Poly-l-lactide-co-ε-caprolactone (PLCL) and poly-l-lactic acid (PLLA)/gelatin electrospun subacromial spacer improves extracellular matrix (ECM) deposition for the potential treatment of irreparable rotator cuff tears.

Biodegradable subacromial spacer implantation has become practicable for the treatment of irreparable rotator cuff tears (IRCT). However, the relative high degradation rate and inferior tissue regeneration properties of current subacromial spacer may lead to failure regards to long-term survival. It is reported that satisfactory clinical results lie in the surrounding extracellular matrix (ECM) deposition after implantation. This study aims to develop a biological subacromial spacer that would enhance tissue regeneration properties and results in better ECM deposition. Physicochemical properties were characterized on both poly-l-lactide-co-ε-caprolactone (PLCL) dip-coating spacer (monolayer spacer, MS) and PLCL dip-coating + Poly-l-Lactic Acid (PLLA)/Gelatin electrospun spacer (Bilayer Spacer, BS). Cytocompatibility, angiogenesis, and collagen inducibility were evaluated with tendon fibroblasts and endothelial cells. Ultrasonography and histomorphology were used to analyze biodegradability and surrounding ECM deposition after the implantation in vivo. BS was successfully fabricated with the dip-coating and electrospinning technique, based on the human humeral head data. In vitro studies demonstrated that BS showed a greater cytocompatibility, and increased secretion of ECM proteins comparing to MS. In vivo studies indicated that BS promoted ECM deposition and angiogenesis in the surrounding tissue. Our research highlights that BS exhibits better ECM deposition and reveals a potential candidate for the treatment of IRCT in future.

In Vivo Anatomical Research by 3D CT Reconstruction Determines Minimum Acromiohumeral, Coracohumeral, and Glenohumeral Distances in the Human Shoulder: Evaluation of Age and Sex Association in a Sample of the Chinese Population.

Accurate measurement of the minimum distance between bony structures of the humeral head and the acromion or coracoid helps advance a better understanding of the shoulder anatomical features. Our goal was to precisely determine the minimum acromiohumeral distance (AHD), coracohumeral distance (CHD), and glenohumeral distance (GHD) in a sample of the Chinese population as an in vivo anatomical analysis. We retrospectively included 146 patients who underwent supine computed tomography (CT) examination of the shoulder joint. The minimum AHD, CHD, and GHD values were quantitatively measured using three-dimensional (3D) CT reconstruction techniques. The correlation between minimum AHD, CHD, and GHD value and age with different sexes was evaluated using Pearson Correlation Coefficient. The mean value of minimum AHD in males was greater than that in females (male 7.62 ± 0.98 mm versus female 7.27 ± 0.86 mm, p = 0.046). The CHD among different sexes differed significantly (male 10.75 ± 2.40 mm versus female 8.76 ± 1.38 mm, p < 0.001). However, we found no statistical differences in GHD with different sexes (male 2.00 ± 0.31 mm versus female 1.96 ± 0.36 mm, p > 0.05). In terms of age correlation, a negative curve correlation existed between age and AHD among the different sexes (male R2 = 0.124, p = 0.030, female R2 = 0.112, p = 0.005). A negative linear correlation was found in CHD among the different sexes (male R2 = 0.164, p < 0.001, female R2 = 0.122, p = 0.005). There were no differences between age and minimum GHD in both sexes. The 3D CT reconstruction model can accurately measure the minimum AHD, CHD, and GHD value in vivo and is worthy of further investigation for standard clinical anatomical assessment. Aging may correlate with AHD and CHD narrowing for both sexes.

The Regenerative Role of Gelatin in PLLA Electrospun Membranes for the Treatment of Chronic Massive Rotator Cuff Injuries.

Failing to regenerate native tendon tissue in chronic massive rotator cuff tears (CMRCTs) results in high retear rates after surgery. Gelatin is a hydrolyzed form of collagen which is bioactive and biocompatible. This study intends to investigate the suitability of integrating gelatin to poly (l-lactic acid) (PLLA) fibrous membranes for promoting the healing of CMRCTs. PLLA/Gelatin electrospun membranes (PGEM) are fabricated using electrospinning technology. The fourier transform infrared, static contact angles are tested sequentially. Cytocompatibility is evaluated with rat tendon fibroblasts and human umbilical endothelial cells (HUEVCs) lines. CMRCTs rat models are established and assigned into three groups (the sham group, the repaired group, and the augmentation group) to perform histomorphological and biomechanical evaluations. Gelatin is successfully integrated into PLLA fibrous membranes by the electrospinning technique. In vitro studies indicate that PGEM shows a great cytocompatibility for rat tendon fibroblasts and HUEVCs. In vivo studies find that applications of PGEM significantly promote well-aligned collagen I fibers formation and enhance biomechanical properties of the repaired tendon in CMRCTs rat models. In summary, gelatin promotes tendon fibroblasts and HUEVCs adhesion, migration, and proliferation on the PLLA fibrous membranes, and PGEM may provide a great prospect for clinical application.

Clinical guideline for vascularized composite tissue cryopreservation.

At the Summit on Organ Banking through Converging Technologies held recently in Boston, tissue and organ cryopreservation technology was a topic of considerable interest. Although cryopreservation has been widely used in clinical practice, it currently remains limited to bloodless tissues with simple structures and functions that are small or thin, for example, ultra-thin skin, ovarian tissue slices, and other similar tissues. For whole organs, except for successful cryopreservation of rat ovaries (2002) and hind limbs (August 2002), successful cryopreservation of vascularized animal tissues or organs and their replantation have not yet been reported. We conducted histological and electron microscopic examinations on muscle after blood supply restoration to explain this problem and describe our experience with the goal of informing our colleagues to further develop the technology. To achieve broad application of vascularized tissue and organ cryopreservation, we have summarized our experience and established a clinical application scope for vascularized composite tissue cryopreservation.

Effects of Cryopreservation and Replantation on Muscles: Application Scope of Limb Cryopreservation.

BACKGROUND: Wang successfully replanted the severed fingers of 2 patients after cryopreservation in 2002 and 2003, which has enabled us to share our own experience for the knowledge interests of our colleagues and to further develop this technology. METHODS: Fifteen healthy adult male Sprague-Dawley rats were selected and divided into 5 groups (group 1: normal control, group 2: cryopreservation with protectant, group 3: cryopreservation without protectant, group 4: 6-hour postoperative, and group 5: 72-hour postoperative). After harvesting the hind limbs, cryoprotectant was applied to 20 limbs, and the rest were cryopreserved without cryoprotectant for 15 days. After being thawed, the amputated limb was replanted in situ. Nerves, skins and gastrocnemius muscles were collected for hematoxylin and eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and transmission electron microscopy observation. RESULTS: Muscle and skin tissues treated with cryoprotectant restored a better outline after being frozen than those not treated, whereas nerves were not significantly different between the 2 groups. After replantation, some of the myofibrils of the muscle were in disarray, but the sarcomere structure remained intact at approximately 6 hours postoperatively. At 72 hours, a transmission electron microscopy scan showed that the myofibrillar arrangement was disorderly, with segmental myofilament breakage, and the sarcomere structure was destroyed in some cases. In addition, the scan revealed increased apoptotic cells and collapse of basic structures in the skin and nerves. CONCLUSIONS: Relative to that of skin and neuronal tissue, the replantation of muscle tissues through the cryopreservation method is more difficult.

A symptomatic cyamella in the popliteus tendon causing snapping knee: a case report and literature review.

BACKGROUND: Cyamella,the sesamoid bones of the popliteus muscle, are rare in humans. Snapping knee is an uncommon problem which can be difficult to diagnose. CASE PRESENTATION: In this case, we report a 24-year-old male with snapping knee caused by symptomatic cyamella in the popliteus tendon. A large cyamella was identified upon surgery and was removed. Postoperatively, the patient had immediate relief of preoperative symptoms, and there were no signs of recurrence after 1 years of follow-up. CONCLUSIONS: Although not previously suggested, symptomatic cyamella in the popliteus tendon should be considered as part of the differential diagnosis of the snapping knee.