Inductive Materials for Regenerative Engineering.

Regenerative engineering has pioneered several novel biomaterials to treat critical-sized bone injuries. However, despite significant improvement in synthetic materials research, some limitations still exist. The constraints correlated with the current grafting methods signify a treatment paradigm shift to osteoinductive regenerative engineering approaches. Because of their intrinsic potential, inductive biomaterials may represent alternative approaches to treating critical bone injuries. Osteoinductive scaffolds stimulate stem cell differentiation into the osteoblastic lineage, enhancing bone regeneration. Inductive biomaterials comprise polymers, calcium phosphate ceramics, metals, and graphene family materials. This review will assess the cellular behavior toward properties of inductive materials.

PDLA/PLLA and PDLA/PCL nanofibers with a chitosan-based hydrogel in composite scaffolds for tissue engineered cartilage.

Osteoarthritis (OA) is the most prevalent musculoskeletal disease in humans, causing pain, loss of joint motility and function, and severely reducing the standard of living of patients. Cartilage tissue engineering attempts to repair the damaged tissue of individuals suffering from OA by providing mechanical support to the joint as new tissue regenerates. The aim of this study was to create composite three dimensional scaffolds comprised of electrospun poly(D,L-lactide)/poly(L-lactide) (PDLA/PLLA) or poly(D,L-lactide)/polycaprolactone (PDLA/PCL) with salt leached pores and an embedded chitosan hydrogel to determine the potential of these scaffolds for cartilage tissue engineering. PDLA/PLLA-hydrogel scaffolds displayed the largest compressive moduli followed by PDLA/PCL-hydrogel scaffolds. Dynamic mechanical tests showed that the PDLA/PLLA scaffolds had no appreciable recovery while PDLA/PCL scaffolds did exhibit some recovery. Primary canine chondrocytes produced both collagen type II and proteoglycans (primary components of extracellular matrix in cartilage) while being cultured on scaffolds composed of electrospun PDLA/PCL. As a result, a composite electrospun embedded hydrogel scaffold shows promise for treating individuals suffering from OA.

Lactoferrin: a biologically active molecule for bone regeneration.

Lactoferrin, a member of the "Siderophilin" family, is an iron binding glycoprotein. Lactoferrin is produced by various exocrine glands in our body and is abundantly present in milk and colostrums. The uniqueness of lactoferrin as a skeletal regenerative molecule lies in its ability to favorably modulate the responses of the various cell types involved in musculoskeletal regeneration. Lactoferrin exhibits pleiotropic functions and recent studies indicate that lactoferrin promotes the proliferation and differentiation of osteoblast cells and inhibits osteoclast-mediated bone resorption. Human lactoferrin is also known to promote neovascularization. This review aims to summarize the most recent studies on lactoferrin focusing on its anabolic effect to bone tissue and the ability to modulate immune responses with specific focus on osteoimmunology.

Formation and properties of composites comprised of calcium-deficient hydroxyapatites and ethyl alanate polyphosphazenes.

Composites comprised of calcium-deficient hydroxyapatite (HAp) and biodegradable polyphosphazenes were formed via cement-type reactions at physiologic temperature. The composite precursors were produced by blending particulate hydroxyapatite precursors with 10 wt% polymer using a solvent/non-solvent technique. HAp precursors having calcium-to-phosphate ratios of 1.5 (CDH) and 1.6 (CDS) were used. The polymeric constituents were poly[bis(ethyl alanato)phosphazene] (PNEA) and poly[(ethyl alanato)(1) (p-phenylphenoxy)(1) phosphazene] (PNEA(50)PhPh(50)). The effect of incorporating the phenyl phenoxy group was evaluated as a means of increasing the mechanical properties of the composites without retarding the rates of HAp formation. Reaction kinetics and mechanistic paths were characterized by pH determination, X-ray diffraction analyses, scanning electron microscopy, and infrared spectroscopy. The mechanical properties were analyzed by compression testing. These analyses indicated that the presence of the polymers slightly reduced the rate HAp formation. However, surface hydrolysis of polymer ester groups permitted the formation of calcium salt bridges that provide a mechanism for bonding with the HAp. The compressive strengths of the composites containing PNEA(50)PhPh(50) were superior to those containing PNEA, and were comparable to those of HAp produced in the absence of polymer. The current composites more closely match the structure of bone, and are thus strongly recommended to be used as bone cements where high loads are not expected.

Effects of malaria infection on pregnancy.

A study of the effects of malaria infection on the progress and outcome of pregnancy was carried out during 1987-88 in the Medical College Hospital, Surat, Gujarat. Pregnant women were highly susceptible to the infection (SPR, 57.7) compared to the general population (SPR, 18.6). P. falciparum infection was predominant (62.4%). The infection rate was also found to be higher (SPR, 72.2%) in second trimester compared to first and third semesters. Primigravidae seemed to be at a greater risk as the mean parasitaemia level was higher (39%) and the outcome poor as compared to multigravidae (29%). Infection during pregnancy caused severe maternal complications like abortion (9.7%), premature labour (59.6%), and still-births (5.7%), which were higher in P. falciparum infection. Microcytic anaemia combined with dimorphic anaemia was predominant in the infected group (89.5%). Cord blood in 4 cases and on baby's blood were found positive for malaria parasite, showing transplacental passage of malaria parasites, which is rare. The infection was found to have a definite bearing on the low birth weight of babies. Chemoprophylaxis could obviate much of the complications.