The inflammatory process The inflammatory process and immune reactions and immune reactions

associated with implant useassociated with implant useProfessor Peter A Revell

Implant Biology ResearchBiomaterials and Tissue Engineering Division

Eastman Dental InstituteLondon WC1X 8LD

prevell@eastman.ucl.ac.uk

WHENEVER a foreign material, organisms or cells are introduced into the body, inflammatory and immunological reactions take place

Consider:-venesection and injectionssurgical implantsinfectionsblood transfusion organ transplantation

WHENEVER a foreign material, organisms or cells are introduced into the body, inflammatory and immunological reactions take place

Consider:-venesection and injectionssurgical implantsinfectionsblood transfusion organ transplantation

Use of implants in bone

Orthopaedics - joint replacement- fracture fixation- screws, nails, wires

Dentistry - dental implants

When a joint is replaced, large pieces of foreign materials are placed in wounds created in bone by drilling, gouging and sawing

The healing process takes place in the continued presence of the foreign body which cannot, of course, be removed by any natural process

Inflammation

• occurs when any foreign material is introduced into the body

• may be acute ( and transient) with resolution and healing

• may be chronic, when the noxious stimulus persists

Resolution and healing

•inflammation resolves completely if damaging stimulus is removed OR

•healing with or without fibrous scarring

•may become chronic, when the noxious stimulus persists

Chronic Inflammation

• typically shows the presence of macrophages and lymphocytes

• is accompanied by the development of an immune response

Fibrous tissue and new bone formation

Lymphocytes, macrophages and multinucleate giant cells

(MNGC)

T & B cells, plasma cells

Healing with fibrous tissue

IMPLANT

BONE

Macrophages and multinucleate giant cells(MNGC) are found

-on biomaterial surfaces

-in relation to debris

Development of osteolysis

Aseptic loosening and osteolysis

Materialpropertiesdifference Micromovement

Wear debris &inflammation

At implantation

At implantation

Professor Peter A RevellOsteoarticular ResearchDepartment of HistopathologyRoyal Free Campus Royal Free & University College Medical SchoolLONDON NW3 2PF Large particles in

giant cells

There is gradual accumulationof particles deeper down betweenthe implant and the bone. This isaccompanied by an inflammatorycellular response which gives riseto bone loss - so called ‘osteolysis’

Particles can get down between the implant and bone carried by this fluid in continuity with the joint

Osteolysis

Macrophages & MNGCs

- ACTIVATED, expressing HLA-class II, cell surface epitopes, integrins (CD11a,b,c)(Revell & Jellie 1998; Curtis 2002)

CD11bαM / β2

Human macrophage in tissue culture

INTEGRIN Focal Adhesion Kinase

Macrophages and foreign body multinucleate giant cells make cytokines, chemical mediators, which influence their own behaviour and that of other cells

IL 1, IL 6, TNF are proinflammatorycytokines which perpetuate the inflammatory process. They have been shown in studies from various centresto be present in cells of the interface membrane and to be produced by macrophages on culture with particles.

Activated macrophages & MNGCs

GMGM--CSFCSF

Bone

Implant

Macrophages, giant cells and cytokines

TGFα, GM-CSF and M-CSF are responsible for promoting the formation of giant cells

Pro-inflammatory

Osteoclastogenic

Removal of bone by osteoclasts

Lymphocytes are present

Immune reactions

ave specificity ( antibody - antigen )

nvolve B lymphocytes and plasma cells which make antibodies OR

nvolve T lymphocytes which on stimulation produce chemical mediators

An immune reaction is aimed at a particular target

An immune reaction is aimed at a particular target

BUT

there may be collateral damage

HYPERSENSITIVITY REACTIONS

Mast cells and antibodies

Antibodies

Antibodies

Cell mediated,T lymphocytes

Clinical evidence forhypersensitivity reactions

in relation to implanted biomaterials

Metal sensitivity in patients with orthopaedic implants Hallab, Merritt, Jacobs (2001) J Bone Jt Surg 83A 428-436

The prevalence of dermal sensitivity in patients with a joint replacement device, particularly those with a failed implant, is substantially higher than that in the general population

THE ROLE OF LYMPHOCYTES

Passive role ? Bystanders ?

(Agins et al,1988; Lombardi et al, 1989;Santavirta et al, 1990,1991)

Active role ? Immune process ?

(Lalor & Revell, 1991;Weyand et al, 1998; Hercus & Revell, 2001; Bainbridge et al, 2001)

(Lalor & Revell,1991; Revell et al,1997; Al Saffar & Revell,1999; Weyand et al,1998)

6 to 16 per cent of cells

6 to 16 per cent of cells (Hercus, 2005)

T lymphocytes having immune memory

CD 45 RO positive staining

(Revell & Al-Saffar, 1994)

( Revell & Jellie, 1998 )

Ki 67

T H : T C / S = 7.2 : 1

Determine which sub-type of T helper lymphocyte

is involved in theimmunological process

Th 1 cells Th 2 cellsCell mediated immunity Humoural immunityMacrophages & natural B lymphocytes &

killer (NK) cells plasma cells

Helper T cell polarisation

Th1 > Th2 (Weyand et al ,1998; Hercus & Revell, 2001; Hercus, Saeed & Revell, 2002;Hercus, 2005)

No Th1 predominance (Arora et al, 2003)

Helper T cell polarisation

Multiplex PCR (Hercus)

Helper T cell polarisation

Cytokine profile

Th1 cell IL-2, IL-12 & IFN-γ

Th2 cell IL-4, IL-5 & IL-10

Th1 > Th2 Contact sensitisation process

T lymphocytes in the interface tissues in known nickel sensitivity

CD45Ro positive lymphocytes

Bainbridge, Revell & Al-Saffar (2001) J Biomed Mater Res 54, 328

Antigen presenting cells

Bainbridge, Revell & Al-Saffar (2001) J Biomed Mater Res 54, 328

Macrophages and lymphocytes

Macrophages and lymphocytes

P selectin

E selectin

E-selectin mediates T cell adhesion to endothelial cells and migration in skin contact hypersensitivity (Norris et al, 1991; de Vries et al, 1997)

Other adhesion molecules are also present (Revell et al, 1997; McFarlane & Revell, 2004)

Functional studies

Western blot of IL15 protein prior to deglycosylation: A

rHuIL15, B-E interface samples

Western blot of IL15 protein after

degycosylation: A rHuIL15, B-D interface samples

Macrophages and the IL15 receptor

Lymphocytes and the IL2 receptor

Ki 67

Macrophages and lymphocytes

CD40 Ro

Interleukin 15 is able to sustain the proliferation and survival

of T lymphocytes

In coculture experiments T lymphocytes are sustained

by U937 macrophagesphagocytosing particles

(Saeed, Damien and Revell, 2002a)

Submicron sized particles can be isolated from perimplant tissues and characterised

Phagocytosis of these particles activates macrophages which produce cytokines

Some of these are “pro-inflammatory”,others promote giant cell formation

The inflammatory response to the persistenceof these particles gives rise to bone loss

and implant loosening

Activated lymphocytes are present in large numbers in some cases

Immune sensitisation may be present in response to some metals

Evidence of sensitisation is provided by:-

•activated and proliferating T lymphocytes•T cells sustained by IL15•T helper cell predominance and T H1 > T H2•T memory cells•presence of P- and E-selectins on vessels•evidence for antigen presentation