Vinpocetine protects against chloroquine-induced cardiotoxicity by mitigating oxidative stress.

Chloroquine (CQ) and hydroxychloroquine (HCQ) are classical antimalarial drugs, and recently have been used for other applications including coronavirus disease 2019 (COVID-19). Although they are considered safe, cardiomyopathy may associate CQ and HCQ applications particularly at overdoses. The goal of the present study was to evaluate the potential protective effect of the nootropic agent vinpocetine against CQ and HCQ adverse effects with a specific focus on the heart. For this purpose, a mouse model of CQ (0.5 up to 2.5 g/kg)/HCQ (1 up to 2 g/kg) toxicity was used, and the effect of vinpocetine was evaluated by survival, biochemical, as well as histopathological analyses. Survival analysis revealed that CQ and HCQ caused dose-dependent lethality, which was prevented by co-treatment with vinpocetine (100 mg/kg, oral or intraperitoneal). To gain deeper understanding, a dose of 1 g/kg CQ-which did not cause death within the first 24 h after administration-was applied with and without vinpocetine administration (100 mg/kg, intraperitoneal). The CQ vehicle group showed marked cardiotoxicity as evidenced by significant alterations of blood biomarkers including troponione-1, creatine phosphokinase (CPK), creatine kinase-myocardial band (CK-MB), ferritin, and potassium levels. This was confirmed at the tissue level by massive alteration of the heart tissue morphology and coincided with massive oxidative stress. Interestingly, co-administration of vinpocetine strongly ameliorated CQ-induced alterations and restored the antioxidant-defense system of the heart. These data suggest that vinpocetine could be used as an adjuvant therapy together with CQ/HCQ applications.

Correction of Huntington's Disease Phenotype by Genistein-Induced Autophagy in the Cellular Model.

Huntington's disease (HD) is a monogenic disorder, caused by mutations in the HTT gene which result in expansion of CAG triplets. The product of the mutated gene is misfolded huntingtin protein that forms aggregates leading to impairment of neuronal function, neurodegeneration, motor abnormalities and cognitive deficits. No effective cure is currently available for HD. Here we studied effects of genistein (trihydroxyisoflavone) on a HD cellular model consisting of HEK-293 cells transfected with a plasmid bearing mutated HTT gene. Both level of mutated huntingtin and number of aggregates were significantly decreased in genistein-treated HD cell model. This led to increased viability of the cells. Autophagy was up-regulated while inhibition of lysosomal functions by chloroquine impaired the genistein-mediated degradation of the mutated huntingtin aggregates. Hence, we conclude that through stimulating autophagy, genistein removes the major pathogenic factor of HD. Prolonged induction of autophagy was suspected previously to be risky for patients due to putative adverse effects; however, genistein has been demonstrated recently to be safe and suitable for long-term therapies even at doses as high as 150 mg/kg/day. Therefore, results presented in this report provide a basis for the use of genistein in further studies on development of the potential treatment of HD.

Induction of the Vitamin D Receptor Attenuates Autophagy Dysfunction-Mediated Cell Death Following Traumatic Brain Injury.

BACKGROUND/AIMS: Traumatic brain injury (TBI) is a major public health problem in the world and causes high rates of mortality and disability. Recent evidence suggests that vitamin D (VD) has neuroprotective actions and can promote function recovery after TBI. In vitro and in vivo studies have demonstrated that autophagy could be enhanced following supplementation with an active metabolite of VD (calcitriol). However, it is unclear whether autophagy participates in the protective effects of calcitriol after TBI. To test this hypothesis, we examined the protective effects of calcitriol on TBI-induced neurological impairment and further investigated whether calcitriol could modulate autophagy dysfunction-mediated cell death in the cortex region of rat brain. METHODS: Eighty-five male rats (250-280 g) were randomly assigned to sham (n=15), TBI model (TBI, n=35) and calcitriol treatment (calcitriol, n=35) groups. Rats were injected intraperitoneally with calcitriol (1 µg/kg) at 30 min, 24 h and 48 h post-TBI in the calcitriol group. The lysosomal inhibitor, chloroquine (CQ), was used to evaluate autophagic flux in the TBI and calcitriol groups. Neurological functions were evaluated via the modified neurological severity score test at 1-7 days after TBI or sham operation, and the terminal deoxynucleotidyl transferase-mediated FITC-dUTP nick-end labeling method was used to evaluate the ability of calcitriol to inhibit apoptosis. The expression of VDR, LC3 and p62 proteins was measured by western blot analysis at 1, 3 and 7 days post-injury Results: Calcitriol treatment attenuated mNSS at 2-7 days post-TBI (P < 0.05 versus TBI group). Calcitriol dramatically increased VDR protein expression compared with the untreated counterparts at 1, 3 and 7 days post-TBI (P < 0.05). The rate of apoptotic cells in calcitriol-treated rats was significantly reduced compared to that observed in the TBI group (P < 0.05). The LC3II/LC3I ratio was decreased in the cortex region at 1, 3 and 7 days post-TBI in rats treated with calcitriol (p < 0.05 versus TBI group), and the p62 expression was also attenuated (p < 0.05 versus TBI group). The LC3II/LC3I ratio in the calcitriol group was significantly increased when pretreated with CQ (P < 0.05). CONCLUSION: Calcitriol treatment activated VDR protein expression and attenuated neurological deficits in this rat TBI model. The protective effects might be associated with the restoration of autophagy flux and the decrease in apoptosis in the cortex region of rat brain.

Comparative cytotoxicity of artemisinin and cisplatin and their interactions with chlorogenic acids in MCF7 breast cancer cells.

In parts of Africa and Asia, self-medication with a hot water infusion of Artemisia annua (Artemisia tea) is a common practice for a number of ailments including malaria and cancer. In our earlier work, such an extract showed better potency than artemisinin alone against both chloroquine-sensitive and -resistant parasites. In this study, in vitro tests of the infusion in MCF7 cells showed high IC50 values (>200 µM). The combination of artemisinin and 3-caffeoylquinic acid (3CA), two major components in the extract, was strongly antagonistic and gave a near total loss of cytotoxicity for artemisinin. We observed that the interaction of 3CAs with another cytotoxic compound, cisplatin, showed potentiation of activity by 2.5-fold. The chelation of cellular iron by 3CA is hypothesized as a possible explanation for the loss of artemisinin activity.

Synthesis and antiplasmodial evaluation of novel (4-aminobutyloxy)quinolines.

A variety of 5-, 6- and 8-(4-aminobutyloxy)quinolines as novel oxygen analogues of known 4- and 8-(4-aminobutylamino)quinoline antimalarial drugs was generated from hydroxyquinolines through a three-step approach with a rhodium-catalyzed hydroformylation as the key step. Antiplasmodial assays of these new quinolines revealed micromolar potency for all representatives against a chloroquine-sensitive strain of Plasmodium falciparum, and three compounds showed submicromolar activity against a chloroquine-resistant strain of P. falciparum with IC(50)-values ranging between 150 and 680 nM.

Murine toxicology and pharmacokinetics evaluation of retinoic acid metabolism blocking agent (RAMBA), VN/12-1.

PURPOSE: Novel retinoic acid metabolism blocking agent (RAMBA), VN/12-1, is a highly potent anti-cancer agent that induces autophagy. Its combination with autophagy inhibitor chloroquine (CHL) has been shown to synergistically enhance apoptosis in breast cancer cells. The purpose of this study was to determine the toxicity and pharmacokinetic profile of VN/12-1 and its combination with CHL. METHODS: Preliminary toxicology of VN/12-1 was determined using female SCID mice (n = 4 for each group). ATRA was used for comparison. We selected four different doses of VN/12-1 and ATRA. Two of the doses were low and less frequent (2.5 and 5 mg/kg twice a week), and the remaining doses were high and more frequent (10 and 20 mg/kg every day). The dose of CHL was 50 mg/kg twice a week. For pharmacokinetic (PK) study, 20 mg/kg of VN/12-1 was injected subcutaneously (s.c.) into the mice, and their plasma was collected at various intervals (n = 2) and analyzed by HPLC. RESULTS: The lower and less frequent doses of VN/12-1 and ATRA were found to be least toxic. However, high and more frequent doses of these compounds were toxic to the mice. PK results showed that VN/12-1 has a half-life of 6 h. The area under the curve (AUC) for VN/12-1 was 83.78 h µg/ml. CONCLUSIONS: VN/12-1 and ATRA are non-toxic when used as 5 mg/kg twice a week as single agents or in combination with CHL. The favorable PK properties of VN/12-1 can potentially be used for its further advanced pre-clinical and clinical development.

CGRPα-expressing sensory neurons respond to stimuli that evoke sensations of pain and itch.

Calcitonin gene-related peptide (CGRPα, encoded by Calca) is a classic marker of nociceptive dorsal root ganglia (DRG) neurons. Despite years of research, it is unclear what stimuli these neurons detect in vitro or in vivo. To facilitate functional studies of these neurons, we genetically targeted an axonal tracer (farnesylated enhanced green fluorescent protein; GFP) and a LoxP-stopped cell ablation construct (human diphtheria toxin receptor; DTR) to the Calca locus. In culture, 10-50% (depending on ligand) of all CGRPα-GFP-positive (+) neurons responded to capsaicin, mustard oil, menthol, acidic pH, ATP, and pruritogens (histamine and chloroquine), suggesting a role for peptidergic neurons in detecting noxious stimuli and itch. In contrast, few (2.2±1.3%) CGRPα-GFP(+) neurons responded to the TRPM8-selective cooling agent icilin. In adult mice, CGRPα-GFP(+) cell bodies were located in the DRG, spinal cord (motor neurons and dorsal horn neurons), brain and thyroid-reproducibly marking all cell types known to express Calca. Half of all CGRPα-GFP(+) DRG neurons expressed TRPV1, ∼25% expressed neurofilament-200, <10% contained nonpeptidergic markers (IB4 and Prostatic acid phosphatase) and almost none (<1%) expressed TRPM8. CGRPα-GFP(+) neurons innervated the dorsal spinal cord and innervated cutaneous and visceral tissues. This included nerve endings in the epidermis and on guard hairs. Our study provides direct evidence that CGRPα(+) DRG neurons respond to agonists that evoke pain and itch and constitute a sensory circuit that is largely distinct from nonpeptidergic circuits and TRPM8(+)/cool temperature circuits. In future studies, it should be possible to conditionally ablate CGRPα-expressing neurons to evaluate sensory and non-sensory functions for these neurons.

Role of curcumin on chloroquine phosphate-induced reproductive toxicity.

The present study was conducted to screen the efficacy of curcumin against chloroquine phosphate (CQ)-induced reproductive toxicity in adult male Swiss albino mice. Animals were given oral doses of 100, 200, 300 mg/kg body weight (b.w.), and high dose of CQ (300 mg/kg b.w.) + curcumin (80 mg/kg b.w.) for 45 days. Animals of the withdrawal group were given high dose of CQ (300 mg/kg b.w.) for 45 days and, at day 46, were kept for another 45 days. Effects were observed on some key enzymes, such as alkaline phosphatase, which was found to be decreased, whereas acid phosphatase was increased and succinate dehydrogenase and adenosine triphosphatase were decreased. Oxidative parameters, such as superoxide dismutase declined, whereas thiobarbituric acid-reactive substances were found to be elevated. Protein level was also decreased. Gravimetric indices were also recorded. Results obtained indicated adverse effects of CQ in a dose-dependent manner. The presence of curcumin with CQ alleviated its toxic effects. Hence, it can be concluded that curcumin has beneficial influences and appears able to ameliorate CQ toxicity.

Antipruritic activity of extracts of Humulus scandens, the combinations of bioactive flavonoids.

The antipruritic effects of the ethanol fractions of Humulus scandens on the 4-AP (4-aminopyridine)-induced and chloroquine-induced scratching in ICR mice were examined. The 40% ethanol fractions of H. scandens suppressed both the 4-AP- and chloroquine-induced scratching behavior, which significantly inhibited degranulation of rat peritoneal mast cell and antigen-stimulated histamine release. Further studies proved that the 40% ethanol fractions of H. scandens decreased the content of IL4 in serum of chloroquine-induced scratching ICR mice. The results suggest that the 40% ethanol fractions of H. scandens has antipruritic effects on both antihistamine-resistant and -sensitive pruritus.

Current malaria status and distribution of drug resistance in East and Southeast Asia with special focus to Thailand.

Malaria is the world's most important parasitic infection ranking among the major health and developmental challenges. Despite years of continual efforts, malaria is still one of the major causes of morbidity and mortality affecting third-world countries and still a threat to over 2 billion people, representing approximately 40% of the world's population in about 100 countries (Rollback Malaria 2005). During the "eradication era", half a century ago, malaria was eliminated or effectively suppressed in many parts of the world, particularly subtropical regions. The disease is now on the rise again since it is appearing in areas where it had disappeared. The disaster can largely be attributed to antimalarial drug resistance in most malaria endemic countries. Geographical distribution of the disease is worldwide, being found in tropical areas, throughout sub-Saharan Africa and to a lesser extent in South Africa, Southeast Asia, the Pacific Islands, India and Central and South America. Best estimates currently describe the annual global burden of malaria as 300-500 million cases and 1-2 million deaths. Over 90% of the disease burden is in sub-Saharan Africa. The malaria burden differs according to age and gender; almost all deaths occur in African children under 5 years of age (Snow et al. 2001). Pregnant women in Africa (especially primigravidae) are at high risk, and are the major adult risk group in the continent. An increasing number of imported cases of malaria have been reported particularly as a result of increasing worldwide travel to regions where there is ongoing risk of malaria transmission. Nowadays, cases of malaria acquired by international travelers from developed countries probably number 25,000 cases per year, with 10,000 of them reported annually and approximately 150 deaths per year.

Tetrahydrocurcumin: effect on chloroquine-mediated oxidative damage in rat kidney.

Tetrahydrocurcumin is an antioxidative substance, which is derived from curcumin, the component of turmeric. In the present investigation, the effect of tetrahydrocurcumin and curcumin against chloroquine-induced nephrotoxicity were studied in female wistar rats. Oral administration of tetrahydrocurcumin significantly prevented the occurrence of chloroquine (970 mg/kg body weight)-induced renal damage. Upon administration of tetrahydrocurcumin to chloroquine-treated rats, the level of lipid peroxidation was significantly decreased while the levels of non-enzymic and enzymic antioxidants were significantly increased in kidney. Oral administration (80 mg/kg body weight) attenuated the chloroquine-induced nephrotoxicity by significantly decreased levels of serum urea and creatinine with significant normalization of creatinine clearance. On administration of tetrahydrocurcumin, the depleted renal antioxidant defense system (enzymatic and non-enzymatic antioxidants) was significantly increased in rats treated with chloroquine. These biochemical observations were supplemented by histopathological examination of kidney section. These results suggest that administration of chloroquine imposes an oxidative stress to renal tissue and that tetrahydrocurcumin protects the oxidative damage associated with chloroquine.

Protective role of tetrahydrocurcumin (THC) an active principle of turmeric on chloroquine induced hepatotoxicity in rats.

PURPOSE: Tetrahydrocurcumin (THC) is an antioxidative substance, which is derived from curcumin, the component of turmeric. In the present investigation, the effect of THC and curcumin against chloroquine (CQ) induced hepatotoxicity were studied in female Wistar rats. METHODS: On single oral administration of CQ (970 mg/kg body weight) the activities of serum marker enzymes namely aspartate transaminase, alanine transaminase and alkaline phosphatase and the levels of bilirubin were significantly increased with significant alterations of lipids in serum and lipidperoxidation markers such as thiobarbituric acid reactive substances (TBARS) and hydroperoxides in plasma and liver were also elevated in CQ treated rats. The levels of non-enzymic antioxidants (vitamin C, vitamin E and reduced glutathione) and enzymic antioxidants (superoxide dismutase, catalase and glutathione peroxidase) were also decreased in CQ treated rats. Administration of THC (80 mg/kg body weight) and curcumin (80 mg/kg body weight) for 8 days before and 7 days after single administration of CQ significantly decreased the activities of serum markers and lipids in serum. In addition, the level of TBARS and hydroperoxides were significantly decreased with significant increase in non-enzymic and enzymic antioxidants on treatment with THC and curcumin. The biochemical observation was supplemented by histopathological examination of liver section. The results of the study reveal that THC shows more pronounced protective effect than curcumin against CQ induced toxicity.

Relationship of the CD22 immunotoxin dose and the tumour establishment in a SCID mice model.

Immunotoxins (ITs) may be very potent to erradicate tumour growth in vivo. We investigated the influence of the IT-dose, in relation to the establishment of the tumour, on the anti-tumour activity of CD22-recombinant (rec) ricin A for a disseminated tumour (Ramos) in SCID mice. Furthermore, the enhancement of the IT cytotoxicity in vivo by chloroquine was assessed. CD22-rec ricin A appeared to be highly effective. Paralysis of the hind legs was significantly delayed by a very low IT-dose of 2 microg administered intravenously (i.v.) 7 days after i.v. inoculation of the tumour cells. Even a dose of 30 microg administered 21 days after inoculation of the target cells significantly delayed the onset of paralysis up to 8 days compared with the median paralysis time (MPT) of the control group. The efficacy of treatment was obviously influenced by the establishment of the tumour, the tumour load and localisation. The anti-tumour activity of 10 and 30 microg IT diminished when the IT was administered after increasing the time lag following inoculation of tumour cells. Delaying IT administration resulted in growth of solid tumours. This implies that cells migrate to sanctuaries protected from the IT indicating that the anti-tumour activity was influenced by the accessibility of the IT to the target cells. The in vivo anti-tumour activity of CD22-rec ricin A could not be enhanced by simultaneously administered chloroquine, despite the continuous infusion with an intraperitoneally (i.p.) implanted mini-osmotic pump. Ex vivo experiments revealed that the maximally tolerated serum concentration (3.9 microM) was too low to be effective. In conclusion, CD22-rec ricin A is highly effective for in vivo treatment of B-cell malignancies, in particular if treatment is started when the tumour load is low and before migration takes place to poorly accessible sanctuaries.

Evaluation of the anti-plasmodial activity of bisbenzylisoquinoline alkaloids from Abuta grandifolia.

Three alkaloids were isolated from the bark of the traditional medicinal plant Abuta grandifolia (Mart.) Sandw. (Menispermaceae) and tested for in vitro anti-plasmodial activity. Two of them were identified as the Type VIII bisbenzylisoquinoline alkaloids, krukovine (1) and limacine (2), while the least abundant compound (3) could only be characterised to Type I of the same class. Krukovine exhibited potent anti-plasmodial activity with IC50 values of 0.44 microgram/ml and 0.022 microgram/ml against K1 (chloroquine-resistant) and T9-96 (chloroquine-sensitive) Plasmodium falciparum, respectively. Both limacine and compound 3 exhibited moderate anti-plasmodial activity against K1 with IC50 values of 1.35 micrograms/ml and 1.58 micrograms/ml, respectively. Limacine gave an IC50 value of 0.24 microgram/ml against T9-96. Krukovine and limacine showed greater activity against T9-96 than against K1, exhibiting similar activity profiles to that of chloroquine diphosphate (0.187 microgram/ml and 0.013 microgram/ml against K1 and T9-96, respectively). This indicates that krukovine and limacine may be affected by the mechanism of chloroquine resistance present in K1 P. falciparum.

Effects of the naturally-occurring chemosensitizer malagashanine and its combination with chloroquine on KB and P388 cell lines and isolated auricle.

Besides the determination of its LD50 value, the cytotoxicity against KB and P388 cell lines and the toxicity on isolated guinea pig auricle of malagashanine and its combination with chloroquine were assessed. Malagashanine alone was devoid of cytotoxicity and cardiac effect on isolated auricle, and importantly, when combined to chloroquine, did not affect the inherent toxicity and cardiac toxicity of this antimalarial agent.

Composition and antimalarial activity in vitro of the essential oil of Tetradenia riparia.

The essential oil from the leaves and stems of Tetradenia riparia was analysed by GC and GC/MS and 35 components were identified. The main constituents were alpha-terpineol (22.6%), fenchone (13.6%), beta-fenchyl alcohol (10.7%), beta-caryophyllene (7.9%), and perillyl alcohol (6.0%). Moderate antimalarial activities were recorded against two strains of Plasmodium falciparum.

Correlations between ganglioside storage degree and physiological characteristics of neuronal systems--experimental chloroquine intoxication in miniature pig.

Central nervous neuronal patterns of chloroquine-induced ganglioside storage were investigated in miniature pigs. The systematic distribution of this process was first of all characterized by largely identical reproduction of the current storage patterns of native gangliosidosis. Loss of ganglion cells, cytoarchitectonic disintegration and other degenerative changes resulting in the inborn disease were, however, completely avoided by the experimental conditions. This allowed so far unknown clear-cut and much more comprehensive identification of the intensively as well as of gradually less storing neuronal systems. In this way conspicuous correlations between storage degree and physiological quality of certain neuronal systems became apparent. All identified types of the widely dispersed group of inhibitory interneurons were distinguished by particularly extreme residual body storage. These neurons are physiologically exceptional by their permanent activity which is indispensable for normal function of the nervous system. The most instructive counterpart was documented by extreme poor storage manifestations in the large neuronal perikarya of the nucleus mesencephalicus nervi trigemini. These neurons are comparatively very rarely stressed as they mediate the sensation for pain and temperature exclusively. The mentioned and numerous further experimentally ascertained examples substantiated the conclusion that the degree of ganglioside storage in a ganglion cell type in the experimental pig model might essentially be conditioned by frequency and intensity of its neurotransmission activity. The origin of this correlation could be traced back to the participation of ganglioside in the synaptic release of transmitters. The storage process in neuronal systems of the experimental pigs might hence essentially depend on the chloroquine-conditioned impairment in lysosomal degradation of gangliosided which had been involved in the latter process.

In vivo activity of ajoene against rodent malaria.

Ajoene (4,5,9-trithiadodeca-1,6,11-triene 9-oxide), a product initially isolated from extracts of garlic (Allium sativum), was tested for its antimalarial activity in vivo in a well-characterized murine model. A single ajoene dose of 50 mg/kg, on the day of infection, suppressed the development of parasitemia; there were no obvious acute toxic effects from the tested dose. The combination of ajoene (50 mg/kg) and chloroquine (4.5 mg/kg), given as a single dose on the day of the infection, completely prevented the subsequent development of parasitemia in treated mice.

Antimalarials and ophthalmologic safety.

Antimalarial drugs were shown to be useful agents in the treatment of discoid and systemic lupus erythematosus in 1951. However, by 1966, fear of retinal toxicity and the availability of alternative therapies had led to limited use of antimalarials. Continued experience with these alternative therapies has made their intrinsic, sometimes devastating toxicities more evident and has contributed to the renewed interest in antimalarial agents evident in the number of comprehensive reviews appearing recently in the dermatology literature. Many of these reviews, while generally excellent, have propagated some apparent misconceptions by disregarding or de-emphasizing data suggesting that irreversible retinal toxicity due to antimalarials can be easily avoided by judicious daily dosage and regular ophthalmologic follow-up. This article will discuss the historical basis of these misconceptions and the subsequent studies which suggest that antimalarial retinal toxicity can be avoided without sacrificing the therapeutic efficacy of these agents.

Podophyllum: suspected teratogenicity from topical application.

A case demonstrating suspected teratogenic effects of topical podophylium is presented. Podophyllum resin was applied five times for a duration of 4 hr from the 23rd to the 29th week of pregnancy. At birth a simian crease on the left hand and a preauricular skin tag were noted. It is suggested that podophyllum be avoided during pregnancy. Alternative treatment for warts of the vaginal, perineal, or anal area are presented.