Zoriy I.A., Pashkovskaya N.V.

PECULIARITIES OF CARBOHYDRATE METABOLISM EXPERIENCINGBY PATIENTS DIABETES MELLITUS TYPE 2 COMPLICATED WITH DIABETIC POLYNEUROPATHY

Introduction. The number of people with diabetes worldwide continues to increase. Diabetes mellitus (DM) is one of the most important problems of clinical medicine, because of its wide distribution, clinical polymorphism, complications (Law D.W., 2012). One of the most spread and difficult in the treatment complication of diabetes is diabetic polyneuropathy (DP), that significantly reduces the quality of life, contributes to the neuropathic forms of diabetic foot syndrome development, Charcot arthropathy (Tesfaye S., 2010, Ndip A. et al., 2012 ).

The aim of the study: Study of peculiarities of carbohydrate metabolism experiencing by patients diabetes mellitus type 2 complicated with diabetic polyneuropathy.

Material and methods.

110 patients with DM type 2, complicated DP were examined (average age is 56,6±2,79 years) who were on treatment at the Chernivtsi Regional Endocrinology center and 20 almost healthy persons, included the control group. Patients distribution was carried out taking into account the level of DP: mild DP (31%) was diagnosed for 34 patients with, moderate (52,7 %) – for 58 patients and in severe patients with DP -18 (16,3%).

To establish DP severity all patients were neurologically examined according to the scale of Neuropathic Symptomatic Score (NSS), the Modified Neuropathic Dysfunctional Score (NDS), Total Symptoms Score (TSS) (Solomon T. et al., 2010).

The level of glycemia was studied by the glucose oxidase method using standard reagent kits produced by “Phyllis Diagnostics” company (Ukraine). Glycated hemoglobin (HbA1c) was determined by liquid chromatography of high pressure on the automatic analyzer of glycated hemoglobin D10 of the company “Bio-Rad Laboratories Inc.”(France), using the reagents by firm “Biomedinvest” (Ukraine). The level of immunoreactive insulin (IRI) and C-peptide was determined using the immunosorbent method on the analyzer STAT-Fax Plus-303 (USA), using the reagents of firm “DRG International Inc.” (the USA).

Statistical processing was performed using MS® Excel® 2003tm, Biostat®, Statistika® 6. Reliability of the received data was calculated by using Student t-criteria. Possible difference in the samples distribution was determined by χ2. P-value <0.05 was considered correct.

Results and discussion.

It is generally known that first of all the DP is the consequence of metabolic disorders in peripheral nerves, in particular, caused by hyperglycemia, the activation of the polyol way of glucose exchange accumulating osmotically active substances in the nerve cells; oxidative stress with activating, formation of free radical compounds, increasing nonenzymatic glycosylation of proteins nerves, nerve ischemia and many other factors (Won J.C. et al., 2012).

It should be noted that the initially DM type 2 for 13% of examined patients was displayed with features of neurological injury of peripheral nerves. We compared each stage of DP depending on the degree of metabolic control of diabetes. Determination of HbA1c was performed for all patients. It’s worth to underline that the adequate metabolic control (HbA1c <7%) was observed only for 4,8% of diabetic patients, the rest was in the process of sub-and decompensated disease.

The characteristics of carbohydrate metabolism in the studied groups are shown in Table 1. Comparing the control group and patients with DM type 2 complicated by DP depending on the levels of severity of changes in fasting glucose, HOMA index-IR, glycated hemoglobin (HbA1c), immunoreactive insulin and C-peptide were observed.

Table 1.

Indicators of Carbon Metabolism for Patients with Diabetes Mellitus Type 2 in Accordance with the Severity of Diabetic Polyneuropathy

Indicators	Controls n = 20	Mild DP n = 34	Moderate DP n = 58	Severe DP n = 18
Glucose, mmol/l	5,1±0,356	9,06±0,537*	11,72±0,431*/**	12,64±0,456*/**
Glycated hemoglobin (HbA1c),%	5,7±0,79	8,36±0,357*	9,31±0,342*	10,92±0,658*/**
НОМА-IR	1,31±0,183	5,10±0,776*	8,15±0,837*/**	8,49±1,710*/**
Immunoreactive insulin, lU/ml	12,92±1,078	19,10±1,829*	26,51±2,121*/**	28,14±1,239*/**
C-peptide, ng/ml	1,34±0,136	2,43±0,015*	2,78±0,634*	3,44±0,082*/**

Note: * - p <0.05 - significant difference compared with the control group, ** - p <0.05 - significant difference in comparison with mild DP.

The data of Table 1 show that all DP stages are characterized by statistically high rates of indicators of HbA1c, fasting glucose, the IRI and C-peptide comparison with control. These indicators are progradiently increasing due to severity of DP. Patients with mild DP had HbA1c level 32,1% higher than the control group, with moderate DP – 39,0% higher, and with severe DP – 46,2% higher (p <0,05). It also observed a significant growth of fasting and postprandial blood glucose for 43,2%, 56,4% and 59,5%, respectively.

According to the indicator index HOMA-IR, the examined patients had severe tissue insulin resistance (IR) that is connected with much higher levels of insulin and elevated acute glucose-stimulated insulin secretion in response to glycaemia. Increasing IRI fasting indicators were observed for patients with moderate (24,5%) and severe PD (32,4 %). These parameters were significantly higher compared with controls and patients with mild DP (p<0.05). The level of C-peptide is more stable indicator of insulin secretion than the rapidly changing insulin level. During our research, the highest level of C-peptide, that was beyond the limit of norm was observed for patients with severe DP (p<0.05).

Conclusion. Diabetic polyneuropathy of diabetes mellitus type 2 is associated with high rates of indicators glycated hemoglobin, fasting glucose, immunoreactive insulin and C-peptide. These violations are strengthening in proportion to the stages of diabetic polyneuropathy development.