REVIEW OF LITERATUREIndia is considered as diabetic capital of the world. Diabetes is growing alarmingly in our

country. Diabetes gained a status of epidemic in India with more than 65 million diabetic

individuals currently diagnosed with the disease and its rapid growth in country.

Approximately 9% of urban and 3% of rural population is estimated to have diabetes21.

The etiology of diabetes in India is multifactorial and includes genetic factors coupled

with environmental influences such as obesity associated with rising living standards,

steady urbanization and lifestyle changes. Delayed wound healing is one of the most

common complications of diabetes which increase the chance of amputation by

compared to normal people. People with diabetes has 50 times more likely to undergo

amputations than people without diabetes22.

Why diabetic wounds delay in healing?

Diabetic wounds pose a challenge to even to most experienced health professional.

There are many factors responsible for delayed healing and chronicity of wounds:

Figure 1: factors contributing for delayed wound healing in diabetics

DELAYED WOUND HEALING

WOUND INFECTIONS

ISCHEMIA

FAULTY WOUND HEALIN

G

IMMUNOPATHY IN DIABETES:

Diabetics have impaired polymorphonuclear function with decreased capacity to migrate

to the site of infection, decreased capacity to phagocytosis14. A significantly lower

chemotaxis has been found in polymorphonucleocytes of diabetic patients (type 1 and

type 2) than in those of controls15, 16, 17. The mean HbA1c concentration was lower

(better regulation) in patients without impaired phagocytosis18 than in those with

impaired phagocytosis19. Polymorphonucleocytes of diabetic patients have shown lower

phagocytic capacity compared to polymorphonucleocytes of controls.

NEUROPATHY IN DIABETES:

In diabetics there will be decreased sensitivity to pain, leading to small wounds due to

trauma. These wounds later gets infected and become chronic. Initially when patient get

injured, they do not notice wound as it is not painful. This makes wound more prone to

get infected6. Localized pressure also plays major role in diabetics, for example bed

sore, infected corn in the foot, if not treated properly can progress into chronic ulcer.

VACULOPATHY IN DIABETICS:

Diabetics will have micro and macroangiopathy. Decreased oxygenation and ischemia

activates inflammation at the site of wound that attracts neutrophils. Neutrophils release

inflammatory cytokines, proteolytic enzymes, reactive oxygen species (ROS) which

damage cells at wound site, prevent proliferation and wound healing. Neutrophils stay

for longer time in diabetic wounds compared to other acute wounds, leading to fact that

chronic diabetic wounds have higher levels of inflammatory cytokines and reactive

oxygen species (ROS) 7.

INADEQUATE LEVELS OF GROWTH FACTORS:

In chronic wounds, compared to acute wounds the levels of proteolytic enzymes

(elastase, matrix metallo proteinases) are high, while the concentration of growth factors

(platelet derived growth factor, keratinocyte growth factor etc.) are low. Inadequate

growth factors play a major role in defective wound healing in diabetics8.

Figure 2:

BACTERIA AND BIOFILMS:

In diabetics chronic wounds affects patients quality of life more than vision loss or renal

failure. Recently alteration in skin microbiota is emerging to have an impact on delayed

healing of diabetic wounds. Diabetic wounds will have high microbial burden. 85% of

amputations in patients with diabetes are preceded by infected wounds. Diabetic ulcers

are polymicrobial and multi drug resistant with ability to form biofilms. Biofilm forming

bacteria are 1000 times more resistant to antibiotics9. So biofilm formation is a very

important virulence factor and main reason for treatment failure. Most common

organism that infect chronic diabetic foot ulcer is Staphylococcus aureus13, followed by

Escherichia coli, Pseudomonas aeruginosa, Citrobacter species, Klebsiella oxytoca,

Proteus respectively. Among the above mentioned bacteria Staphylococcus aureus is

the most common biofilm former followed by Pseudomonas aeruginosa and Citrobacter.

80% of bacterial species isolated from diabetic foot ulcers were multi drug resistant.

Most commonly used antibiotic is amoxicillin + clavulanic acid followed by clindamycin.

50% of gram negative bacterial organisms show resistance to amoxicillin + clavulanic

acid. Imepenum, piperacillin + tazobactum, cefaperazone + sulbactum reported as most

effective drugs against diabetic foot ulcer infections.

Biofilm structure has been analyzed microscopically and biochemically. Biofilm is made

up of multilayered matrix containing water, bacterial cells, proteins, DNA and

polysaccharides.

Figure 3: Composition of Biofilm.

Close cell to cell contact in biofilms always allow easy transfer of plasmid containing

multi drug resistance (MDR) genes amongst one another. Organisms which form

biofilms are also characterized by tolerance which is temporary and non-heritable

character. Mechanism for tolerance:

a) Antibiotics that prevent cell division are ineffective against organisms producing

biofilms.

b) Drug penetration is hindered by polysaccharide matrix.

c) Drug efficacy is altered by pH of microenvironment of biofilm.

d) Biofilms hide microorganisms from host defense

Effective debridement of chronic wounds can overcome this problem.

FAULTY FIBROBLASTS:

Fibroblasts in diabetics have a reduced capacity to produce extra cellular matrix

proteins and keratinocytes that epithelize the wound11.

Epithelial progenitor cells (EPC’s) which are derived from bone marrow travel to the site

of injury and help in formation of blood vessels and wound healing. In study by Omaida

et al, EPC’s that are essential for wound healing are decreased both in circulation and

at wound site. They also found that impaired nitric oxide synthase (NOS) activation and

decreased stromal cell derived factor - 1 alpha (SDF-1 alpha) at wound site is also a

main reason for impaired wound healing.

In diabetics every scratch on skin is a matter of concern, as they have impaired wound

healing. Every small wound has potential to become infected chronic wound leading to

sepsis, amputation and even death.

OTHER CAUSES:

Many factors affect wound healing in diabetics such as age, comorbidities, Wound

etiology, size of wound, location of wound, heavy bio burden, nutritional status etc.

stress also plays a major role in wound healing. Diabetics with non-healing wounds are

at tremendous stress which will have negative effect on wound healing. Stress increase

cortisol levels that lowers immunity and inflammation, thereby increase chance of

infections12. Co-morbid conditions always contribute for wound to become chronic in

Diabetics e.g. diabetics with chronic disease are more prone to methicillin resistant

staphylococcus aureus (MRSA) 10.

Figure 4: multiple factors contributing to diabetic foot ulcers

IMPACT OF DELAYED WOUND HEALING:

Chase et al introduced the concept of “FOREVER HEALING AND PERMANENT WOUNDING” in diabetics. Patients with chronic diabetic wounds will have poor quality

of life. It involves loss of time because of multiple hospital visits over months, time off

work or loss of employment with significant financial burden on patient and his family.

Also affects the social wellbeing of the patient. Diabetic wounds resulting in amputation

increase threefold risk of death in next 18 months to 2 years5. Diabetic wounds are most

common cause of disabling chronic and expensive complication of diabetes.

Figure 5: Increased chance of mortality after amputation in diabetics

MANAGEMENT OF CHRONIC DIABETIC WOUNDS

It is estimated that 15% of diabetes patients will develop Diabetic foot ulcer once in their

life time, and approximately 14% of diabetic ulcers lead to amputation unless a prompt,

rational, multidisciplinary approach to therapy is taken. Factors that affect development

and healing of diabetic patient’s foot ulcer include the degree of metabolic control, the

presence of ischemia or infection, and continuing trauma to feet from excessive plantar

pressure or poorly fitting shoes. Appropriate wound care for diabetic patients addresses

these issues and provides optimal local ulcer therapy with debridement of necrotic

tissue, provision of a moist wound healing environment and applying topical agents

locally that help in healing. During the prolonged healing process of a chronic wound,

rapid and accurate evaluation of the healing progress is critical so that unsuccessful

treatments can be discontinued and alternate treatments be initiated as soon as

possible.

The “TIME” framework in diabetic wound management encompasses tissue

management, inflammation and infection control, moisture balance, and epithelial

(edge) advancement20. Tissue management aims to remove the necrotic tissue burden

via various methods of debridement. Infection and inflammation control by reduction of

bacterial biofilms, antibiotic use, local topical agents, Achieving a moist wound healing

environment without excessive wound moisture or dryness will result in moisture

balance. Epithelial advancement is promoted via removing the physical and biochemical

barriers for migration of epithelium from wound edges. These systematic and holistic

approaches will potentiate the healing abilities of the chronic diabetic ulcers, including

those that are recalcitrant.

Figure 6: “TIME” acronym for management of chronic diabetic wounds.

Adequate debridement, application of topical wound healing agents and dressings is

needed for chronic diabetic ulcers. Many techniques are available for wound dressing

and all essentially reduce infection and improve granulation tissue growth. In this study

the wound healing potential of topical placental extract was evaluated and compared

with topical ionic silver.

Importance of placental extracts in chronic diabetic

wounds:

It is known from traditional folk knowledge that the placenta, supporting the baby's

growth and development in the mother’s womb, contains a wide range of biologically

active components. Research over decades has been uncovering more and more of

these compounds. Indeed, it is claimed that the placenta is capable of producing just

about any substance found in any organ of the body. This biochemical treasure house

supplies the growing fetus with substances that the fetus itself cannot synthesize.

Though a rich source of bioactive components unless recovered, placenta becomes a

biomedical waste immediately after childbirth. Use of human placenta as a therapeutic

agent in no way hampers ecological balance rather promotes resource recovery from a

designated biomedical waste. Research on human placental extract gained a

momentum with the description of the preparation of its extract by Russian

ophthalmologist Prof. V.P. Filatov, he used placental extracts in grafting human corneas

in the year 1912.

Placenta serves as a natural storehouse of many biologically active components with

significant healing attributes. It actually involves in almost every stage of healing. Only

aqueous form is biologically active. Modern indigenous aqueous placental extract is

prepared employing Filatov’s procedure. Fresh placenta retrieved after baby’s birth is

tested for HIV, HBsAg and HCV. Single hot and cold aqueous extractions were done

after incubating placenta at 90oC and 6oC respectively. This was followed by sterilization

of extract under saturated steam (pressure 15-lbs/sq. inch at 120oC for 40 min). After

filtration and addition of 1.5% benzyl alcohol as preservative, ampoules were filled and

sterilized once again under the said condition for 20 minutes24. Each milliliter of drug

was derived from 0.1 g of fresh placenta. A single batch was prepared from pool of

several placentae.

Figure7: Cellular mechanism of wound repair in placental extract therapy.

MECHANISM OF ACTION OF PLACENTAL EXTRACT

IN HEALING WOUNDS:

Aqueous extract of placenta contains nucleotides like Polydeoxyribonucleotides

(PDRNs), known for their regenerative effect28. Placental extract is rich in enzymes like

alkaline and acid phosphatases, glutamic oxaloacetic acid transaminase; RNA, DNA,

and ATP; Vitamins like B1, B2, B6, pantothenic acid, biotin, Folic acid, B12, choline, and

inositol; Amino acids like alanine, aspartic acid, cysteine, histidine, leucine,

phenylalanine, proline, serine, threonine, tryptophan, valine and tyrosine; steroids;

elements like Na, K, Ca, Mg, Cu, Fe, P. All these components may exert multiple

biological activities. Placental extract also has Corticotropin Releasing Factor (CRF)

which is proven to be promoter of Human Epidermal Keratinocyte Proliferation29.

Placental extract increases collagen synthesis, increases tissue protein, accelerates

neoangiogenesis, and epithelialization. Has immunotropic effect on EGF (Epidermal

Growth Factor) and Fibroblast growth factor. It reduces surrounding tissue inflammation

and edema. Studies have shown that use of topical placental extract increases the rate

of wound healing and patients have an early recovery25.

Chakraborty et al. studied the role of placental extracts on the growth of different

bacteria26. They found that placental extracts prevents the growth of bacteria such as

E.coli from urine and blood culture. They found placenta to also have an inhibitory role

in the growth of bacteria such as Staphylococcus aureus, fungi such as Saccharomyces

cerevisae, Kluyvero-myces fragilis, and Candida albicans. Sudhir et al studied the effect

of topical placental extract dressing over various diabetic ulcers and had similar

results27. No side effect has been noted with placental therapy.

Importance of Ionic silver in chronic Diabetic wounds:

Silver is a precious metal, its medicinal properties were known from ages (over past 200

years) as silver coins and vessels were used for drinking water purification. Most of the

diabetic wounds are infected. Topical ointments containing ionic silver are used to

prevent and manage infection in wide range of wounds. The topical antimicrobial agent

silver has been used for hundreds of years in wound care. For example, silver has been

used to prevent or manage infection in its solid elemental form (e.g. silver wire placed in

wounds), as solutions of silver salts used to cleanse wounds (e.g. silver nitrate solution),

and more recently as creams or ointments containing a silver–antibiotic compound

(silver sulfadiazine (SSD) cream).

Silver is found in a number of forms35:

■ Elemental silver: e.g. Nano crystalline silver.

■ Inorganic compound: e.g. silver oxide, silver phosphate, silver chloride, silver-

calcium-sodium phosphate, silver zirconium compound, Silver sulfadiazine.

■ Organic complex: e.g. silver-zinc allantoinate, silver alginate, silver

carboxymethylcellulose.

Mechanism of action of silver at wound site:

In metallic (elemental) form, silver is unreactive and cannot kill bacteria. To become

bactericidal, silver atoms (denoted as Ag ) must lose an electron and become positively

charged silver ions (Ag+). Elemental silver ionizes in air, but ionizes more readily when

exposed to an aqueous environment such as wound exudate. Silver ions are highly

reactive and affect multiple sites within bacterial cells, ultimately causing bacterial cell

death. They bind to bacterial cell membranes, causing disruption of the bacterial cell

wall and cell leakage. Silver ions transported into the cell disrupt cell function by binding

to proteins and interfering with energy production, enzyme function and cell

replication36. Silver ions are active against a broad range of bacteria, fungi and viruses,

including many antibiotic-resistant bacteria, such as meticillin-resistant Staphylococcus

aureus (MRSA) and vancomycin-resistant Enterococci (VRE) 37. Ionic silver reduce

bacterial adhesion and destabilize the biofilm matrix, as well as kill bacteria within the

matrix and increase susceptibility of bacteria to antibiotics38. Ionic silver have be found

to have anti-inflammatory effect, increase neovascularization at wound site39.

Antibiotics act only at single site on target bacterial cell, which is the main reason for

increasing antibiotic resistance. Compared to antibiotics, ionic silver acts at multiple

sites on a target cell30. Therefore, chance of developing resistance to ionic silver is less.

So it can play a potential role in controlling infection and limiting antibiotic use, thereby

decreasing further chance of developing antibiotic resistance.

The aim of treatment with silver dressings is to reduce wound bioburden, treat local

infection and prevent systemic spread. Their main purpose is not to promote wound

healing directly. Clinical guidelines recommend that silver dressings are used for

wounds where infection is already established or an excessive wound bioburden is

delaying healing31, 32. Silver dressings should not be used on wounds where bioburden

is not a problem, i.e. they should be reserved for use in wounds with or at risk of high

bioburden or local infection34.

Figure 8: Mechanism of action of ionic silver on bacterial cell- attachment to the

bacterial cell wall, its diffusion into bacterial cell and coagulating bacterial

proteins/enzymes.

Silver dressings occasionally cause local skin discoloration or staining which is

harmless and usually reversible. This discoloration is not true systemic argyria, which is

rare and usually related to oral ingestion of silver solutions as an alternative health

practice. So ionic silver preparations are non-toxic and few studies even found that ionic

silver promotes wound healing in chronic wounds33. Studies show ionic silver have

antimicrobial activity against a wide range of microorganisms, including resistant forms

such as MRSA and VRE, and fungi and anaerobes40, 41.

.