Peripheral neuropathy

Altered glutathione system is associated with the presence of distal symmetric peripheral polyneuropathy in type 2 diabetic subjects

Distal symmetric peripheral polyneuropathy (DSPN) is a highly prevalent complication of diabetes. However, underlying pathophysiological mechanisms are multiple and not well understood. The aim of our study was to analyze the oxidative stress levels in circulating mononuclear cells by measuring the glutathione system, malondialdehyde and oxidized-LDL, in 60 type 2 diabetic patients from a well-characterized cohort of 196 type 2 diabetic patients. Using a nested case-control design, we studied 30 type 2 diabetic patients with distal symmetric polyneuropathy and 30 diabetic controls without this complication, according to the Neuropathy Disability Score. We have found that diabetic patients with distal symmetric polyneuropathy showed significantly lower values of reduced glutathione (GSH) and reduced glutathione/oxidized glutathione (GSH/GSSG) ratio. These data indicate an increased consumption of glutathione in mononuclear cells from patients with distal symmetric polyneuropathy. No significant differences were found in malondialdehyde or in oxidized-LDL levels comparing both groups. These data show an altered glutathione response in circulating monocytes from diabetic patients with distal symmetric polyneuropathy.

[Correlation between plasma concentrations of homocysteine and diabetic polyneuropathy evaluated with the Semmes-Weinstein monofilament test in patients with type 2 diabetes mellitus]

BACKGROUND AND OBJECTIVE

Few modifiable risk factors are known to be associated with the presence and progression of diabetic polyneuropathy (DPN).

MATERIAL AND METHOD

We have analyzed in 405 type 2 diabetic (T2DM) subjects (169 women) the association of plasma homocysteine with the presence of DPN measured with the Semmes-Weinstein (SW) monofilament test. A score below 4 was considered an altered SW monofilament test. Plasma homocysteine, vitamin B12 and folic acid were measured using standard procedures (ELISA).

RESULTS

Patients with T2DM with altered SW test have significantly higher age, evolution of disease, HbA1c and lower creatinine clearance values. In addition, plasma homocysteine values were independently and significantly higher in T2DM with DPN measured as altered SW test (13.64 ± 4.93 vs. 12.22 ± 4.48 μmol/l, P<.01) with similar vitamin B12 and folic acid values comparing the 2 groups.

CONCLUSION

Plasma homocysteine and HbA1c values are the 2 modifiable biological factors associated with the presence of DPN evaluated as an altered SW monofilament test in T2DM subjects.

Plasma homocysteine levels are independently associated with the severity of peripheral polyneuropathy in type 2 diabetic subjects

Peripheral polyneuropathy (PN) is a frequent complication of diabetes. However, mechanisms underlying the development of PN are multifactorial and not well understood. Our aim was to examine the association of plasma homocysteine (Hcy) with the prevalence and grade of peripheral PN in patients with type 2 diabetes (T2DM). We studied a cohort of 196 subjects with T2DM classified according to the grade of PN (Neuropathy Disability Score, NDS). Subjects with the highest grade of PN were older and had significantly increased levels of creatinine, microalbuminuria, HbA1c, and plasma Hcy compared to the other two groups. The differences in plasma Hcy values were maintained after correcting for confounding factors. Plasma Hcy, HbA1c, duration of diabetes, and age were predictors of the grade of PN. In conclusion, for each increase of 1 µmol in plasma Hcy there was a 23% increase of the risk of diabetic PN evaluated by NDS. Moreover, the grade of PN was predicted by plasma Hcy and HbA1c values, age and duration of diabetes. Further prospective studies should be conducted to confirm the association of plasma Hcy levels with the grade of PN in subjects with T2DM.

Painful peripheral neuropathies

BACKGROUND AND OBJECTIVES

Painful neuropathies are common and often difficult to treat. The objective of this report was to review the subject to facilitate diagnosis and pain relief.

CONTENTS

The classification, causes, type of fibers involved, manifestations, diagnosis, adjuvant tests, questionnaires used in the diagnosis, and treatment are described.

CONCLUSIONS

The subject is very broad and involves several causes and treatments that often should be combined to obtain adequate pain control.

Sensory perception thresholds in men with chronic pelvic pain syndrome

OBJECTIVES

To compare sensory thresholds in different nerve-fiber types in men with chronic pelvic pain syndrome (CPPS) and healthy controls, using thermal sensory testing and measuring current perception thresholds (CPT).

METHODS

We enrolled 22 men with CPPS and 20 healthy control participants. We determined the thermal sensory perception thresholds of C and Adelta nerve fibers on the perineum and left posterior thigh. To test CPT, we used sine wave electrical stimulation at 5, 250, and 2000 Hz, resulting in the selective depolarization of small unmyelinated C fibers, small myelinated Adelta, and large myelinated Abeta fibers, respectively. We bilaterally tested the hypothenar surface of the palms, medial parts of soles, midshaft of penis, and 1 site in the midperineum, for a total of 7 sites.

RESULTS

The mean age of men with CPPS was similar to that of controls [42.8 (standard deviation, 9.4) and 40.4 (standard deviation, 13.2) years, respectively, P = .548]. There was no significant difference between the 2 groups for thermal perception thresholds in both the perineum and left thigh (P >.05). There was also no difference between the 2 groups for CPT values of all 3 frequencies of stimuli in each area tested (P >.05 for all comparisons).

CONCLUSIONS

The absence of sensory threshold differences between men with CPPS and controls, with either thermal stimulation of C and Adelta fiber afferents or electrical stimulation of C, Adelta, and Abeta fiber afferents, discounts the existence of a peripheral neuropathy as a cause for pain in men with CPPS.