Effects of empagliflozin on collagen biomarkers in patients with heart failure: Findings from the EMPEROR trials.

AIMS: Extracellular matrix remodelling is one of the key pathways involved in heart failure (HF) progression. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) may have a role in attenuating myocardial fibrosis. The impact of SGLT2i on blood markers of collagen turnover in humans is not fully elucidated. This study aimed to investigate the effect of empagliflozin on serum markers of collagen turnover in patients enrolled in the EMPEROR-Preserved and EMPEROR-Reduced trials. METHODS AND RESULTS: Overall, 1084 patients (545 in empagliflozin and 539 in placebo) were included in the analysis. Procollagen type I carboxy-terminal propeptide (PICP), a fragment of N-terminal type III collagen (PRO-C3), procollagen type I amino-terminal peptide (PINP), a fragment of C-terminal type VIa3 collagen (PRO-C6), a fragment of type I collagen (C1M), and a fragment of type III collagen (C3M) were measured in serum at baseline, 12 and 52 weeks. A mixed model repeated measurements model was used to evaluate the effect of empagliflozin versus placebo on the analysed biomarkers. Higher baseline PICP, PRO-C6 and PINP levels were associated with older age, a more severe HF presentation, higher levels of natriuretic peptides and high-sensitivity troponin T, and the presence of comorbid conditions such as chronic kidney disease and atrial fibrillation. Higher PICP levels were associated with the occurrence of the study primary endpoint (a composite of HF hospitalization or cardiovascular death), and PRO-C6 and PINP were associated with the occurrence of sustained worsening of kidney function. On the other hand, PRO-C3, C1M, and C3M were not associated with worse HF severity or study outcomes. Compared to placebo, empagliflozin reduced PICP at week 12 by 5% and at week 52 by 8% (week 12: geometric mean ratio = 0.95, 95% confidence interval [CI] 0.91-0.99, p = 0.012; week 52: geometric mean ratio = 0.92, 95% CI 0.88-0.97, p = 0.003). Additionally, empagliflozin reduced PRO-C3 at week 52 by 7% (week 12: geometric mean ratio = 0.98, 95% CI 0.95-1.02, p = 0.42; week 52: geometric mean ratio = 0.93, 95% CI 0.89-0.98, p = 0.003), without impact on other collagen markers. CONCLUSION: Our observations are consistent with experimental observations that empagliflozin down-regulates profibrotic signalling. The importance of such an effect for the clinical benefits of SGLT2i in HF remains to be elucidated.

hKLK alleviates myocardial fibrosis in mice with viral myocarditis.

Myocardial fibrosis is the most serious complication of viral myocarditis (VMC). This study aimed to investigate the therapeutic benefits and underlying mechanisms of lentivirus-mediated human tissue kallikrein gene transfer in myocardial fibrosis in VMC mice. We established VMC mouse model via intraperitoneal injection with Coxsackie B3 virus. The effect was then assessed after treatment with vehicle, the empty lentiviral vectors (EZ.null), and the vectors expressing hKLK1 (EZ.hKLK1) via tail vein injection for 30 days, respectively. The results showed that administering EZ.hKLK1 successfully induced hKLK1 overexpression in mouse heart. Compared with EZ.null treatment, EZ.hKLK1 administration significantly reduced the heart/weight ratio, improved cardiac function, and ameliorated myocardial inflammation in VMC mice, suggesting that hKLK1 overexpression alleviates VMC in mice. EZ.hKLK1 administration also significantly abrogated the increased myocardial collagen content, type I/III collagen ratio, TGF-ß1 mRNA and protein expression in VMC mice, suggesting that hKLK1 overexpression reduces collagen accumulation and blunts TGF-ß1 signaling in the hearts of VMC mice. In conclusion, our results suggest that hKLK1 alleviates myocardial fibrosis in VMC mice, possibly by downregulating TGF-ß1 expression.

Fuzheng Huayu preparation (/) combined with tenofovir disoproxil fumarate on hepatitis B: a systematic review and Meta-analysis.

OBJECTIVE: To systematically evaluate the effectiveness of Fuzheng Huayu preparation (/, FZHY) plus tenofovir disoproxil fumarate (TDF) on hepatitis B. METHODS: Numerous databases - PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure Database, WanFang Database, China Science and Technology Journal Database, and China Biological Medicine Database - were searched to identify the randomized controlled trials published from the inception of the database to November 2021. Two researchers independently conducted literature screening, data extraction, and bias risk assessment. RevMan 5.4 software was used for Meta-analysis. RESULTS: Eight studies involving 990 patients met the inclusion criteria in the current Meta-analysis. Levels of alanine transaminase, aspartate aminotransferase, total bilirubin, hyaluronic acid, type III procollagen, laminin, and type IV collagen after combination therapy were significantly lower than those after TDF therapy alone. However, albumin levels did not differ significantly between the two regimens. Subgroup analysis based on disease progression suggested that the combination therapy improved albumin levels in patients with chronic hepatitis B but not in patients with hepatitis B-related cirrhosis. Moreover, subgroup analysis based on treatment duration suggested that the albumin levels were increased and the type III procollagen levels were decreased with the > 24-week combination therapy but not with the ≤ 24-week combination therapy. CONCLUSIONS: A combination regimen of TDF and FZHY is more effective in treating hepatitis B than TDF alone. The combination therapy can effectively alleviate hepatic fibrosis and improve liver function. However, more standardized, high-quality studies with larger sample sizes are warranted to validate the study results.

Indicators of Kidney Fibrosis in Patients with Type 2 Diabetes and Chronic Kidney Disease Treated with Dulaglutide.

INTRODUCTION: In the AWARD-7 study in patients with type 2 diabetes and moderate-to-severe chronic kidney disease, once-weekly dulaglutide slowed the decline in estimated glomerular filtration rate (eGFR) and decreased the urine albumin/creatinine ratio compared to insulin glargine at the end of 52 weeks of treatment. In this exploratory post hoc analysis, changes in two fibrosis biomarkers, serum PRO-C6 (type VI collagen formation) and urine C3M (type III collagen degradation), were evaluated. METHODS: In the groups treated with dulaglutide 1.5 mg or insulin glargine (N = 330), serum PRO-C6 and urine C3M were measured using competitive enzyme-linked immunosorbent assays. Biomarker changes were assessed by a mixed-effects model for repeated measures. Pearson correlation analyses were conducted to determine associations between changes in kidney fibrosis biomarkers and eGFR measures at 52 weeks. RESULTS: At weeks 26 and 52 of treatment in the overall population, serum PRO-C6 levels were significantly lower in the dulaglutide group versus insulin glargine group with percent change from baseline of (least squares mean ± standard error) -4.6% ± 1.9 and -0.2% ± 2.2 versus 5.7% ± 2.0 and 8.0% ± 2.3 (p < 0.01), respectively, and urine C3M levels were significantly higher in the dulaglutide group versus insulin glargine group with percent change from baseline of 10.9% ± 8.2 and 20.7% ± 8.8 versus -10.0% ± 6.5 and -16.9% ± 6.4 (p < 0.05), respectively. These findings appeared greater in the subgroup with macroalbuminuria. Serum PRO-C6 negatively correlated with eGFR, while urine C3M positively correlated with eGFR. CONCLUSION: Dulaglutide treatment was associated with biomarker changes that indicated lower type VI collagen formation and higher type III collagen degradation compared to treatment with insulin glargine, suggesting a potential drug effect to reduce kidney fibrosis.

Dissolving microneedle-encapsulated drug-loaded nanoparticles and recombinant humanized collagen type III for the treatment of chronic wound via anti-inflammation and enhanced cell proliferation and angiogenesis.

Nowadays, diabetic chronic wounds impose a heavy burden on patients and the medical system. Persistent inflammation and poor tissue remodeling severely limit the healing of chronic wounds. For these issues, the first recombinant humanized collagen type III (rhCol III) and naproxen (Nap) loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticle incorporated hyaluronic acid (HA) microneedle (MN) was fabricated for diabetic chronic wound therapy. As the tailored rhCol III was synthesized based on the Gly483-Pro512 segment, which contained the highly adhesive fragments (GER, GEK) in the human collagen type III sequence, it possessed strong cell adhesion. The mechanical strength of the prepared MN was enough to overcome the tissue barrier of necrosis/hyperkeratosis in a minimally invasive way after being applied in wounds. Subsequently, rhCol III and Nap@PLGA nanoparticles were rapidly released to the wound site within a few minutes. The prepared MN possessed favourable biocompatibility and could effectively facilitate the proliferation and migration of fibroblasts and endothelial cells. Furthermore, the regenerative efficacy of the MN was evaluated in vivo using the diabetic rat full-thickness skin wound model. These results illustrated that the prepared MN could accelerate wound closure by reducing the inflammatory response and enhancing angiogenesis or collagen deposition, indicating their significant application value in wound dressings for chronic wound repair.

Vascular Ehlers-Danlos Syndrome: Pathological Variants, Recent Discoveries, and Theoretical Approaches.

Vascular Ehlers-Danlos syndrome (vEDS) is a rare autosomal dominant genetic disorder. It is the most fatal among all types of EDS. In addition to typical EDS characteristics, vEDS patients are at risk of blood vessel rupture due to possession of pathogenic variants of the COL3A1 gene, which encodes type III collagen. Type III collagen is a major component of humans' vascular walls. The management of this disease is possible; however, there is no cure as of present. Recently, discoveries with potential impact on the management of vEDS have been elucidated. Mice with vEDS traits treated with a beta-blocker celiprolol showed significant improvements in their thoracic aorta biomechanical strength. Moreover, it has been demonstrated that the specifically designed small interference RNAs (siRNA) can effectively silence the pathogenic variant allele. To enhance the normal allele expression, an intracellularly expressed lysyl oxidase is shown to regulate the transcription rate of the COL3A1 promoter. Similarly, an embryonic homeobox transcription factor Nanog upregulates the wild-type COL3A1 expression through activation of the transforming growth factor-beta pathway, which increases type III collagen synthesis. Despite numerous advancements, more studies are to be performed to incorporate these discoveries into clinical settings, and eventually, more personalized treatments can be created.

Microenvironment-responsive multifunctional hydrogels with spatiotemporal sequential release of tailored recombinant human collagen type III for the rapid repair of infected chronic diabetic wounds.

Recently, the incidence of chronic diabetic wounds increases continuously, and the existing clinical treatment is less effective. Thus, it is an urgent need to solve these problems for better clinical treatment effects. Herein, we prepared a brand-new tailored recombinant human collagen type III (rhCol III) and constructed a multifunctional microenvironment-responsive hydrogel carrier based on multifunctional antibacterial nanoparticles (PDA@Ag NPs) and our tailored rhCol III. The multifunctional smart hydrogel disintegrated quickly at the chronic diabetic wound sites and achieved the programed on-demand release of different therapeutic substances. The first released PDA@Ag NPs showed great antibacterial properties against S. aureus and E. coli. They could kill bacteria rapidly, and also showed antioxidant and anti-inflammatory effects at the wound site. The subsequent release of our tailored rhCol III could promote the proliferation and migration of mouse fibroblasts and endothelial cells during the proliferation and remodeling process of wound healing. Relevant results showed that the multifunctional smart hydrogel could promote the expression levels of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), decrease the inflammatory response, accelerate the deposition of collagen and increase cell proliferation and angiogenesis, thereby speeding up the healing of infected chronic wounds. In a word, the hydrogel, which took into consideration the complex microenvironment at the wound site and multi-stage healing process, could achieve programmed and responsive release of different therapeutic substances to meet the treatment needs in different wound healing stages. More importantly, our work illustrated the great application potential of our brand-new rhCol III in promoting chronic wound repair and regeneration.

Intravaginal Administration of Human Type III Collagen-Derived Biomaterial with High Cell-Adhesion Activity to Treat Vaginal Atrophy in Rats.

Vaginal atrophy (VA) is the thinning and drying of the vaginal walls, which can lead to a variety of symptoms. VA is usually initiated by decreasing estrogen levels in post-menopausal women; so, the traditional treatment of VA is hormone therapy (HT). Here, we sought nonhormonal therapies aimed at treating this condition safely and effectively. Collagen is an excellent biomaterial and has important biological functions in skin and mucosal tissues. In particular, collagen can bind to epithelial cells to promote proliferation and differentiation. In this study, recombinant protein T16, which was derived from human type III collagen to provide potent cell-adhesion activity, was used as a safe alternative therapy to treat VA in ovariectomy rat models. After T16 was administered intravaginally for 2 weeks, the autologous collagen arrangement was improved in the epithelium and muscle layer of the rat vagina, and the thickness of epithelium tissue also increased significantly. Compared with the sham group, collagen therapy was found to influence the expression levels of several important proteins in the vaginal tissue, resulting in the upregulation of TIMP-1, Collagen I, Collagen III, Ki-67, VEGF, and AQP-2 and the downregulation of MMP-1 and IL-6. Cells in the collagen treatment group exhibited better proliferation and less apoptosis properties. These results not only provide support for additional animal experiments to further evaluate collagen therapy in VA treatment but also suggest the potential for wide applications of collagen biomaterials with high cell-adhesion activities.

Good clinical results with autologous matrix-induced chondrogenesis (Amic) technique in large knee chondral defects.

PURPOSE: Autologous matrix-induced chondrogenesis (AMIC) is a treatment for focal full-thickness cartilage defects combining microfracturing with an exogenous I/III collagen matrix (Chondro-Gide). The aim of the present study was to determine the 7 years outcomes of patients treated with the AMIC technique for knee chondral defects larger than 2 cm2. The hypothesis was that the positive short-term outcomes achieved in the previous series would not deteriorate at a 7-year follow-up. METHODS: Twenty-one patients treated with the AMIC technique were retrospectively analysed. Patients were assessed through the IKDC subjective knee evaluation questionnaire and the Lysholm scoring system. All patients underwent a complete imaging study including radiographs and magnetic resonance. The median defect size was found to be 4.3 (range 2.9-8) cm2. RESULTS: At a median follow-up of 7 (±1.4) years, the mean IKDC score improved from 31.7 (±8.9) points preoperatively, to 80.6 (±5.3) at the latest follow-up (p < 0.05). The mean Lysholm score improved from 38.8 (±12.4) points preoperatively to 72.6 (±19.5) points at the last follow-up (p < 0.05). At the last follow-up, 76.2% of patients were satisfied or extremely satisfied with their outcomes, while 66.6% of patients showed good quality repair tissue on magnetic resonance imaging. CONCLUSION: AMIC was found to be an effective method to treat full-thickness knee chondral defects larger than 2 cm2, with significant clinical and functional improvement maintained over a 7-year follow-up. LEVEL OF EVIDENCE: IV.

Stage-two surgery using collagen soft tissue grafts: clinical cases and ultrastructural analysis.

OBJECTIVE: To present the application of two different soft tissue grafts around dental implants during stage-two surgery. Furthermore, the ultrastructure of these materials is shown and discussed using scanning electron microscopy (SEM). SUMMARY: Although soft tissue autografts may be currently regarded as the gold standard, harvesting of these grafts might lead to higher morbidity, longer chair time, and intra-/postoperative complications at the donor site. New developments in collagen scaff olds have provided an alternative to successfully replace autologous grafts in clinical practice. The SEM pictures clearly show the different composition of a bilayer scaff old (collagen matrix, CM) and a porcine acellular dermal matrix (ADM). These distinctive properties lead to different possible indications. Within the presented cases, ADM was used to augment the ridge contour and was placed into a buccal pouch to achieve complete coverage and an uneventful closed healing. On the other side, CM was left exposed to the oral cavity to successfully gain keratinized mucosa around and between two dental implants.

Randomized, controlled clinical trial to evaluate a xenogeneic collagen matrix as an alternative to free gingival grafting for oral soft tissue augmentation.

BACKGROUND: The standard of care for increasing keratinized tissue (KT) and vestibular area is an autogenous free gingival graft (FGG) and vestibuloplasty; however, there is morbidity associated with the harvest of autogenous tissue, and supply is limited. The purpose of this study is to determine if a xenogeneic collagen matrix (CM) might be as effective as FGG. METHODS: This study is a single-masked, randomized, controlled, split-mouth study of 30 patients with insufficient zones of KT (<2 mm). It uses a within-patient treatment-comparison design to establish non-inferiority of the test (CM) versus control (FGG) therapy. The primary efficacy endpoint was change in KT width (∆KT) from surgery to 6 months post-surgery. Secondary endpoints included traditional periodontal measures, such as clinical attachment level, recession, and bleeding on probing. Patient-reported pain, discomfort, and esthetic satisfaction were also recorded. Biopsies were obtained at 6 months. RESULTS: Surgery and postoperative sequelae were uneventful, with normal healing observed at both test and control sites. The primary outcome, ∆KT width at 6 months, did not establish non-inferiority of CM compared to FGG (P = 0.9992), with the FGG sites averaging 1.5 mm more KT width than CM sites. However, the amount of new KT generated for both therapies averaged ≥2 mm. Secondary outcomes were not significantly different between test and control sites. All site biopsies appeared as normal mucoperiosteum with keratinized epithelium. CM sites achieved better texture and color matches, and more than two-thirds of patients preferred the appearance of their CM sites. CONCLUSION: With the proviso of sufficient KT (≈2 mm in width) and study goals of lower morbidity, unlimited supply, and patient satisfaction, CM appears to be a suitable substitute for FGG in vestibuloplasty procedures designed to increase KT around teeth.

Treatment of gingival recession defects using coronally advanced flap with a porcine collagen matrix compared to coronally advanced flap with connective tissue graft: a randomized controlled clinical trial.

BACKGROUND: Connective tissue graft (CTG) plus coronally advanced flap (CAF) is the reference therapy for root coverage. The aim of the present study is to evaluate the use of a porcine collagen matrix (PCM) plus CAF as an alternative to CTG+CAF for the treatment of gingival recessions (REC), in a prospective randomized, controlled clinical trial. METHODS: Eighteen adult patients participated in this study. The patients presented 22 single Miller's Class I or II REC, randomly assigned to the test (PCM+CAF) or control (CTG+CAF) group. REC, probing depth, clinical attachment level (CAL), and width of keratinized tissue (KG) were evaluated at 12 months. In addition, the gingival thickness (GT) was measured 1mm apical to the bottom of the sulcus. RESULTS: At 12 months, mean REC was 0.23 mm for test sites and 0.09 mm for control sites (P <0.01), whereas percentage of root coverage was 94.32% and 96.97%, respectively. CAL gain was 2.41 mm in test sites and 2.95 mm in control sites (P <0.01). KG gain was 1.23 mm in the test group and 1.27 mm in the control group (P <0.01). In test sites, GT changed from 0.82 to 1.82 mm, and in control sites, from 0.86 to 2.09 mm (P <0.01). CONCLUSIONS: Within the limits of the study, both treatment procedures resulted in significant reduction in REC at 12 months. No statistically significant differences were found between PCM+CAF and CTG+CAF with regard to any clinical parameter. The collagen matrix represents a possible alternative to CTG.

The use of mucograft collagen matrix to augment the zone of keratinized tissue around teeth: a pilot study.

This prospective split-mouth pilot case series compared the use of a bilayer collagen matrix (CM) to an autogenous gingival graft (AGG) in the ability to increase the zone of keratinized attached gingiva. Five patients with inadequate amounts of keratinized attached gingiva bilaterally in the posterior mandible were enrolled using a split-mouth design. There were statistically significant increases in attached gingiva at all test (CM) and control (AGG) sites. The CM sites at 12 months blended well with surrounding tissues, while the AGG sites were morphologically dissimilar to the adjacent areas. Biopsy results showed intrapatient histologic similarity between CM and AGG treatments, with all sites exhibiting mature connective tissue covered by keratinized epithelium. Thus, the obtained data support further investigations in evaluating the role of CM as a viable alternative to AGG in augmenting areas deficient in keratinized gingiva.

Skin repair using a porcine collagen I/III membrane--vascularization and epithelization properties.

BACKGROUND: Collagen membranes have been developed to overcome the problem of limited availability of skin grafts. Vascularization and restricted functional epithelization limit the success of bioartificial constructs. OBJECTIVE: To compare the vascularization, epithelization, and integration of a porcine collagen I/III membrane with that of split-thickness skin grafts on skin wounds. MATERIALS AND METHODS: In 21 adult pigs, full-thickness skin defects on the rear side of the ear healed by split-thickness skin grafting, by covering with the membrane, or by free granulation. Skin samples on postoperative days 1, 3, 7, 14, 21, and 28 were evaluated histologically (hematoxylin-eosin, Sirius Red) and using immunohistochemistry (cytokeratin 5/6, transforming growth factor beta receptor (TGFbetaR-III) and immunoblot (TGFbeta(1,3), Smad2/3). Epithelial thickness and TGFbetaR-III-positive capillary area were quantitatively assessed. RESULTS: Epithelization and vascularization in the membrane group were not significantly different from in the group treated with a split-thickness skin graft. Free granulation showed significantly slower epithelization and vascularization (p<.05). TGFbeta(1) and Smad2/3 complex expression were high during free granulation. Matrix was distinguishable until day 7. CONCLUSIONS: This membrane serves as a suitable full-thickness dermal substitute, because the membrane is vascularized faster than free granulation tissue and enables early epithelization.

Lateral ridge augmentation using equine- and bovine-derived cancellous bone blocks: a feasibility study in dogs.

OBJECTIVES: The aim of the present study was to histologically evaluate and compare a new prototype collagen type I/III-containing equine- (EB) and a bovine- (BB) derived cancellous bone block in a dog model. MATERIALS AND METHODS: Four standardized box-shaped defects were bilaterally created at the buccal aspect of the alveolar ridge in the lower jaws of five beagle dogs and randomly allocated to either EB or BB. Each experimental site was covered by a native (non-crosslinked) collagen membrane and left to heal in a submerged position for 12 weeks. Dissected blocks were processed for semi-/and quantitative analyses. RESULTS: Both groups had no adverse clinical or histopathological events (i.e. inflammatory/foreign body reactions). BB specimens revealed no signs of biodegradation and were commonly embedded in a fibrous connective tissue. New bone formation and bony graft integration were minimal. In contrast, EB specimens were characterized by a significantly increased cell (i.e. osteoclasts and multinucleated giant cells)-mediated degradation of the graft material (P<0.001). The amount and extent of bone ingrowth was consistently higher in all EB specimens, but failed to reach statistical significance in comparison with the BB group (P>0.05). CONCLUSIONS: It was concluded that the application of EB may not be associated with an improved bone formation than BB.

Xenogeneic collagen matrix with coronally advanced flap compared to connective tissue with coronally advanced flap for the treatment of dehiscence-type recession defects.

BACKGROUND: For root coverage therapy, the connective tissue graft (CTG) plus coronally advanced flap (CAF) is considered the gold standard therapy against which alternative therapies are generally compared. When evaluating these therapies, in addition to traditional measures of root coverage, subject-reported, qualitative measures of esthetics, pain, and overall preferences for alternative procedures should also be considered. This study determines if a xenogeneic collagen matrix (CM) with CAF might be as effective as CTG+CAF in the treatment of recession defects. METHODS: This study was a single-masked, randomized, controlled, split-mouth study of dehiscence-type recession defects in contralateral sites; one defect received CTG+CAF and the other defect received CM+CAF. A total of 25 subjects (8 male, 17 female; mean age: 43.7 +/- 12.2 years) were evaluated at 6 months and 1 year. The primary efficacy endpoint was recession depth at 6 months. Secondary endpoints included traditional periodontal measures, such as width of keratinized tissue and percentage of root coverage. Subject-reported values of pain, discomfort, and esthetic satisfaction were also recorded. RESULTS: At 6 months, recession depth was on average 0.52 mm for test sites and 0.10 mm for control sites. Recession depth change from baseline was statistically significant between test and control, with an average of 2.62 mm gained at test sites and 3.10 mm gained at control sites for a difference of 0.4 mm (P = 0.0062). At 1 year, test percentage of root coverage averaged 88.5%, and controls averaged 99.3% (P = 0.0313). Keratinized tissue width gains were equivalent for both therapies and averaged 1.34 mm for test sites and 1.26 mm for control sites (P = 0.9061). There were no statistically significant differences between subject-reported values for esthetic satisfaction, and subjects' assessments of pain and discomfort were also equivalent. CONCLUSION: When balanced with subject-reported esthetic values and compared to historical root coverage outcomes reported by other investigators, CM+CAF presents a viable alternative to CTG+CAF, without the morbidity of soft tissue graft harvest.

Effects of collagen membranes enriched with in vitro-differentiated N1E-115 cells on rat sciatic nerve regeneration after end-to-end repair.

Peripheral nerves possess the capacity of self-regeneration after traumatic injury but the extent of regeneration is often poor and may benefit from exogenous factors that enhance growth. The use of cellular systems is a rational approach for delivering neurotrophic factors at the nerve lesion site, and in the present study we investigated the effects of enwrapping the site of end-to-end rat sciatic nerve repair with an equine type III collagen membrane enriched or not with N1E-115 pre-differentiated neural cells. After neurotmesis, the sciatic nerve was repaired by end-to-end suture (End-to-End group), end-to-end suture enwrapped with an equine collagen type III membrane (End-to-EndMemb group); and end-to-end suture enwrapped with an equine collagen type III membrane previously covered with neural cells pre-differentiated in vitro from N1E-115 cells (End-to-EndMembCell group). Along the postoperative, motor and sensory functional recovery was evaluated using extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. After 20 weeks animals were sacrificed and the repaired sciatic nerves were processed for histological and stereological analysis. Results showed that enwrapment of the rapair site with a collagen membrane, with or without neural cell enrichment, did not lead to any significant improvement in most of functional and stereological predictors of nerve regeneration that we have assessed, with the exception of EPT which recovered significantly better after neural cell enriched membrane employment. It can thus be concluded that this particular type of nerve tissue engineering approach has very limited effects on nerve regeneration after sciatic end-to-end nerve reconstruction in the rat.

Cell carriers as the next generation of cell therapy for cartilage repair: a review of the matrix-induced autologous chondrocyte implantation procedure.

BACKGROUND: Since the first patient was implanted with autologous cultured chondrocytes more than 20 years ago, new variations of cell therapies for cartilage repair have appeared. Autologous chondrocyte implantation, a first-generation cell therapy, uses suspended autologous cultured chondrocytes in combination with a periosteal patch. Collagen-covered autologous cultured chondrocyte implantation, a second-generation cell therapy, uses suspended cultured chondrocytes with a collagen type I/III membrane. Today's demand for transarthroscopic procedures has resulted in the development of third-generation cell therapies that deliver autologous cultured chondrocytes using cell carriers or cell-seeded scaffolds. PURPOSE: To review the current evidence of the matrix-induced autologous chondrocyte implantation procedure, the most widely used carrier system to date. Also discussed are the characteristics of type I/III collagen membranes, behavior of cells associated with the membrane, surgical technique, rehabilitation, clinical outcomes, and quality of repair tissue. STUDY DESIGN: Systematic review. METHODS: Relevant publications were identified by searching Medline from its inception (1949) to December 2007; peer-reviewed publications of preclinical and clinical cell behavior, manufacturing process, surgical technique, and rehabilitation protocols were identified. Preclinical and clinical studies were included if they contained primary data and used a type I/III collagen membrane. RESULTS: Data from these studies demonstrate that patients treated with matrix-induced autologous chondrocyte implantation have an overall improvement in clinical outcomes. Reduced visual analog scale pain levels (range, 1.7-5.32 points) and improvements in the modified Cincinnati (range, 3.8-34.2 points), Lysholm-Gillquist (range, 23.09-47.6 points), Tegner-Lysholm (range, 1.39-3.9 points), and International Knee Documentation Classification scale (P <.05) were observed. Patients had good-quality (hyaline-like) repair tissue as assessed by arthroscopic evaluation (including International Cartilage Repair Society score), magnetic resonance imaging, and histology, as well as a low incidence of postoperative complications. CONCLUSION: The findings suggest that matrix-induced autologous chondrocyte implantation is a promising third-generation cell therapy for the repair of symptomatic, full-thickness articular cartilage defects.

Sequential outcome following autologous chondrocyte implantation of the knee: a six-year follow-up.

This prospective six-year longitudinal study reviews the clinical outcome of patients undergoing autologous chondrocyte implantation (ACI) and a porcine type I/III collagen membrane cover for deep chondral defects of the knee. We present 57 patients (31 male, 26 female) with a mean age of 31.6 years (range 15-51 years) that have undergone ACI since July 1998. The mean size of the defect was 3.14 cm(2) (range 1.0-7.0 cm(2)). All patients were assessed annually using seven independent validated clinical rating scores with the data analysed using ANOVA. ACI using a porcine type I/III collagen membrane cover produced statistically significant improvements (p < 0.001), maintained for up to six years, in knee symptoms compared to pre-operative levels. This study provides evidence of the medium-term benefit achieved by transplanting autologous chondrocytes to osteochondral defects.