derangement of wound healing in diabetic neuropathy

1. Dr. Vijay Viswanathan, M.D, Ph.D, MNAMS
Joint Director
Diabetes Research Centre &
M. V. Hospital for Diabetes
Chennai.
WHO Collaborating Centre for Research,
Education & Training in diabetes

2. Factors found in Diabetes and Impaired wound healing
Peripheral neuropathy
• Loss of protective sensation
• Autonomic dysfunction
• Impaired neuroinflammatory reflex
Wound hypoxia
• Macrovascular disease
• Microvascular disease
• Capillary loss
• Microvascular endothelial dysfunction

3. 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

4. HEMOSTASIS 1 hour
W
O
U
N
D
I
N
G
Platelets
Fibrin
INFLAMMATION days 1 through 7
Proteoglycans
Neutrophils
Macrophages]
Lymphocytes
PROLIFERATION days 2 through 20
Phases of normal wound healing
Fibroblasts[produce growth factors]
Collagen
Epithelial Cells
Endothelial Cells
REMODELING 1 week to 6 months
Collagen Fibril Crosslinking
Scar Maturation
Time from injury

5. 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 - α), Interleukin
(IL - 1β)
Due to (1) Bacterial contamination
(2) Recurrent painless tissue trauma
What happens in diabetes mellitus to wound healing

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
(a) Diminished neuroinflammatory signalling
↓ NGF ↓ Nerve content
↓ Substance P ↓ Neuroinflammatory signalling
↓ Glucose ↓ NEP activity

7. 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

8. 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 - β1
↓ Angiogenesis
↓ NOS
activity
↑ NOS
activity
↓ NO
↑ NO
↓ IL - 6 ↓ bFGF
↓ IL - 6
↓ KGF
↓ VEGF
↓ NGF↓ TGF - β1↓ IGF - 1 ↓ TGF - β1
↓ NGF
↓ KGF
↓ bFGF
↓ IL - 6

9. 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 - β1
↓ ECM deposition↓ NO
↓ IGF - 1
↓ Collagen synthesis ↓ GAG synthesis
↑ Neutrophil elastase and
cathepsin G activities
↓ TIMP
↓ TGF - β1
↑ MMP activity
↑ TNFα

10. 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

11. 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

12. Aim
To study the role of the inflammatory
status in the delayed wound healing of
diabetic patients

13. 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)

14. 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

15. 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

19. 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.

20. The over expression of matrix
metalloprotinases in the wound tissue
contribute to the delayed wound healing.

21. 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]

22. Components of Optimal Wound Care
• A comprehensive, standardised
wound 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)

23. Wound dressings and treatments

24. • 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)

25. 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.

26. 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.

27. 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.

28. 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