Omega-3 Polyunsaturated Fatty Acid Attenuates Uremia-Induced Brain Damage in Mice

Therapeutic potential of plant-derived natural compounds in Alzheimer's disease: Targeting microglia-mediated neuroinflammation

Microglia are resident immune cells of the central nervous system (CNS) with roles in sensing, housekeeping, and defense. Exploring the role of microglia in the occurrence and development of Alzheimer's disease (AD) and the possible therapeutic mechanism of plant-derived natural compounds (PDNCs) that regulate microglia-associated neuroinflammation may potentially help in elucidating the pathogenesis of AD and provide novel insights for its treatment. This review explores the role of abnormal microglial activation and its dominant neuroinflammatory response, as well as the activation of their target receptors and signaling pathways in AD pathogenesis. Additionally, we report an update on the potential pharmacological mechanisms of multiple PDNCs in modulating microglia-associated neuroinflammation in AD treatment. Dysregulated activation of microglial receptors and their downstream pathways impaired immune homeostasis in animal models of AD. Multiple signaling pathways, such as mitogen-activated protein kinase (MAPK), nuclear factor kappa light chain enhancer of activated B cells (NF-κB), and Toll-like receptors, play important roles in microglial activation and can exacerbate microglia-mediated neuroinflammation. PDNCs, such as magnolol, stigmasterol, matrine, naringenin, naringin, and resveratrol, can delay the progression of AD by inhibiting the proinflammatory receptors of microglia, activating its anti-inflammatory receptors, regulating the receptors related to β-amyloid (Aβ) clearance, reversing immune dysregulation, and maintaining the immune homeostasis of microglial downstream pathways. This review summarizes the mechanisms by which microglia cause chronic inflammation in AD and evaluates the beneficial effects of PDNCs on immune regulation in AD by regulating microglial receptors and their downstream pathways.

Association between Serum GDF-15 and Cognitive Dysfunction in Hemodialysis Patients

Cognitive dysfunction is more frequent in end-stage renal disease (ESRD) patients undergoing hemodialysis compared with the healthy population, emphasizing the need for early detection. Interest in serum markers that reflect cognitive function has recently increased. Elevated serum growth differentiation factor 15 (GDF-15) levels are known to be associated with an increased risk of decreased renal function and cognitive dysfunction. This study investigated the relationship between GDF-15 and cognitive dysfunction in hemodialysis patients using a retrospective analysis of 92 individuals aged ≥ 18 years. Cognitive function was assessed using the Korean version of the Mini-Mental Status Examination (K-MMSE), categorizing patients into normal (≥24 points) and cognitive dysfunction (<24 points). As a result, serum GDF-15 concentrations were at significantly higher levels in the cognitive dysfunction group (7500.42 pg/mL, p = 0.001). Logistic regression indicated an increased risk of K-MMSE scores < 24 points when serum GDF-15 exceeded 5408.33 pg/mL. After indoxyl sulfate exposure in HT22 cells, HT22 cells survival was decreased and GDF-15 expression in HT22 cells was increased. Similarly, exposure to indoxyl sulfate in mouse brain tissue resulted in an increased expression of GDF-15. This study highlights the potential of serum GDF-15 as a marker for cognitive dysfunction in hemodialysis patients, offering a valuable screening tool. Serum GDF-15 is related to cognitive dysfunction in hemodialysis patients and may be helpful in screening for cognitive dysfunction in hemodialysis patients.

ω-3 Polyunsaturated Fatty Acids Improve the Blood-Brain-Barrier Integrity in Contrast-Induced Blood-Brain-Barrier Injury in Uremic Mice

In patients with chronic kidney disease, the need for examinations using contrast media (CM) increases because of underlying diseases. Although contrast agents can affect brain cells, the blood-brain barrier (BBB) protects against brain-cell damage in vivo. However, uremia can disrupt the BBB, increasing the possibility of contrast-agent-induced brain-cell damage in patients with chronic kidney disease (CKD). ω-3 polyunsaturated fatty acids (PUFAs) have shown protective effects on various neurological disorders, including uremic brain injury. This study examined whether ω-3 PUFAs attenuate damage to the BBB caused by uremia and contrast agents in a uremic mouse model and evaluated its associated mechanisms. C57BL/6 mice (eight weeks old, male) and fat-1 mice (b6 background/eight weeks old, male) were divided into groups according to uremic induction, CM, and ω-3 PUFA administration. Uremia was induced via 24 h ischemia-reperfusion (IR) renal injury. One day after CM treatment, the brain tissue, kidney tissue, and blood were collected. The expression levels of glial fibrillary acidic protein (GFAP), claudin 5, CD31, laminin α4, and laminin α5 increased in ω-3 PUFA + CM-treated uremic mice and the brain of fat-1 + CM-treated uremic mice compared with those in the brains of CM-treated uremic mice. The pro-apoptotic protein expression decreased, whereas the anti-apoptotic proteins increased in ω-3 PUFA + CM-treated uremic mice and fat-1 + CM-treated uremic mice compared with CM-treated uremic mice. In addition, the brain-expression levels of p-JNK, p-P53, and p-P38 decreased in the ω-3 PUFA + CM-treated uremic mice and fat-1 + CM-treated uremic mice compared with those in wild-type uremic mice. Our results confirm that uremic toxin and CM damage the BBB and cause brain-cell death. ω-3 PUFAs play a role in BBB protection caused by CM in uremic mice.

Mfsd2a attenuated hypoxic-ischemic brain damage via protection of the blood-brain barrier in mfat-1 transgenic mice

Previous studies have shown that mfat-1 transgenic mice have protective effects against some central nervous system (CNS) disorders, owing to the high docosahexaenoic acid (DHA) content enriched in their brains. However, whether this protective effect is connected to the blood-brain barrier (BBB) remains unclear. This study aims to investigate the mechanisms of the protective effect against hypoxic-ischemic brain damage (HIBD) of mfat-1 transgenic mice. mfat-1 mice not only demonstrated a significant amelioration of neurological dysfunction and neuronal damage but also partly maintained the physiological permeability of the BBB after HIBD. We initially showed this was associated with elevated major facilitator superfamily domain-containing 2a (Mfsd2a) expression on the BBB, resulting from more lysophosphatidylcholine (LPC)-DHA entering the brain. Wild-type (WT) mice showed a similar Mfsd2a expression trend after long-term feeding with an LPC-DHA-rich diet. Knockdown of Mfsd2a by siRNA intra-cerebroventricular (ICV) injection neutralized the protective effect against HIBD-induced BBB disruption in mfat-1 mice, further validating the protective function of Mfsd2a on BBB. HIBD-induced BBB high permeability was attenuated by Mfsd2a, primarily through a transcellular pathway to decrease caveolae-like vesicle-mediated transcytosis. Taken together, these findings not only reveal that mfat-1 transgenic mice have higher expression of Mfsd2a on the BBB, which partly sustains BBB permeability via vesicular transcytosis to alleviate the severity of HIBD, but also suggest that dietary intake of LPC-DHA may upregulate Mfsd2a expression as a novel therapeutic strategy for BBB dysfunction and survival in HIBD patients.

Study on Nursing Effect of Psychological Intervention on Uremic Hemodialysis Patients

Aim

Patients in the hemodialysis stage are prone to psychological pressure of depression and anxiety and have resistance, which affects the clinical treatment effect. Effective psychological intervention plays a very important role in improving patients' psychological pressure and patients' compliance. The aim of this study is to explore the nursing effect of psychological intervention on uremic hemodialysis patients.

Methods

There were 126 uremic hemodialysis patients admitted to the hospital from August 2020 to December 2021. The patients were randomly divided into the routine nursing care group (n = 63) and psychological intervention group (n = 63). The routine nursing care group received routine nursing care for uremia hemodialysis patients. The psychological intervention group implemented psychological intervention on uremia hemodialysis patients. The methods of psychological intervention mainly include establishing a good nurse-patient relationship, popularizing hemodialysis knowledge, timely psychological counseling for patients, and organizing patient communication meetings. The treatment compliance, Self-rating Anxiety Scale (SAS) and Self-rating Depression Scale (SDS) of the two groups were compared before and after nursing. SF-36 scale was used to evaluate the quality of life of patients. The incidence of complications and nursing satisfaction were compared between the two groups.

Results

The treatment compliance rate and nursing satisfaction of hemodialysis uremic patients in the psychological intervention group were significantly higher than the routine nursing care group. The SAS and SDS of hemodialysis uremia patients in the psychological intervention group were significantly lower than the routine nursing care group after psychological intervention, and SF-36 scale was significantly higher than the routine nursing group. The main complications of uremic hemodialysis patients are hypotension, hyperkalemia, internal fistula occlusion, and infection. Compared with the routine nursing care group, the incidence of complications in the psychological intervention group was significantly reduced.

Conclusion

The implementation of psychological nursing intervention for uremic hemodialysis patients have a very significant effect on reducing the incidence of complications and improving anxiety, depression, treatment compliance, and the quality of life and the nursing satisfaction.