Brain insulin resistance and Alzheimer's disease: a systematic review.

The disability of cells to react to insulin, causing glucose intolerance and hyperglycemia, is referred to as insulin resistance. This clinical condition, which has been well-researched in organs such as adipose tissue, muscle, and liver, has been linked to neurodegenerative diseases like Alzheimer's disease (AD) when it occurs in the brain. Objective: The authors aimed to gather data from the current literature on brain insulin resistance (BIR) and its likely repercussions on neurodegenerative disorders, more specifically AD, through a systematic review. Methods: A comprehensive search was conducted in multiple medical databases, including the Cochrane Central Register of Controlled Trials, EMBASE, Medical Literature Analysis and Retrieval System Online (Medline), and PubMed®, employing the descriptors: "insulin resistance", "brain insulin resistance", "Alzheimer's disease", "neurodegeneration", and "cognition". The authors focused their search on English-language studies published between 2000 and 2023 that investigated the influence of BIR on neurodegenerative disorders or offered insights into BIR's underlying mechanisms. Seventeen studies that met the inclusion criteria were selected. Results: The results indicate that BIR is a phenomenon observed in a variety of neurodegenerative disorders, including AD. Studies suggest that impaired glucose utilization and uptake, reduced adenosine triphosphate (ATP) production, and synaptic plasticity changes caused by BIR are linked to cognitive problems. However, conflicting results were observed regarding the association between AD and BIR, with some studies suggesting no association. Conclusion: Based on the evaluated studies, it can be concluded that the association between AD and BIR remains inconclusive, and additional research is needed to elucidate this relationship.

A incapacidade das células de reagir à insulina, ocasionando intolerância à glicose e hiperglicemia, é chamada de resistência à insulina. Essa condição clínica, que tem sido bem pesquisada em órgãos como tecido adiposo, músculo e fígado, tem sido associada às doenças neurodegenerativas como a doença de Alzheimer (DA) quando ocorre no cérebro. Objetivo: O objetivo dos autores foi reunir os dados da literatura atual sobre a resistência insulínica cerebral (RIC) e sua provável repercussão em doenças neurodegenerativas, mais especificamente na DA, por meio de uma revisão sistemática da literatura. Métodos: Foi realizada uma pesquisa abrangente em vários bancos de dados médicos, incluindo o Cochrane Central Register of Controlled Trials, EMBASE, Medical Literature Analysis and Retrieval System Online (Medline) e PubMed, empregando os descritores: "resistência à insulina", "resistência insulínica cerebral", "doença de Alzheimer", "neurodegeneração" e "cognição". Os autores concentraram sua busca em estudos no idioma inglês publicados entre 2000 e 2023 que investigaram a influência da RIC em distúrbios neurodegenerativos ou ofereceram insights sobre os mecanismos subjacentes da RIC. Dezessete estudos que atenderam aos critérios de inclusão foram selecionados. Resultados: Os resultados demonstram que a RIC é um fenômeno observado em uma variedade de doenças neurodegenerativas, incluindo a DA. Estudos sugerem que a utilização e captação prejudicadas de glicose, a produção reduzida de trifosfato de adenosina (ATP) e as alterações na plasticidade sinápticas causadas pela RIC estão ligadas a problemas cognitivos. No entanto, foram observados resultados conflitantes com relação à associação entre DA e RIC, com alguns estudos sugerindo nenhuma associação. Conclusão: Com base nos estudos avaliados, pode-se concluir que a associação entre DA e RIC ainda é inconclusiva, e pesquisas adicionais são necessárias para elucidar essa relação.

Estimated average blood glucose level based on fructosamine level.

Objective: To define the mathematical relationship between fructosamine levels and average glucose values. Subjects and methods: The study comprised laboratory data of 1,227 patients with type 1 or 2 diabetes mellitus. Fructosamine levels measured at the end of a 3-week period were compared against the average blood glucose levels of the previous 3 weeks. Average glucose levels were determined by the weighted average of the daily fasting capillary glucose results performed during the study period, and the plasma glucose measured in the same sample collected for fructosamine measurement. Results: In total, 9,450 glucose measurements were performed. Linear regression analysis between fructosamine levels and average glucose levels showed that for each 1.0 µmol/L increase in fructosamine level there was a 0.5 mg/dL increase in average glucose level, as estimated by the equation Mean glucose level = (0.5157 × Fructosamine) - 20. The coefficient of determination (r2 = 0.353492, p < 0.006881) allowed the calculation of the estimated average glucose based on fructosamine level. Conclusion: Our study demonstrated a linear correlation between fructosamine level and mean blood glucose level, suggesting that fructosamine levels can be a proxy for the average glucose level in assessing the metabolic control of patients with diabetes.

Estimated average blood glucose level based on fructosamine level

ABSTRACT Objective: To define the mathematical relationship between fructosamine levels and average glucose values. Subjects and methods: The study comprised laboratory data of 1,227 patients with type 1 or 2 diabetes mellitus. Fructosamine levels measured at the end of a 3-week period were compared against the average blood glucose levels of the previous 3 weeks. Average glucose levels were determined by the weighted average of the daily fasting capillary glucose results performed during the study period, and the plasma glucose measured in the same sample collected for fructosamine measurement. Results: In total, 9,450 glucose measurements were performed. Linear regression analysis between fructosamine levels and average glucose levels showed that for each 1.0 µmol/L increase in fructosamine level there was a 0.5 mg/dL increase in average glucose level, as estimated by the equation Mean glucose level = (0.5157 x Fructosamine) - 20. The coefficient of determination (r2 = 0.353492, p < 0.006881) allowed the calculation of the estimated average glucose based on fructosamine level. Conclusion: Our study demonstrated a linear correlation between fructosamine level and mean blood glucose level, suggesting that fructosamine levels can be a proxy for the average glucose level in assessing the metabolic control of patients with diabetes.

Biogenic silver nanoparticles (AgNp-Bio) restore testosterone levels and increase TNF-α and IL-6 in Leydig cells infected with Toxoplasma gondii.

Toxoplasma gondii, a protozoan parasite, is responsible for toxoplasmosis. The available therapy for patients with toxoplasmosis involves a combination of pyrimethamine and sulfadiazine, which have several adverse effects, including bone marrow suppression, megaloblastic anemia, leukopenia, and granulocytopenia. The development of therapeutic alternatives is essential for the management of toxoplasmosis, emphasizing the recent advances in nanomedicine. This study aimed to evaluate the in vitro effects of biogenic silver nanoparticles (AgNp-Bio) on tachyzoite forms and Leydig cells infected with T. gondii. We observed that the AgNp-Bio reduced the viability of the tachyzoites and did not exhibit cytotoxicity against Leydig cells at low concentrations. Additionally, treatment with AgNp-Bio reduced the rate of infection and proliferation of the parasite, and lowered the testosterone levels in the infected cells. It increased the levels of IL-6 and TNF-α and reduced the levels of IL- 10. Among the morphological and ultrastructural changes, AgNp-Bio induced a reduction in the number of intracellular tachyzoites and caused changes in the tachyzoites with accumulation of autophagic vacuoles and a decrease in the number of tachyzoites inside the parasitophorous vacuoles. Collectively, our data demonstrate that the AgNp-Bio affect T. gondii tachyzoites by activating microbicidal and inflammatory mechanisms and could be a potential alternative treatment for toxoplasmosis.

Myocardial Insulin Resistance

Background: The low available of Glut-4 transporters in sarcolemma of the cardiac cells is what characterizes the myocardial insulin resistance (MIR), which is triggered separately of generalized insulin resistance. Insulin receptors are quite evident in the heart muscle and vessels, and mitochondrial activity performs a significant function in MIR preserving cellular homeostasis by cell reproduction, cells livelihoods, and energy generation. Objective: To evaluate the MIR mechanism and through the signaling pathway design. Methods: PubMed database was employed to search for reviews publications with MIR. The referenced data of the signaling pathway was chosen aggregating references of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. A signaling pathway was designed based on MIR research manuscripts, where we show several mechanisms included in the MIR. The KEGG server was employed to exploit the interrelationship protein-protein, and elaborate signaling pathway diagram. The signaling pathway mapping was carried out with PathVisio software. Results: We selected 42 articles from a total of 450 articles in the PubMed database that presented a significant association between the terms "insulin resistance myocardial" AND "signaling pathway". Founded on database-validated research papers, we choose well-founded pathways and we succeeded representative description of these pathways. The reproduction contigs taken from the KEGG database designed the signaling pathway of the bio-molecules that lead to MIR. Thus, the acting among multiple mechanisms releases factors that participate of the development of MIR. Conclusion: The interaction among various mechanisms and molecular interactions are important factors in development of MIR.

"Incidentalormones" - Macro-hormones

Introduction: Complexes of monomeric hormone molecules immunoglobulin-associated lead to the formation of macro-complexes biologically inactive that are called macro-hormones. Patients' presenting unexpectedly elevated hormones values indicates the need that the existence of macro-hormones must be researched. Objective: To describe the macro-hormones discovered incidentally in laboratory tests, which we refer to as "incidentalormones". Methods: An integrative review was conducted, and data was gathered from the published articles in medical database. The different forms of macro-hormones are reviewed; the biochemical significance and laboratory assays of macro-hormones are also revised within the ambit of current laboratory medicine. We discussed diagnostic difficulty encountered in patients with "incidentalormones", as well as methods of macro-hormone detection, immunoglobulin involved, clinical significance and associations with other diseases. Conclusion: The presence of macro-hormones, often guides us to intervention in laboratory trials, and could result in false-positive diagnosis with inadequate therapy. Laboratories should follow a diagnostic algorithm to carefully recognize and examine possible immunoassay interferences.

Potential targets for the hepatitis C virus-mediated autoimmune thyroiditis

Introduction: The mechanisms by which hepatitis C virus (HCV) infection induces autoimmune thyroiditis (AIT) have been studied, and it was suggested that inflammatory cytokines during HCV infection would change the thyroperoxidase (TPO) signaling cascade and thyroglobulin (Tg) determining autoimmune thyroid disease. Objective: To show the signaling pathway, of TPO and Tg, and their potential targets mediated HCV in individuals with hepatitis C. Methods: The mapping of the signaling pathway was based on a review study approach and performed using the automatic annotation server of the Kyoto and Genome Encyclopedia (KEGG). PathVisio is free software for analysis and design of open source routes, and was used for the graphic representation of the signaling pathway. Results: The contigs were extracted from the KEGG database and their mapped transcription represents the signaling pathway of the main biomolecules that triggers the AIT. The action of HCV or its treatment can trigger AIT that is characterized by the presence of autoantibodies against TPO and Tg. In AIT, autoreactive CD4 + T lymphocytes recruit B cells and CD8 + T cells in the thyroid. The progression of the disease leads to the death of thyroid cells and hypothyroidism. Conclusion: HCV or its treatment activates several signaling pathways with thyroid cells damage resulting in AIT and secondary hypothyroidism to cellular apoptosis.