Inflammation has long been recognized as playing a critical role in the pathophysiology of various neurological disorders. Recent studies have identified a correlation between inflammation in the blood and altered levels of proteins in the cerebrospinal fluid (CSF), which surrounds the brain and spinal cord. Such findings suggest that there is a relationship between inflammatory markers in blood and CSF that could point toward possible causal factors in neurological disorders. This article presents a systematic review and meta-analysis of the association between inflammatory markers in blood and CSF, exploring the potential connection between inflammation and neurological conditions.
Recent research has focused on the relationship between inflammatory markers and neurodegenerative and psychiatric disorders. A systematic review and meta-analysis published in Frontiers in Neurology investigated the association between C-reactive protein (CRP), an inflammatory biomarker, and Parkinson’s disease (PD). The study analyzed data from 7 cohort studies involving a total of 25952 participants. The findings indicated that elevated levels of CRP were associated with an increased risk of developing PD.
Another systematic review and meta-analysis published in JAMA Neurology examined the levels of inflammatory cytokines in the blood of patients with PD. The study reviewed data from 51 studies involving a total of 2901 patients. The results suggested that peripheral levels of inflammatory cytokines were elevated in patients with PD compared to healthy controls.
Similarly, a meta-analysis published in the Journal of Neuropsychiatry and Clinical Neurosciences investigated the relationship between inflammatory markers and Alzheimer’s disease (AD) and mild cognitive impairment (MCI). The study analyzed data from 170 studies involving over 13000 participants. The results showed that inflammatory markers were significantly elevated in patients with AD and MCI compared to healthy controls.
In another meta-analysis published in Sci Rep, the authors examined the levels of inflammatory cytokines in patients with amyotrophic lateral sclerosis (ALS). The study reviewed data from 14 studies involving a total of 789 patients. The results indicated that peripheral levels of inflammatory cytokines were increased in patients with ALS compared to healthy controls.
In addition to neurodegenerative disorders, studies have also investigated the relationship between inflammatory markers and psychiatric disorders. For example, a meta-analysis published in Molecular Psychiatry analyzed data from 112 studies involving over 14000 patients with schizophrenia, bipolar disorder, or depression. The results suggested that peripheral levels of inflammatory cytokines were elevated in patients with all three disorders compared to healthy controls.
The relationship between inflammatory markers and psychosis risk was analyzed in another meta-analysis published in Psychoneuroendocrinology. The study reviewed data from 26 studies involving over 10000 participants. The results suggested that elevated levels of inflammatory markers were associated with an increased risk of psychosis.
Other studies have investigated the relationship between inflammatory markers and autism spectrum disorders (ASD). For example, a meta-analysis published in the Journal of Psychiatric Research examined the levels of pro-inflammatory cytokines in patients with ASD. The study analyzed data from 40 studies involving over 3000 participants. The results suggested that peripheral levels of pro-inflammatory cytokines were elevated in patients with ASD compared to healthy controls.
Overall, these studies suggest a link between peripheral levels of inflammatory markers and the development and progression of various neurological and psychiatric disorders. The blood-brain barrier (BBB) and the choroid plexus are important structures that play a crucial role in regulating the entry of inflammatory cells and cytokines into the central nervous system. Dysfunction of the BBB and the choroid plexus is thought to contribute to the infiltration of inflammatory cytokines into the brain, leading to neuroinflammation and neuronal damage. Further research is needed to better understand the intricate relationship between peripheral and central inflammation and the pathogenesis of these disorders.
In conclusion, the findings of this systematic review and meta-analysis provide evidence for the association between inflammatory markers in blood and cerebrospinal fluid. The results indicate that these markers play a key role in the pathogenesis of several neurological disorders. However, further research is required to establish the causal relationship between these markers and disease progression. The implications of this study could be significant for the development of diagnostic and therapeutic strategies for various neurological disorders. We hope that this study will encourage more research in this area and stimulate further investigation into the complex relationship between inflammation and neurological diseases.
