Renal lesions aggravation are prevented by low doses of sitagliptin in a rat model of type 2 diabetes Cristina Mega, Helena Vala, Jorge Oliveira, Rosa

Renal lesions aggravation are prevented Renal lesions aggravation are prevented

by low doses of sitagliptin in a rat model by low doses of sitagliptin in a rat model

of type 2 diabetes of type 2 diabetes

Renal lesions aggravation are prevented Renal lesions aggravation are prevented

by low doses of sitagliptin in a rat model by low doses of sitagliptin in a rat model

of type 2 diabetes of type 2 diabetes

Cristina Mega, Helena Vala, Jorge Oliveira, Rosa Fernandes, Filipa Mascarenhas-Melo, Belmiro Parada, Rui Pinto, Frederico Teixeira, Flávio Reis, Edite Teixeira de Lemos


Macrovascular Microvascular

Heine RJ, Spijkerman AM. 2006.

Major complications of Type 2 Diabetes Mellitus (T2DM)

Cardiovascular diseasesCardiovascular diseases

NeuropathyNeuropathy

RetinopathyRetinopathy

NephropathyNephropathy

• Diabetic nephropathy is a major microvascular complication of T2DM

• Incidence of T2DM is rapidly increasing, as well as the prevalence of chronic kidney disease (CKD), resulting from these diabetic complications

• In different regions of the World, it accounts for almost one-third of all cases of end-stage renal disease (ESRD)

• Diabetic nephropathy is a major microvascular complication of T2DM

• Incidence of T2DM is rapidly increasing, as well as the prevalence of chronic kidney disease (CKD), resulting from these diabetic complications

• In different regions of the World, it accounts for almost one-third of all cases of end-stage renal disease (ESRD)

Diabetic Nephropathy – A Major Diabetic Complication

Diabetes remains the single

most important cause of kidney failure

Diabetes remains the single

most important cause of kidney failure

Prevention of Diabetes-Induced dysmetabolism and associated

vascular complications

Blood Glucose levelsBlood Glucose levels Insulin secretion/action

Insulin secretion/action

Therapeutic Goals in Type 2 Diabetes Mellitus (T2DM)

Until now, anti-diabetic drugs were able to

Hyperglycaemia Hyperglycaemia

None were able to preserve β-cells

None were able to preserve β-cells

Therapeutic Goals in Type 2 Diabetes Mellitus (T2DM)

Anti-diabetic drugsAnti-diabetic drugs

incretin defect is a major contributor to β-cell dysfunction

incretins stimulate release of insulin by β-cells incretin inhibits glucagon release by α-cells and that in T2DM the incretin effect is decreased

Sitagliptin

Knowing thatKnowing that

New anti-diabetic drugs, focus on the increase of incretin levels in diabetic patients, like SitagliptinNew anti-diabetic drugs, focus on the increase of incretin levels in diabetic patients, like Sitagliptin

a dipeptidyl peptidase-4 (DPP-4) inhibitor and one of the best known incretin enhancersa dipeptidyl peptidase-4 (DPP-4) inhibitor and one of the best known incretin enhancers

Sitagliptin targets 2 physiologic glucose-lowering actions with a single oral agent

Improves 24 h

glycaemic control

Incretin hormones GLP-1 and GIP are released by the intestine throughout the day

Their levels increase in response to a meal and are found to be reduced in Diabetes

InactiveGIP

DPP-4 enzyme

InactiveGLP-1

Beta cellsBeta cells Insulin(GLP-1 and GIP)

Glucose dependentGlucose dependentGlucose dependentGlucose dependent

Glucagon(GLP-1)Alpha cellsAlpha cellsAlpha cellsAlpha cells

Glucose Glucose uptake byuptake byperipheral peripheral tissuestissues

Glucose Glucose productionproduction

by liver by liver

SITAGLIPTIN allows SITAGLIPTIN allows for a longer for a longer

circulation life for circulation life for incretinsincretins

X

2 - 4 minutes2 - 4 minutes

BBLLOOOODD GGLLUUCCOOSSEE

BBLLOOOODD GGLLUUCCOOSSEE

GIPGLP-1

Preserving pancreatic function

Inhibition of DPP-4 activity, by incretin enhancers, such as Sitagliptin (Known Effects)

but the real impact of low-dose sitagliptin treatment on diabetic nephropathy remains to be elucidated

but the real impact of low-dose sitagliptin treatment on diabetic nephropathy remains to be elucidated

Improve glycaemic control, in diabetic patients

by prolonging the actions of incretin hormones

Prevention of Diabetes-Induced dysmetabolism and microvascular

complications – Diabetic Nephropathy

Assess the effects

SITAGLIPTINAssess the effects

SITAGLIPTIN

????

Evaluate the effects of chronic (6 weeks) inhibition of DPP-4 by low doses of Evaluate the effects of chronic (6 weeks) inhibition of DPP-4 by low doses of

sitagliptin, in the ZDF rat, an animal model of T2DM, on progression ofsitagliptin, in the ZDF rat, an animal model of T2DM, on progression of

renal lesionsrenal lesions

AIM:AIM:

Animals and experimental design:

Divided in 2 subgroups (n = 8 rats)treated with:

- Sitagliptin 10 mg/kg/BW/day oror- Vehicle (orange juice)

SID (6:00 PM), for 6 weeksSID (6:00 PM), for 6 weeks

♂ Zucker Diabetic Fatty (ZDF fa/fa) (n=16)

Age: 20 weeksAge: 20 weeks

Controls: their lean littermates (ZDF +/+) (n=8)

Age: 20 weeksAge: 20 weeks

Sample Collection and Preparation

Blood and tissues - collected at 20 weeks (Ti) and at 26 weeks (Tf) Blood and tissues - collected at 20 weeks (Ti) and at 26 weeks (Tf)

Renal specimens were paraffin-embedded and the 3 µm thick sections

stained for routine histopathological diagnosis with haematoxylin and

eosin (HE) and Periodic Acid of Schiff (PAS)

All samples were examined by light microscopy using a Zeiss Axioplan 2

microscope

Renal specimens were paraffin-embedded and the 3 µm thick sections

stained for routine histopathological diagnosis with haematoxylin and

eosin (HE) and Periodic Acid of Schiff (PAS)

All samples were examined by light microscopy using a Zeiss Axioplan 2

microscope

Arteriolar hyalinosis

Arteriosclerosis.


Arteriosclerosis.Inflammation

Hyaline cylinders

Tubular basement membrane irregularity

Tubular calcification

Interstitial fibrosis/tubular atrophy (IFTA)

Inflammation

Hyaline cylinders

Tubular basement membrane irregularity

Tubular calcification

Interstitial fibrosis/tubular atrophy (IFTA)

Histomorphological EvaluationHistomorphological Evaluation

Mesangial expansionGBM thickeningCapsule of Bowman thickeningNodular sclerosisGlomerulosclerosisAtrophy Hyalinosis of the vascular pole

Mesangial expansionGBM thickeningCapsule of Bowman thickeningNodular sclerosisGlomerulosclerosisAtrophy Hyalinosis of the vascular pole

R

E

N

A

L

L

E

S

I

O

N

S

R

E

N

A

L

L

E

S

I

O

N

S

0 = absent1 = mild2 = moderate3 = severe

0 = < 25%1 = 25 - 50%2 = 50 - 75%3 = > 75 %

Scored in single blind fashionScored in single blind fashion

Severity Severity

ExtensionExtension

Semi-quantitative scoring of lesions Semi-quantitative scoring of lesions

(Except IFTA)(Except IFTA)

All lesions were evaluated on the total tissue on the slide. All lesions were evaluated on the total tissue on the slide.

++


0 = absent

1 = one arteriole with hyalinosis was present

2 = more than one arteriole was observed Arteriosclerosis

0 = no intimal thickening was present

1 = intimal thickening was < than media thickness

2 = intimal thickening > than media thickness


0 = absent

1 = one arteriole with hyalinosis was present

2 = more than one arteriole was observed Arteriosclerosis

0 = no intimal thickening was present

1 = intimal thickening was < than media thickness

2 = intimal thickening > than media thickness

0 = absent

1 = < 25%,

2 = 25 - 50%

3 = > 50%

(of affected area)

0 = absent

1 = < 25%,

2 = 25 - 50%

3 = > 50%

(of affected area)

IFTA IFTA

Scoring of lesions Scoring of lesions

VASCULARVASCULAR

RESULTS RESULTS

Sitagliptin Reduced Kidney Oxidative Stress Sitagliptin Reduced Kidney Oxidative Stress (Positive Impact on (Positive Impact on Lipid Peroxidation Levels Lipid Peroxidation Levels in renal tissues)in renal tissues)

Tf (26 wks)Tf (26 wks)Ti (20 wks)Ti (20 wks)

Treated Diabetic

Rats

Sitagliptin Reduced Kidney DysfunctionSitagliptin Reduced Kidney Dysfunction((Decrease of Blood Urea NitrogenDecrease of Blood Urea Nitrogen – BUN) – BUN)

Effect of Sitagliptin on Glomerular Lesions Effect of Sitagliptin on Glomerular Lesions Diabetic ZDF (Diabetic ZDF (Sita-treatedSita-treated vs Untreated) vs Untreated)

UNTREATEDUNTREATED SITA-TREATED RATSSITA-TREATED RATS

50µm50µm

25µm 25µm

Effect of Sitagliptin on Glomerular Lesions Effect of Sitagliptin on Glomerular Lesions Diabetic ZDF (Diabetic ZDF (Sita-treatedSita-treated vs Untreated) vs Untreated)

UNTREATEDUNTREATED SITAGLIPTIN-TREATEDSITAGLIPTIN-TREATED

50µm50µm

25µm 25µm

mnng

Effect of Sitagliptin on Effect of Sitagliptin on Glomerular Lesions Glomerular Lesions Diabetic ZDF (Diabetic ZDF (Sita-treatedSita-treated vs Untreated) vs Untreated)

SITAGLIPTIN-TREATEDSITAGLIPTIN-TREATED

Effect of Sitagliptin on Tubulointersticial Lesions Effect of Sitagliptin on Tubulointersticial Lesions Diabetic ZDF (Sita-Diabetic ZDF (Sita-treatedtreated vs Untreated) vs Untreated)

50µm 50µm

25µm

UNTREATEDUNTREATED

50µm

All TAll Tubulointerstitialubulointerstitial Lesions improved Lesions improvedDiabetic ZDF (Diabetic ZDF (Sita-treatedSita-treated vs Untreated) vs Untreated)

25µm

25µm

The Improvement of The Improvement of Glomerular & TubulointerstitialGlomerular & Tubulointerstitial Lesions Lesions Diabetic ZDF (Diabetic ZDF (Sita-treatedSita-treated vs Untreated) vs Untreated)

Effect of Sitagliptin on Vascular Lesions Effect of Sitagliptin on Vascular Lesions Diabetic ZDF (Sita-Diabetic ZDF (Sita-treatedtreated vs Untreated) vs Untreated)

UNTREATEDUNTREATED SITA-TREATED ANIMALSSITA-TREATED ANIMALS

25µm25µm



25µm25µm



25µm25µm



25µm 25µm

Effect of Sitagliptin on Vascular Lesions Effect of Sitagliptin on Vascular Lesions Diabetic ZDF (Sita-treated vs Untreated)Diabetic ZDF (Sita-treated vs Untreated)

ConclusionsConclusionsIn an animal model of T2DM, a 6 week once daily treatment with a low dose In an animal model of T2DM, a 6 week once daily treatment with a low dose of Sitagliptin promotedof Sitagliptin promoted::In an animal model of T2DM, a 6 week once daily treatment with a low dose In an animal model of T2DM, a 6 week once daily treatment with a low dose of Sitagliptin promotedof Sitagliptin promoted::

- Glomerulosclerosis

- Tubulointerstitial lesions

- Vascular lesions

- Glomerulosclerosis

- Tubulointerstitial lesions

- Vascular lesions

IMPROVEMENT OF

DIABETIC NEPHROPATHY

IMPROVEMENT OF

DIABETIC NEPHROPATHY

REGULATION OF DIABETIC DISMETABOLISM

REGULATION OF DIABETIC DISMETABOLISM

HyperglycaemiaHypertriglyceridaemiaHyperglycaemiaHypertriglyceridaemia

RENAL FUNCTIONRENAL FUNCTION

Oxidative stressBlood Urea NitrogenOxidative stressBlood Urea Nitrogen

Has the effect in

ConclusionsConclusionsSitagliptin was able to delay the development of diabetic Sitagliptin was able to delay the development of diabetic nephropathy in this model of T2DM, viewed by reduction of renal nephropathy in this model of T2DM, viewed by reduction of renal lesionslesions

This effect might be, at least, partially due, to its benefits on This effect might be, at least, partially due, to its benefits on correction of diabetes dysmetabolism (hyperglicaemia, correction of diabetes dysmetabolism (hyperglicaemia, dyslipidaemia and insulin production/sensitivity), as well as due to dyslipidaemia and insulin production/sensitivity), as well as due to a favorable impact on kidney lipid peroxidation a favorable impact on kidney lipid peroxidation

Sitagliptin was able to delay the development of diabetic Sitagliptin was able to delay the development of diabetic nephropathy in this model of T2DM, viewed by reduction of renal nephropathy in this model of T2DM, viewed by reduction of renal lesionslesions

This effect might be, at least, partially due, to its benefits on This effect might be, at least, partially due, to its benefits on correction of diabetes dysmetabolism (hyperglicaemia, correction of diabetes dysmetabolism (hyperglicaemia, dyslipidaemia and insulin production/sensitivity), as well as due to dyslipidaemia and insulin production/sensitivity), as well as due to a favorable impact on kidney lipid peroxidation a favorable impact on kidney lipid peroxidation

TThe he prevention of diabetic nephropathy evolution might prevention of diabetic nephropathy evolution might represent a key step forward in the management of T2DM represent a key step forward in the management of T2DM

and these serious complications and these serious complications

TThe he prevention of diabetic nephropathy evolution might prevention of diabetic nephropathy evolution might represent a key step forward in the management of T2DM represent a key step forward in the management of T2DM

and these serious complications and these serious complications

This presentation was supported by the Polytechnic Institute of Viseu, PortugalThis presentation was supported by the Polytechnic Institute of Viseu, Portugal

Muito obrigada! Muito obrigada!



Thank you very much!Thank you very much!

Paljon kiitoksia

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Documents

Renal lesions aggravation are prevented by low doses of sitagliptin in a rat model of type 2 diabetes Cristina Mega, Helena Vala, Jorge Oliveira, Rosa