The silent occurrence of cerebral small vessel disease in nonelderly patients with type 2 diabetes mellitus

BACKGROUND

The prevalence of cerebral small vessel disease (SVD) increases in elderly patients with type 2 diabetes (T2DM), exacerbating cognitive decline. However, the prevalence and the severity of SVD in dementia-free nonelderly T2DM patients were largely unknown. Our primary aim is to investigate SVD in such patients, with a specific focus on the correlation between SVD and diabetic peripheral sensorimotor polyneuropathy (DSP).

METHODS

We recruited 180 young and middle-aged subjects without cognitive impairment (106 with T2DM, 74 controls). Signs of cerebral SVD on magnetic resonance image were investigated, and the overall SVD burden was evaluated by a combined score. Patients with T2DM underwent further detailed DSP assessment. Regression models were used to investigate the association of SVD with the presence of T2DM, and the associations of the prevalence and severity of SVD and DSP were also explored in patients with T2DM.

RESULTS

The prevalence of microbleeds and overall burden of SVD were significantly higher in T2DM patients than in the controls. Further, the presence of DSP related to an increased risk of SVD after adjustment in diabetic group. Moreover, Toronto Clinical Scoring System values were positively associated with the increased SVD scores, and bilateral sural sensory nerve conduction velocities were negatively associated with increasingly severity of SVD scores.

CONCLUSION

The current findings extended the increasing prevalence of SVD to dementia-free nonelderly patients with T2DM, suggesting that the time for cognitive screening and prevention might be moved forward in T2DM patients, especially for those with DSP.

Decreased Microstructural Integrity of the Central Somatosensory Tracts in Diabetic Peripheral Neuropathy

CONTEXT

Although diabetic peripheral neuropathy (DPN) is predominantly considered a disorder of the peripheral nerves, some evidence for central nervous system involvement has recently emerged. However, whether or to what extent the microstructure of central somatosensory tracts may be injured remains unknown.

OBJECTIVE

This work aimed to detect the microstructure of central somatosensory tracts in type 2 diabetic patients and to correlate it with the severity of DPN.

METHODS

A case-control study at a tertiary referral hospital took place with 57 individuals with type 2 diabetes (25 with DPN, 32 without DPN) and 33 nondiabetic controls. The fractional anisotropy (FA) values of 2 major somatosensory tracts (the spinothalamic tract and its thalamocortical [spino-thalamo-cortical, STC] pathway, the medial lemniscus and its thalamocortical [medial lemnisco-thalamo-cortical, MLTC] pathway) were assessed based on diffusion tensor tractography. Regression models were further applied to detect the association of FA values with the severity of DPN in diabetic patients.

RESULTS

The mean FA values of left STC and left MLTC pathways were significantly lower in patients with DPN than those without DPN and controls. Moreover, FA values of left STC and left MLTC pathways were significantly associated with the severity of DPN (expressed as Toronto Clinical Scoring System values) in patients after adjusting for multiple confounders.

CONCLUSION

Our findings demonstrated the axonal degeneration of central somatosensory tracts in type 2 diabetic patients with DPN. The parallel disease progression of the intracranial and extracranial somatosensory system merits further attention to the central nerves in diabetic patients with DPN.