Pediatric tuberculosis in Mexico and the COVID-19 phenomenon: Past and present

In endemic regions, tuberculosis in children constitutes a bigger fraction of total cases as compared to those in low endemic regions, regardless of the implications, this phenomenon has been historically neglected. Pediatric tuberculosis has an insidious onset and quickly develops into disseminated disease and the young are at a special risk for dissemination. Some studies suggest that measures to contain adult tuberculosis are not enough to manage tuberculosis in children, meaning that pediatric tuberculosis needs dedicated attention. Children are harder to diagnose than adults, because collecting samples is difficult, and their bacterial yield is low. In endemic countries, such as Mexico, where contact with Mycobacterium tuberculosis is common, immunological tests are inconsistent, especially in immunocompromised children. With the disruption of Mexican healthcare services by the COVID-19 pandemic, there is an uncertainty of how the situation has evolved, current data about tuberculosis indicates a drop in the national report of cases: 15.4 per 100,000 persons in 2021, compared with pre-COVID 2019 17.7 per 100,000 persons, a small increase in mortality: 1.7 per 100,000 in 2021 compared with 2019 1.6 per 100,000, a drop in treatment success: 80.4% in 2021 compared with 85.4% in 2019, and a decrease in national vaccination rates: an estimate of 86.6% children between 1 and 2 years-old were vaccinated in 2021 compared with 97.3% reported national rate in 2018-2019. There is a need for new research on regions with high tuberculosis incidence, to clarify the current situation of pediatric tuberculosis and improve epidemiological surveillance.

Effects of postnatal exposure to cadmium on male sexual incentive motivation and copulatory behavior: Estrogen and androgen receptors expression in adult brain rat

There are numerous evidence showing that cadmium (Cd) is an endocrine disruptor that exerts multiple toxic effects at different reproductive levels, including male sexual behavior (MSB). The effect of early exposure to Cd on sexual incentive motivation (SIM) and MSB in adult stage, and the immunoreactivity of receptors for hormones such as estrogens and androgens in brain regions that are relevant for the SIM and MSB display, have not been studied until now. The present study evaluated the effects of 0.5 and 1 mg/kg CdCl2 from day 1-56 of postnatal life on SIM and MSB in adults rats, as well as serum testosterone concentrations, Cd concentration in blood, testis, and brain areas, and the immunoreactivity in estrogen receptors (ER-α and -β), and androgen receptor (AR) in the olfactory bulbs (OB), medial preoptic area (mPOA), and medial amygdala (MeA). Our results showed that both doses of Cd decreased SIM and MSB, accompanied by low serum concentrations of testosterone. Also, there was a significant reduction in immunoreactivity of ER-α and AR in mPOA, and a significant reduction in AR in MeA on male rats treated with Cd 1 mg/kg. These results show that exposure to high doses of Cd in early postnatal life could alter the correct integration of hormonal signals in the brain areas that regulate and display SIM and MSB in adult male rats.

Repurposing Simvastatin in Parkinson's Disease Model: Protection Is throughout Modulation of the Neuro-Inflammatory Response in the Substantia nigra

Parkinson's disease is a neurodegenerative disorder characterized by oxidative stress and immune activation in the nigro-striatal pathway. Simvastatin regulates cholesterol metabolism and protects from atherosclerosis disease. Simvastatin-tween 80 was administered 7 days before sterotaxic intrastriatal administration of MPP⁺ (1-methyl-4-phenylpyridine) in rats. Fluorescent lipidic product formation, dopamine levels, and circling behavior were considered damage markers. Twenty-four hours and six days after, the animal group lesioned with MPP⁺ showed significant damage in relation to the control group. Animals pretreated with simvastatin significantly reduced the MPP⁺-induced damage compared to the MPP⁺ treated group. As apoptosis promotes neuroinflammation and neuronal degeneration in Parkinson's disease, and since there is not currently a proteomic map of the nigro-striatum of rats and assuming a high homology among the identified proteins in other rat tissues, we based the search for rat protein homologs related to the establishment of inflammation response. We demonstrate that most proteins related to inflammation decreased in the simvastatin-treated rats. Furthermore, differential expression of antioxidant enzymes in striated tissue of rat brains was found in response to simvastatin. These results suggest that simvastatin could prevent striatal MPP⁺-induced damage and, for the first time, suggest that the molecular mechanisms involved in this have a protective effect.

Neurocognitive function in adult residents of a mining district in Mexico after reducing manganese exposure: Follow-up after 11 years

BACKGROUND

Little is known about the neurotoxic effects of chronic exposure to airborne Mn once exposure has been reduced. The environmentally exposed and the reference adult populations evaluated in 2002 were followed, after an environmental management program (EMP) was implemented to reduce the exposure in a mining district in Mexico.

OBJECTIVE

The aim of this study was to compare the association between exposure to Mn and neurocognitive performance in environmentally exposed and reference groups of adults before and after EMP implementation.

METHODS

In 2013, the same battery of neurocognitive tests used in the initial study (2002) was applied to 58 adults exposed to airborne Mn and 30 adults from the reference community. A cumulative exposure index (CEI) was estimated for the study population before and after the EMP. Categorical outcomes were analyzed using logistic regression, and the resulting ORs were compared between studies. Continuous outcomes were analyzed using linear regression. All models were adjusted for age, years of education, socioeconomic status and blood lead levels.

RESULTS

Exposed adults from the post-EMP study showed an improvement in fine motor and verbal regulation of motor skills (OR < 1) compared to the exposed adults from the pre-EMP study (OR > 1). In both pre- and post-studies, the exposed adults showed a deterioration in their dynamic organization of motor activity compared to the reference group (p < 0.05); however, they showed no significant change in attention and working-memory performance.

DISCUSSION

After four years of a significant reduction in airborne Mn levels resulting from EMP implementation, chronically exposed adults showed an improvement in fine motor and verbal regulation of motor skills; however, the remaining areas of their motor and cognitive functions remained impaired.

A phase 2, double-blind, placebo-controlled trial of a valproate/lithium combination in ALS patients

BACKGROUND

Few treatments are currently available for amyotrophic lateral sclerosis (ALS). A combination of lithium carbonate and valproic acid (VPA-Li) was shown to inhibit motor neuron death and delay disease progression.

METHODS

Outpatients with a typical ALS presentation were enrolled in a randomized, placebo-controlled trial to assess the efficacy of orally administered VPA-Li. Changes in a functional scale score (ALSFRS-R) and survival rate were chosen as primary outcome variables. Secondary outcome variables included BMI, respiratory monitoring, quality of life, and a global impression of the treatment.

RESULTS

Out of 42 patients enrolled, 20 individuals receiving VPA-Li and 18 on placebo treatment were included in the final analysis. Forty-five percent of patients receiving VPA-Li completed the trial, whereas only 22.22% of patients in the placebo group attended the final visit 18 months later (P = 0.09). Major changes in the ALSFRS-R score were observed, including a decrease of 1.195 points/month in the placebo group (95% CI: 0.7869-1.6031) and of 0.5085 under VPA-Li treatment (95% CI: 0.2288-0.7882) between months 6 and 14. Adverse events included bad mouth taste, constipation, and anorexia. Survival rate, body weight, and quality of life were positive outcomes by the end of the trial despite a high sample reduction, especially in the placebo group. The inclusion of 212 subjects in each group would confirm these differences.

CONCLUSIONS

Combined VPA-Li treatment associated with slower ALS progression and better secondary outcomes. This dual treatment overcame the futility threshold and merits further investigation in ALS.

Captopril and losartan attenuate behavioural sensitization in mice chronically exposed to toluene

Inhalants are consumed worldwide for recreational purposes. The main component found in many inhalants is toluene. One of the most deleterious behavioural effects caused by chronic exposure to inhalants is addiction. This response has been associated with activation of the mesolimbic dopaminergic pathway, and it is known that the renin angiotensin system plays a role in the modulation of this dopaminergic system. In the present work, we hypothesize that blockade of the RAS with angiotensin converting enzyme inhibitors or angiotensin II type 1 receptor blockers is able to attenuate the addictive response induced by toluene. We exposed mice to toluene for four weeks to induce locomotor sensitization. In the second phase of the work, captopril or losartan were administered for 20 days. Subsequently, the expression of behavioural sensitization was evaluated with a toluene challenge. To exclude false associations between the observed responses and treatments, motor coordination and blood pressure were analysed in animals treated with captopril or losartan. At the end of the behavioural studies, animal brains were harvested and Ang II/Ang-(1-7) and Ang-(1-7)/Ang II ratios were analysed in the nucleus accumbens (NAc) and prefrontal cortex (PFCx). The results showed that toluene induced behavioural sensitization, while captopril or losartan treatment attenuated the expression of this response. No significant differences were observed in motor coordination or blood pressure. Repeated toluene administration decreased Ang-(1-7)/Ang II ratio in the PFCx. On the other hand, treatment with captopril or losartan decreased the Ang II/Ang-(1-7) ratio and enhanced the Ang-(1-7)/Ang II ratio in the NAc. This work suggests that blockade of RAS attenuates the toluene-induced behavioural sensitization.

The acute systemic toxicity of thallium in rats produces oxidative stress: attenuation by metallothionein and Prussian blue

Thallium (TI) is one of the most toxic heavy metals. Human exposure to Tl occurs through contaminated drinking water and from there to food, a threat to health. Recently, environmental contamination by Tl has been reported in several countries, urging the need for studies to determine the impact of endogenous and exogenous mechanisms preventing thallium toxicity. The cytoprotective effect of metallothionein (MT), a protein with high capacity to chelate metals, at two doses (100 and 600 µg/rat), was tested. Prussian blue (PB) (50 mg/kg) was administered alone or in combination with MT. A dose of Tl (16mg/kg) was injected i.p. to Wistar rats. Antidotes were administered twice daily, starting 24h after Tl injection, for 4 days. Tl concentrations diminished in most organs (p < 0.05) by effect of PB, alone or in combination with MT, whereas MT alone decreased Tl concentrations in testis, spleen, lung and liver. Likewise, brain thallium also diminished (p < 0.05) by effect of PB and MT alone or in combination in most of the regions analyzed (p < 0.05). The greatest diminution of Tl was achieved when the antidotes were combined. Plasma markers of renal damage increased after Tl administration, while PB and MT, either alone or in combination, prevented the raise of those markers. Only MT increased the levels of reduced glutathione (GSH) in the kidney. Finally, increased Nrf2 was observed in liver and kidney, after treatment with MT alone or in combination with PB. Results showed that MT alone or in combination with PB is cytoprotective after thallium exposure.

Glutamate, Glutamine, GABA and Oxidative Products in the Pons Following Cortical Injury and Their Role in Motor Functional Recovery

Brain injury leads to an excitatory phase followed by an inhibitory phase in the brain. The clinical sequelae caused by cerebral injury seem to be a response to remote functional inhibition of cerebral nuclei located far from the motor cortex but anatomically related to the injury site. It appears that such functional inhibition is mediated by an increase in lipid peroxidation (LP). To test this hypothesis, we report data from 80 rats that were allocated to the following groups: the sham group (n = 40), in which rats received an intracortical infusion of artificial cerebrospinal fluid (CSF); the injury group (n = 20), in which rats received CSF containing ferrous chloride (FeCl₂, 50 mM); and the recovery group (n = 20), in which rats were injured and allowed to recover. Beam-walking, sensorimotor and spontaneous motor activity tests were performed to evaluate motor performance after injury. Lipid fluorescent products (LFPs) were measured in the pons. The total pontine contents of glutamate (GLU), glutamine (GLN) and gamma-aminobutyric acid (GABA) were also measured. In injured rats, the motor deficits, LFPs and total GABA and GLN contents in the pons were increased, while the GLU level was decreased. In contrast, in recovering rats, none of the studied variables were significantly different from those in sham rats. Thus, motor impairment after cortical injury seems to be mediated by an inhibitory pontine response, and functional recovery may result from a pontine restoration of the GLN-GLU-GABA cycle, while LP may be a primary mechanism leading to remote pontine inhibition after cortical injury.

Catecholamine levels and gene expression of their receptors in tissues of adults with osteosarcoma

AIM

The purpose of this work was to identify and measure catecholamines, their metabolites, and the gene expression of catecholamine receptors in osteosarcoma tissue.

MATERIALS AND METHODS

The levels of 3,4-dihydroxyphenylacetic acid, norepinephrine, serotonin, and 5-hydroxyindoleacetic acid in cancer tissue and in adjacent and non-oncological bone tissue were analysed by high-performance liquid chromatography, and the gene expression of catecholamine receptors and of dopamine β-hydroxylase, monoaminoxidase, ki67, and Runx2 in the osteosarcoma tissue, tissue adjacent to the tumour, non-oncological bone, and human brain tissue was analysed by RT-PCR.

RESULTS

We found significantly higher levels of 3,4-dihydroxyphenylacetic acid and norepinephrine in the cancer sample than in adjacent and non-oncological bone. We found that β-adrenergic receptors and dopaminergic receptors, dopamine β-hydroxylase, ki67, Runx2, and serotonergic receptor gene expression were significantly higher in tumour tissue than in adjacent and non-oncological bone.

CONCLUSION

Catecholamines and their receptors could be potential molecular markers for osteosarcoma progression.

Alterations in gene expression due to chronic lead exposure induce behavioral changes

Lead (Pb) is a pollutant commonly found in the environment, despite the implementation of public health policies intended to remove it. Due to its chemical characteristics as a divalent ion, Pb interacts with cells, enzymes, and tissues, causing pathological, physical, and behavioral alterations. Recent biotechnological advances have helped us to understand the mechanisms underlying the damage caused by Pb in human populations and in experimental models, and new evidence on the epigenetic alterations caused by exposition to environmental Pb is available. It is known that Pb exposure impacts on behavior (causing aggressiveness, anxiety, and depression), leading to learning deficit and locomotor activity alterations, and its presence has been linked with the abnormal release of neurotransmitters and other biochemical changes involved in these disorders. Still, further reductionist studies are required to determine the effects of Pb exposure on DNA and protein expression and understand the processes underlying the diseases caused by Pb. This will also indicate possible therapeutic targets to offset the negative effects of the heavy metal. By elucidating the epigenetic changes involved, it would be possible to manipulate them and propose novel therapeutic approaches in this area. This review is aimed to provide an overview of studies that link Pb exposure to behavioral changes, as well as biochemical and epigenetic alterations at a neurotransmitter level, considering the importance of this metal in behavior abnormalities.

Postnatal cadmium administration affects the presence and distribution of carbohydrates in the sperm membrane during maturation in the epididymis in adult Wistar rats

Cadmium (Cd) is a heavy metal related to a decrease in sperm parameters. The transit of spermatozoa through the epididymis is necessary to generate changes in the sperm membrane, such as the assembly of various carbohydrates that are added to the spermatazoan's surface to prepare it for successful fertilisation of the oocyte. No studies have yet analysed whether Cd alters the presence and distribution of these carbohydrates. We aimed to evaluate the changes induced by Cd in the distribution pattern of N-acetylglucosamine, sialic acid, mannose and fucose on the sperm membrane in the epididymis (e.g. caput, corpus, cauda) and if it alters the epididymal epithelium. Male Wistar pups were treated with Cd doses (0.125, 0.25 and 0.5mg/kg) on postnatal days 1-49. At postnatal day 90, they were humanely killed, sperm samples were obtained from the epididymis and tissue samples were taken for histological analysis. Cd concentrations in the blood and epididymis increased in proportion to the dose administered and decreased the serum testosterone levels and sperm quality. Histological analysis revealed alterations in the epithelium in all Cd-treated groups. Cd altered the distribution patterns of carbohydrates and fluorescence indices. All these alterations affected the structure and functioning of sperm.

Characterization of Mechanical Allodynia and Skin Innervation in a Mouse Model of Type-2 Diabetes Induced by Cafeteria-Style Diet and Low-Doses of Streptozotocin

Background: Painful distal symmetrical polyneuropathy (DPN) is a frequent complication of type-2 diabetes mellitus (T2DM) that commonly presents as neuropathic pain and loss of skin nerve fibers. However, there are limited therapies to effectively treat DPN and many of the current animal models of T2DM-induced DPN do not appear to mirror the human disease. Thus, we validated a DPN mouse model induced by a cafeteria-style diet plus low-doses of streptozotocin (STZ).

Methods: Female C57BL/6J mice were fed either standard (STD) diet or obesogenic cafeteria (CAF) diet for 32 weeks, starting at 8 weeks old. Eight weeks after starting diets, CAF or STD mice received either four low-doses of STZ or vehicle. Changes in body weight, blood glucose and insulin levels, as well as oral glucose- and insulin-tolerance tests (OGTT and ITT) were determined. The development of mechanical hypersensitivity of the hindpaws was determined using von Frey filaments. Moreover, the effect of the most common neuropathic pain drugs was evaluated on T2DM-induced mechanical allodynia. Finally, the density of PGP -9.5⁺ (a pan-neuronal marker) axons in the epidermis from the hindpaw glabrous skin was quantified.

Results: At 22–24 weeks after STZ injections, CAF + STZ mice had significantly higher glucose and insulin levels compared to CAF + VEH, STD + STZ, and STD + VEH mice, and developed glucose tolerance and insulin resistance. Skin mechanical sensitivity was detected as early as 12 weeks post-STZ injections and it was significantly attenuated by intraperitoneal acute treatment with amitriptyline, gabapentin, tramadol, duloxetine, or carbamazepine but not by diclofenac. The density of PGP-9.5⁺ nerve fibers was reduced in CAF + STZ mice compared to other groups.

Conclusion: This reverse translational study provides a painful DPN mouse model which may help in developing a better understanding of the factors that generate and maintain neuropathic pain and denervation of skin under T2DM and to identify mechanism-based new treatments.

Delay in puberty indices of Wistar rats caused by Cadmium. Focus on the redox system in reproductive organs

Puberty is a transitional period from juvenile stage to adulthood, followed by the functional maturation of gonads and reproductive organs. This period is sensitive to environmental pollutants like cadmium (Cd), a heavy metal that represents a serious health risk. Cd is an endocrine disruptor that interferes with reproduction by causing oxidative stress in the reproductive organs, affecting the sexual function and decreasing testosterone (T) levels. However, little research has been done on the effects of Cd on puberty markers and antioxidant systems. In this study, we evaluated the effects of Cd on puberty markers: preputial separation, testes descent and T levels, and the antioxidant activity (SOD, CAT, GSH/GSSG and TAC) in the seminal vesicles, testis and epididymis. Male Wistar pups were treated with 1 mg/kg Cd or saline solution by i.p. injection from day 1 to 35; the other treatment was administrated for 49 days. At the end of treatment, the animals were sacrificed, and the tissues of interest dissected, weighed and prepared for the respective assays. Cd treated rats from birth to puberty showed a delay onset in the puberty markers and a low weight in reproductive organs. Also, Cd induced differential effects on the redox system in reproductive organs and decreased T levels, these effects played a pivotal role in the delay of puberty markers onset (testes descent and preputial separation), affecting the development and sexual maturity of the male rats.

Rich fatty acids diet of fish and olive oils modifies membrane properties in striatal rat synaptosomes

Background: Essential fatty acids (EFAs) and non-essential fatty acids (nEFAs) exert experimental and clinical neuroprotection in neurodegenerative diseases. The main EFAs, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), nEFAs, and oleic acid (OA) contained in olive and fish oils are inserted into the cell membranes, but the exact mechanism through which they exert neuroprotection is still unknown. Objectives and Methods: In this study, we assessed the fatty acids content and membrane fluidity in striatal rat synaptosomes after fatty acid-rich diets (olive- or a fish-oil diet, 15% w/w). Then, we evaluated the effect of enriching striatum synaptosomes with fatty acids on the oxidative damage produced by the prooxidants ferrous sulfate (FeSO4) or quinolinic acid (QUIN). Results and Discussion: Lipid profile analysis in striatal synaptosomes showed that EPA content increased in the fish oil group in comparison with control and olive groups. Furthermore, we found that synaptosomes enriched with fatty acids and incubated with QUIN or FeSO4 showed a significant oxidative damage reduction. Results suggest that EFAs, particularly EPA, improve membrane fluidity and confer antioxidant effect.

In vitro inhibition of brain phosphate-activated glutaminase by ammonia and manganese

INTRODUCTION

As a consequence of the loss of liver function in chronic liver disease, increased levels of ammonia, manganese, and glutamine have been observed in the brain of hepatic encephalopathy patients.

OBJECTIVE

In the present study, we explored phosphate activated glutaminase (PAG) activity in mitochondrial enriched fractions under treatment with ammonia and manganese.

METHODS

We dissected out the brain cortex, striatum, and cerebellum of male Wistar rats 250-280 g weight; brain sections were pooled to obtain enriched mitochondrial fractions by differential centrifugation. Aliquots equivalent to 200 μg of protein were incubated with semi-log increasing concentrations of ammonia and/or manganese both as chloride salts (from 0 to 10 000 μM) and glutamine (4 mM) for 30 min. Then, the glutamate produced by the reaction was determined by HPLC coupled with fluorescence detection.

RESULTS AND DISCUSSION

Both manganese and ammonia inhibited PAG in a concentration-dependent manner. Non-linear modeling was used to determine IC50 and IC20 for ammonia (120 μM) and manganese (2 mM). We found that PAG activity under the combination of IC20 of ammonia and manganese was equivalent to the sum of the effects of both substances, being PAG inhibition more pronounced in mitochondrial fractions from cerebellum. The PAG inhibition observed here could potentially explain a pathway for glutamine accumulation, by means of the inhibition of PAG activity as a consequence of increased concentrations of manganese and ammonia in the brain under liver damage conditions.

Whole-brain irradiation differentially modifies neurotransmitters levels and receptors in the hypothalamus and the prefrontal cortex

BACKGROUND

Whole-brain radiotherapy is a primary treatment for brain tumors and brain metastasis, but it also induces long-term undesired effects. Since cognitive impairment can occur, research on the etiology of secondary effects has focused on the hippocampus. Often overlooked, the hypothalamus controls critical homeostatic functions, some of which are also susceptible after whole-brain radiotherapy. Therefore, using whole-brain irradiation (WBI) in a rat model, we measured neurotransmitters and receptors in the hypothalamus. The prefrontal cortex and brainstem were also analyzed since they are highly connected to the hypothalamus and its regulatory processes.

METHODS

Male Wistar rats were exposed to WBI with 11 Gy (Biologically Effective Dose = 72 Gy). After 1 month, we evaluated changes in gamma-aminobutyric acid (GABA), glycine, taurine, aspartate, glutamate, and glutamine in the hypothalamus, prefrontal cortex, and brainstem according to an HPLC method. Ratios of Glutamate/GABA and Glutamine/Glutamate were calculated. Through Western Blott analysis, we measured the expression of GABAa and GABAb receptors, and NR1 and NR2A subunits of NMDA receptors. Changes were analyzed comparing results with sham controls using the non-parametric Mann-Whitney U test (p < 0.05).

RESULTS

WBI with 11 Gy induced significantly lower levels of GABA, glycine, taurine, aspartate, and GABAa receptor in the hypothalamus. Also, in the hypothalamus, a higher Glutamate/GABA ratio was found after irradiation. In the prefrontal cortex, WBI induced significant increases of glutamine and glutamate, Glutamine/Glutamate ratio, and increased expression of both GABAa receptor and NMDA receptor NR1 subunit. The brainstem showed no statistically significant changes after irradiation.

CONCLUSION

Our findings confirm that WBI can affect rat brain regions differently and opens new avenues for study. After 1 month, WBI decreases inhibitory neurotransmitters and receptors in the hypothalamus and, conversely, increases excitatory neurotransmitters and receptors in the prefrontal cortex. Increments in Glutamate/GABA in the hypothalamus and Glutamine/Glutamate in the frontal cortex indicate a neurochemical imbalance. Found changes could be related to several reported radiotherapy secondary effects, suggesting new prospects for therapeutic targets.

Protection induced by estradiol benzoate in the MPP+ rat model of Parkinson's disease is associated with the regulation of the inflammatory cytokine profile in the nigro striatum

Previously, we have demonstrated that β-estradiol-3-benzoate (EB) has a protective effect on the neurodegenerative experimental model of Parkinson's disease. The protective effect is through the induction of the expression of paraoxonase-2 (PON2) in the striatum. PON2 has proven to have antioxidant and anti-inflammatory activity, this protein has a beneficial effect in MPP⁺ model in rats decreasing the lipid peroxidation and the oxidative stress. Furthermore, the molecular effect and the pathway by which EB induces protection were not further pursued. This study shows the regulation by EB of the anti-inflammatory effect through the modulation of cytokines, antioxidant enzymes and PON2 in the rat striatum. Rats were gonadectomized and 30 days after were randomly assigned into four experimental groups; only vehicles (Control group); EB treatment (EB group); MPP⁺ injury (M group); EB plus MPP⁺ injured (EB/M group). EB treatment consisted of 100 μg of the drug administered every 48 h for 11 days. Results showed that EB (group EB/M) treatment decrease significantly (40%) the number of ipsilateral turns respect to the M group and prevents significantly the dopamine (DA) decreased induced by MPP⁺ (~75%). This results are correlate with a significant decrease in the level of lipid peroxidation (60%) of the EB/M group respect to the M group. The EB treatment showed protection against neurotoxicity induced with MPP⁺, this could be due to EB capacity to prevent the increase in the expression level of proinflammatory cytokines TNF-α, IL-1 and IL-6 induced by MPP⁺. While, TGF-β1 and TGF-β3 expression was reduced in the rats treated only with MPP⁺, in the rats of EB/M group the expression of both cytokines was increased. EB protective effect against MPP⁺ neurotoxicity is related to antioxidant effect of PON2, pro-inflammatory cytokines and GSHR but not to SOD2, catalase, GPX1 or GPX4.

COVID-19: a basic approach to understanding potential treatments

SARS-CoV-2 virus has been identified as the causative agent of the COVID-19 pandemic. Even when no standard treatment is available, antivirals such as remdesivir and other drugs such as chloroquine and ivermectin, which interfere with viral replication, have been assayed. Some strategies aimed at reducing immune mechanisms, such as the use of tocilizumab and natural antioxidants, have also been tested. The use of drugs related to the renin-angiotensin system has been controversial. Pathogenicity mechanisms, as well as controlled treatments, still have to be studied in detail in order to propose a viable therapeutic option that prevents the entry and replication of the virus or enhances the host immune system.

El virus SARS-CoV-2 ha sido identificado como el agente patológico causante de la pandemia de COVID-19. Aun cuando no se cuenta con un tratamiento estándar, se han probado antivirales como remdesivir y otros fármacos como cloroquina e ivermectina, que interfieren con la replicación del virus. También se han intentado algunas estrategias encaminadas a disminuir los mecanismos inmunitarios, como el uso de tocilizumab y antioxidantes naturales. Los fármacos relacionados con el sistema renina-angiotensina han resultado controversiales. Aún se debe estudiar con detalle los mecanismos de patogenicidad, así como los tratamientos controlados para proponer alguna opción terapéutica viable que evite la entrada y replicación del virus o que aumente los sistemas inmunitarios del huésped.

Hydroxytyrosol inhibits MAO isoforms and prevents neurotoxicity inducible by MPP+ invivo

Parkinson's disease is considered to be due to an increase in the catabolism of dopamine by the action of monoamine oxidase (MAO) enzymes which leads to an increase in reactive oxygen species (ROS) and loss of dopaminergic neurons. Here, in a model of neurotoxicity inducible by 1-methyl-4-phenylpyridinium (MPP+), we tested the effect of hydroxytyrosol (HTy), a potent antioxidant, on generation of ROS. Five minutes after a single intravenous administration of 1.5 mg/Kg of Hty, Wistar rats received an intrastriatal micro-injection of 10 micrograms of MPP+ while control animals received saline solution. Six days later, all animals were treated with apomorphine (1 mg/Kg), subcutaneously and ipsilateral rotations were assessed within an hour. Then, the rats were sacrificed, striatal tissues were removed and their catecholamines and MAO-A and B activities were quantitated. Pretreatment with HTy significantly diminished the number of ipsilateral rotations. This recovery correlated with significant preservation of striatal dopamine and significant inhibition of of the MAO activity. These results are consistent with the inhibitory effect of HTy on the MAO isoforms and form a basis for the neuroprotective mechanism of this phenylpropanoid in MPP+ induced Parkinson's disease.

Clozapine and desmethylclozapine: correlation with neutrophils and leucocytes counting in Mexican patients with schizophrenia

PURPOSE

The aim of present study is to measure plasma clozapine (CLZ) and N-desmethyl clozapine (DMC) as biomarkers to correlate drug concentrations with the appearance of preclinical adverse hematic effects.

METHODS

A high-performance liquid chromatographic method, using a diode-array (ultraviolet) detector, was validated to obtain reliable concentrations of CLZ and DMC, its main metabolite, in plasma of 41 schizophrenic patients taking CLZ. Blood neutrophils and leucocytes counting were concurrently assessed as a proxy to subclinical adverse reactions.

RESULTS

The analytical method employed was linear, reproducible, and stable to measure concentrations of CLZ between 30 and 1000 ng/mL, while 12.5-560 ng/mL of the metabolite. The method allowed us to correlate CLZ plasma concentrations, the time taking CLZ and CLZ dose as determinants of neutrophils' counting with a R² = 0.447, using a multiple regression analysis model. Likewise, the correlation of leucocyte counting vs CLZ plasma levels and CLZ time, showed a R² = 0.461. DMC correlated significantly with both neutrophils and leucocytes counting, but was excluded from the regression when CLZ concentration was included in the model. Finally, no other hematological adverse reactions were recorded. One patient presented a cardiovascular complication. The negative correlation between clozapine and neutrophil count observed in patients, suggest that CLZ itself, but not DMC, could be related to hematologic side-effects.

CONCLUSION

The findings of this study, demonstrate for the first time, that plasma levels of CLZ and time taking the drug are independent determinants of blood neutrophils and leucocytes, so the monitoring of plasma CLZ may be useful in the clinic practice to determine safe dosing of the drug.

Advanced-stage mycosis fungoides: role of the signal transducer and activator of transcription 3, nuclear factor-κB and nuclear factor of activated T cells pathways

BACKGROUND

The malignant mechanisms that control the development of cutaneous T-cell lymphoma (CTCL) are beginning to be identified. Recent evidence suggests that disturbances in specific intracellular signalling pathways, such as RAS-mitogen-activated protein kinase, T-cell receptor (TCR)-phospholipase C gamma 1 (PLCG1)-nuclear factor of activated T cells (NFAT) and Janus kinase (JAK)-signal transducer and activator of transcription (STAT), may play an essential role in the pathogenesis of CTCL.

OBJECTIVES

To investigate the mechanisms controlling disease development and progression in mycosis fungoides (MF), the most common form of CTCL.

METHODS

We collected 100 samples that were submitted for diagnosis of, or a second opinion regarding, MF between 2001 and 2018, 80% of which were in the early clinical stages of the disease. Formalin-fixed paraffin-embedded tissues were used for histological review and to measure the expression by immunohistochemistry of surrogate markers of activation of the TCR-PLCG1-NFAT, JAK-STAT and NF-κB pathways. Folliculotropism and large-cell transformation were also examined.

RESULTS

NFAT and nuclear factor kappa B (NF-κB) markers showed a comparable activation status in early and advanced stages, while STAT3 activation was more frequent in advanced stages and was associated with large-cell transformation. Consistently with this observation, STAT3 activation occurred in parallel with MF progression in two initially MF-negative cases. A significant association of NFAT with NF-κB markers was also found, reflecting a common mechanism of activation in the two pathways. Genomic studies identified nine mutations in seven genes known to play a potential role in tumorigenesis in T-cell leukaemia/lymphoma, including PLCG1, JAK3 and STAT3, which underlies the activation of these key cell-survival pathways. A higher mutational allele frequency was detected in advanced stages.

CONCLUSIONS

Our results show that STAT3 is activated in advanced cases and is associated with large-cell transformation, while the activation of NFAT and NF-κB is maintained throughout the disease. These findings could have important diagnostic and therapeutic implications. What's already known about this topic? Mycosis fungoides is characterized by a clonal expansion of T cells in the skin. The mechanisms controlling disease development and progression are not fully understood. What does this study add? An association of the nuclear factor of activated T cells and nuclear factor kappa B pathways was found, which could reflect a common mechanism of activation. These pathways were activated in early and advanced stages at the same level. Signal transducer and activator of transcription 3 activation was associated with large-cell transformation and was more frequent in advanced stages. A genomic analysis of cutaneous T-cell lymphoma-associated genes was performed. Nine mutations were detected. What is the translational message? These results could have important implications for the treatment of MF in the near future.

GABAergic imbalance is normalized by dopamine D1 receptor activation in the striatum contralateral to the cortical injury in motor deficit-recovered rats

RATIONALE

The sensorimotor cortex and the striatum are interconnected by the corticostriatal pathway, suggesting that cortical injury alters the striatal function, which may be modulated by dopamine.

OBJECTIVES

We studied whether the activation of dopamine D₁ receptors (D₁Rs) modulates the γ-aminobutyric acid (GABA) and glutamate levels in the striatum of recovered rats at 192 h after cortical injury.

METHODS

The D₁R agonist SKF-38393 (0, 2, 3, or 4 mg/kg) was administered at 24, 48, 96, and 192 h post-injury, and then rats were decapitated to determine GABA and glutamate levels and the levels of D₁R mRNA on both sides of the striatum.

RESULTS

GABAergic imbalance in the striatum contralateral to the injury site was normalized by the administration of the D₁R agonist, but this treatment did not produce a significant effect on glutamate levels, suggesting that glutamate was metabolized into GABA. The administration of SKF-38393 (2 mg/kg) decreased the levels of D₁R mRNA in the striatum contralateral to the injury, and this effect was blocked by the coadministration of the D₁R antagonist SCH-23390 (2 mg/kg). In the striatum ipsilateral to the injury, the D₁R agonist increased the D₁R mRNA levels, an effect that was blocked by SCH-23390.

CONCLUSION

The reversal of the GABAergic imbalance in the striatum contralateral to the cortical injury can be modulated by extrastriatal D₁R activation, and the D₁R agonist-induced increases in the D₁R mRNA levels in the striatum ipsilateral to the injury suggest that the striatum may be necessary to achieve functional recovery.

Chronic administration of the histamine H3 receptor agonist immepip decreases L-Dopa-induced dyskinesias in 6-hydroxydopamine-lesioned rats

RATIONALE

Histamine H₃ receptors (H₃Rs) are co-expressed with dopamine D₁ receptors (D₁Rs) by striato-nigral medium spiny GABAergic neurons, where they functionally antagonize D₁R-mediated responses.

OBJECTIVES AND METHODS

We examined whether the chronic administration of the H₃R agonist immepip modifies dyskinesias induced by L-3,4-dihydroxyphenylalanine, L-Dopa (LIDs), in rats lesioned with 6-hydroxydopamine in the substantia nigra pars compacta, and the effect of D₁R and H₃R co-activation on glutamate and GABA content in dialysates from the dorsal striatum of naïve rats.

RESULTS

The systemic administration (i.p.) of L-Dopa for 14 days significantly increased axial, limb, and orolingual abnormal involuntary movements (AIMs) compared with the vehicle group. The chronic administration of the H₃R agonist immepip alongside L-Dopa significantly decreased axial, limb, and orolingual AIMs compared with L-Dopa alone, but AIMs returned to previous values on immepip withdrawal. Chronic immepip was ineffective when administered prior to L-Dopa. The chronic administration of immepip significantly decreased GABA and glutamate content in striatal dialysates, whereas the administration of L-Dopa alone increased GABA and glutamate content.

CONCLUSIONS

These results indicate that chronic H₃R activation reduces LIDs, and the effects on striatal GABA and glutamate release provide evidence for a functional interaction between D₁Rs and H₃Rs.

Epicatechin Reduces Spatial Memory Deficit Caused by Amyloid-β25⁻35 Toxicity Modifying the Heat Shock Proteins in the CA1 Region in the Hippocampus of Rats

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by dementia and the aggregation of the amyloid beta peptide (Aβ). Aβ_25-35 is the most neurotoxic sequence, whose mechanism is associated with the neuronal death in the Cornu Ammonis 1 (CA1) region of the hippocampus (Hp) and cognitive damage. Likewise, there are mechanisms of neuronal survival regulated by heat shock proteins (HSPs). Studies indicate that pharmacological treatment with flavonoids reduces the prevalence of AD, particularly epicatechin (EC), which shows better antioxidant activity. The aim of this work was to evaluate the effect of EC on neurotoxicity that causes Aβ_25-35 at the level of spatial memory as well as the relationship with immunoreactivity of HSPs in the CA1 region of the Hp of rats. Our results show that EC treatment reduces the deterioration of spatial memory induced by the Aβ_25-35, in addition to reducing oxidative stress and inflammation in the Hp of the animals treated with EC + Aβ_25-35. Likewise, the immunoreactivity to HSP-60, -70, and -90 is lower in the EC + Aβ_25-35 group compared to the Aβ_25-35 group, which coincides with a decrease of dead neurons in the CA1 region of the Hp. Our results suggest that EC reduces the neurotoxicity induced by Aβ_25-35, as well as the HSP-60, -70, and -90 immunoreactivity and neuronal death in the CA1 region of the Hp of rats injected with Aβ_25-35, which favors an improvement in the function of spatial memory.

Analysis of Flavonoids Bioactivity for Cholestatic Liver Disease: Systematic Literature Search and Experimental Approaches

Flavonoids are naturally occurring compounds that show health benefits on the liver. However, there is little investigation about identification and evaluation of new flavonoid-containing drugs for cholestatic liver disease, one of the most common liver illnesses. We aimed to a systematic search regarding efficacy of flavonoids for treatment of cholestatic liver disease, and then evaluate naringenin (NG) as representative flavonoid in an obstructive cholestasis model. We searched for information of experimental and clinical studies in four major databases without time and language limits. Intervention was defined as any flavonoid derivate compared with other flavonoid, placebo, or without comparator. In addition, we evaluated NG on a bile duct-ligated model in order to contribute evidence of its actions. Eleven experimental reports that support the efficacy of flavonoids in cholestatic liver disease were identified. However, there was no homogeneity in efficacy endpoints evaluated and methodology. On the other hand, NG showed beneficial effects by improving specific metabolic (cholesterol and lipoproteins) and liver damage (bilirubin and alkaline phosphatase) biomarkers. The review lacks homogeneous evidence about efficacy of flavonoids in experimental settings, and is susceptible to risk for bias. NG only showed improvements in specific disease biomarkers. More investigation is still needed to determine its potential for drug development.

Blood cadmium determinants among males over forty living in Mexico City

BACKGROUND

Mexico City has air, water and food pollution problems; however, human exposure to cadmium and its sources have not been described.

OBJECTIVES

To determine the blood cadmium (BCd) level and its main exposure sources among males aged 40 years or older living in different areas of Mexico City.

METHODS

After receiving informed consent, we interviewed 702 males aged ≥40 years to collect data on their sociodemographic characteristics, lifetime occupation, smoking history, and dietary habits, using a validated questionnaire. The BCd level (μg/L) was determined by atomic absorption spectrophotometry.

RESULTS

The BCd mean level ± SD was 2.61 ± 0.82 μg/L, and 20% of men reported a potential cadmium occupational exposure. After adjusting for age and other potential confounders, the main determinants of the BCd level were the current smoking status at interview, with low (β_{≤8.5packs/year vs. non-smoker} = 0.46; 95% CI: 0.28-0.64 μg/L; p < 0.01) and high (β_{> 8.5 packs/year vs. non-smoker} = 0.71; 95% CI: 0.56-0.87 μg/L; p < 0.01) smoking intensity, and living in the Center (β_{Center vs. South} = 0.20; 95% CI: 0.02-0.37 μg/L; p = 0.02) or West area of the city (β_{West vs. South} = 0.40, 95% CI: 0.21-0.58 μg/L; p < 0.001). Moreover, the potential dietary sources of BCd included: liver (β_{Yes vs. No} = 0.13, 95% CI: 0.03-0.23 μg/L; p = 0.01), "Chorizo" (β_{>1-3servings/month vs. No} = 0.14, 95% CI: 0.01-0.26 μg/L; p < 0.001), sausage and ham.

CONCLUSIONS

The BCd levels observed in this population are high and only similar to those observed in workers from a sanitary landfill area in Southern Thailand. Potential environmental Cd exposure sources, such as industrial activity and previous land use, in the West and Center areas of the city should be explored in detail, especially in vulnerable population groups, such as children.

A Hypothesis of the Interaction of the Nitrergic and Serotonergic Systems in Aggressive Behavior Induced by Exposure to Lead

The effects caused by exposure to lead (Pb) are still considered as a relevant health risk despite public policies aimed to restricting the use of this element. The toxicity limit in the blood (10 μg/dL, established by the Center for Disease Control and Prevention) has been insufficient to prevent adverse effects and even lower values have been related to neurobehavioral dysfunctions in children. Currently, there is not a safe limit of exposure to Pb. A large body of evidence points to environmental pollutant exposure as the cause of predisposition to violent behavior, among others. Considering the evidence by our group and others, we propose that Pb exposure induces alterations in the brain vasculature, specifically in nitric oxide synthases (NOS), affecting in turn the serotonergic system and leading to heightened aggressive behavior in the exposed individuals. This review article describes the consequences of Pb exposure on the nitrergic and serotonergic systems as well as its relationship with aggressive behavior. In addition, it summarizes the available therapy to prevent damage in gestation and among infants.

β-Estradiol-3-benzoate confers neuroprotection in Parkinson MPP+ rat model through inhibition of lipid peroxidation

Estradiol (E2), in addition to its known hormone function, is a neuroactive steroid that has shown neuroprotective profile in several models of neurological diseases. The present study explores the antioxidant effect of β-estradiol-3-benzoate (EB) on the neurotoxicity elicited by MPP⁺ in rat striatum. Male Wistar rats, that were gonadectomized 30days prior to EB, were given 100µgEB per rat every 48h for 11days and animals were infused with MPP⁺ via intrastriatal at day six after beginning EB treatment. EB treatment completely prevented the fall in dopamine caused by MPP⁺, such result was related with decreased lipid peroxidation, a marker of oxidative stress; diminished number of ipsilateral-to-lesion turns and increased signal of the dopamine-synthesizing enzyme Tyrosin Hydroxylase in substantia nigra. The protection elicited by EB was not related to Mn or Cu-Zn superoxide dismutase enzymatic activities or glutathione modulation since none of these parameters were influenced by EB at the times assayed. Whereas, increased expression of PON2 as a result of EB treatment was observed, this phenomenon could be one of the mechanism by which the steroid conferred protection to dopaminergic cells against MPP⁺ injury.

[Lead poisoning and marginalization in newborns of Morelos, Mexico]

Objective:

To determine the prevalence of lead (Pb) poisoning at birth in Morelos, analyze its distribution by social marginalization level, and estimate the association with the use of lead glazed ceramics (LGC).

Materials and methods:

Blood lead level (BLL) in umbilical cord was measured in a representative sample of 300 randomly selected births at the Morelos Health Services and state IMSS.

Results:

The prevalence of Pb poisoning at birth (BLL> 5μg/dL) was 14.7% (95%CI: 11.1, 19.3) and 22.2% (95%CI: 14.4, 32.5) in the most socially marginalized municipalities. 57.1% (95%CI: 51.3, 62.7) of the mothers used LGC during pregnancy, and the frequency of use was significantly associated with BLL.

Conclusion:

This is the first study to document the proportion of newborns with Pb poisoning who are at risk of experiencing the related adverse effects. It is recommended to monitor BLL at birth and take action to reduce this exposure, especially in socially marginalized populations.

Copper sulfate pretreatment prevents mitochondrial electron transport chain damage and apoptosis against MPP+-induced neurotoxicity

Intrastriatal injection of 1-methyl-4-phenylpyridinium (MPP⁺) is considered a model to reproduce some biochemical alterations observed in Parkinson's disease (PD) patients. Among those alterations, inhibition of mitochondrial complex I activity, increased free radical production and reduced antioxidant responses have been reported. Copper (Cu) plays an important role in the metabolism and antioxidative responses through its participation as a cofactor in the cytochrome c oxidase enzyme (COX), Cu/Zn-superoxide dismutase (Cu/Zn-SOD), and metallothioneins. We tested the effect of copper sulfate (CuSO₄) pretreatment on the mitochondrial electron transport chain (METC) in the striatum after MPP⁺ toxicity in rats. The results showed that the MPP⁺ intrastriatal injection reduced mitochondrial complex I, II, IV and V activities; while 10 μmol of CuSO₄ pretreatment counteracted this damage. Activities of complexes I, II and IV, were coincident with ATP recovery. Moreover, Cu/Zn-SOD activity was reduced as a consequence of MPP⁺ damage; however, copper pre-treatment kept the striatal Cu/Zn-SOD activity unchanged in MPP⁺-damaged animals. We observed that MPP⁺ also reduced the metallothionein (MT) content and that CuSO₄ pretreatment maintained baseline values. CuSO₄ pretreatment also reduced the striatal caspase-3 and caspase-9 activities that were increased three days after MPP⁺-induced damage. The present study provided evidence that copper pretreatment reduced MPP⁺-induced apoptotic damage, probably through direct action on copper-dependent proteins or indirectly on proteins in the apoptotic pathway.

Effects of manganese exposure on visuoperception and visual memory in schoolchildren

BACKGROUND

Manganese (Mn) is an essential metal involved in multiple physiological functions. Environmental exposure to airborne Mn is associated with neurocognitive deficits in humans. Children, whose nervous system is in development, are particularly susceptible to Mn neurotoxicity.

OBJECTIVE

The objective of this study was to assess the association between Mn environmental exposure, and effects on visuoperception and visual memory in schoolchildren.

METHODS

We assessed schoolchildren between 7 and 11 years old, with similar socioeconomic status, from the mining district of Molango (n=148) and Agua Blanca (n=119, non-mining area) in Hidalgo state, Mexico. The Rey-Osterrieth Complex Figure (ROCF) test was used to assess visuoperception and short-term visual memory. Hair manganese (MnH) concentrations were determined. Linear regression models were constructed to estimate the associations between MnH and ROCF scores, adjusted for potential confounders.

RESULTS

The geometric mean MnH was nine times higher in schoolchildren from the Mn mining area (5.25μg/g) than in schoolchildren from the non-mining area (0.55μg/g). For the ROCF Copy trial, MnH was significantly associated with an increase in distortion errors (tangency, closure), angle errors, overtracing (partial overtracing). In the Immediate Recall trial, MnH was significantly associated with increased overtracing (partial overtracing) and omissions, and negatively associated with the number of perceptual drawn units, total score and percentage immediate recall.

CONCLUSIONS

MnH is associated with alterations in visuoperception and short-term visual memory in schoolchildren exposed to airborne Mn.

Glazed clay pottery and lead exposure in Mexico: Current experimental evidence

OBJECTIVES

Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach.

METHODS

We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period.

RESULTS AND DISCUSSION

We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

Sensorimotor recovery from cortical injury is accompanied by changes on norepinephrine and serotonin levels in the dentate gyrus and pons

Monoamines such as norepinephrine (NE) and serotonin (5-HT) have shown to play an important role in motor recovery after brain injury. The effects elicited by these neurotransmitters have been reported as distal from the area directly affected. Remote changes may take place over minutes to weeks and play an important role in post-stroke recovery. However, the mechanisms involved in spontaneous recovery have not been thoroughly delineated. Therefore, we determined the NE and 5-HT content, in the pons and hippocampal dentate gyrus (DG) as well as motor deficit and spontaneous activity in rats after 3, 10 and 20 days cortical iron injection. Three days post-lesion the pontine NE content diminished, this effect was accompanied by deficient spontaneous activity and impaired sensorimotor evaluation. Ten and twenty days after lesion the NE levels were similar to those of control group, and animals also showed behavioral recovery. Monoamines content on DG 3 days post-lesion showed no differences as compared to controls. Interestingly, ten and twenty days after cortical injury, animals showed increased NE and 5-HT. These results suggest that behavioral recovery after brain damage involve changes on monoamines levels on DG, an important structure to plastic processes. In addition, the results herein support evidence to propose these neurotransmitters as key molecules to functional recovery in the central nervous system.

Supplementation with rumen-protected L-arginine-HCl increased fertility in sheep with synchronized estrus

The aim of the present study was to evaluate the effects of L-arginine-HCl supplementation on ovulation rate, fertility, prolificacy, and serum VEGF concentrations in ewes with synchronized oestrus. Thirty Suffolk ewes with a mean body weight of 45 ± 3 kg and a mean body condition score (BCS) of 2.4 ± 0.28 were synchronized for estrus presentation with a progestin-containing sponge (20 mg Chronogest® CR) for 9 days plus PGF2-α (Lutalyse; Pfizer, USA) on day 7 after the insertion of the sponge. The ewes were divided into two groups; i.e., a control group (n = 15) that was fed on the native pasture (basal diet) and an L-arginine-HCl group (n = 15) that received 7.8 g of rumen-protected L-arginine-HCl from day 5 of the sponge insertion until day 25 after mating plus the basal diet. The L-arginine-HCl was administered daily via an esophageal probe between days 5 and 9 of the synchronization protocol and every third day subsequently. Blood samples were drawn from the jugular vein every 6 days throughout the entire experimental period. The results revealed that the L-arginine-HCl supplementation increased fertility during the synchronized estrus (P = 0.05). However, no effects were observed on the final BCS (P = 0.78), estrus presentation (P = 0.33), multiple ovulations (P = 0.24), prolificacy (P = 0.63), or serum VEGF concentration. In conclusion, L-arginine-HCl supplementation during the period used in this study increased fertility in sheep with synchronized estrus possibly due to improved embryo-fetal survival during early pregnancy.