Preliminary Comparison of Subcortical Structures in Elderly Subclinical Depression: Structural Analysis with 3T MRI

ADSC-derived exosomes provide neuroprotection in sepsis-associated encephalopathy by regulating hippocampal pyroptosis

AIMS

Adipose-derived stem cell (ADSC)-derived exosomes have been recognized for their neuroprotective effects in various neurological diseases. This study investigates the potential neuroprotective effects of ADSC-derived exosomes in sepsis-associated encephalopathy (SAE).

METHODS

Behavioral cognitive functions were evaluated using the open field test, Y-maze test, and novel object recognition test. Brain activity was assessed through functional magnetic resonance imaging (fMRI). Pyroptosis was measured using immunofluorescence staining and western blotting.

RESULTS

Our findings indicate that ADSC-derived exosomes mitigate cognitive impairment, improve survival rates, and prevent weight loss in SAE mice. Additionally, exosomes protect hippocampal function in SAE mice, as demonstrated by fMRI evaluations. Furthermore, SAE mice exhibit neuronal damage and infiltration of inflammatory cells in the hippocampus, conditions which are reversed by exosome treatment. Moreover, our study highlights the downstream regulatory role of the NLRP3/caspase-1/GSDMD signaling pathway as a crucial mechanism in alleviating hippocampal inflammation.

CONCLUSION

ADSC-derived exosomes confer neuroprotection in SAE models by mediating the NLRP3/caspase-1/GSDMD pathway, thereby ameliorating cognitive impairment.

Increased Resting-State Functional Connectivity of the Hippocampus in Rats With Sepsis-Associated Encephalopathy

Background

Sepsis-associated encephalopathy (SAE) has been identified as a frequent complication of sepsis, featured by an aberrant level of cognitive and affective functions. The present study is designed to explore the changes in functional connectivity (FC) of the hippocampus in rats with SAE utilizing resting-state functional magnetic resonance imaging (rs-fMRI).

Methods

Sprague-Dawley rats were randomly assigned to the SAE and control groups. We acquired rs-fMRI data using a 7T MRI to evaluate hippocampal network functional differences between the two groups with a seed-based approach. Behavioral performance was assessed using the open field test and forced swimming test. Statistical analysis was undertaken to evaluate the correlation between the hippocampal FC and behavioral findings.

Results

Compared with the control group, the SAE group showed increased FC between the bilateral hippocampus and thalamus, septum, bed nuclei stria terminalis (BNST), left primary forelimb somatosensory cortex (S1FL), primary motor cortex (M1), and inferior colliculus. Increased FC between the left hippocampus and thalamus, septum, BNST, left S1FL, and inferior colliculus was observed. While with the right hippocampus, FC in thalamus, septum, left S1FL and inferior colliculus was enhanced. Additionally, positive correlations were found between the hippocampal FC and the immobility time in the forced swimming test.

Conclusion

Hippocampus-related brain networks have significant alterations in rats with SAE, and the elevated hippocampal resting-state FC was positively related to affective deficits. Changes in FC between the hippocampus and other brain regions could be a potential neuroimaging biomarker of cognitive or mental disorders triggered by SAE.