COVID-19 vaccine hesitancy prevalence in Mexico: A systematic review and metanalysis.

Background: Vaccine hesitancy (VH) is a recognized threat to public health that undermines efforts to mitigate disease burden. This study aims to gather available evidence regarding COVID-19 VH in Mexico, estimate the prevalence of VH, and its determinants to inform policymaking in this country. Methods: Following PRISMA guidelines, a systematic review of the MEDLINE literature, articles that estimated the prevalence of COVID-19 VH in Mexico were included in the analysis to obtain a pooled estimate. We used a binomial-normal model for meta-analysis of proportions (i.e., generalized linear mixed model) to perform the metanalysis. We then performed a narrative review of COVID-19 VH in Mexican subpopulations. Results: Seven studies met inclusion criteria. We estimated a pooled prevalence of COVID-19 VH of 16 % (95 % CI: 11-23 %) in Mexico. We found an association between VH and demographic characteristics, intrinsic vaccine factors, and beliefs. Subgroup analyses from specific studies suggested that patients with clinical conditions such as breast cancer or rheumatologic diseases had a higher prevalence of VH. Conclusions: VH is a highly complex and dynamic phenomenon in Mexico. Characterizing and understanding COVID-19 vaccine hesitancy in the Mexican population helps target future policy interventions to mitigate the spread and impact of infectious diseases. The implications of VH differ among groups that may be at higher risk of severe disease, underscoring the importance of prompt research among these groups as well as targeted interventions to address VH.

Chronic kidney disease acquired knowledge in a diabetic and hypertensive population using a translated and validated questionnaire.

Chronic kidney disease (CKD) is the progressive and irreversible functional and/or structural impairment of the kidney; its main etiologies include hypertension and diabetes. Mexico has the second highest prevalence of CKD worldwide with a high economic burden affecting public and private health systems. Patients with higher knowledge about CKD increase their adherence to preventive treatment. In this study we aim to describe the knowledge of CKD in a sample of Mexican high-risk population, comparing it with general Mexican population, medical students and nephrologists. A cross-sectional, observational study was performed divided in two phases: translation and validation of the knowledge questionnaire to Spanish, and cross-sectional survey to evaluate the knowledge of CKD in patients with diagnosis of diabetes and/or hypertension. We interviewed medical students, general population, and nephrologists to attain validation of the questionnaire in Spanish. The questionnaire was answered by 1,061 participants within the high-risk population. The results of the questionnaire were: 22/24, 18/24, 13.8/24, and 13.4/24 in nephrologists, medical students, normal subjects, and high-risk population, respectively. The questions with least correct answers were related to kidney functions and CKD risk factors. To our knowledge this is the first time a questionnaire for CKD knowledge is applied in Mexican population. These findings suggest poor understanding of kidney functions, risk factors, and symptoms of CKD. It is important not only to provide medical treatment to chronic illness but also awareness of the consequences of not achieving goals of treatment.

Determinants of COVID-19 vaccine hesitancy among pregnant persons.

BACKGROUND: Vaccines reduce the risk of contracting and developing complications from coronavirus disease 2019 (COVID-19). Pregnant people are at increased risk of disease-related complications but have a higher prevalence of vaccine hesitancy (VH) than their nonpregnant counterparts. OBJECTIVE: This study aimed to describe risk factors and COVID-19- and vaccine-related perspectives that lead to VH among pregnant people in Mexico to target strategies to increase vaccine acceptance in this population. METHODS: A cross-sectional survey-based study to evaluate risk factors and COVID-19- and vaccine-related perspectives associated with VH among pregnant people was conducted. Respondents were pregnant people of all ages attending a regular follow-up visit or admitted to labor and delivery in a third-level maternity hospital in Mexico. VH was defined as not having received a COVID-19 vaccine and either declining or being undecided to accept a vaccine during their pregnancy. We used bivariate and multivariable logistic regression models to estimate assess the relationship among demographic factors, COVID-19- and vaccine-related perspectives, and VH. RESULTS: A total of 1475 respondents completed the questionnaire; 216 (18%) were under the age of 18 years, and 860 (58%) had received at least one dose of a COVID-19 vaccine. In this sample, 264 (18%) were classified as vaccine hesitant. Key factors associated with VH were adolescence, having family as a primary source of information, first pregnancy, and history of vaccines in previous pregnancies. COVID-19 perspectives were also strongly associated with VH. CONCLUSIONS: Among pregnant people in Mexico, VH is associated with demographic factors, vaccination history, sources of information, and perceived risks to the fetus. This information is relevant to policy makers and health care professionals to identify those more likely to be hesitant and to inform strategies to increase vaccine uptake among pregnant people.

Universal screening for SARS-CoV-2 in obstetric patients.

Not available.

Differential Profile of Systemic Extracellular Vesicles From Sporadic and Familial Alzheimer's Disease Leads to Neuroglial and Endothelial Cell Degeneration.

Evidence suggests that extracellular vesicles (EVs) act as mediators and biomarkers of neurodegenerative diseases. Two distinct forms of Alzheimer disease (AD) are known: a late-onset sporadic form (SAD) and an early-onset familial form (FAD). Recently, neurovascular dysfunction and altered systemic immunological components have been linked to AD neurodegeneration. Therefore, we characterized systemic-EVs from postmortem SAD and FAD patients and evaluated their effects on neuroglial and endothelial cells. We found increase CLN-5 spots with vesicular morphology in the abluminal portion of vessels from SAD patients. Both forms of AD were associated with larger and more numerous systemic EVs. Specifically, SAD patients showed an increase in endothelial- and leukocyte-derived EVs containing mitochondria; in contrast, FAD patients showed an increase in platelet-derived EVs. We detected a differential protein composition for SAD- and FAD-EVs associated with the coagulation cascade, inflammation, and lipid-carbohydrate metabolism. Using mono- and cocultures (endothelium-astrocytes-neurons) and human cortical organoids, we showed that AD-EVs induced cytotoxicity. Both forms of AD featured decreased neuronal branches area and astrocytic hyperreactivity, but SAD-EVs led to greater endothelial detrimental effects than FAD-EVs. In addition, FAD- and SAD-EVs affected calcium dynamics in a cortical organoid model. Our findings indicate that the phenotype of systemic AD-EVs is differentially defined by the etiopathology of the disease (SAD or FAD), which results in a differential alteration of the NVU cells implied in neurodegeneration.

Multifunctional magnetite nanoparticles to enable delivery of siRNA for the potential treatment of Alzheimer's.

Therapeutic drugs for Alzheimer's disease have been extensively studied due to its recurrence and abundance among neurodegenerative diseases. It is thought that the accumulation of amyloid precursor protein (APP) products, a consequence of an up-regulation of the ß-site APP-cleaving enzyme 1 (BACE1), is the main triggering mechanism during the early stages of the disease. This study aims to explore the ability of a multifunctional conjugate based on magnetite nanoparticles for the cellular delivery of siRNA against the expression of the BACE1 gene. We immobilized the siRNA strand on PEGylated magnetite nanoparticles and investigated the effects on biocompatibility and efficacy of the conjugation. Similarly, we co-immobilized the translocating protein OmpA on PEGylated nanoparticles to enhance cellular uptake and endosomal escape. BACE1 suppression was statistically significant in HFF-1 cells, without any presence of a cytotoxic effect. The delivery of the nanoconjugate was achieved through endocytosis pathways, where endosome formation was likely escaped due to the proton-sponge effect characteristic of PEGylated nanoparticles or mainly by direct translocation in the case of OmpA/PEGylated nanoparticles.

The Role of Astrocytes in Neuroprotection after Brain Stroke: Potential in Cell Therapy.

Astrocytes are commonly involved in negative responses through their hyperreactivity and glial scar formation in excitotoxic and/or mechanical injuries. But, astrocytes are also specialized glial cells of the nervous system that perform multiple homeostatic functions for the survival and maintenance of the neurovascular unit. Astrocytes have neuroprotective, angiogenic, immunomodulatory, neurogenic, and antioxidant properties and modulate synaptic function. This makes them excellent candidates as a source of neuroprotection and neurorestoration in tissues affected by ischemia/reperfusion, when some of their deregulated genes can be controlled. Therefore, this review analyzes pro-survival responses of astrocytes that would allow their use in cell therapy strategies.

Targeting CDK5 post-stroke provides long-term neuroprotection and rescues synaptic plasticity.

Post-stroke cognitive impairment is a major cause of long-term neurological disability. The prevalence of post-stroke cognitive deficits varies between 20% and 80% depending on brain region, country, and diagnostic criteria. The biochemical mechanisms underlying post-stroke cognitive impairment are not known in detail. Cyclin-dependent kinase 5 is involved in neurodegeneration, and its dysregulation contributes to cognitive disorders and dementia. Here, we administered cyclin-dependent kinase 5-targeting gene therapy to the right hippocampus of ischemic rats after transient right middle cerebral artery occlusion. Cyclin-dependent kinase 5 RNA interference prevented the impairment of reversal learning four months after ischemia as well as neuronal loss, tauopathy, and microglial hyperreactivity. Additionally, cyclin-dependent kinase 5 silencing increased the expression of brain-derived neurotrophic factor in the hippocampus. Furthermore, deficits in hippocampal long-term potentiation produced by excitotoxic stimulation were rescued by pharmacological blockade of cyclin-dependent kinase 5. This recovery was blocked by inhibition of the TRKB receptor. In summary, these findings demonstrate the beneficial impact of cyclin-dependent kinase 5 reduction in preventing long-term post-ischemic neurodegeneration and cognitive impairment as well as the role of brain-derived neurotrophic factor/TRKB in the maintenance of normal synaptic plasticity.

BACE1 RNAi Restores the Composition of Phosphatidylethanolamine-Derivates Related to Memory Improvement in Aged 3xTg-AD Mice.

ß-amyloid (Aß) is produced by the ß-secretase 1 (BACE1)-mediated enzymatic cleavage of the amyloid precursor protein through the amyloidogenic pathway, making BACE1 a therapeutic target against Alzheimer's disease (AD). Alterations in lipid metabolism are a risk factor for AD by an unknown mechanism. The objective of this study was to determine the effect of RNA interference against BACE1 (shBACEmiR) on the phospholipid profile in hippocampal CA1 area in aged 3xTg-AD mice after 6 and 12 months of treatment compared to aged PS1KI mice. The shBACEmiR treatment induced cognitive function recovery and restored mainly the fatty acid composition of lysophosphatidylethanolamine and etherphosphatidylethanolamine, reduced the cPLA2's phosphorylation, down-regulated the levels of arachidonic acid and COX2 in the hippocampi of 3xTg-AD mice. Together, our findings suggest, for the first time, that BACE1 silencing restores phospholipids composition which could favor the recovery of cellular homeostasis and cognitive function in the hippocampus of triple transgenic AD mice.

LXR activation protects hippocampal microvasculature in very old triple transgenic mouse model of Alzheimer's disease.

The vascular hypothesis of Alzheimer's disease postulates that disruption of the brain microvasculature is important for the accumulation of amyloid beta and increased neuroinflammation. Liver X Receptor agonist, GW3965, has been demonstrated to successfully modulate neuroinflammation and lipid metabolism in murine models of AD. This is partially due to increased expression of ApoE levels and increased mobility of endothelial progenitor cells. This paper analyzes changes in the neurovascular unit and in astrocytes and microglia markers following oral administration of GW3965 in a very old triple transgenic AD mice (3xTg-AD mice). We found that astrogliosis, but not activation of microglia, decreased in very old (24 months) 3xTg-AD mice treated with GW965. In addition, GW3965 increased LRP1 levels in neuron-like cells and partially restored microvascular morphology by decreasing tortuosity and increasing length as shown by Lectin immunostaining. Interestingly, these changes were associated with decreased Aß in blood vessels. In conclusion, short-term treatment of 3xTg-AD mice with GW3965 restored microvascular architecture which may be important in the cognitive improvement previously shown.

CDK5 knockdown prevents hippocampal degeneration and cognitive dysfunction produced by cerebral ischemia.

Acute ischemic stroke is a cerebrovascular accident and it is the most common cause of physical disabilities around the globe. Patients may present with repeated ictuses, experiencing mental consequences, such as depression and cognitive disorders. Cyclin-dependent kinase 5 (CDK5) is a kinase that is involved in neurotransmission and plasticity, but its dysregulation contributes to cognitive disorders and dementia. Gene therapy targeting CDK5 was administered to the right hippocampus of ischemic rats during transient cerebral middle artery occlusion. Physiologic parameters (blood pressure, pH, pO2, and pCO2) were measured. The CDK5 downregulation resulted in neurologic and motor improvement during the first week after ischemia. Cyclin-dependent kinase 5 RNA interference (RNAi) prevented dysfunctions in learning, memory, and reversal learning at 1 month after ischemia. These observations were supported by the prevention of neuronal loss, the reduction of microtubule-associated protein 2 (MAP2) immunoreactivity, and a decrease in astroglial and microglia hyperreactivities and tauopathy. Additionally, CDK5 silencing led to an increase in the expression of brain-derived neurotrophic factor (BDNF), its Tropomyosin Receptor kinase B (TRKB) receptor, and activation of cyclic AMP response element-binding protein (CREB) and extracellular signal-regulated kinase (ERK), which are important targets in neuronal plasticity. Together, our findings suggest that gene therapy based on CDK5 silencing prevents cerebral ischemia-induced neurodegeneration and motor and cognitive deficits.

Comparative analysis of autophagy and tauopathy related markers in cerebral ischemia and Alzheimer's disease animal models.

Alzheimer's disease (AD) and cerebral ischemia (CI) are neuropathologies that are characterized by aggregates of tau protein, a hallmark of cognitive disorder and dementia. Protein accumulation can be induced by autophagic failure. Autophagy is a metabolic pathway involved in the homeostatic recycling of cellular components. However, the role of autophagy in those tauopathies remains unclear. In this study, we performed a comparative analysis to identify autophagy related markers in tauopathy generated by AD and CI during short-term, intermediate, and long-term progression using the 3xTg-AD mouse model (aged 6,12, and 18 months) and the global CI 2-VO (2-Vessel Occlusion) rat model (1,15, and 30 days post-ischemia). Our findings confirmed neuronal loss and hyperphosphorylated tau aggregation in the somatosensory cortex (SS-Cx) of the 3xTg-AD mice in the late stage (aged 18 months), which was supported by a failure in autophagy. These results were in contrast to those obtained in the SS-Cx of the CI rats, in which we detected neuronal loss and tauopathy at 1 and 15 days post-ischemia, and this phenomenon was reversed at 30 days. We proposed that this phenomenon was associated with autophagy induction in the late stage, since the data showed a decrease in p-mTOR activity, an association of Beclin-1 and Vps34, a progressive reduction in PHF-1, an increase in LC3B puncta and autophago-lysosomes formation were observed. Furthermore, the survival pathways remained unaffected. Together, our comparative study suggest that autophagy could ameliorates tauopathy in CI but not in AD, suggesting a differential temporal approach to the induction of neuroprotection and the prevention of neurodegeneration.

Long- and short-term CDK5 knockdown prevents spatial memory dysfunction and tau pathology of triple transgenic Alzheimer's mice.

CDK5 is a member of the cyclin-dependent kinase family with diverse functions in both the developing and mature nervous system. The inappropriate activation of CDK5 due to the proteolytic release of the activator fragment p25 from the membrane contributes to the formation of neurofibrillary tangles and chronic neurodegeneration. At 18 months of age 3xTg-AD mice were sacrificed after 1 year (long term) or 3 weeks (short term) of CDK5 knockdown. In long-term animals CDK5 knockdown prevented insoluble Tau formation in the hippocampi and prevented spatial memory impairment. In short-term animals, CDK5 knockdown showed reduction of CDK5, reversed Tau aggregation, and improved spatial memory compared to scrambled treated old 3xTg-AD mice. Neither long-term nor short-term CDK5 knock-down had an effect on old littermates. These findings further validate CDK5 as a target for Alzheimer's disease both as a preventive measure and after the onset of symptoms.

Cyclin-dependent kinase 5, a node protein in diminished tauopathy: a systems biology approach.

Alzheimer's disease (AD) is the most common cause of dementia worldwide. One of the main pathological changes that occurs in AD is the intracellular accumulation of hyperphosphorylated Tau protein in neurons. Cyclin-dependent kinase 5 (CDK5) is one of the major kinases involved in Tau phosphorylation, directly phosphorylating various residues and simultaneously regulating various substrates such as kinases and phosphatases that influence Tau phosphorylation in a synergistic and antagonistic way. It remains unknown how the interaction between CDK5 and its substrates promotes Tau phosphorylation, and systemic approaches are needed that allow an analysis of all the proteins involved. In this review, the role of the CDK5 signaling pathway in Tau hyperphosphorylation is described, an in silico model of the CDK5 signaling pathway is presented. The relationship among these theoretical and computational models shows that the regulation of Tau phosphorylation by PP2A and glycogen synthase kinase 3ß (GSK3ß) is essential under basal conditions and also describes the leading role of CDK5 under excitotoxic conditions, where silencing of CDK5 can generate changes in these enzymes to reverse a pathological condition that simulates AD.

Neural differentiation of transplanted neural stem cells in a rat model of striatal lacunar infarction: light and electron microscopic observations.

The increased risk and prevalence of lacunar stroke and Parkinson's disease (PD) makes the search for better experimental models an important requirement for translational research. In this study we assess ischemic damage of the nigrostriatal pathway in a model of lacunar stroke evoked by damaging the perforating arteries in the territory of the substantia nigra (SN) of the rat after stereotaxic administration of endothelin-1 (ET-1), a potent vasoconstrictor peptide. We hypothesized that transplantation of neural stem cells (NSCs) with the capacity of differentiating into diverse cell types such as neurons and glia, but with limited proliferation potential, would constitute an alternative and/or adjuvant therapy for lacunar stroke. These cells showed neuritogenic activity in vitro and a high potential for neural differentiation. Light and electron microscopy immunocytochemistry was used to characterize GFP-positive neurons derived from the transplants. 48 h after ET-1 injection, we characterized an area of selective degeneration of dopaminergic neurons within the nigrostriatal pathway characterized with tissue necrosis and glial scar formation, with subsequent behavioral signs of Parkinsonism. Light microscopy showed that grafted cells within the striatal infarction zone differentiated with a high yield into mature glial cells (GFAP-positive) and neuron types present in the normal striatum. Electron microscopy revealed that NSCs-derived neurons integrated into the host circuitry establishing synaptic contacts, mostly of the asymmetric type. Astrocytes were closely associated with normal small-sized blood vessels in the area of infarct, suggesting a possible role in the regulation of the blood brain barrier and angiogenesis. Our results encourage the use of NSCs as a cell-replacement therapy for the treatment of human vascular Parkinsonism.

Tyrannobdella rex n. gen. n. sp. and the evolutionary origins of mucosal leech infestations.

BACKGROUND: Leeches have gained a fearsome reputation by feeding externally on blood, often from human hosts. Orificial hirudiniasis is a condition in which a leech enters a body orifice, most often the nasopharyngeal region, but there are many cases of leeches infesting the eyes, urethra, vagina, or rectum. Several leech species particularly in Africa and Asia are well-known for their propensity to afflict humans. Because there has not previously been any data suggesting a close relationship for such geographically disparate species, this unnerving tendency to be invasive has been regarded only as a loathsome oddity and not a unifying character for a group of related organisms. PRINCIPAL FINDINGS: A new genus and species of leech from Perú was found feeding from the nasopharynx of humans. Unlike any other leech previously described, this new taxon has but a single jaw with very large teeth. Phylogenetic analyses of nuclear and mitochondrial genes using parsimony and Bayesian inference demonstrate that the new species belongs among a larger, global clade of leeches, all of which feed from the mucosal surfaces of mammals. CONCLUSIONS: This new species, found feeding from the upper respiratory tract of humans in Perú, clarifies an expansion of the family Praobdellidae to include the new species Tyrannobdella rex n. gen. n. sp., along with others in the genera Dinobdella, Myxobdella, Praobdella and Pintobdella. Moreover, the results clarify a single evolutionary origin of a group of leeches that specializes on mucous membranes, thus, posing a distinct threat to human health.

Down-regulation of Bcl-2 in rat substantia nigra after focal cerebral ischemia.

After occlusion of the middle cerebral artery in rats, a robust neuronal loss occurs in the ipsilateral substantia nigra reticulata. In this study we have assessed whether degeneration of the substantia nigra is accompanied by changes in the expression of the anti-apoptotic protein Bcl-2. Neuronal loss was assessed by neuronal nuclei (NeuN) immunoreactivity. A significant decrease of Bcl-2 expression was observed in the substantia nigra 12, 24 and 72 h after middle cerebral artery occlusion. These results suggest that the secondary neuronal loss in the substantia nigra could be related with the modification of proteins regulating programmed cell death. Exo-focal cell death may explain the appearance of neuropsychiatric symptoms that are not correlated with the primary site of lesion.