Correlation of acetylator phenotype with peripheral, autonomic and central neuropathy in Northern Indian non-insulin-dependent diabetes mellitus patients

Proton magnetic resonance spectroscopy and single photon emission computed tomography study of the brain in asymptomatic young hyperlipidaemic Asian Indians in North India show early abnormalities

OBJECTIVE

To evaluate brain metabolism and cerebral blood flow in young patients with hyperlipidaemia.

PATIENTS AND METHODS

Proton magnetic resonance spectroscopy ((1)H MRS) and single photon emission computed tomography (SPECT) of the brain was carried out in 19 asymptomatic young patients with hyperlipidaemia (mean age 32.6 +/- 6.0 years, range 22-45 years) and 21 age-matched healthy controls divided into the following three groups; (i) hyperlipidaemics on pharmacological treatment (group 1, n = 13), (ii) hyperlipidaemics not on pharmacological treatment (group 2, n = 6) and (iii) control group of healthy subjects (group 3, n = 21).

RESULTS

No statistical difference was observed in the brain metabolite ratios between controls and hyperlipidaemic patients (both treatment naive and treated) in the (1)H NMR study. Two hyperlipidaemic patients showed a lactate peak and one had a lipid peak. The SPECT study was abnormal in seven hyperlipidaemic patients. In the pooled data, 50% subjects with high serum triglyceride (TG) levels as opposed to 14% subjects with normal serum TG levels showed cerebral hypoperfusion. The choline/creatine (Cho/Cr) ratio of the occipital region of the brain showed correlation with the excess percentage of body fat (%BF) and low levels of high density lipoprotein cholesterol (HDL-C) compared to those with normal %BF and normal HDL-C levels, respectively, in pooled data of all subjects. The N-acetyl aspartate (NAA)/Cho ratio also showed correlation with hypercholesterolaemia. Serum TG levels were positively correlated with the NAA/Cr ratio (r = 0.62, P < 0.05) and the Cho/Cr ratio (r = 0.63, P < 0.05) in the parieto-temporal area in group 1 patients.

CONCLUSION

The study revealed no difference in the brain metabolite ratios between controls and hyperlipidaemic patients, while some hyperlipidaemic patients showed abnormalities of cerebral blood flow. Brain metabolite ratios were also influenced by certain parameters of body composition and lipids. As abnormal body composition, hypertriglyceridaemia and low levels of HDL-C are prevalent in Asian Indians, such data are important and indicate a need for further study.

Peripheral Neuropathy

This chapter focuses on peripheral neuropathy, which is the third or fourth most common neurologic disorder, even among the elderly. It begins with a description of the classification system for peripheral neuropathies. Because the underlying etiology or precipitating events of peripheral neuropathy are identifiable for the majority of affected individuals, epidemiologic research has largely focused on descriptive studies of disease frequency or on identifying the factors that modify the influence of the already existing risk factors. Three of the most common neuropathies are covered in detail: diabetic neuropathy, carpal tunnel syndrome, and Guillain–Barré syndrome. Each of these conditions is discussed in terms of distribution and risk factors, and is concluded with a discussion of future research directions to address unanswered questions. The chapter emphasizes methodologic approaches that that could be employed to improve the rigor of studies of these conditions.