Development of macroangiopathy in sand rats (Psammomys obesus), an animal model of non-insulin-dependent diabetes mellitus: Effect of gliclazide

Development of Macroangiopathy in Sand Rats (Psammomys obesus), an Animal Model of Non-Insulin-Dependent Diabetes Mellitus: Effect of Gliclazide GEORGES MARQUK, M.D., Tou/ouse, France, JACQUES DUHAULT, Ph.D., Suresnes, France

PETER

HADJIISKY,

M.D.,

The risk of developing macroangiopathy associated with diabetes led us to study in sand rats the long-term consequences of non-insulindependent diabetes on the development of arterial lesions promoted by feeding a high-cholesterol diet. Gliclazide, an agent whose preventive effect has previously been suggested in other experimental models of atheroma, was also investigated in these diabetic and hypercholesterolemic animals. Sand rats were fed a natural diet (ND group), a standard laboratory feed (StD group), or a high-cholesterol feed (HCD group) for 15 months. Biologic parameters were monitored throughout the period of the study, and histologic and histochemical examinations were conducted when the animals were killed (month 15). One StD group and one HCD group were treated with gliclazide from month 3 to month 15. The StD group developed a syndrome of obesity, hyperglycemia, hyperinsulinemia, and triglyceridemia. The high cholesterol feed further increased hypercholesterolemia. These biologic abnormalities were accompanied by arterial lesions (thickening of the intima, deposition of glycosaminoglycans). Foam cells were seen in the intima, and microthrombi were present in the lumen of the arteries of animals in the HCD group. Long-term gliclazide medication at doses that normalized serum glucose levels also reduced the obesity, hyperinsulinemia, lipid disorders, and it prevented or retarded the appearance of arterial lesions.

From Centre de Recherches de Physropathologie Experimentale de la Nutntron, Unrversrte P. Sabatrer, Toulouse, France; Centre de Recherches des Maladres cardro-vascularres, Faculte de Medecrne Prtre Salpetnere, Parrs, France; and lnstrtut de Recherches Servrer. Suresnes. France. Requests for reprints should be addressed to Jacques Duhault, M.D., lnstrtut de Recherches Sewer, 11 rue des Moulrneaux 92150, Suresnes, France.

Paris, France, OLIVIER

ARNAUD,

Ph.D.,

I

t has been reported that sand rats, naturally feeding on low-caloric-value plants, become obese and develop hyperglycemia when fed a standard laboratory diet [l-3]. We demonstrated in a large-scale study that the sand rat may be an interesting model for investigation of both maturityonset non-insulin-dependent diabetes mellitus (NIDDM) [4-61. The metabolic disorders were accompanied by nephropathy [7] and microvascular changes [8,9]. Therefore, we wondered whether this diabetic animal would develop macroangiopathic complications that could be exacerbated by supplying additional dietary cholesterol, an atherogenic factor. We also examined the effects of long-term treatment with gliclazide, a hypoglycemic sulfonylurea, on this potential diabetic macroangiopathy, in view of the fact that this sulfonamide prevents the development of diabetes and degenerative complications in sand rats [lO,ll], as well as atheromatosis in other animal species [12,13].

MATERIALSAND METHODS Animals The animals used were sand rats (Psammomys obesus) aged 3 months, weighing 65-70 g, of either sex, native to North Africa. Living conditions in its natural habitat and in the laboratory have been previously described [5]. Diet Three types of feed were administered to the following groups: the control group received a natural vegetable diet (ND); the other two groups received standard laboratory feed alone (StD) or standard feed plus cholesterol (2% wt/wt) (HCD). The composition of succulent plants (Salsola Joetida) and laboratory chow was determined by chemical analysis. The succulent plant had a very high water content, very little total sugar, and a high proportion of salt mixture with respect to caloric substances (Table I). The caloric value of these plants is approximately 0.4 kcallg wet weight, and the daily calorie intake was 20 ? 1 kcal/animal. When the sand rats were fed on laboratory chow (3.25 kcallg),

June 24, 1991

The American Journal of Medicine

Volume 90 (suppl 6A)

6A-55s

SYMPOSIUM

ON GLICLAZIDE / MARQUIt

ET AL

TABLE I Nutritional Composition of Experimental Diets Succulent PI&s

of the Chenopodiaceae

Comp9nerlts

Water Ash Lipids Proteins kirbabydrates Total sugars Lignin Hemi-cellulose Cellulose Other (not specified) Laboratory

Family (SaMa

foetida)

Percentage of wet wt 80.79 6.86 0.40 3.53 8.42 A:iii 1;:;:;

(2.27)

Chow

Cpmponents Water Ash Lipids Proteins Cellulose Carbohydrates

Expressed as percentage 9 7.1 7.5 25 4;.4

their food consumption (10 g/day) represented a higher caloric intake (32.5 + 3 kcal/day/animal). The composition of the diet is indicated in Table I. Experimentation A total of 101 animals were used, followed up for 15 months after being divided into five groups (Figure 1): 27 control animals receiving the natural vegetable diet (ND), 1’7 animals fed on standard feed (StD), 18 on standard feed plus gliclazide (StD + Gli), 18 on 2% cholesterol feed (HCD), and 21 on 2% cholesterol feed plus gliclazide (HCD + Gli). Gliclazide treatment was only instituted as of month 3, immediately after onset of the first diabetic signs. Glidazide was administered in suspension by intragastric tube. The dose was adjusted (5-20 mg/kg/day) ‘to maintain blood sugar levels as close as possible to normal (checked once a week). The consumption of the standard laboratory feed with or without cholesterol was strictly the same whether in the treated or untreated animals. Specimens for Analysis Body weight was determined twice weekly. The animals were bled from the retro-orbital venous plexus weekly and blood was collected between 9 and 10 PM to determine plasma glucose and insulin. Glucose and ketone bodies in urine were detected with Labstix (Ames). I&lling was carried out after 15 months in control and treated sand rats (nonfasted animals), At autopsy, liver, aorta, and heart specimens were obtained. Assays Blood glucose was measured by using the glucase-oxidase reaction (Boehringer’s test). Plasma 6A-56s

June 24, 1991

The American Journal of Medicine

immunoreactive insulin (IRI) was estimated by the Phadebas insulin test. Rat insulin (Novo) was used as standard. Extraction of plasma and hepatic lipids was carried out using the method of Folch et al [14]. Total lipids were measured gravimetrically, and total and HDL cholesterol by the test combination (Boehringer). Phospholipids were determined by the method of Chen et al [15]. Triglycerides, cholesterol esters, and free cholesterol levels were determined in plasma and liver by thin-layer chromatography according to Landriscrina et al [16], followed by densitometric quantification. Glycogen was extracted from liver samples in KOH at 100°C and assayed by the glucose-oxidase procedure after acid hydrolysis (1 M HCl). Histologic Staining Samples from aorta, heart, and liver were removed, immersed in MacManus fixative (formal/ calcium/cobalt), embedded in paraffin and cut and stained: hematoxylin-eosin/saffran, Goldner’s trichrome, Al&m blue/periodic acid-Schiff (PAS) for glycoprotein and glycosaminoglycan substances; picro-Sirius red for collagen. For quantitative evaluation, five blocks from thoracic and abdominal aorta were cut; five sections per block were stained and 25 sections per aorta were examined (with a variation of lo-12%) by two independent microscopists (P. Hadjiisky and H. Bouissou). To express severity of lesions, the following score values were applied: 1 = no change; 2 = circumscribed and slight change; 3 = circumscribed and strong change; 4 = generalized and slight change; 5 = generalized’ and strong change. Slides were evaluated double-blind, and data from the two observers were pooled. The index of morbidity was established as the following: morbidity index (IM) = V/n x n’ . 100/n where v = score value, n = number of animals, n’ = number of animals with lesions; theoretical maximum of IM = 500. For histochemistry, samples from aorta were rapidly removed. The specimens from different experimental groups were arranged side by side to form a common block, immersed in liquid nitrogen, and cut in Harris cryotome. Each section contained all juxtaposed samples that were stained together. The following enzyme activities and macromolecular substances were compared and the previously described method [17,18] applied; enzyme activities: sorbitol dehydrogenase (EC 1.1.1.14), /3naphthyl esterase (EC 3.1.1.8), butyryl-cholinesterase (EC 3.1.3.2) leucyl-aminopeptidase (EC 3.4.1.7), aryl-sulfatase (EC 3.1.1.6), acid phosphatase (EC 3.1.3.2); macromolecular substances: PAS reaction after cxand p amylase and Dimedin treat-

Volume 90 (suppl 6A)

SYMPOSIUM

3

0 Groups

r

( number)

Duratiop

of diet,

DN GLICLAZIDE / MARQUIt

ET AL

15

in months

,1

I

I

4

natural

StD (17)

4

standard

feed

*

StD

4

standard gliclazide

feed + treatment

*

ND (18)

1

+ Gli(18)

+

diet

ND (9)

4

natural

HCD

(18)

4

2 % cholesterol

HCD

+ Gli (21)

4

diet

*

feed

2 % cholesterol feed gliclazide treatment

M-

I

*

*

)

+

Figure 1. Distribution of animals in different groups.

TABLE II Biochemical Analysis of Plasma in Different Groups of Control, Diabetic, and Hypercholesterolemic Without Gliclazide Medication (at month 15)

Bodywt(mmolll) Glucose M Insulin (pmol/L) Cholesterol (mmolil) Triglycerides (mmolil)

Control (ND)

Obese and Diabetic WI

Obese and Diabetic t Gliclatide (StD t Gli)

(16) 106.4 3.7t2 2.9 0.1

WI 142.6 13.722 7.4* 2.0*

110.7 3.6+‘3.5t ? 0.2t

220?r7 1.84t 0.06

3,013f 282* 3.90i- 0.34*

1,0062 74*$ 2.17? O.llt

246k 23 1.96+ 0.08

1.41 k 0.07

4.13 i 0.56*

1.41 i 0.08$

1.07 t 0.05

(1’3)

Control (ND)

(9) 110.6 3.9?rf 30.1

Sand Rats Treated With and

Diabetic and Hyperckolesterolemic (HCD)

(181

Diabetic and Hypercholesterolemic t Gliclazide (HCD t Gli)

(21)

137.6 15.7?r i 2.9* 1.3*

1099;z ;J

2,808+ 154* 23.25?r0.87* 8.402 0.19*

1,044 40*$ 8.22+ 0.29*+ 2.86k O.ll*t

mevalues are expressed as mean + SEM. The number of ammals In each group IS indicated In parenthesis. D, natural vegetable diet; StD, standard lab chow diet; HCD, high cholesterol diet. le degree of significance is *p
ment (glycoproteins and glycogen), toluidine blue Merck 0.5% at pH 4.6 (glycosaminoglycans), Nile blue sulfate and Sudan black B (acid and neutral lipids), Unna-Pappenheim method with Brachet’s test (ribonucleoproteins). Evaluation of the results with the same level of variation previously mentioned was effected by two microscopists (P. Hadjiisky and N. Peyri). The following indexes of positivity were used: 0, 0.5, 1, 2, 3, and 4 indicating “nil, ” “very slight,” “slight,” “moderate,” “strong,” and “very strong” activity, respectively.

used. The exact probability was calculated, and the significance level was considered as p ~0.05.

RESULTS Metabolic and Morphologic Studies of Sand Rats Feg Exclusively with Natural Plant Matter (ND Group) Biochemical plasma and tissue parameters were similar to those of sand rats killed in their biotope. No hyperglycemia, glycosuria, or hyperlipemia was noted during the 12 months (Table II); only insulin showed a slight increase, from 160 + 11 and 161 f 19 pmol/L at month 3, to 220 -t 7 and 246 t 23 pmol/L at month 15 in the Statistical Analysis respective StD and HCD control groups. These aniThe results are expressed as mean values I~I mals were free from aortic lesions (Table III), and SEM. Two-way analysis of variance with repeated no biologic abnormalities were found in the liver measurement [19] and Newman-Keuls test were (Table IV). June 24,

1991 The Amencan Journal of Medicine

Volume 90 (suppl 6A)

6A-57s

SYhlPOSlUMON GLICIAZIDEIMARQUli ET AL 1 TABLE III Distribution of Morbidity Index Values in the Various Groups (index maximum = 500)

I

Cellular Proliferation Groups ND PI StD (13)

;;D;lt; (13) HCD t Gli (15)

Media

lntima

Deposition of GAG

2!*

1!*

12!*

3II*

*Y*

4!*

15II*

A*

0

13

0

0

Interstitial Fibrosis

Foam Cells

Microthrombi

The number of animals in each group is indicated in parenthesis. Abbreviatlons as in Table II; GAG, glycosaminoglycans. The degree of significance IS calculated for nontreated animals versus gliclazide-treated animals; *p ~0.05.

TABLE IV Biochemical Analysis of Liver in Different Groups of Control, Riabetic, and Hypercholesterolemic Without Gliclazidti Medication (at month i5)

control WI

08) Bodywt (9) Weight af liver (g) Biomedical parameters

Total cholesterol Cholesterol esters Free cholesterol

p&

WI

081

control (ND1

(9)

Diabetic and Hypercholesterolemic (HCDI

(18)

106.4 + 2.9

142.6 k 7.4*

110.7 ?r 35t

110.6 ? 3.0

137.6 * 2.9*

3,710 ? 60

4,810 2

Ml* 3,5905 150* 427kk 10* 18* 154 2692 lO* 3,061 840rt* 56* 345*

4,080+ lOO*t 3,1302 90t 307L2 7*t 12t 104 192?r 13.7t 2,017? 392* 15t 159*t

3,821 r 153

3,220k 116 300 69 22 12 5 230? 7 54 327+ 30 700

6,447c 163*

3.43+ 0.14

(mg/lOO4: Total lipids Phospholipids

Obese and Diabetic WI

Obese and Diabetic t G!iclazide (SD t 611)

Sand Rats Treated With and

3,096?r45 277*10 63 5 3 218*7 328 731c+ 71 18

5.Wk 0.36*

4.12+ 0.20*t

3.63r 0.10

5.70f 0.22*

;4’a; 1790:51: T ;:2* 3542 15* 3,0332 37* 1,228 177*

Diabetic and Hypercholesterolemic t Gliclazide (HCD t Gli)

(21) 109.7+ 1.4t 4.05k o.o7*t 4,999k a7*t 3,687+ 55*t ;!j; ff ;;:; 245i8t 2,012 643k? 64*t 29*t

?sults are expressed as weight of fresh tissue, with the values expressed as mean -t SEM. )breviations as in Table I. le degree of significance is “p
Metabolic and Vascular Patterns in Sand Rats Fed on Laboratory Chow With or Without the Addition of Cholesterol During the first 3 months, whereas no significant difference existed in the ND group, the animals fed on laboratory chow without (StD) or with (HCD) the addition of cholesterol showed a weight gain of about 25 g. These animals were hyperglycemic (8.7 + 0.8 and 9.0 + 0.6 mmol/L in the StD and HCD groups, respectively) and hyperinsulinemic (1,394 _+ 107 and 1,330 ? 63 pmol/L in StD and HCD, respectively). In the StD group triglyceride and cholesterol increased to 2.13 f 0.24 and 2.73 rt 0.2 mmol/L, respectively; in the HCD group these two parameters increased to 4.03 + 0.14 and 11.78 +- 0.55 mmol/L, respectively. During the 12month study (Table II), sand rats developed obesity and elevated plasma insulin levels. In some, plasma glucose values remained normal, although the glucose tolerance tests become progressively more abnormal. In others, ip addition to worsening oQesity, blood glucose values were nearly 17 pmol/L. Glycosuria and albuminuria were strongly positive. Plasma immunoreactive insulin increased continu6A-58s

June 24,

1991 The American Journal of Medicine

ously, reaching a peak of 4,300 pmol/L for some animals. Plasma lipids, triglycerides in particular, showed an increase. Abundant lipid deposition was observed in the livers (Table IV). After adding cholesterol to the standard feed, the course of diabetes was not appreciably altered. Only hyperlipidemia markedly worsened (Table II), leading to genuine hepatic steatosis (Table IV). In a few animals, body weight decreased dramatically (89.0 + 5.5 versus 143.0 + 7.0 g in diabetic hyperinsulinemic animals). Plasma immunoreactive insulin levels declined sharply (158 -+ 36 pmol/L). These animals were treated with insuiin to prevent diabetic coma and were not included in the present study. Anatomically, thickening of the media was the only significant change observed in diabetic sand rats (StD group). Myocytes were larger, the extracellular space appeared lighter; this reflects parietal edema, which accompanies an increase in metachromatic glycosaminoglycans (Table III). Some animals showed either foci or cellular proliferation or interstitial fibrosis and microthrombi. Histochemically, there was hyperactivity of sor-

Volume 90 (suppl 6A)

SYMPOSIUM

ON GLICLAZIOE I MARQUIt

ET AL

Figure 2 Vessel wall of thoracic aorta from sand rats in HCD group (A$) and HCD t Gli group (6.0). Note the increase in the thickness of the tunica media (A), which is normal in B. The voluminous mass of foam cells, formed from the monocytes, have entered the intima (C); these are absent in D.

bitol dehydrogenase (5 of 13 animals), decreased choline&erase activity (6 of 13 animals), peptidase and lysosomal sulfatase hypoactivity (5 of 13 animals), and an increase in ribonucleoproteins (4 of 13 animals). The absence of glycogen deposits and extra- and endocellular lipids is noteworthy. The same findings were observed in hypercholesterolemic diabetic animals (HCD group). In addition, atheromatous lesions were observed in some animals, as lipid lesions of the aortic intima (Figure 2), characterized by intra- and extracellular lipids, mononuclear foam cells, and slight cell proliferation.

Effects of Gliclazide on Metabolic and Vascular Patterns in Sand Rats Fed on Laboratory Chow With or Without Cholesterol Gliclazide treatment maintained blood sugar levels within the normal range in sand rats of StD and

HCD groups. It stopped the development of a diabetic syndrome and even caused regression of hyperinsulinemia; insulin levels, however, remained higher than in the ND group. It should be underlined that the weight gain in animals that received gliclazide was the same as that in animals receiving natural vegetable feed (Table II). Lastly, in the two groups (StD + Gli and HCD + Gli), gliclazide medication inhibited the progress of hyperlipidemia (total cholesterol plus triglycerides) and considerably reduced the severity of fatty deposition in the liver (Table IV), which was observed in the HCD group. In the diabetics treated with gliclazide (StD + Gli group), the media showed near-normal thickness except in two cases in which sorbitol dehydrogenase was active. Lipolytic cholinesterase remained active. The activity of lysosomal enzymes was not reduced. In the HCD + Gli group, the thickness of the media was practically normal (Fig-

June 24, 1991

The American Journal of Medicine

Volume 90 (suppl 6A)

6A-59s

SYMPOSIUM

ON GUCLAZIDE/MARQUI~

ETAL

ure 2) Metachromasia (presence of glycosaminoglycans) was as moderate as in control animals. There was no evidence of intimal lipidosis, although lipidloaded blood cells were present in the vascular lumen. No microthrombi were detected (Table III).

COMMENTS The results of this study confirm the role of the high-caloric diet in the development of hyperinsulinemia, obesity, and ultimately NIDDM in sand rats [5]. This caloric excess in fact causes insulin overproduction, leading to weight excess and lipid anomalies that generate insulin resistance, itself in turn exacerbating hyperinsulinemia. Conversely, in these animals, the return to a natural plant diet (caloric intake virtually identical to restricted caloric feeding of laboratory chow) induced a sharp decline in body weight, completely normalized blood glucose, and lipid metabolism returned to normal [53. Abundant lipid deposition was observed in the liver of animals (StD group). Hyperinsulinemia could be responsible for the lipid abnormalities. Indeed, it has been previously demonstrated that increased insulin levels tend to increase triglyceride secretion rates [ZO]. The in vitro sensitivity of adipose tissue to insulin decreased to a nearly complete resistance in diabetic sand rats 151. The addition of cholesterol exacerbates these marked lipid anomalies, in particular the cholesterol overload, but it does not increase the hyperinsulinemia induced by the standard diet alone (Table II). The progression of this diabetes is accompanied by generalized microangiopathy [8,91 and severe glomerulopathy [7]. However, the vascular complications remain relatively mild. The increased intima1 thickness is the most consistent manifestation of diabetic macroangiopathy observed in our study. It is undoubtedly due to the parietal edema induced by the high sorbitol content of the aortic media, which causes hyperosmotic disorders. The enhanced sorbitol dehydrogenase activity and increased glycosaminoglycan content of the media support this hypothesis. The addition of cholesterol to the diabetogenic diet does not cause true atherosclerosis in HCD animals, despite the significant changes in lipid parameters. It seems as though hypercholesterolemia and the diabetic syndrome acting jointly were unable to overcome the probable athero-resistance of this rodent species. Indeed, in this study, the sand rat behaves like the laboratory rat, well-known for its resistance to both spontaneous and induced atherosclerosis [Zl]. However, some of the Psammomys of the HCD group do develop intimal lipidosis with evidence of numerous foam cells, probably of monocyte origin. In these same animals, there is a de6AdOS

June 24, 1991

The American Journal of Medicine

crease in cholinesterase activity involved in parietal lipolysis [ZZ]. The diabetic syndrome seems to act by decreasing the parietal lipolytic defense, paving the way to a lipoprotein invasion. The enrichment of the intima and media in glycosaminoglycans is probably not unrelated to the development of induced lipidosis; these compounds are able to take up and retain low-density lipoproteins that have penetrated through the wall [23]. Gliclazide treatment markedly reduces the excess weight of diabetic sand rats (StD + Gli group), completely normalizes blood glucose, and markedly regulates lipid metabolism. Hyperinsulinemia decreases dramatically but remains high in comparison with normal controls (ND group). The extrapancreatic effects of hypoglycemic sulfonylureas remain controversial [24], but the normalization of pancreatic response kinetics can be partly explained by the reduction in insulin level [25,26]. It should be underscored that the weight loss after gliclazide treatment, as after a natural low-calorie diet [5], represents a major factor that may contribute favorably to the reduction in blood sugar, insulinemia, and hyperlipidemia; this effect had also been observed in hypercholesterolemic rabbits after gliclazide treatment [ 121. Gliclazide also reduces lipid disorders caused by the addition of cholesterol (HCD + Gli group) and confirms the results in other hypercholesterolemic animal models [12,13]. The mechanisms remain unclear, in particular, as concerns the reduction of cholesterol overload. As concerns plasma and liver triglycerides, their reduction by gliclazide treatment is most likely related to the improved glucose tolerance and concomitant reduction in hyperinsulinemia [5]. Preventive gliclazide treatment was beneficial to the vascular complications of diabetes in the StD + Gli group. Indeed, this sulfonamide favorably affects diabetic macroangiopathy by acting at two levels: reduction of parietal edema and prevention of thrombotic complications. The disappearance of parietal edema is probably the consequence of the marked reduction in sorbitol production, as evidenced by the decreased tissue sorbitol dehydrogenase activity, secondary to the normalization of serum glucose level. The absence of thrombotic complications in these treated animals confirms the many studies on the prevention of capillary microthrombi in normal or diabetic animals [27] with gliclazide. The stimulation of parietal or plasma fibrinolysis by gliclazide [283, as well as the antiplatelet effects [29,30], may explain the absence of microthrombi in the vascular lumen of rats treated with this sulfonamide. Gliclazide also exerts a favorable effect on experimental atheromatosis. The absence of atheroma-

Volume 90 (suppl 6A)

tous lesions in the HCD + Gli group is noteworthy. The reduction in lipid anomalies after gliclazide and the sustained lipolytic enzymatic activity in the aorta may probably be explained by the absence of extra- and intracellular lipids and foam cells in the aorta. Lastly, the absence of signs of cell proliferation, which were mild in hypercholesterolemic diabetic animals despite the marked hyperinsulinemia, is very likely related to the decrease in plasma insulin level achieved with the sulfonamide. To summarize, our results demonstrate the resistance to cholesterol-induced atherosclerosis in sand rats, as in laboratory rats. However, by causing the reduction in parietal lipolytic enzymatic activity, the diabetic syndrome promotes the development of pre-atheromatous lesions in the presence of lipid anomalies. Gliclazide exerts a favorable effect on diabetic manifestations by promoting weight loss, regulating blood glucose and lipid metabolism, and reducing hyperinsulinemia. Moreover, it prevents or delays the onset of signs of arterial involvement, preatheromatosis lesions, thus confirming the results in other experimental animal models [X.2,13].

REFERENCES 1. Schmidt-Nielsen K, Haines HB, Hackel DB. Diabetes mellitus in the sand induced by standard laboratory drets. Science 1964; 143: 689-90. 2. Harries HB, Hackel DB, Schmidt-Nielsen K. Experimental diabetes mellitus duced by diet in the sand rat. Am J Physiol 1965; 208: 297-300. 3. Hackel DB, Frohmam LA, Mikat E, Lebovitz HE, Schmidt-Nielsen K, Kinney Revrew of current studres on effect of diet on the glucose tolerance of the sand

rat inTD. rat

(Psammomys obesus). Ann NY Acad Sci 1965; 131: 459-63. 4. Marquie G. Petkov P, Duhault J. Diabetic syndrome in sand rats (Psammomys obesus) with special reference to the pancreas. Abstract. Diabetologia 1980; 19: 297. 5. Marquie G, Duhault J, Jacotot B. Diabetes mellitus in sand rats (Psammomys obesus). Metabolic pattern during development of the drabetic syndrome. Diabetes 1984; 33: 438-43. 6. Petkov P, Marquee G, Donev S, Dahmanr Y, Duhault J. Morphology of the endocnne pancreas in diabetic sand rat (Psammomys obesus). Cell Mol Biol 1985; 31: 61-74. 7. Du Borstesselin R, Favart P, Lechaire JP, Boulanger M, Marquie G., Duhault J. Renal changes in sand rats with plethoric diabetic syndrome; histological and ultra structural studies. 11th Congress IDF, Nairobi, 1982. 8. Marquie G, Duhault J, Petkov P, et al. Microangiopathy and diabetes mellitus in sand rats (Psammomys obesus). 11th Congress IDF, Nairobi, 1982. 9. Marquie G, Duhault J, HadJrisky P, Petkov P, Bouissou H. Diabetes mellitus In sand

rats (Psammomys obesus): Microangiopathy during development of the diabetic syndrome. Cell Mol Biol (in press). 10. Marquie G, Khemicr D, Hadjiisky P, Bouissou H. Preventive effects of glrclazide on microangiopathy, atherosclerosis and diabetes mellitus in sand rats (Psammomys obesus). F&D, 22nd Annual Meeting, Rome, Italy, 1986. 11. Hadjiisky P, Duhault J, Marquie G. Diabetic nephropathy in sand rats and effect of gliclazide. Diabetes Res Clin Pratt 1988; 5 (Suppl 1): S290. 12. Marquie G, Preventive effect of gliclazide on experimental atherosclerosis in rabbits. Drabetologia 1978; 14: 269-75. 13. Smit-Srbinga CT, Wieringa RA. The effect of gliclazide on irradiation-Induced experimental atheromatosis. J Drug Res 1979; 4: 479-84. 14. Folch J, Lees M, Stanley GHS. A simple method for the isolabon and purification of total lipids from animal tissues. J Biol Chem 1957; 226: 497-509. 15. Chen PS, Toribara TY, Warner H. Microdetermination of phosphorus. Anal Chem 1956; 28: 1756-7. 16. Landnscina C, Gnonr GV, Quagliariello E. Fatty acids biosynthesis: Physiological role of the elongation system present in microsomes and mitochrondria of rat liver. Eur J Biochem 1972; 29: 188-96. 17. Hadjiisky P, Renais J, Scebart L. Developpement et senescence de I’aorte du rat. Histochimre et histoenzymologie comparative. Atherosclerosis. 1975; 22: 1938. 18. Hadjiisky P, Peyri N, Grosgogeat Y. Tunica media changes in the spontaneously hypertensrve rat (SHR). Atherosclerosis 1987; 65: 125-37. 19. Winer BJ. Statishcal princtples in experimental design. 2nd ed. New York McGraw-Hill, 1971. 20. Robertson RP, Smith PH. Stress-Induced inhibition of trrglycende secretion in vivo in sand rats (Psammomys obesus). Metabolism 1976; 25: 1583-90. 21. Hadjrrsky P, Renais J, Scebat L. A comparative study of the arterial tissue metabolic in atheroresistant species. Comparison between rabbit and rat aortas, Arterial Wall 1981; 7/4: 155-66. 22. Szendzikowskr S, Patelski J, Pearse AGE. The influence of cholinesterase inhibitors on the lipolyhc activity of rat aorta. Enzymol Biol Clin 1961; 1: 125-37. 23. Falcone DJ, Hajjar DP, Mrnick CR. Enhancement of cholesterol and cholesteryl ester accumulation in reendotheliakzed aorta. Am J Pathol 1980; 99: 81-104. 24. Bak JF, Schmidt 0, Sorensen NS, Pedersen 0. Post-receptor effects of sulfonylurea on skeletal muscle glycogen synthase activity in type II diabetrc patients, Diabetes (In press). 25. Brogard JM, Pinget M. Leconte A, Dorner M. Effets a moyen terme (3 mois) du traitement sulfamide hypglycemrant (gliclazide) sur la secretion insulinique de diabetiques noninsulino-dependants. J Int Med 1985; 11: 60-7. 26. Mosker JP, Rudenski AS, Burnett MA, Matthews DR, Turner RC. Similar reduction of first- and second-phase B-cell responses at three different glucose levels in type II diabetes and the effect of gliclazide therapy. Metabolism 1989; 38: 767-72. 27. Duhault J, Lebon F, Boulanger M. Pharmacologic du S1702. Action sur la glycemie et le systeme microvascularre d’animaux normaux et diabetiques. In: Journees Annuelles de Diabetologie de I’HBtel-Dieu. Paris. Flammarion, 1971: 25760. 28. Gram J, Jespersen J, Kold A. Effects of an oral antidiabetic drug on the fibrinolyt~c system of blood in Insulin-treated diabebc patients. Metaboksm 1988; 37: 937-43. 29. Desnoyers P, Labaume J, Anstett M, Herrera M, Pesquet J, Sebasben J. The pharmacology of S1702, a new highly effective oral antidiabetic drug with unusual properties. 3 Antistickiness actwity, fibrinolytic properties and hemostatic parameters study. Arzneimrttel Forschung 1972; 22: 1691-1965. 30. Duhault J, Regnault F, Boulanger M, Tiserand F. Prevention of experimental obstrucbons in the retinal microcirculation. Ophthalmologica 1975; 170: 345-52.

June 24, 1991

The American Journal of Medicine

Volume 90 (suppl 6A)

6A-61S