HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Coste, T. C. Articles by Raccah, D. Search for Related Content PubMed PubMed Citation Articles by Coste, T. C. Articles by Raccah, D. Social Bookmarking                What's this?

Neuroprotective Effect of Docosahexaenoic Acid-Enriched Phospholipids in Experimental Diabetic Neuropathy

¹ UPRES EA 2193, Faculte de Medecine Timone, Marseille, France
² INSERM U476, Faculte de Medecine Timone, Marseille, France

	ABSTRACT

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS DISCUSSION REFERENCES

 
A deficiency in essential fatty acid metabolism has been widely reported in both human and animal diabetes. Fish oil supplementations (n-3 fatty acids), containing docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), were less effective on diabetic neuropathy than (n-6) fatty acids. This partial effect of (n-3) fatty acids might be attributed to the presence of EPA, a competitor of arachidonic acid, which enhanced the diabetes-induced decrease of this fatty acid in serum and tissues. For determining whether a supplementation with DHA alone could prevent neuropathy in streptozotocin-induced diabetes, diabetic rats were given daily, by gavage, liposomes containing DHA phospholipids, at a dose of 60 mg/kg. Eight weeks of diabetes induced significant decreases in nerve conduction velocity (NCV), nerve blood flow (NBF), and sciatic nerve and erythrocyte (red blood cells [RBCs]) Na,K-ATPase activities. DHA phospholipids totally prevented the decrease in NCV and NBF observed during diabetes when compared with the nonsupplemented diabetic group. DHA phospholipids also prevented the Na,K-ATPase activity decrease in RBC but not in sciatic nerve. Moreover, DHA level in sciatic nerve membranes was correlated with NCV. These results demonstrate a protective effect of daily doses of DHA on experimental diabetic neuropathy. Thus, treatment with DHA phospholipids could be suitable for evaluation in clinical trials.

It was demonstrated recently that dietary supplementation with GLA (8,9) and with fish oil, containing EPA and DHA (9,10), prevented completely for GLA and partially for fish oil the diabetes-induced decrease in nerve conduction velocity (NCV), a physiological marker of diabetic neuropathy. These results could be explained in part by a normalization of eicosanoid synthesis, which is depressed in diabetic nerve, and/or by a direct effect on incorporation of these fatty acids into the plasma membranes (1,8,11). By changing membrane properties, PUFA can modify the activity of transmembrane enzymes, such as the Na,K-ATPase, which is implicated in the propagation of nerve impulses. We previously reported that diets deficient in -linolenic acid or, in contrast, rich in EPA and DHA modulate the functional properties of Na,K-ATPase isoenzymes (12,13). In diabetic neuropathy, Na,K-ATPase activity is dramatically decreased in rat and human sciatic nerve and erythrocytes (14–16).

Nevertheless, we previously found that the preventive effect of fish oil on NCV and Na,K-ATPase activity is only partial in diabetic rats (10,17). Moreover, fish oil treatment has been demonstrated to have some deleterious effects in retinopathy (18). This could be due to a counteracting effect of EPA, which enhances the decrease in AA levels in plasma and tissue phospholipids, by competition for desaturase enzyme, as a result of a structural homology.

In the present study, we investigated the effects of DHA supplementation using liposomes containing DHA phospholipids on neurophysiological, i.e., NCV and nerve blood flow (NBF), and biological parameters, i.e., Na,K-ATPase activity and erythrocyte/sciatic nerve membrane fatty acid compositions. Our results present evidence for a marked neuroprotective effect of DHA on diabetic neuropathy.

	RESEARCH DESIGN AND METHODS

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS DISCUSSION REFERENCES

 
Animals.
The study was done according to the guidelines of the French Department of Agriculture, Fishing and Diet on the experimental use of laboratory rats with agreement number A 13823. The principles of laboratory animal care (National Institutes of Health) were followed. Male Sprague-Dawley rats (n = 40; Iffa Credo, Saint Germain de l’Arbresle, France) were entered in the study after acclimatization for 1 week. Their body weight at the beginning of the study averaged 232 ± 12 g, and they were randomly assigned to four weight-matched groups (n = 10). For the two diabetic groups, diabetes was induced by a single intravenous injection of streptozotocin (STZ; 65 mg/kg; Sigma, St. Louis, MO), freshly dissolved in citrate sodium buffer (0.01 mol/l, pH 5.5). Control rats received an injection of buffer only. All diabetic rats were maintained without insulin. Diabetes was checked 3 days after the STZ induction and on the last day of the study by the presence of hyperglycemia (>25 mmol/l) in blood samples collected from the tip of the tail (Reflolux; Boehringer Mannheim, Mannheim, Germany). Animals were given a standard nonpurified rodent diet (A04; UAR, Epinay sur Orge, France) and water ad libitum. Gavage was started on the day of STZ or buffer administration. Two groups were given no supplementation, i.e., the control (C) and diabetic (D) groups. The control (CDHA) and diabetic (DDHA) groups were given DHA phospholipids at a daily dose of 0.8 g · kg^-1 · day^-1 corresponding to 60 mg/kg DHA per day. DHA supplementation was administered daily at 0900. No difference in food intake was observed between the supplemented groups. After 8 weeks of supplementation, rats were killed by intraperitoneal anesthesia using pentobarbital (50–100 mg/kg).

Preparation and composition of the supplementation.
The supplementation consisted of an egg-phospholipid preparation enriched in DHA. Egg phospholipids were extracted with alcohol. After evaporation of the alcoholic phase using a rotative evaporator, the phospholipids were hydrated at 60% with distilled water. Note that phospholipids, in particular DHA phospholipids, are reported to be more stable than triglycerides toward peroxidation (19). The phospholipid preparation was prepared freshly every week, maintained under nitrogen in the dark and at 4°C, and regularly analyzed to monitor lipid peroxidation. The fatty acid composition of the standard diet and supplementation are given in Table 1. After these analyses, we were able to determine the daily intake of the principal fatty acids concerned with this study.

NBF measurement.
After NCV was recorded, NBF was assessed according to Yasuda et al. (21) using a laser Doppler flowmeter (Periflux, model 4001 master; Perimed, Stockholm, Sweden) as previously described (11). Briefly, the left sciatic nerve was exposed without bleeding, and the probe was lowered at a right angle to the surface of the perineurium at 1 cm below the sciatic notch. NBF was then recorded continuously for at least 10 min, and the values were averaged to one value.

Tissue preparations.
After physiological measurements, blood was collected by cardiac puncture into 0.11 mol/l sodium citrate tubes. Sciatic nerves from the spine to the peroneal bifurcation were dissected and frozen in liquid nitrogen after removal of adherent tissue. Samples were preserved at -80°C until use.

Erythrocyte and plasma.
Plasma was separated by centrifugation at 1,500g for 15 min. Leukocytes and platelets were removed from the blood samples by filtration through a microcrystalline cellulose column (22). Erythrocytes were hemolyzed in 11 mmol/l Tris buffer and centrifuged (30,000g for 30 min at 4°C), and the membrane pellet obtained was resuspended in 30 ml of buffer. The centrifugation step was repeated three times, as previously described (23). The washed erythrocyte membranes were then stored for Na,K-ATPase activity measurement and fatty acid composition determination.

Sciatic nerve.
On the day of the homogenate preparation, sciatic nerve segments were measured, weighed, and rinsed in ice-cold saline solution. Sciatic nerves were chopped into small pieces and then homogenized at 4°C in 2 ml of ice-cold saline (11 mmol/l Tris buffer, pH 7.4) with a motorized Potter homogenizer (model 94348; Heildoph, Keilheim, Germany) using three 15-s bursts. The resulting homogenate was passed through a cellulose filter (600F4252; Fioroni, La Chapelle St. Mesmin, France) to remove impurities and was aliquoted for Na,K-ATPase activity measurement and fatty acid composition determination.

Na,K-ATPase activity measurement.
Na,K-ATPase activity was measured on purified plasma membranes from erythrocytes or sciatic nerves as previously described (23). Briefly, the release of inorganic phosphate (P_i) from ATP was measured using spectrophotometry with or without 1 mmol/l ouabain (Sigma), a specific Na,K-ATPase inhibitor. After incubation with 4 mmol/l Vanadate-free ATP (Sigma) at 37°C for 10 min, the reaction was stopped by addition of ice-cold trichloroacetic acid at a final concentration of 5%. After centrifugation (5,500g, 10 min) at 4°C, the amount of P_i in the supernatant was determined according to the method of Hurst (24). Na,K-ATPase activity was calculated as the difference between P_i released per milligram of protein per hour in the presence and absence of ouabain. Membrane protein concentration was determined using a protein assay (Bio-Rad Laboratories, Munich, Germany). All assays were performed in triplicate, and blanks were included to determine the endogenous phosphate and non-enzyme-related breakdown of ATP.

Membrane fatty acid phospholipid composition.
Total plasma, erythrocyte membranes, and sciatic nerve homogenate lipids were extracted with methanol and chloroform according to the method of Bligh and Dyer (25), modified by the use of a sonicator. Fatty acid composition was determined after methylation with BF3-methanol (Sigma) according to Ohta et al. (26). The fatty acid methyl esters were analyzed by gas chromatography on a Perkin Elmer Autosystem XL (Perkin Elmer, Courtaboeuf, France) using a fused silica capillary column BPX 70 (60 m x 0.22 mm inner diameter; SGE, Villeneuve St. Georges, France) equipped with a flame ionization detector and using hydrogen as the carrier gas. The temperature program ranged from 160 to 205°C with a rise of 1°C/min. Peak areas from the resulting chromatogram were measured with a Perkin Elmer 1022S integrator. Fatty acids were identified by their retention times on the column with respect to appropriate standards.

Statistical analysis.
Results are expressed as means ± SEM. A Kolmogorov-Smirnov test for normality and a Bartlett test for homogeneous variance were performed for each group. All of the data were analyzed using a nonparametric Kruskal-Wallis test, and differences between groups were tested using the Mann-Whitney U test. P < 0.05 was considered significant. All analyses were done using the STATVIEW software (Abacus Concepts, Berkeley, CA) on a Macintosh iMac (Apple Computer, Les Ulis, France).

	RESULTS

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS DISCUSSION REFERENCES

 
DHA does not correct abnormal diabetes-induced metabolic characteristics.
Plasma glucose levels in both diabetic groups were increased 500% relative to all nondiabetic control groups (36 ± 1.8 vs. 8.5 ± 0.3 mmol/l; P < 0.0001). Body weight gain was decreased in diabetic groups as compared with control groups (252 ± 10 vs. 444 ± 5 g; P < 0.0001). Lipid supplementation had no effect on these parameters with the exception of DHA, which increased body weight by 7% in DHA-supplemented control animals compared with nonsupplemented ones (464 ± 9 vs. 434 ± 5; P = 0.01).

The observed decrease in sciatic NCV in diabetic rats is totally prevented by DHA supplementation.
Eight weeks of diabetes induced a 30% decrease in sciatic NCV (P < 0.0001; Fig. 1). This deficit was completely prevented by supplementation with 60 mg/kg DHA (P < 0.0002). Moreover, DHA supplementation slightly increased the NCV in control rats (6%; P < 0.006).

View larger version (15K): [in this window] [in a new window]   FIG. 1. NCV was recorded from control (C) and diabetic (D) rats supplemented or not with DHA liposomes (60 mg · kg-1 · d-1). Results, expressed in m/s, are means ± SEM (n = 10). Bars not bearing at least one same superscript letter are significantly different.

View larger version (14K): [in this window] [in a new window]   FIG. 2. NBF was recorded from control (C) and diabetic (D) rats supplemented or not with DHA liposomes (60 mg · kg-1 · day-1). Results, expressed in arbitrary units, are means ± SEM (n = 10). Bars not bearing at least one same superscript letter are significantly different.

The alteration in sciatic nerve Na,K-ATPase activity in diabetic rats is not prevented with DHA supplementation.
Na,K-ATPase activity was decreased in sciatic nerve homogenates from diabetic rats (-25%; P < 0.0001; Fig. 3). DHA supplementation was unable to prevent the diabetes-induced decrease in Na,K-ATPase activity in the diabetic group (P < 0.01). Moreover, DHA supplementation decreased the basal level of Na,K-ATPase activity in control and diabetic groups when compared with the control and diabetic group without supplementation. Nevertheless, these decreases did not affect NCV.

View larger version (15K): [in this window] [in a new window]   FIG. 3. Sciatic Nerve (SN) Na,K-ATPase activity was recorded from control (C) and diabetic (D) rats supplemented or not with DHA liposomes (60 mg · kg-1 · day-1). Results, expressed in nmol Pi · mg protein-1 · h-1, are mean ± SEM (n = 10). Bars not bearing at least one same superscript letter are significantly different.

View larger version (14K): [in this window] [in a new window]   FIG. 4. RBC Na,K-ATPase activity was recorded from control (C) and diabetic (D) rats supplemented or not with DHA liposomes (60 mg · kg-1 · day-1). Results, expressed in nmol Pi · mg protein-1 · h-1, are means ± SEM (n = 10). Bars not bearing at least one same superscript letter are significantly different.

Diabetes and DHA supplementation modify RBC membrane fatty acid composition.
As described for plasma fatty acids, diabetes induced an increase in LA level (P = 0.006) and a decrease in MUFA level (P = 0.002) in erythrocyte membranes. Although AA levels tended to decrease after induction of diabetes, it did not reach significance (Table 2). DHA supplementation decreased the RBC membrane SFA level in both diabetic and control groups. Moreover, a significant increase in PUFA level, resulting from increases in LA and AA levels, was observed (Table 2).

Changes in sciatic nerve membrane fatty acid composition are only minor.
Eight weeks of diabetes was not long enough to observe substantial changes in the fatty acid composition of sciatic nerve membranes. DHA supplementation slightly influenced the sciatic nerve membrane fatty acid composition with a decrease in PUFA level and an increase in DHA level in both control and diabetic groups (Table 3).

	DISCUSSION

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS DISCUSSION REFERENCES

 
The present study demonstrates a neuroprotective effect of egg phospholipids enriched with DHA in rat diabetic neuropathy. We showed a beneficial effect of DHA on two neurophysiological indexes of diabetic neuropathy, NCV and NBF.

In experimental diabetic neuropathy, dramatic decreases in NCV and NBF have been widely reported (3,8,27,28). For explaining these defects in nerve physiology, numerous hypotheses have been proposed as reviewed by Cameron and Cotter (1). Among these, the importance of a decrease in Na,K-ATPase activity has been actively debated (1,3,27). Indeed, it has been shown that the sciatic nerve and RBC Na,K-ATPase activities are decreased in diabetes, in both human and animal studies (8,14–16). Das et al. (29) first described this decrease in sciatic nerve from diabetic rat, and this hypothesis was then incorporated by Greene et al. (30) in their physiopathological scheme of the polyol pathway. A decrease in sciatic nerve Na,K-ATPase activity could alter the normal membrane axon repolarization after the depolarization induced by an action potential, and one therefore could expect a decrease in NCV. Moreover, a similar decrease in RBC Na,K-ATPase activity could alter the NBF by increasing erythrocyte volume, which in turn reduces their deformability (31).

Wright and Nukada (28) found significant reductions in NCV after 16 weeks of diabetes, with trends apparent after 4 weeks. Because diabetes was induced in mature rats in this study, there was a delay before the NCV decrease became significant. Indeed, when diabetes is induced in growing rats, a significant decrease in NCV is observed as early as 2 weeks (32). Here, we found a similar impairment in the NCV in the diabetic group after 8 weeks of disease, in agreement with our previous studies (8,10,11). Although only partial, fish oil supplementation has shown a beneficial effect on NCV (9,10). In contrast to the fish oil supplementation, DHA supplementation was able to totally prevent the diabetes-induced decrease in NCV. Lastly, DHA (60 mg · kg^-1 · day^-1) significantly induced a slight increase in NCV in nondiabetic control rats. These findings could be explained in part by the positive correlation between DHA level in sciatic nerve membranes and NCV. This correlation remained when the results from additional groups, i.e., soybean and DHA 30 mg · kg^-1 · day^-1 groups, were included (data not shown).

Disturbances in Na,K-ATPase activity in the sciatic nerve have been proposed to be partially but not fully responsible for the slowing of NCV in the diabetic rat (1,3) because, in some studies, the slowing of motor NCV seems to precede the decrease in enzyme activity (28,32). In our studies, we always observe a partial restoration of Na,K-ATPase activity associated with either partial (10) or total (8) restoration of conduction velocity in sciatic nerve of diabetic rats. In addition, Coppey et al. (32) showed that the temporal decrease between these two parameters was similar, although the decrease in motor NCV became significant more rapidly (14 days) than the decrease in Na,K-ATPase activity (28 days). All of these observations argue for a partial rather than a primordial implication of a decrease in Na,K-ATPase as the cause of the diabetes-induced decrease in NCV. Some authors hypothesized that the early defect in NBF could be responsible for the decrease in NCV (1,32) and that a treatment reversion of nerve ischemia, i.e., an increase in NBF, could gradually improve NCV by an action on nerve microvessels (33). However, we have observed that the decrease in NCV can be partially prevented by a half-dose of DHA phospholipids (30 mg · kg^-1 · day^-1) or soybean phospholipid supplementations without correcting the NBF in diabetic rats (data not shown). So, like Na,K-ATPase activity, NBF seems to be only partially implicated in diabetes-induced changes in NCV. It therefore seems likely that several parameters contribute to the diabetes-induced changes in NCV.

The role of NBF and the presence of peripheral nerve ischemia in triggering early diabetic neuropathy are controversial (1,34). Some groups have postulated that early reductions in NBF account for pathogenesis of diabetic neuropathy (35,36), and a 50% reduction in NBF as early as 3 days after the induction of diabetes has been reported (32). Others, in contrast, have not identified early ischemia in animal (37) or human (38) studies. These discrepancies may be explained, in part, by the different methods used as well as by the duration and severity of diabetes in animals and humans (1). Cameron and Cotter (1) proposed that during the course of diabetes, there is first a hyperperfusion, which results in an increase in blood flow, followed by a hypoperfusion as vessel disease progresses; the hyperperfusion period could be dramatically shortened by the severity of hyperglycemia. With the laser Doppler flowmetry method used in the present study, we showed a decrease in NBF in rats after 8 weeks of experimental diabetes. Importantly, we showed that DHA supplementation (60 mg · kg^-1 · day^-1) fully prevented the decrease in NBF in diabetic animals. Alterations in membrane fluidity have been implicated in the regulation of Na,K-ATPase activity, and a positive correlation between DHA incorporation into RBC membranes and membrane deformability has been reported (39,40). Nevertheless, our results demonstrated that an increase in Na,K-ATPase activity did not correlate with increased NBF. Furthermore, we found no relationship between the RBC level of DHA and NBF. It is possible that the DHA effect reflects a direct role of this fatty acid rather than one mediated via alteration in membrane properties and/or Na,K-ATPase activity. Supplementation with DHA could be expected to lead to step retroconversion of DHA to EPA. This retroconversion could reverse the diabetes-induced vasoconstriction by enhancing the production of vasoactive eicosanoids from series 1 and 3 and inducing a diminution of eicosanoids from series 2 (9). These altered eicosanoid profiles may therefore affect the vascular endothelium-dependent relaxation and thus improve NBF (41).

Previous studies demonstrated dramatic changes in PUFA composition of diabetic tissues and also in phosphatidylinositol turnover in sciatic nerve (42,43). In this study, only minor changes in fatty acid levels occurred in the sciatic nerve of diabetic rats. We did not find the slight but significant decrease in AA level as previously described by Gerbi et al. (44). However, we have examined the fatty acid composition of sciatic nerve homogenates as compared with purified sciatic nerve membranes, and this particularity could explain the observed differences. Moreover, DHA supplementation induced an increase of its incorporation into the sciatic nerve membranes and could explain in part the observed decrease in basal level of sciatic nerve Na,K-ATPase activity. In contrast, DHA supplementation induced a twofold increase in RBC Na,K-ATPase activity in the diabetic group and totally prevented the diabetes-induced decrease. Further studies will be required to link this finding to increased Na,K-ATPase subunit membrane expression or in Na,K-ATPase phosphorylation mediated by protein kinase C isoform. The effect of DHA supplementation on RBC Na,K-ATPase activity and NCV and the positive correlation between these two parameters are interesting for human studies. Indeed, RBCs are readily accessible in humans and could represent a reliable surrogate for the assessment of DHA supplementation-induced effects on nerve function in clinical studies (15).

But how can we explain the effectiveness of DHA in the prevention of experimental diabetic neuropathy? Although, at present, the mechanism is not known, the following scenario may apply: Diabetes is known to induce histological damage to the sciatic nerve fibers, including endoneural edema and axonal degeneration, with occasional secondary segmental demyelination (45). Plasmalogens are lipids that are important components of myelin (46). It is interesting that peroxisomes are involved in the breakdown of long-chain PUFAs, by the process called ß-oxidation, and particularly in the last step of DHA synthesis, i.e., from C24:6 (n-3) to C22:6 (n-3) (47), and that they are also required for the synthesis of plasmalogens. Indeed, it has been suggested that peroxisomal synthesis of plasmalogens plays an important role in the prevention of demyelination (48), and DHA is preferentially incorporated in sn-2 position in ethanolamine plasmalogens, relative to other PUFAs. Moreover, peroxisome proliferation is regulated by the peroxisome proliferator-activated receptors (PPARs), which in turn are regulated by polyunsaturated C20 and C22 fatty acids, including DHA (49). Thus, one could expect that nutritional supplementation with DHA leads to an upregulation of PPARs, causing proliferation of the peroxisomes and therefore a rise in synthesis of ethanolamine plasmalogens containing DHA. This would therefore result in the prevention of segmental demyelination in sciatic nerve induced by diabetes (Fig. 5). This hypothesis could also explain the prevention of segmental demyelination observed in diabetic rats supplemented with fish oil (10).

View larger version (19K): [in this window] [in a new window]   FIG. 5. DHA may prevent the development of diabetic neuropathy.

	ACKNOWLEDGMENTS

 
Critical review of the manuscript by Drs. Judith Storch and Marie-Josee Duran is gratefully acknowledged. This work is dedicated to the memory of David F. Horrobin for indefectible support.

Address correspondence and reprint requests to Dr. Thierry Coste, UPRES EA 2193, Faculte de Medecine Timone, 27, Boulevard Jean Moulin, 13385 Marseille Cedex 05, France. E-mail: Thierry.Coste{at}medecine.univ-mrs.fr

Received for publication February 27, 2003 and accepted in revised form July 7, 2003

Abbreviations: AA, arachidonic acid; DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; GLA, -linolenic acid; LA, linoleic acid; MUFA, monounsaturated fatty acid; NBF, nerve blood flow; NCV, nerve conduction velocity; P_i, inorganic phosphate; PPAR, peroxisome proliferator-activated receptor; PUFA, polyunsaturated fatty acid; RBC, red blood cell; SFA, saturated fatty acid; STZ, streptozotocin

	REFERENCES

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS DISCUSSION REFERENCES

 

1. Cameron NE, Cotter MA: Metabolic and vascular factors in the pathogenesis of diabetic neuropathy. Diabetes46 (Suppl. 2) :S31 –S37,1997
2. Stevens MJ, Feldman EL, Greene DA: The aetiology of diabetic neuropathy: the combined roles of metabolic and vascular defects. Diabet Med12 :566 –579,1995[Medline]
3. Sima AAF, Sugimoto K: Experimental diabetic neuropathy: an update. Diabetologia42 :773 –788,1999[Medline]
4. Horrobin DF: The roles of essential fatty acids in the development of diabetic neuropathy and other complications of diabetes mellitus. Prostaglandins Leukot Essent Fatty Acids31 :181 –197,1988[Medline]
5. Ruiz-Gutierrez V, Stiefel P, Villar J, Garcia-Donas MA, Acosta D, Carneado J: Cell membrane fatty acid composition in type 1 (insulin-dependent) diabetic patients: relationship with sodium transport abnormalities and metabolic control. Diabetologia36 :850 –856,1993[Medline]
6. Huang YS, Horrobin DF, Manku MS, Mitchell J, Ryan MA: Tissue phospholipid fatty acid composition in the diabetic rat. Lipids19 :367 –370,1984[Medline]
7. Chattopadhyay J, Thompson EW, Schmid HH: Nonesterified fatty acids in normal and diabetic rat sciatic nerve. Lipids27 :513 –517,1992[Medline]
8. Coste T, Pierlovisi M, Leonardi J, Dufayet D, Gerbi A, Lafont H, Vague P, Raccah D: Beneficial effects of gamma linolenic acid supplementation on nerve conduction velocity, Na+, K+ ATPase activity, and membrane fatty acid composition in sciatic nerve of diabetic rats. J Nutr Biochem10 :411 –420,1999
9. Dines KC, Cotter MA, Cameron NE: Contrasting effects of treatment with omega-3 and omega-6 essential fatty acids on peripheral nerve function and capillarization in streptozotocin-diabetic rats. Diabetologia36 :1132 –1138,1993[Medline]
10. Gerbi A, Maixent JM, Ansaldi JL, Pierlovisi M, Coste T, Pellissier JF, Vague P, Raccah D: Fish oil supplementation prevents diabetes-induced nerve conduction velocity and neuroanatomical changes in rats. J Nutr129 :207 –213,1999[Abstract/Free Full Text]
11. Djemli-Shipkolye A, Coste T, Raccah D, Vague P, Pieroni G, Gerbi A: Na,K-ATPase alterations in diabetic rats: relationship with lipid metabolism and nerve physiological parameters. Cell Mol Biol47 :297 –304,2001[Medline]
12. Gerbi A, Zerouga M, Debray M, Durand G, Chanez C, Bourre JM: Effect of dietary alpha-linolenic acid on functional characteristic of Na+/K(+)-ATPase isoenzymes in whole brain membranes of weaned rats. Biochim Biophys Acta1165 :291 –298,1993[Medline]
13. Gerbi A, Maixent JM: Fatty acid-induced modulation of ouabain responsiveness of rat Na,K-ATPase isoforms. J Membr Biol168 :19 –27,1999[Medline]
14. Raccah D, Lamotte-Jannot MF, Issautier T, Vague P: Effect of experimental diabetes on Na/K-ATPase activity in red blood cells, peripheral nerve and kidney. Diabetes Metab20 :271 –274,1994
15. Raccah D, Fabreguettes C, Azulay JP, Vague P: Erythrocyte Na⁺-K⁺-ATPase activity, metabolic control, and neuropathy in IDDM patients. Diabetes Care19 :564 –568,1996[Abstract]
16. Scarpini E, Bianchi R, Moggio M, Sciacco M, Fiori MG, Scarlato G: Decrease of nerve Na+,K(+)-ATPase activity in the pathogenesis of human diabetic neuropathy. J Neurol Sci120 :159 –167,1993[Medline]
17. Gerbi A, Barbey O, Raccah D, Coste T, Jamme I, Nouvelot A, Ouafik L, Levy S, Vague P, Maixent JM: Alteration of Na,K-ATPase isoenzymes in diabetic cardiomyopathy: effect of dietary supplementation with fish oil (n-3 fatty acids) in rats. Diabetologia40 :496 –505,1997[Medline]
18. Hammes HP, Weiss A, Furher D, Kamer HJ, Papavassilis C, Grimminger F: Acceleration of experimental diabetic retinopathy in the rat by omega-3 fatty acids. Diabetologia39 :251 –255,1996[Medline]
19. Song JH, Inoue Y, Miyazawa T: Oxidative stability of docosahexaenoic acid-containing oils in the form of phospholipids, triacylglycerols, and ethyl esters. Biosci Biotechnol Biochem61 :2085 –2088,1997[Medline]
20. Stevens MJ, Lattimer SA, Kamijo M, Van Huysen C, Sima AA, Greene DA: Osmotically-induced nerve taurine depletion and the compatible osmolyte hypothesis in experimental diabetic neuropathy in the rat. Diabetologia36 :608 –614,1993[Medline]
21. Yasuda H, Sonobe M, Yamashita M, Terada M, Hatanaka I, Huitian Z, Shigeta Y: Effect of prostaglandin E1 analogue TFC 612 on diabetic neuropathy in streptozocin-induced diabetic rats: comparison with aldose reductase inhibitor ONO 2235. Diabetes38 :832 –838,1989[Abstract]
22. Beutler E, West C, Blume KG: The removal of leukocytes and platelets from whole blood. J Lab Clin Med88 :328 –333,1976[Medline]
23. Raccah D, Gallice P, Pouget J, Vague P: Hypothesis: low Na/K-ATPase activity in the red cell membrane, a potential marker of the predisposition to diabetic neuropathy. Diabetes Metab18 :236 –241,1992
24. Hurst RO: The determination of nucleotide phosphorus with a stannous chloride hydrazine sulphate reagent. Can J Biochem42 :287 –292,1964
25. Bligh EG, Dyer WY: A rapid method of total lipid extraction and purification. Can J Biochem Physiol37 :911 –917,1959
26. Ohta A, Mayo MC, Kramer N, Lands WE: Rapid analysis of fatty acids in plasma lipids. Lipids25 :742 –747,1990[Medline]
27. Raccah D, Coste T, Cameron NE, Dufayet D, Vague P, Hohman TC: Effect of the aldose reductase inhibitor tolrestat on nerve conduction velocity, Na/K ATPase activity, and polyols in red blood cells, sciatic nerve, kidney cortex, and kidney medulla of diabetic rats. J Diabetes Complications12 :154 –162,1998[Medline]
28. Wright RA, Nukada H: Vascular and metabolic factors in the pathogenesis of experimental diabetic neuropathy in mature rats. Brain117 :1395 –1407,1994[Abstract/Free Full Text]
29. Das PK, Bray GM, Aguayo AJ, Rasminsky M: Diminished ouabain-sensitive, sodium-potassium ATPase activity in sciatic nerves of rats with streptozotocin-induced diabetes. Exp Neurol53 :285 –288,1976[Medline]
30. Greene DA, Lattimer SA, Sima AA: Are disturbances of sorbitol, phosphoinositide, and Na⁺-K⁺-ATPase regulation involved in pathogenesis of diabetic neuropathy. Diabetes37 :688 –693,1988[Abstract]
31. Kowluru R, Bitensky MW, Kowluru A, Dembo M, Keaton PA, Buican T: Reversible sodium pump defect and swelling in the diabetic rat erythrocyte: effects on filterability and implications for microangiopathy. Proc Natl Acad Sci U S A86 :3327 –3331,1989[Abstract/Free Full Text]
32. Coppey LJ, Davidson EP, Dunlap JA, Lund DD, Yorek MA: Slowing of motor nerve conduction velocity in streptozotocin-induced diabetic rats is preceded by impaired vasodilation in arterioles that overlie the sciatic nerve. Int J Exp Diabetes Res1 :131 –143,2000[Medline]
33. Kihara M, Schmelzer JD, Poduslo JF, Curran GL, Nickander KK, Low PA: Aminoguanidine effects on nerve blood flow, vascular permeability, electrophysiology, and oxygen free radicals. Proc Natl Acad Sci U S A88 :6107 –6111,1991[Abstract/Free Full Text]
34. Zochodne DW: Diabetic neuropathies: features and mechanisms. Brain Pathol9 :369 –391,1999[Medline]
35. Cameron NE, Cotter MA, Low PA: Nerve blood flow in early experimental diabetes in rats: relation to conduction deficits. Am J Physiol261 :E1 –E8,1991
36. Stevens EJ, Carrington AL, Tomlinson DR: Nerve ischaemia in diabetic rats: time-course of development, effect of insulin treatment plus comparison of streptozotocin and BB models. Diabetologia37 :43 –48,1994[Medline]
37. Ido Y, Chang K, Lejeune W, Tilton RG, Monafo WW, Williamson JR: Diabetes impairs sciatic nerve hyperemia induced by surgical trauma: implications for diabetic neuropathy. Am J Physiol273 :E174 –E184,1997
38. Theriault M, Dort J, Sutherland G, Zochodne DW: Local human sural nerve blood flow in diabetic and other polyneuropathies. Brain120 :1131 –1138,1997[Abstract/Free Full Text]
39. Forst T, De La Tour DD, Kunt T, Pfutzner A, Goitom K, Pohlmann T, Schneider S, Johansson BL, Wahren J, Lobig M, Engelbach M, Beyer J, Vague P: Effects of proinsulin C-peptide on nitric oxide, microvascular blood flow and erythrocyte Na+,K+-ATPase activity in diabetes mellitus type I. Clin Sci98 :283 –290,2000[Medline]
40. Pöschl JM, Leray C, Groscolas R, Ruef P, Linderkamp O: Dietary docosahexaenoic acid improves red blood cell deformability in rats. Thromb Res81 :283 –288,1996[Medline]
41. Lands WE: Biochemistry and physiology of n-3 fatty acids. FASEB J6 :2530 –2536,1992[Abstract]
42. Holman RT, Johnson SB, Gerrard JM, Mauer SM, Kupcho-Sandberg S, Brown DM: Arachidonic acid deficiency in streptozotocin-induced diabetes. Proc Natl Acad Sci U S A80 :2375 –2379,1983[Abstract/Free Full Text]
43. Zhu X, Eichberg J: A myo-inositol pool utilized for phosphatidylinositol synthesis is depleted in sciatic nerve from rats with streptozotocin-induced diabetes. Proc Natl Acad Sci U S A87 :9818 –9822,1990[Abstract/Free Full Text]
44. Gerbi A, Maixent JM, Barbey O, Jamme I, Pierlovisi M, Coste T, Pieroni G, Nouvelot A, Vague P, Raccah D: Alterations of Na,K-ATPase isoenzymes in the diabetic neuropathy: protective effect of dietary supplementation with n-3 fatty acids. J Neurochem71 :732 –740,1998[Medline]
45. Dyck PJ, Karnes JL, Lais A, Lofgren EP, Stevens JC: Pathological alterations of the peripheral nervous system of human. In Peripheral Neuropathy. Dyck P, Thomas P, Lambert E, Bunge R, Eds. Philadelphia, WB Saunders, 1984, p. 760–870
46. Diagne A, Fauvel J, Record M, Chap H, Douste-Blazy L: Studies on ether phospholipids. II. Comparative composition of various tissues from human, rat and guinea pig. Biochim Biophys Acta793 :221 –231,1984[Medline]
47. Ferdinandusse S, Denis S, Mooijer PA, Zhang Z, Reddy JK, Spector AA, Wanders RJ: Identification of the peroxisomal beta-oxidation enzymes involved in the biosynthesis of docosahexaenoic acid. J Lipid Res42 :1987 –1995,2001[Abstract/Free Full Text]
48. Lazarow PB: The role of peroxisomes in mammalian cellular metabolism. J Inherit Metab Dis10 (Suppl. 1) :11 –22,1987
49. Desvergne B, Wahli W: Peroxisome proliferator-activated receptors: nuclear control of metabolism. Endocr Rev20 :649 –688,1999[Abstract/Free Full Text]
50. Horrocks LA, Yeo YK: Health benefits of docosahexaenoic acid (DHA). Pharmacol Res40 :211 –225,1999[Medline]
51. Goss JR, Goins WF, Lacomis D, Mata M, Glorioso JC, Fink DJ: Herpes simplex-mediated gene transfer of nerve growth factor protects against peripheral neuropathy in streptozotocin-induced diabetes in the mouse. Diabetes51 :2227 –2232,2002[Abstract/Free Full Text]

CiteULike

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				S. Pitel, D. Raccah, A. Gerbi, G. Pieroni, P. Vague, and T. C. Coste At Low Doses, a {gamma}-Linolenic Acid-Lipoic Acid Conjugate Is More Effective Than Docosahexaenoic Acid-Enriched Phospholipids in Preventing Neuropathy in Diabetic Rats J. Nutr., February 1, 2007; 137(2): 368 - 372. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Coste, T. C. Articles by Raccah, D. Search for Related Content PubMed PubMed Citation Articles by Coste, T. C. Articles by Raccah, D. Social Bookmarking                What's this?