Potential Protein Blood-based Biomarkers in Different Types of Dementia: A Therapeutic Overview.

Biomarkers capable of identifying and distinguishing types of dementia, such as Alzheimer's disease (AD), Parkinson's disease dementia (PDD), Lewy body dementia (LBD), and frontotemporal dementia (FTD), have become increasingly relentless. Studies on possible biomarker proteins in the blood that can help formulate new diagnostic proposals and therapeutic visions of different types of dementia are needed. However, due to several limitations of these biomarkers, especially in discerning dementia, their clinical applications are still undetermined. Thus, updating biomarker blood proteins that can help in the diagnosis and discrimination of these main dementia conditions is essential to enable new pharmacological and clinical management strategies with specificities for each type of dementia. This paper aimed to review the literature concerning protein bloodbased AD and non-AD biomarkers as new pharmacological targets and/or therapeutic strategies. Recent findings related to protein-based AD, PDD, LBD, and FTD biomarkers are focused on in this review. Protein biomarkers are classified according to the pathophysiology of the dementia types. The diagnosis and distinction of dementia through protein biomarkers is still a challenge. The lack of exclusive biomarkers for each type of dementia highlights the need for further studies in this field. Only after this, blood biomarkers may have a valid use in clinical practice as they are promising to help in the diagnosis and in the differentiation of diseases.

Associations between inflammatory markers and muscle strength in older adults according to the presence or absence of obesity.

BACKGROUND: We investigated the association between inflammatory markers and muscle strength in older adults according to the presence or absence of obesity. Dynapenia is the age-related decline in muscle strength and results in negative outcomes to older adults. Accordingly, obesity is more prevalent throughout aging and is associated with comorbidities, such as type 2 diabetes, dyslipidemia and cardiovascular diseases. Both dynapenia and obesity are strongly linked to chronic inflammation, sharing common signaling pathways. METHODS: We recruited 247 older adults aged 60 or older and collected sociodemographic, anthropometric and metabolic data. Dynapenia was diagnosed according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Circulating inflammatory cytokines were measured in plasma using a multiplex panel kit. Anthropometric, sociodemographic, lipid profile, and fasting blood glucose were also assessed. RESULTS: Dynapenic participants were predominantly males (74.4%), had insufficiently active lifestyle and higher IL-10 plasma levels (0.95 pg/mL; 0.40-2.12). The prevalence of obesity was higher among non-dynapenic participants (45.3%; 95% CI, 37.7-53). In dynapenic older adults, obesity was predominant in males (53.6%) and subjects with normal muscle strength had higher serum levels of TNF-ß (0.63 pg/mL; 0.30-1.30) and lower hand-grip strength (24 kg; 20.00-28.00). Using a multivariate quantile regression analysis, we found a strong and negative association between IL-10 and muscle strength. CONCLUSIONS: This study can help to understand the association of inflammation, obesity and muscle strength to promote interventions in order to avoid or delay the negative outcomes associated with dynapenia and sarcopenia in older adults.

Higher levels of tumor necrosis factor ß are associated with frailty in socially vulnerable community-dwelling older adults.

BACKGROUND: The complex physiology underpinning the frailty syndrome is responsible for the absence of robust biomarkers that can be used for screening, diagnostic and/or prognostic purposes and has made clinical implementation difficult. Considering socially vulnerable populations, who have poor health status and increased morbidity and mortality, this scenario is even more complex. However, to the best of our knowledge, there are no studies available to investigate frailty biomarkers in socially vulnerable populations. Thus, the aim of this cross-sectional study was to identify potential blood-based biomarkers of frailty in a socially vulnerable population. METHODS: A sample consisting of 347 community-dwelling older people living in a context of high social vulnerability was divided into non-frail (robust), pre-frail and frail groups, according to modified Fried frailty phenotype criteria. Blood samples were collected and analyzed for basic metabolic parameters and for inflammatory cytokines. RESULTS: Levels of Interleukin-1α (IL-1α) and Tumor Necrosis Factor α (TNF-α) were significantly higher in pre-frail subjects, compared to non-frail ones. Tumor Necrosis Factor ß (TNF-ß) levels presented higher values in the frail compared to non-frail individuals. Interleukin-6 (IL-6) levels in pre-frail and frail subjects were significantly higher compared to the levels of non-frail subjects. Using an ordinal regression analysis, we observed that socially vulnerable older people at higher risk of developing frailty were subjects above 80 years old (OR: 2.5; 95% CI: 1.1-5.6) and who presented higher levels of TNF-ß (≥0.81 pg/mL, OR: 2.53; 95% CI: 1.3-4.9). CONCLUSION: As vulnerable populations continue to age, it is imperative to have a greater understanding of the frailty condition, identifying novel potential blood-based biomarkers. The results presented here could help to implement preventive healthcare strategies by evaluating frailty and at the same time measuring a set of inflammatory biomarkers, paying special attention to TNF-ß plasmatic levels.