Dr. Vijay Viswanathan, M.D, Ph.D, MNAMS

Joint DirectorDiabetes Research Centre &M. V. Hospital for Diabetes

Chennai.

WHO Collaborating Centre for Research, Education & Training in diabetes

Factors found in Diabetes and Impaired wound healing

Peripheral neuropathy• Loss of protective sensation

• Autonomic dysfunction

• Impaired neuroinflammatory

reflexWound hypoxia• Macrovascular disease

• Microvascular disease

• Capillary loss

• Microvascular endothelial

dysfunction

Factors found in Diabetes and Impaired wound healing

Abnormal cellular pathways• Chemotaxis

• Fibroblast responsiveness

Excess inflammation• Oxidative stress

• Endothelial dysfunction and impaired nitric oxide

signaling

• Increased inflammatory cytokine expression

• Advanced glycosylation end products (AGEs) and

receptors (RAGE)Deficient precursor cells

HEMOSTASIS 1 hour

W

O

U

N

D

I

N

G

Platelets

Fibrin

INFLAMMATION days 1 through 7

Proteoglycans

Neutrophils

Macrophages]

LymphocytesPROLIFERATION days 2 through 20

Phases of normal wound healing

Fibroblasts[produce growth factors]

Collagen

Epithelial Cells

Endothelial CellsREMODELING 1 week to 6 months

Collagen Fibril Crosslinking

Scar Maturation

Time from injury

These stimulate synthesis of proteases (MMP’S)

Degrade matrix proteins & growth factors

Disruption in wound healing

Prolonged inflammatory reaction

in no. of neutrophils in the wound

These secrete proinflammatory cytokines (TNF - ), Interleukin (IL - 1)

Due to (1) Bacterial contamination (2) Recurrent painless tissue trauma

What happens in diabetes mellitus to wound healing

Changes at the molecular level in diabetes and their potential interrelationships leading to alterations of macromolecular

functions, which contribute to poor healing and ulcer formation

(a) Diminished neuroinflammatory signalling

NGF Nerve content

Substance P

Neuroinflammatory signalling

Glucose NEP activity

Changes at the molecular level in diabetes and their potential interrelationships leading to alterations of macromolecular

functions, which contribute to poor healing and ulcer formation

(b) Pathways of oxygen free radical production which in turn could damage DNA of cells involved in wound

healing

Glucose Glycation AGE

Activity antioxidant enzymes

GSH

Oxygen free radicals

Damage cellular

DNA

Arginase and NOS activities

Changes at the molecular level in diabetes and their potential interrelationships leading to alterations of macromolecular

functions, which contribute to poor healing and ulcer formation(c) Decreased angiogenesis

TGF - 1

Angiogenesis

NOS activity

NOS activity

NO

NO

IL - 6 bFGF

IL - 6

KGF

VEGF

NGF TGF - 1 IGF - 1 TGF - 1

NGF

KGF

bFGF

IL - 6

Changes at the molecular level in diabetes and their potential interrelationships leading to alterations of macromolecular

functions, which contribute to poor healing and ulcer formation

(d) Diminished ECM deposition

TGF - 1

ECM deposition NO

IGF - 1

Collagen synthesis

GAG synthesis

Neutrophil elastase and cathepsin G activities

TIMP

TGF - 1

MMP activity

TNF

Imbalances in the molecular environments of acute healing wounds and chronic non-healing

wounds

Molecular environment of wounds

Healing wounds

High Mitogenic activity

Low inflammatory cytokines

Low proteases

Mitotically competent cells Chronic Ulcers

Low Mitogenic activity

High inflammatory cytokines

High proteases

Senescent cells

Vijay Viswanathan *, Shiny John Vairamon **, A. Ramachandran *, C. Snehalatha * and Mary Babu **

* : Diabetes Research Centre, Royapuram, Chennai – 13, India

** : Biomaterial division, Central Leather Research Institute, Adyar, Chennai – 20 , India

Aim

To study the role of the inflammatory

status in the delayed wound healing of

diabetic patients

Subjects:

Study groups were:

• Group 1: Non-diabetic controls (n=10)

• Group 2: Patients with diabetes (n=10)

• Group 3: Diabetic neuropaths with foot ulceration [non infected] (n=10)

• Group 4: Diabetic neuropaths with foot ulceration [infected] (n=10)

• Group 5: Diabetic patients with neuroischemia and foot ulceration

[non infected] (n=10)

• Group 6: Diabetic patients with neuroischemia and foot ulceration

[infected] (n=10)

Matrix – degrading metalloproteinases (MMP)

Physiologic mediators of matrix degradation

Zinc dependent endopeptidases, which are capable of collectively degrading all kinds of extracellular matrix proteins

Play an important role in tissue remodeling

Matrix – degrading metalloproteinases (MMP)

Collagenases Gelatinases Stromelysins

Gelatinase A (MMP – 2)

Gelatinase B (MMP – 9)

Product of other cell types, including neutrophils and

keratinocytes

Methods

o Neuropathy was diagnosed ad VPT>25V by biothesiometer

o Peripheral vascular disease was diagnosed as ankle brachial

index (ABI)<0.8

o The expression of Matrix Metalloprotinases in tissue

homogenates (MMP-9) of diabetic foot ulcers and also in the

serum of the subjects (MMP-2) by Zymogram & Western

Blot

Results

MMP-9 active form was expressed in the tissue homogenate

of diabetic patients both in neuropathy & neuroischemic

with infective foot ulcer and not in diabetic patients with

callus

MMP-2 active form was expressed more in the serum of

diabetic patients both in neuropathy and neuroischemic with

infective foot ulceration.

The over expression of matrix

metalloprotinases in the wound tissue

contribute to the delayed wound healing.

Platelet – derived growth factor (PDGF)

PDGF plays a role in most phases of wound healing

displaying a variety of activities including as a

chemoattractant

stimulating cells to secrete growth factors and

inducing the production of several matrix molecules.

[Heldin CH et al., Physiol Rev 1999; 79: 1283 – 1316]

[Goldman R et al., Adv Skin Wound Care 2004; 17: 24 - 35]

Lack of PDGF protein was found in chronic wound fluid from

diabetic patients.

[Castronuovo JJ Jr et al., Am J Surg 1998; 176: 61S – 67S]

Addition of PDGF has been shown to enhance wound healing

and increase wound – breaking strength.

[Pierce GF et al., J Cell Biol 1989; 109: 429 - 440]

Components of Optimal Wound Care

• A comprehensive, standardisedwound care regimen

• Correct underlying condition

• Control infection

• Address ischaemia

• Correct structural defects

• Adequate glycaemic control for diabetic patients

• Adequate debridement

• Appropriate topical management (eg growth factors)

Wound dressings and treatments

• Today there are more than 2000 wound care products available, most of which are different varieties of dressings (Cohen IK, 1998) .

• Most modern dressings contain materials that are highly absorbent, such as alginates or foam. The list of modern wound dressings available is long and impressive; some types include :

Alginates Composites Exudate absorbers Foams Gauzes Hydrocolloids Hydrogels Skin Sealants Transparent Films

(Mulder GD, Haberer PA, Jeter KF, 1998)

Use of Biatin Silver in different types of Diabetic Foot Wounds

Why add Silver?

The antimicrobial of silver (or more accurately silver ions, Ag+) were

exploited long before microbes were discovered.

They selectively bind to thiol groups, which are widely distributed in

bacterial cell wall proteins

Also bind to bacterial DNA [Lansdown, 2002]

The silver added to advanced wound management products (AWMP)

is added in forms designed to make the cations more readily available.

Name : Mrs. Pusphammal

Age: 61 years Sex: Female

Diabetic for 10 years ; HbA1c: 12.2%;

H/O pinprick over right heel – 3 wks back; came

with a right heel abscess; discharging pus;; X-

ray foot showed osteomyelitis of right

calcaneum

Urea / Creatinine / Neuropathy: Normal

Patient underwent debridement and bone

curettage on 6/3/06 ; Normal vascularity

Started on Biatain Ag dressing from 1st Post

operative day

Came for review on 30/3/06 and 5/4/06

Wound looks clean; size has decreased ;

granulations have started covering calcaneum.

Name : Mr. Chinnaiah.P

Age: 68 years Sex: Male

Diabetic for 6 years ; HbA1c: 6.5%;

Admitted with left charcot foot with midfoot

collapse with plantar midfoot ulcer 5 x 5cm with a

cavity underneath with cellulitis leg.

Ulcer debrided on 5/3/06 ; OM of underlying bones

+ ; infected bones curetted ; good vascularity

Started on Biatain dressing from 7/3/06

CAD / Nephropathy (S. Creat : 4.8) ; Neuropathy +

Came for review on 27/3/06

Ulcer has decreased in size ; some maceration

present.

Hippocrates said that: “Healing is a matter

of time, but it is sometimes also a matter of

opportunity”.

Hippocrates (460 BC – 377 BC), Precepts.

This is very relevant concept when applied to

the diabetic foot