Inosine inhibits inflammatory cytokine production by a posttranscriptional mechanism and protects against endotoxin-induced shock

Extracellular purines, including adenosine and ATP, are potent endogenous immunomodulatory molecules. Inosine, a degradation product of these purines, can reach high concentrations in the extracellular space under conditions associated with cellular metabolic stress such as inflammation or ischemia. In the present study, we investigated whether extracellular inosine can affect inflammatory/immune processes. In immunostimulated macrophages and spleen cells, inosine potently inhibited the production of the proinflammatory cytokines TNF-alpha, IL-1, IL-12, macrophage-inflammatory protein-1alpha, and IFN-gamma, but failed to alter the production of the anti-inflammatory cytokine IL-10. The effect of inosine did not require cellular uptake by nucleoside transporters and was partially reversed by blockade of adenosine A1 and A2 receptors. Inosine inhibited cytokine production by a posttranscriptional mechanism. The activity of inosine was independent of activation of the p38 and p42/p44 mitogen-activated protein kinases, the phosphorylation of the c-Jun terminal kinase, the degradation of inhibitory factor kappaB, and elevation of intracellular cAMP. Inosine suppressed proinflammatory cytokine production and mortality in a mouse endotoxemic model. Taken together, inosine has multiple anti-inflammatory effects. These findings, coupled with the fact that inosine has very low toxicity, suggest that this agent may be useful in the treatment of inflammatory/ischemic diseases.

Guanosine and inosine display antioxidant activity, protect DNA in vitro from oxidative damage induced by reactive oxygen species, and serve as radioprotectors in mice

The effect of ribonucleosides on 8-oxoguanine formation in salmon sperm DNA dissolved in 1 mM phosphate buffer, pH 6.8, upon exposure to gamma rays was examined by ELISA using monoclonal antibodies against 8-oxoguanine. Nucleosides (1 mM) decreased the radiation-induced yield of 8-oxoguanine in the order Guo > Ino > Ado > Thd > Urd > Cyd. Guanosine and inosine considerably reduced deamination of cytosine in the DNA solutions upon heating for 24 h at 80 degrees C. The action of nucleosides on the heat-induced generation of reactive oxygen species in the phosphate buffer was studied. The concentration of hydrogen peroxide was measured by enhanced chemiluminescence in a peroxidase-luminol-p-iodophenol system; the hydroxyl radical formation was measured fluorometrically by the use of coumarin-3-carboxylic acid. Guanosine and inosine considerably decreased the heat-induced production of both hydrogen peroxide and OH radicals. Guanosine and inosine increased survival of mice after a lethal dose of radiation. They especially enhanced the survival of animals when were administered shortly after irradiation. The results indicate that guanosine and inosine, natural antioxidants, prevent oxidative damage to DNA, decrease the generation of ROS, and protect mice against gamma-radiation-induced death.

Inosine reduces ischemic brain injury in rats

BACKGROUND AND PURPOSE

Purinergic nucleoside inosine elicits protection and regeneration during various injuries. The purpose of this study was to examine the protective effects of inosine against cerebral ischemia.

METHODS

Adult Sprague-Dawley rats were anesthetized. Inosine, hypoxathine, or vehicle was administered intracerebroventricularly before transient right middle cerebral artery occlusion (MCAo). Animals were placed in behavioral chambers 2 days to 2 weeks after MCAo and then euthanized for tri-phenyl-tetrazolium chloride staining. Glutamate release was measured by microdialysis/high-performance liquid chromatography, and single-unit action potentials were recorded from neurons in the parietal cortex.

RESULTS

Stroke animals receiving inosine pretreatment demonstrated a higher level of locomotor activity and less cerebral infarction. Intracerebroventricular administration of the same dose of hypoxanthine did not confer protection. Coadministration of selective A3 receptor antagonist 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1, 4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS1191) significantly reduced inosine-mediated protection. Inosine did not alter basal glutamate release, nor did it reduce ischemia-evoked glutamate overflow from cerebral cortex. However, inosine antagonized glutamate-induced electrophysiological excitation in cerebral cortical neurons.

CONCLUSIONS

Inosine inhibits glutamate postsynaptic responses and reduces cerebral infarction. Its protective effect against ischemia/reperfusion-related insults may involve activation of adenosine A3 receptors.

Inosine alters gene expression and axonal projections in neurons contralateral to a cortical infarct and improves skilled use of the impaired limb

Recovery after stroke and other types of brain injury is restricted in part by the limited ability of undamaged neurons to form compensatory connections. Inosine, a naturally occurring purine nucleoside, stimulates neurons to extend axons in culture and, in vivo, enhances the ability of undamaged neurons to form axon collaterals after brain damage. The molecular changes induced by inosine are unknown, as is the ability of inosine to restore complex functions associated with a specific cortical area. Using a unilateral injury model limited to the sensorimotor cortex, we show that inosine triples the number of corticospinal tract axons that project from the unaffected hemisphere and form synaptic bouton-like structures in the denervated half of the spinal cord. These changes correlate with improved recovery in animals' ability to grasp and consume food pellets with the affected forepaw. Studies using laser-capture microdissection and microarray analysis show that inosine profoundly affects gene expression in corticospinal neurons contralateral to the injury. Inosine attenuates transcriptional changes caused by the stroke, while upregulating the expression of genes associated with axon growth and the complement cascade. Thus, inosine alters gene expression in neurons contralateral to a stroke, enhances the ability of these neurons to form connections on the denervated side of the spinal cord, and improves performance with the impaired limb.

Enhanced preservation of the ischaemic kidney with inosine

The function of rat kidneys subjected to 60 minutes of warm ischaemia at body-temperature was notably protected by the prior administration of the purine nucleoside inosine as a 40 mg/ml solution maintained at 37 degrees C. With direct intrarenal arterial perfusion of the kidney at the onset of ischaemia or with intraperitoneal (i.p.) injection 40 minutes before ischaemia, the plasma-creatinine at 24 hours was significantly lower (P less than 0-001) than that of untreated 60-minute-ischaemia controls and not significantly different from that of non-ischaemic unilateral-nephrectomy controls. Intravenous inosine 20 minutes beforehand also afforded significant (P less than 0-01) protection. 7-day survival was 100% in 30 inosine-pretreated rats and 65% in 45 rats with all other types of pre-treatment (P less than 0-001). Although i.p. adenosine was better (P less than 0-05) than no treatment, i.p. inosine was better (P less than 0-02) than i.p. adenosine. Allopurinol, phenoxybenzamine, A.T.P., or cyclic A.M.P. caused no improvement over controls. Kidneys perfused with inosine maintained higher purine-nucleotide levels during ischaemia and rapidly resynthesised A.T.P. when blood-flow was restored in vivo.

Inactivation of peroxynitrite in multiple sclerosis patients after oral administration of inosine may suggest possible approaches to therapy of the disease

Peroxynitrite has been implicated in the pathogenesis of multiple sclerosis (MS) and its animal model experimental allergic encephalomyelitis (EAE). Previously, we have shown that administration of uric acid (UA), a peroxynitrite scavenger, is therapeutic in EAE We have also shown that MS patients have lower levels of serum uric acid than healthy individuals or those with other neurological diseases. The aim of this investigation was therefore to raise serum UA levels in MS patients. Oral administration of UA failed to increase low serum UA levels, evidently due to its degradation by gastrointestinal bacteria. However, serum UA could be raised and maintained at elevated levels for a year and more without reported side-effects by oral administration of its precursor inosine. Three of 11 patients given inosine showed some evidence of clinical improvement and there was no sign of disease progression in the remaining patients. Gadolinium-enhanced lesions, observed in two patients before receiving inosine, could not be detected after either 10 or IS months inosine treatment These data provide evidence that serum UA levels can be readily manipulated and that the benefit of higher levels to individuals with MS should be studied further in greater number of patients.

Screening and characterization of purine nucleoside degrading lactic acid bacteria isolated from Chinese sauerkraut and evaluation of the serum uric acid lowering effect in hyperuricemic rats

Hyperuricemia is well known as the cause of gout. In recent years, it has also been recognized as a risk factor for arteriosclerosis, cerebrovascular and cardiovascular diseases, and nephropathy in diabetic patients. Foods high in purine compounds are more potent in exacerbating hyperuricemia. Therefore, the development of probiotics that efficiently degrade purine compounds is a promising potential therapy for the prevention of hyperuricemia. In this study, fifty-five lactic acid bacteria isolated from Chinese sauerkraut were evaluated for the ability to degrade inosine and guanosine, the two key intermediates in purine metabolism. After a preliminary screening based on HPLC, three candidate strains with the highest nucleoside degrading rates were selected for further characterization. The tested biological characteristics of candidate strains included acid tolerance, bile tolerance, anti-pathogenic bacteria activity, cell adhesion ability, resistance to antibiotics and the ability to produce hydrogen peroxide. Among the selected strains, DM9218 showed the best probiotic potential compared with other strains despite its poor bile resistance. Analysis of 16S rRNA sequences showed that DM9218 has the highest similarity (99%) to Lactobacillus plantarum WCFS1. The acclimated strain DM9218-A showed better resistance to 0.3% bile salt, and its survival in gastrointestinal tract of rats was proven by PCR-DGGE. Furthermore, the effects of DM9218-A in a hyperuricemia rat model were evaluated. The level of serum uric acid in hyperuricemic rat can be efficiently reduced by the intragastric administration of DM9218-A (P<0.05). The preventive treatment of DM9218-A caused a greater reduction in serum uric acid concentration in hyperuricemic rats than the later treatment (P<0.05). Our results suggest that DM9218-A may be a promising candidate as an adjunctive treatment in patients with hyperuricemia during the onset period of disease. DM9218-A also has potential as a probiotic in the prevention of hyperuricemia in the normal population.

Manipulation of plasma uric acid in broiler chicks and its effect on leukocyte oxidative activity

Birds have high metabolic rates, body temperatures, and plasma glucose concentrations yet physiologically age at a rate slower than comparably sized mammals. These studies were designed to test the hypothesis that the antioxidant uric acid protects birds against oxidative stress. Mixed sex broiler chicks (3 wk old) were fed diets supplemented or not with purines (0.6 mol hypoxanthine or inosine). Study 1 consisted of 18 female Cobb x Cobb broilers that were fed purines for 7 days, whereas study 2 consisted of 12 males in a 21-day trial. Study 3 involved 30 mixed sex broilers that were fed 40 or 50 mg allopurinol/kg body mass (BM) for 21 days, a drug that lowers plasma uric acid (PUA). PUA and leukocyte oxidative activity (LOA) were determined weekly for all studies. For study 2, pectoralis major shear force, relative kidney and liver sizes (RKS and RLS), and plasma glucose concentrations were also determined. In study 1, PUA concentration was increased three- and twofold (P < 0.001) in birds fed inosine or hypoxanthine, respectively, compared with control birds. LOA of birds supplemented with inosine was lower (P < 0.05) than that of control or hypoxanthine birds. In study 2, PUA concentrations were increased fivefold (P < 0.001) in birds fed inosine and twofold (P < 0.001) in birds fed hypoxanthine compared with control birds at day 21. RKS (g/kg BM) was greater (P < 0.001) for chicks fed purine diets compared with control chicks. Muscle shear value was lower (P < 0.05) in chicks fed purine diets. PUA concentration was decreased (P < 0.001) in birds consuming allopurinol diets, whereas LOA was increased (P < 0.01) in study 3. These studies show that PUA concentrations can be related to oxidative stress in birds, which can be linked to tissue aging.

Inosine promotes recovery of skilled motor function in a model of focal brain injury

Recovery of function following traumatic brain injury (TBI) is partly through neuronal plasticity. However plasticity is limited in the adult CNS compared with young animals. In order to test whether treatments that enhance CNS plasticity might improve functional recovery after TBI, a new rat head injury model was developed, in which a computer-controlled impactor produced full thickness lesions of the forelimb region of the sensorimotor cortex. Behavioural deficits were seen in several sensorimotor tasks, most of which recovered spontaneously by 21 days. However, skilled paw reaching behaviour, a task that requires corticospinal function, was only approximately 40% recovered by 28 days. In order to promote plasticity inosine was infused into the lateral ventricles for 28 days. This treatment produced an almost complete recovery of skilled paw reaching ability, associated with sprouting of the uninjured corticospinal axons across the midline into the territory of the lesioned pathway. In the cervical spinal cord the number of corticospinal axons originating from the uninjured cortex that innervated the contralateral cervical cord was five times that of controls, and in the red nucleus the number of contralaterally projecting axons was four times control values. Inosine treatment did not affect recovery in unskilled behavioural tasks, most of which recovered to normal levels by 28 days without treatment. Animals were placed in an enriched environment as an alternative method to promote plasticity. This resulted in more rapid recovery in several tasks including skilled paw function, but by 28 days normally housed animals had caught up to the same level of improvement.

A novel, biodegradable polymer conduit delivers neurotrophins and promotes nerve regeneration

OBJECTIVE/HYPOTHESIS

A wide variety of substances have been shown to promote neuritic extension after nerve injury. An obstacle to achieving the maximal benefit from these substances has been the difficulty in effectively delivering the substances over a protracted time course that promotes maximal, directed growth. In this study the delivery of a growth-promoting substance through a biodegradable conduit, using materials originally designed for drug delivery applications, was hypothesized to promote more robust neural regeneration than through conduits lacking the substance. The objectives of this study were to create a growth factor-loaded biodegradable nerve guidance conduit, and to assess in vivo nerve regeneration through the conduit compared with that through conduits lacking the substance.

MATERIALS/METHODS

Inosine, a purine analogue thought to promote axonal extension following neural injury, was loaded into cylindrical polymer foams composed of a polylactide-co-glycolide copolymer. First, in vitro extravasation of inosine was measured over a several week period using spectrophotometry. Second, the foams were fashioned into single-channel cylindrical nerve guidance conduits via a novel, low-pressure injection molding technique. The conduits were then used to bridge 7-mm defects in the rat sciatic nerve (n = 8). Control conduits lacking inosine were implanted into another set of animals as controls (n = 12).

RESULTS

In vitro spectrophotometric measurements indicated appreciable leaching of inosine from the loaded foams over a period of at least 9 weeks. In the in vivo model, after 10 weeks, a higher percentage cross sectional area composed of neural tissue existed through the inosine-loaded conduits compared with controls (mean 44%, SD 7.5% vs. 36%, SD 8.6%, respectively). A difference was also found in mean fiber diameter between the two groups, with the inosine-loaded tubes showing a statistically significantly larger diameter than controls (P < .05).

CONCLUSIONS

A nerve regeneration conduit was successfully created that delivers growth promoting substances over a protracted time course. In an in vivo model, the presence of inosine, a purine analogue, yielded neural regeneration whose histological features suggest possible superior long-term motor function.

Secondary degeneration reduced by inosine after spinal cord injury in rats

STUDY DESIGN

Assessment of the potential protective effects of inosine on an animal model of spinal cord injury.

OBJECTIVES

Our previous studies have demonstrated that inosine can directly protect neurons in vitro from zinc-induced injury and axotomized retinal ganglion cells of rats in vivo. This investigation was carried out to examine the possible protective effects of inosine on spinal cord secondary degeneration.

SETTING

Institute of Neurosciences, The Fourth Military Medical University, Xi'an, China.

METHODS

Compressive spinal cord injury (95-g load for 1 min) model was established in rats, and inosine was administrated beginning at different time points (2, 12, or 24 h) after spinal cord injury.

RESULTS

Using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) technique and hematoxylin and eosin staining, our study demonstrated that administration of inosine as late as 12 h after injury significantly reduced the total volume of spinal cord degenerative areas and the number of apoptotic cells 3 days following the trauma.

CONCLUSION

Inosine can significantly reduce the spread of secondary degeneration and the cell death following spinal cord injury in adult rats. These findings may find a clinical application in the treatment of acute spinal cord injury.

Synergism between 9-deazainosine and DL-alpha-difluoromethylornithine in treatment of experimental African trypanosomiasis

Kinetoplastid hemoflagellates are sensitive to growth inhibition by various purine analogs. In this study the activities of 9-deazainosine (9-DINO), formycin B, and sinefungin were compared in experimental murine Trypanosoma brucei subsp. brucei infections, both singly and in combination with the ornithine decarboxylase inhibitor DL-alpha-difluoromethylornithine (DFMO, eflornithine). Used singly, all of the purine analogs were able to suppress an acute T. brucei subsp. brucei infection. 9-DINO and formycin B were the most active. None of the purine analogs was curative when used singly against a strain causing chronic central nervous system infection. 9-DINO was highly effective when used in combination with DFMO in curing this central nervous system infection and another more stringent experimental infection. Neither sinefungin nor formycin B was active in combination with DFMO in curing the central nervous system experimental infection. 9-DINO was metabolized to phosphorylated derivatives of 9-deazaadenosine and 9-deazaguanosine by bloodstream trypomastigotes, but not by murine erythrocyte suspensions or kidney or liver homogenates--a potential rationale for the selectivity of the analog. These studies indicate that 9-DINO is a potent, nontoxic purine analog which, in combination with DFMO, is capable of late-stage cures of African trypanosomiasis.

Effects of coenzyme athletic performance system as an ergogenic aid on endurance performance to exhaustion

This study examined the effects of the Coenzyme Athletic Performance System (CAPS) on endurance performance to exhaustion. CAPS contains 100 mg coenzyme Q10, 500 mg cytochrome C, 100 mg inosine, and 200 IU vitamin E. Eleven highly trained male triathletes were given three daily doses of either CAPS or placebo (dicalcium phosphate) for two 4-week periods using a double-blind crossover design. A 4-week washout period separated the two treatment periods. An exhaustive performance test, consisting of 90 minutes of running on a treadmill (70% VO2max) followed by cycling (70% VO2max) until exhaustion, was conducted after each treatment period. The mean (+/- SEM) time to exhaustion for the subjects using CAPS (223 +/- 17 min) was not significantly different (p = 0.57) from the placebo trial (215 +/- 9 min). Blood glucose, lactate, and free fatty acid concentrations at exhaustion did not differ between treatments (p < 0.05). CAPS had no apparent benefit on exercise to exhaustion.

Intravenous infusion of adenosine but not inosine stimulates respiration in man

The effects on respiration of intravenous infusions of the endogenous nucleoside adenosine and its deaminated metabolite, inosine, administered in random order, single-blind, were compared in six healthy volunteers. The infusion rate of each nucleoside was initially 3.1 mg min-1 and was increased stepwise every 2 min, as tolerated, up to a possible maximum of 23.4 mg ml-1. The maximum dose rates received by all subjects were 8.5 mg min-1 for adenosine and 16.8 mg min-1 for inosine. Adenosine infusion at rates of 6.1 mg min-1 and above caused a significant increase in minute ventilation, principally due to an increase in tidal volume, with an associated significant fall in end-tidal Pco2. Mean inspiratory flow rate increased and expiratory duration decreased during adenosine infusion, but there was no change in inspiratory duration. Adenosine infusion also caused a significant increase in heart rate and a slight, but significant increase in systolic blood pressure. Infusion of inosine at dose rates up to 16.8 mg min-1 produced no pharmacological effects. This study shows that adenosine by infusion produces sustained respiratory stimulation in man and demonstrates that it does not depend on prior conversion of adenosine to inosine or related metabolites and that it is not secondary to systemic hypotension.

Therapeutic value of serum uric acid levels increasing in the treatment of multiple sclerosis

Background/Aim. Uric acid was successfully used in both, prevention and treatment of the animal model of multiple sclerosis (MS). Recently it has been shown that inosine, a ribosylated precursor of uric acid, might be used to elevate serum uric acid levels in MS patients. The aim of this study was to evaluate the safety and efficacy of oral inosine as a single drug treatment in patients with MS. Methods. We administered inosine orally to 32 MS patients from 2001-2004 year at doses from 1-2 g daily (given twice) depending on the pretreatment serum uric acid levels. The mean follow-up interval was 37.69?6.55 months. The other 32 MS patients, without any treatment except for a relapse period (matched by age, sex, duration of disease and functional disability), were used as controls. The follow-up interval of these patients was 36.39?2.68 months. The neurological disability was evaluated by the Expanded Disability Status Scale score (EDSS). Results. During the observed period the treated MS patients were found to have the lower relapses rate than the non-treated MS patients (Chi-square test, p=0.001). None of the patients have showed any adverse effect of inosine treatment. The non-treated MS patients were found to have a higher increasing in the mean EDSS score than the treated ones (two-way ANOVA repeated measures/factor times, p=0.025). Conclusion. Our results suggested that the treatment approaches based on the elevation of serum uric acid levels might prove beneficial for some MS patients.

Activity of purine analogs against Leishmania donovani in vivo

The dose of orally administered 9-deazainosine calculated to suppress 50% of Leishmania donovani amastigotes in hamster livers was 19 mg/kg (body weight) per day; 96 to 99% of Leishmania organisms were eliminated from the liver and spleen of squirrel monkeys by 50 mg/kg per day. Because these activities were greater than that of the experimental clinical agent allopurinol and comparable to that of the classical agent parenteral pentavalent antimony, 9-deazainosine should be considered for clinical development for visceral leishmaniasis.

Inosine supplementation has no effect on aerobic or anaerobic cycling performance

The two basic aims of this study were to add to the limited literature concerning Inosine as an ergogenic aid, and to determine the effects of Inosine supplementation over a period of 5 and 10 days, at a dosage of 10,000 mg.d-1 on measures associated with aerobic and anaerobic performance. Seven trained, volunteer male subjects (body mass = 63.0 +/- 8.7 kg, VO2max = 67.9 +/- 3.3 ml.kg-1.min-1) participated in this study. The subjects completed three test sessions, each comprising three tests (5 x 6-s sprint, 30-s sprint, and 20-min time trial). Supplementation was carried out in a random, double-blind manner, and the test sessions were undertaken prior to (Baseline, B), on Day 6, and on Day 11. Blood was sampled prior to supplementation as well as on Days 6 and 11 and was analyzed for uric acid and 2,3 DPG. An analysis of the data indicated no performance benefit of supplementation and no improvement in 2,3 DPG concentration. Uric acid concentration increased significantly after both Days 6 and 11 (p < 0.03 and p < 0.004, respectively). It is concluded that Inosine has no ergogenic effects but may cause possible health problems if taken over long periods of time.

Preparation and characterization of host-guest system between inosine and β-cyclodextrin through inclusion mode

Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N₉-glycosidic bond. Inosine is commonly found in tRNAs. Inosine (INS) has been used widely as an antiviral drug. The inclusion complex of INS with β-CDx in solution phase is studied by ground and excited state with UV-visible and fluorescence spectroscopy, respectively. A binding constant and stoichiometric ratio between INS and β-CDx are calculated by BH equation. The lifetime and relative amplitude of INS is increases with increasing the concentrations of β-CDx, confirms the formation of inclusion complex in liquid state. The solid complexes are prepared by kneading method (KM) and co-precipitation method (CP). The solid complex is characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and differential scanning colorimetry (DSC). CP method gives the solid product with good yield than that of physical mixture and KM method. The structure of complex is proposed based on the study of Patch - Dock server.

Protective effects of inosine on mice subjected to lethal total-body ionizing irradiation

Mammals can barely survive total-body ionizing irradiation greater than 10 Gy. To date, there are few drugs available for radioprotective therapy under such circumstances. Inosine, a natural derivative of adenosine, has been known to provide powerful protection for many kinds of cells and tissues against various insults both in vitro and in vivo. In the present study, we examined whether inosine was also beneficial for mammals subjected to an absolutely lethal total-body ionizing irradiation. Immediately after adult Balb/c mice were exposed to (60)Co gamma-rays at a single dose of 12 Gy, a moiety of them were administered daily with inosine or adenosine, either at doses of 375 or 750 micromol/kg up to death, and their body weight and survival time were recorded. Some irradiated mice were administered inosine or adenosine daily at doses of 750 micromol/kg and assessed for spatial memory abilities using the Morris water maze. The results demonstrated that, although inosine could not prevent body weight loss in irradiated mice, it was able to significantly prolong their survival time at doses of 750 micromol/kg. Moreover, inosine but not adenosine could suppress spatial memory deficit in irradiated mice. The data suggested that inosine had protective effects on mammals suffering from total-body ionizing irradiation at a single lethal dose.

Preventive use of hepatoprotectors yields limited efficacy on the liver toxicity of anti-tuberculosis agents in a large cohort of Chinese patients

BACKGROUND AND AIMS

We aimed to explore the effectiveness of preventive usage of hepatoprotectors in patients with tuberculosis (TB) receiving anti-TB treatment.

METHODS

With stratified cluster sampling strategy, a prospective cohort with 4488 sputum smears positive pulmonary TB patients was established from 52 counties of four regions in China. During anti-TB treatment, prescriptions of hepatoprotectors were documented in detail, and liver enzymes were routinely monitored. Anti-TB drug-induced liver injury (ATLI) was assessed based on liver enzymes following the criteria of American Thoracic Society. The incidence of ATLI between the preventive usage group and reference group was compared by propensity score adjusted Cox proportional hazard analysis. Preexisting diseases, history of liver disease, hepatitis B surface antigen status, primary/re-treatment of TB, income per year, and liver enzymes before anti-TB treatment were included in the propensity score model.

RESULTS

After 6-9 months of follow-up and monitoring, 4304 patients sustained in our cohort. Two thousand seven hundred fifty-two (63.9%) patients preventively took hepatoprotectors with a median course of 183 days. Most frequently used drugs were Hu Gan Pian, silymarin, glucurone, and inosine. Two thousand one hundred forty-four (77.9%) patients took those drugs more than 6 months. Sixty-nine (2.4%) patients of preventive usage group and 37 (2.5%) of reference group experienced ATLI, respectively. Statistical significances were not found by propensity score analysis for the association between using hepatoprotectors (hazard ratio[HR] = 0.99, 95% confidence interval [CI]: 0.65-1.52), using hepatoprotectors in the whole course (HR = 0.94, 95% CI: 0.60-1.48), using Hu Gan Pians, silymarin, glucurone, and inosine with ATLI occurrence.

CONCLUSIONS

No preventive effect of hepatoprotectors was observed in patients receiving anti-TB treatment.

Improved Parkinsons disease motor score in a single-arm open-label trial of febuxostat and inosine

BACKGROUND

Cellular energetics play an important role in Parkinsons disease etiology, but no treatments directly address this deficiency. Our past research showed that treatment with febuxostat and inosine increased blood hypoxanthine and ATP in healthy adults, and a preliminary trial in 3 Parkinson's disease patients suggested some symptomatic improvements with no adverse effects.

METHODS

To examine the efficacy on symptoms and safety in a larger group of Parkinsons disease patients, we conducted a single-arm, open-label trial at 5 Japanese neurology clinics and enrolled thirty patients (nmales = 11; nfemales = 19); 26 patients completed the study (nmales = 10; nfemales = 16). Each patient was administered febuxostat 20 mg and inosine 500 mg twice-per-day (after breakfast and dinner) for 8 weeks. The primary endpoint was the difference of MDS-UPDRS Part III score immediately before and after 57 days of treatment.

RESULTS

Serum hypoxanthine concentrations were raised significantly after treatment (Pre = 11.4 μM; Post = 38.1 μM; P < .0001). MDS-UPDRS Part III score was significantly lower after treatment (Pre = 28.1 ± 9.3; Post = 24.7 ± 10.8; mean ± SD; P = .0146). Sixteen adverse events occurred in 13/29 (44.8%) patients, including 1 serious adverse event (fracture of the second lumbar vertebra) that was considered not related to the treatment.

CONCLUSIONS

The results of this study suggest that co-administration of febuxostat and inosine is relatively safe and effective for improving symptoms of Parkinsons disease patients. Further controlled trials need to be performed to confirm the symptomatic improvement and to examine the disease-modifying effect in long-term trials.

A re-assessment of the effects of intracortical delivery of inosine on transmidline growth of corticospinal tract axons after unilateral lesions of the medullary pyramid

This study was undertaken as part of the NIH "Facilities of Research Excellence-Spinal Cord Injury", which supports independent replication of published studies. Here, we repeat an experiment reporting that intracortical delivery of inosine promoted trans-midline growth of corticospinal tract (CST) axons in the spinal cord after unilateral injury to the medullary pyramid. Rats received unilateral transections of the medullary pyramid and 1 day later, a cannula assembly was implanted into the sensorimotor cortex contralateral to the pyramidotomy to deliver either inosine or vehicle. The cannula assembly was attached to an osmotic minipump that was implanted sub-cutaneously. Seventeen or 18 days post-injury, the CST was traced by making multiple injections of miniruby-BDA into the sensorimotor cortex. Rats were killed for tract tracing 14 days after the BDA injections. Sections through the cervical spinal cord were stained for BDA and immunostained for GAP43 and GFAP. Our results revealed no evidence for enhanced growth of CST axons across the midline of the dorsal column in rats that received intracortical infusion of inosine. Possible reasons for the failure to replicate are discussed.

Intravenous nucleosides and a nucleotide promote healing of small bowel ulcers in experimental enterocolitis

Our aim was to evaluate the possible beneficial effect of intravenous nucleosides and a nucleotide in healing small bowel ulceration in a rat model of enterocolitis. Fourteen Lewis female rats were randomized into total parenteral nutrition (TPN, N = 7) and TPN + nucleosides and a nucleotide (NS/NT, N = 7) groups. After adaptation, two doses of indomethacin (7.5 mg/kg) were administered subcutaneously 24 hr apart to each animal in both groups. Concomitant with the first dose of indomethacin, TPN or TPN + NS/NT were infused for four days. The TPN and TPN + NS/NT were isocaloric and isonitrogenous. At the end of four days, total ulcer length in the entire small bowel was measured. The mucosa surrounding ulcers was studied by optical microscopy. Immunohistochemistry was performed for proliferating cell nuclear antigen (PCNA). Ileal crypt and villus lengths were measured with an eyepiece micrometer, crypt-villus ratios were calculated, and crypt mitotic index and percentage of PCNA-labeled cells determined to assess cellular proliferation. Total ulcer length decreased significantly in the TPN + NS/NT group compared to the TPN group (42 vs 76 mm). In the TPN + NS/NT versus TPN group, the ileal mucosa surrounding ulcers showed significantly greater crypt length (21%) and there was increased crypt-villus ratio (0.53 vs 0.39), crypt mitotic index (1.2 vs 0.9), and PCNA labeling (43% vs 30%). We conclude that in rats with indomethacin-induced enterocolitis, administration of TPN + NS/NT for four days resulted in significant healing of small bowel ulcers, as indicated by decreased ulcer length. This effect of NS/NT appears to relate, in part, to increased cell proliferation, evidenced by increased crypt length, crypt-villus ratio, mitotic index, and PCNA labeling.

Development of stealth liposome formulation of 2'-deoxyinosine as 5-fluorouracil modulator: in vitro and in vivo study

PURPOSE

The aims of this study were to develop a stealth, pegylated liposomal formulation of 2'-deoxyinosine (d-Ino), a 5-fluorouracil (5-FU) modulator, to evaluate its efficacy in vitro and in tumor-bearing mice, and to study its pharmacokinetics in rats.

METHOD

After designing a pegylated liposome encapsulating d-Ino (L-d-Ino), we evaluated its efficacy as 5-FU modulator in vitro. Antiproliferative assays, thymidylate synthase (TS) inhibition, and apoptosis studies were carried out to check whether an optimization of 5-FU action was achieved on the 5-FU-resistant SW620 cell line. Animal pharmacokinetic and ex vivo studies were next performed to confirm that L-d-Ino displayed a slower plasma elimination pattern than free d-Ino. Finally, effects on tumor growth of L-d-Ino + 5-FU combination was evaluated in xenografted mice.

RESULTS

We developed a stable, sterile, and homogenous 100-nm population of pegylated liposomes encapsulating 30% of d-Ino. Liposomal d-Ino exhibited a strong potential as 5-FU modulator in vitro by enhancing TS inhibition and subsequent apoptosis induction, while displaying a better pharmacokinetic profile in animals, with a near seven times clearance reduction as compared with the free form. When used in tumor-bearing mice in combination with 5-FU, our results showed next that the association led to 70% of tumor reduction with a doubling median survival time as compared with untreated animals, whereas 5-FU alone was ineffective.

CONCLUSION

Our data show that liposomal d-Ino, through an optimized pharmacokinetic profile, displays a potent effect as fluoropyrimidines modulator, both in vitro and in xenografted mice. Besides, we showed here that it is possible to reverse a resistant phenotype to 5-FU, a major drug extensively described in clinical oncology.