injected group. At doses of 500 mg/kg aminoguanidine, however, no effect was seen on the platinum level of the CCR induced by LPS. Regarding indomethacin, the injection of 5 mg/kg resulted in a decrease in the platinum content of the CCR, but not undetectable level. These results suggest that LPS increases the penetration of cisplatin into the mouse brain, and platinum may be accumulated in the CCR. Nitric oxide and prostaglandins contribute to the penetration of platinum into the cerebral cortex.

Roles of nitric oxide and prostaglandins in the increased permeability of the blood-brain barrier caused by lipopolysaccharide

We investigated the involvement of nitric oxide (NO) and prostaglandins (PGs) in the damage to the blood-brain barrier (BBB) induced by lipopolysaccharide (LPS), using fluorescein as a tracer in mice. Aminoguanidine, a competitive inhibitor of inducible NO synthase (iNOS), when administered s.c. at 5 mg/kg, but not 500 mg/kg, reduced significantly the increase in brain fluorescein level after its i.v. injection in LPS-treated mice. When 1000 mg/kg of l-arginine, a substrate of NOS, were co-administered with 5 mg/kg of aminoguanidine to LPS-treated mice, the inhibitory effect of aminoguanidine on the increased fluorescein level disappeared. N(G)-Nitro-l-arginine methyl ester (l-NAME), a non-isoenzyme-selective NOS inhibitor, when administered s.c. at 5 mg/kg, only slightly reduced the LPS-induced increase in the brain fluorescein level. A pretreatment with dexamethasone, which suppressed the induction of both iNOS and cyclooxygenase 2 (COX-2), tended to decrease the brain fluorescein level in LPS-treated mice. Indomethacin, a COX inhibitor, at 5 mg/kg, but not 10 mg/kg, suppressed significantly the LPS-induced increase in the brain fluorescein level. These results involve that both the NO produced by iNOS and the PGs produced by COX contribute to enhance BBB permeability in LPS-administered mice.