Synteettinen rusto kehitteillä

https://www.ncbi.nlm.nih.gov/pubmed/28773566

Materials (Basel). 2016 Jun 3;9(6). pii: E443. doi: 10.3390/ma9060443.

Hydrogels as a Replacement Material for Damaged Articular Hyaline Cartilage.

Beddoes CM¹, Whitehouse MR², Briscoe WH³, Su B⁴.

Suomennosta abstraktista. 

Hyaliinirusto on kestävää materiaalia, joka toimii nivelten liikkeissä voiteluaineena. Koska rusto (cartilago)  on avaskulaarista- siinä ei ole verisuonia- sen itsestääntoipumiskyky on huono ja tästä nivelen korjaantuminen ennalleen on haasteellista. Jos vaurio on paha, joudutaan rustoa korvamaan.  Tällä hetkellä 2016 ei vielä kyetä replikoimaan hyaliinirustoa ja sen takia käytetään vaihtoehtoismateriaaleja, joiden  ominaisuudet ovat huomattavan erilaisia. Tästa johtuen tulee  epätoivottuja sivuvaikutuksia kuten riittämätön voiteluominaisuus, kulutuksesta  muodostuvaa debristä,  vastapäisen  ruston kulumaa  ja ympäröivien kudosten heikentymää. On tullut ilmeiseksi, että  rustonkorjauskirurgian tarve on lisääntymään päin ja sentakia tarvitaan parempia rustonkaltaisuuksia omaavia aineita, jotka myös antavat tukea  ympärillä olevalle  materiaalille sen  tyyppifunktiossaan. 

Tutkijat esittävät tässä artikkelissaan  lyhyen yleiskatsauksen hyaliiniruston rakenteesta ja ominaisuuksista sekä nykyisistä rustonkorjausmetodeista.  He myös valaisevat muatamia vaihtoehtoisia  kehitteillä olevia materiaaleja, joilla on mahdollisuuksia  toimia korjausmenetelminä . Sitten  seruaa katsaus vahvojen  hydrogeelien  kehittelystä. Erityisesti kaksoisverkostuneet hydrogeelit  ovat lupaava korvausmateriaali, jonka fysikaalisia ominaisuuksia jatkuvasti kohennetaan. Nämä hydrogeelit  yltävät lähemmäksi hyaliiniruston voiman ja vahvuuden  replikoitumista tarjoten samalla myös ovallisen voitelun.    Yhteenvedossa  valaistaan useita eri metodeja, joilla   integroidaan korvaavia materiaaleja  luonnolliseen niveleen  varmistamaan stabiliteettia ja optimaalista toimintaa.

Abstract

Hyaline cartilage is a strong durable material that lubricates joint movement. Due to its avascular structure, cartilage has a poor self-healing ability, thus, a challenge in joint recovery. When severely damaged, cartilage may need to be replaced. However, currently we are unable to replicate the hyaline cartilage, and as such, alternative materials with considerably different properties are used. This results in undesirable side effects, including inadequate lubrication, wear debris, wear of the opposing articular cartilage, and weakening of the surrounding tissue. With the number of surgeries for cartilage repair increasing, a need for materials that can better mimic cartilage, and support the surrounding material in its typical function, is becoming evident.
 Here, we present a brief overview of the structure and properties of the hyaline cartilage and the current methods for cartilage repair. We then highlight some of the alternative materials under development as potential methods of repair; this is followed by an overview of the development of tough hydrogels. In particular, double network (DN) hydrogels are a promising replacement material, with continually improving physical properties. These hydrogels are coming closer to replicating the strength and toughness of the hyaline cartilage, while offering excellent lubrication. We conclude by highlighting several different methods of integrating replacement materials with the native joint to ensure stability and optimal behaviour.

KEYWORDS:
articular cartilage; double network; hydrogels; implant; self-healing

PMID: 28773566 PMCID: PMC5456752 DOI:10.3390/ma9060443 Free PMC Article

• Uudempi artikkeli vuoaelta 2019.
•  Selostetaan  kaksoisverkoston/DN, Double Net)  muodosotumista.

 https://www.ncbi.nlm.nih.gov/pubmed/31009565

iomacromolecules. 2019 Apr 22. doi: 10.1021/acs.biomac.9b00237. [Epub ahead of print]
Double Network Hydrogels that Mimic the Modulus, Strength and Lubricity of Cartilage.

Means AK, Shrode CS, Whitney LV, Ehrhardt DA, Grunlan MA.

Abstract

The development of a hydrogel-based synthetic cartilage has the potential to overcome many limitations of current chondral defect treatments. Many efforts have attempted to replicate the unique characteristics of cartilage in hydrogels, but none simultaneously achieved high modulus, strength and toughness while maintaining the necessary hydration required for lubricity. Herein, double network (DN) hydrogels, composed of a poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) 1st network and a poly(N-isopropyl-acrylamide-co-acrylamide) [P(NIPAAm-co-AAm)] 2nd network, are evaluated as a potential off-the-shelf material for cartilage replacement. While predominantly used for its thermosensitivity, PNIPAAm is employed to achieve superior mechanical properties and its thermal transition temperature tuned above the physiological range. These PNIPAAm-based DNs demonstrate a 50-fold increase in compressive strength (~25 MPa, similar to cartilage) compared to traditional single network hydrogels while also achieving a cartilage-like modulus (~1 MPa) and hydration (~80%). By directly comparing to healthy cartilage (porcine), these hydrogels are confirmed not only to parallel the strength, modulus and hydration of native articular cartilage but also exhibit a 50% lower coefficient of friction (COF). The exceptional cartilage-like properties of the PAMPS/P(NIPAAm-co-AAm) DN hydrogels makes them candidates for synthetic cartilage grafts for chondral defect repair, even in load-bearing regions of the body.

PMID:

31009565

DOI:

10.1021/acs.biomac.9b00237

Kylkiluumurtuma, multippli; epästabiili rintakehä (thesis 2019)

Sammanfattning:	Background: Surgical management of chest wall injuries has received increasing attention in recent years. The aim of this thesis was to study the mechanism of injury (MOI) in relation to chest wall injury patterns and short- and long-term outcome of surgery in patients with multiple rib fractures and unstable thoracic cage injuries. Methods: Paper I is a retrospective study (n=211) of the association of MOI and injury patterns in patients operated for acute chest wall injuries. Paper II is a prospective longitudinal study (n=54) of the long-term outcome of surgery in patients with multiple rib fractures and flail chest. Paper III is a cross-sectional study (n=37) of the use of CT-lung volume estimation as a marker for lung function in patients operated for flail chest. Paper IV is a prospective controlled study (n=139) of the short- and long-term outcome of surgery in patients with unstable thoracic cage injuries. Results: The MOI differs according to age and is associated with different chest wall injury patterns. Lateral and posterior flail segments are the most commonly seen. Symptoms of pain, lung function and Quality of Life (QoL), improve during the first post-operative year. CT-lung volume estimates increase significantly from preoperative values to post-operative values and there is a high correlation between post-operative CT-lung volume and lung function. Surgery for unstable thoracic cage injuries does not decrease the need for mechanical ventilation. However, surgically managed patients have a decreased incidence of pneumonia (17% vs. 36%, p=0.013) and less pain (29% vs. 57%, p<0.05) the first months’ post trauma. Patients operated without thoracotomy have a better residual lung function and lung volume. A gradual improvement in patient symptoms was seen and after one year there was no difference in symptoms, function or QoL between surgically and conservatively managed patients. Conclusions: The MOI influences rib fracture pattern and associated injuries. Lung volume estimated by CT can be used as a marker for lung function. Surgery for unstable thoracic cage injuries decreases the incidence of pneumonia and reduces pain. Patients continue to improve gradually and no difference can be seen between the surgically and conservatively managed patients one year post trauma.
ISBN:	978-91-7833-314-1 (PRINT) 978-91-7833-315-8 (PDF)
URI:	http://hdl.handle.net/2077/58504