Raúl J. Bobes

Flatworms are known for their remarkable regenerative ability, one which depends on totipotent cells known as germinative cells in cestodes. Depletion of germinative cells with hydroxyurea (HU) affects the regeneration of the parasite. Here, we studied the reduction and recovery of germinative cells in T. crassiceps cysticerci after HU treatment (25 mM and 40 mM of HU for 6 days) through in vitro assays. Viability and morphological changes were evaluated. The recovery of cysticerci’s mobility and morphology was evaluated at 3 and 6 days, after 6 days of treatment. The number of proliferative cells was evaluated using EdU. Our results show morphological changes in the size, shape, and number of evaginated cysticerci at the 40 mM dose. The mobility of cysticerci was lower after 6 days of HU treatment at both concentrations. On days 3 and 6 of recovery after 25 mM of HU treatment, a partial recovery of the proliferative cells was observed. Proteomic and Gene Ontology analyses identified modifications in protein groups related to DNA binding, DNA damage, glycolytic enzymes, cytoskeleton, skeletal muscle, and RNA binding.

Background: Neurocysticercosis (NCC) is endemic in non-developed regions of the world. Two forms of NCC have been described, for which neurological morbidity depends on the location of the lesion, which can be either within the cerebral parenchyma or in extraparenchymal spaces. The extraparenchymal form (EXP-NCC) is considered the most severe form of NCC. EXP-NCC often requires several cycles of cysticidal treatment and the concomitant use of glucocorticoids to prevent increased inflammation, which could lead to intracranial hypertension and, in rare cases, to death. Thus, the improvement of EXP-NCC treatment is greatly needed. Methods: An experimental murine model of EXP-NCC, as an adequate model to evaluate new therapeutic approaches, and the parameters that support it are described. EXP-NCC was established by injecting 30 Taenia crassiceps cysticerci, which are less than 0.5 mm in diameter, into the cisterna magna of male and female Wistar rats. Results: Cyst implantation and infection progression were monitored by detecting the HP10 antigen and anti-cysticercal antibodies in the serum and cerebral spinal fluid (CSF) of infected rats and by magnetic resonance imaging. Higher HP10 levels were observed in CSF than in the sera, as in the case of human EXP-NCC. Low cell recruitment levels were observed surrounding established cysticerci in histological analysis, with a modest increase in GFAP and Iba1 expression in the parenchyma of female animals. Low cellularity in CSF and low levels of C-reactive protein are consistent with a weak inflammatory response to this infection. After 150 days of infection, EXP-NCC is accompanied by reduced levels of mononuclear cell proliferation, resembling the human disease. EXP-NCC does not affect the behavior or general status of the rats. Conclusions: This model will allow the evaluation of new approaches to control neuroinflammation and immunomodulatory treatments to restore and improve the specific anti-cysticercal immunity in EXP-NCC.

Dexamethasone (DXM) and methylprednisolone (MEP) are potent glucocorticoids used to control several inflammatory conditions. Evidence of delayed DXM reaching the central nervous system (CNS) as well as tachyphylaxis and systemic, undesirable side effects are the main limitations of peripheral delivery. Intranasal administration offers direct access to the brain as it bypasses the blood–brain barrier. The Mucosal Atomization Device is an optimal tool that can achieve rapid absorption into the CNS and the bloodstream across mucosal membranes. This study was designed to evaluate and compare the bioavailability of DXM and MEP after intranasal versus intravenous administration. Two open-label, balanced, randomized, two-treatment, two-period, two-sequence, single-dose, crossover studies were conducted, which involved healthy male and female adult volunteers. After intranasal administration, DXM and MEP were detected in plasma after the first sampling time. Mean peak concentrations of DXM and MEP were 86.61 ng/mL at 60 min and 843.2 ng/mL at 1.5 h post-administration, respectively. DXM and MEP showed high absolute bioavailability, with values of 80% and 95%, respectively. No adverse effects were observed. DXM and MEP systemic bioavailability by intranasal administration was comparable with the intravenous one, suggesting that the intranasal route can be used as a non-invasive and appropriate alternative for systemic drug delivery.

After more than two years, the COVID-19 pandemic is still ongoing and evolving all over the world; human herd immunity against SARS-CoV-2 increases either by infection or by unprecedented mass vaccination. A substantial change in population immunity is expected to contribute to the control of transmission. It is essential to monitor the extension and duration of the population’s immunity to support the decisions of health authorities in each region and country, directed to chart the progressive return to normality. For this purpose, the availability of simple and cheap methods to monitor the levels of relevant antibodies in the population is a widespread necessity. Here, we describe the development of an RBD-based ELISA for the detection of specific antibodies in large numbers of samples. The recombinant expression of an RBD-poly-His fragment was carried out using either bacterial or eukaryotic cells in in vitro culture. After affinity chromatography purification, the performance of both recombinant products was compared by ELISA in similar trials. Our results showed that eukaryotic RBD increased the sensitivity of the assay. Interestingly, our results also support a correlation of the eukaryotic RBD-based ELISA with other assays aimed to test for neutralizing antibodies, which suggests that it provides an indication of protective immunity against SARS-CoV-2.

The host’s hormonal environment determines the susceptibility, the course, and severity of several parasite infections. In most cases the infection disturbs the host environment, and activates immune responses that end up affecting the endocrine system. In the other hand, a number of reports indicate that parasites have reproductive systems, and some others have shown that these organisms synthetize sex steroid hormones. We have shown that cysticerci, the larval stage of Taenia solium and Taenia crassiceps ORF and WFU, synthesize steroid hormones. This capacity was modified by drugs that act inhibiting the steroid synthesizing enzymes, or blocking the parasite’s hormone receptors. We have also shown that the cysticerci of T. crassiceps WFU and T. solium have the capacity to synthesize corticosteroids as deoxicorticosterone and corticosterone. We also reviewed the effects of insulin on these parasites, and the receptors found for this hormone. A deep knowledge of the parasite’s endocrine properties will contribute to understand their reproduction and the reciprocal interactions with the host. Likewise, may also help designing tools to combat the infection in clinical situations.