Avulsion fracture is associated with more pain after anatomic repair procedure for ATFL injury at the talar side

PURPOSE

To evaluate the clinical outcomes of anatomic repair procedure for chronic anterior talofibular ligament (ATFL) injury at the talar side, and to compare the outcomes between patients with and without concomitant avulsion fractures. It was hypothesized that anatomic repair procedure could produce similarly satisfactory outcomes for those two groups.

METHODS

Thirty-nine consecutive patients with chronic ATFL injuries at the talar side who underwent anatomic repair procedure at the department of sports medicine at Peking University Third Hospital between 2013 and 2018, were retrospectively evaluated. The pain visual analogue scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) score, Tegner score, and Foot & Ankle Outcome Score (FAOS) were recorded as the primary outcomes. Time to return to sports (RTS), surgical satisfaction, deficiency of ankle range of motion (ROM), recurrent sprain, and postoperative complications were recorded as the secondary outcomes. Outcomes were compared between patients with (Group A, 16 cases) and without (Group B, 23 cases) concomitant avulsion fractures.

RESULTS

The mean follow-up time was 79.4 ± 17.0 and 76.6 ± 18.5 months for Group A and B, respectively. VAS, AOFAS, Tegner, FAOS, and all subscale scores of FAOS were significantly improved in both groups at the final follow up. Patients in group A had inferior postoperative VAS, AOFAS, FAOS, and pain score of FAOS compared to group B (1.1 ± 1.1 vs. 0.4 ± 0.5, 89.1 ± 10.1 vs. 95.2 ± 5.2, 87.2 ± 7.2 vs. 91.5 ± 4.1, and 88.4 ± 11.3 vs. 96.7 ± 3.5, respectively).The mean time to RTS, rate of satisfaction and recurrent sprain had no significant differences between group A and B (6.1 ± 2.8, 93.8%, and 18.8% vs. 5.2 ± 2.2, 100.0%, and 13.0%, respectively), and the rate of ROM deficiency was significantly higher in group A (37.5 vs. 8.7%). Avulsion fracture was identified as an independent risk factor for inferior pain score of FAOS.

CONCLUSION

Anatomic repair procedure for chronic ATFL injuries at the talar side produces favourable results for patients with and without avulsion fractures at 5 to 10 years follow-up, however, avulsion fracture is associated with more pain.

LEVEL OF EVIDENCE

III.

The lowest point of fibula (LPF) could be used as a reliable bony landmark for arthroscopic anchor placement of lateral ankle ligaments ----compared with open Broström procedure

BACKGROUND

Arthroscopic technique procedures was wide accepted for the treatment of chronic ankle instability (CAI). But little acknowledge was involved to the bony landmarks and anatomic features of different bundles of lateral ligaments under arthroscopic view.

METHODS

Sixty patients with acute or chronic lateral ankle ligaments injury (LAI) were collected prospectively, and divided randomly into two groups. In arthroscopic group, the bone tunnels were made on the LPF arthroscopically. And in open group, the bone tunnels were made on the Fibular obscure tubercle (FOT) in open procedure. The inferior bundle of ATFL and Arcuate fibre was also identified reference to the LPF and labeled by a PDS II suture penetration. Following that, The distances of the bone tunnels to the different bony markers were measured and compare between two groups. The penetrating locations of PDS II on the inferior bundle of ATFL and Arcuate fibre were also confirmed intraoperatively. And the safe angle of anchor implantation on the axial view was measured on postoperative CT scan.

RESULTS

The distances of bone tunnel to the fibular tip, the fibular insertion of anterior-inferior tibiofibular ligament (AITFL), and the FOT in arthroscopic and open locating groups were 4.9 ± 2.2 and 6.3 ± 2.2 mm, 13.5 ± 2.7 and 12.4 ± 1.1 mm, 5.8 ± 2.2 and 5.6 ± 1.0 mm, respectively. The distances of bone tunnels to the FOT and fibular tip on 3d-CT view was 4.4 ± 1.5 and 4.6 ± 0.9 mm, 14.4 ± 3.2 and 13.2 ± 1.8 mm in arthroscopic and open group, and there were no significant differences between two groups. The safe angle of arthroscopic anchor placement on the axial plan was ranged from 24.9 ± 6.3o to 58.1 ± 8.0o. The PDS II sutures penetrating on the inferior bundles of ATFL and the arciform fibres were also comfirmed successfully by open visualizaion.The average distance of penetration point to the horizontal line cross the fibular tip was 2.3 ± 2.7 mm (ranged from - 3.1 to 6.0 mm), and to the vertical line cross the FOT was 2.7 ± 2.7 mm (ranged from - 2.5 to 7.5 mm).

CONCLUSION

Take the lowest point of fibula under arthroscopy (LPF) as a bony reference, we could identify the iATFL under arthroscopic visualization. By this way, we could place the suture anchors properly to the fibular footprint and suture the iATFL fibres successfully.

E7 Peptide Enables BMSC Adhesion and Promotes Chondrogenic Differentiation of BMSCs Via the LncRNA H19/miR675 Axis

Therapeutic strategies based on utilizing endogenous BMSCs have been developed for the regeneration of bone, cartilage, and ligaments. We previously found that E7 peptide (EPLQLKM) could enhance BMSC homing in bio-scaffolds and, therefore, promote cartilage regeneration. However, the profile and mechanisms of E7 peptide in cartilage regeneration remain elusive. In this study, we examined the effect of E7 peptide on the BMSC phenotype, including adhesion, viability and chondrogenic differentiation, and its underlying mechanism. The konjac glucomannan microsphere (KGM), a carrier material that is free of BMSC adhesion ability, was used as the solid base of E7 peptide to better explore the independent role of E7 peptide in BMSC behavior. The results showed that E7 peptide could support BMSC adhesion and viability in a comparable manner to RGD and promote superior chondrogenic differentiation to RGD. We examined differentially expressed genes of BMSCs induced by E7 compared to RGD. Subsequently, a real-time PCR validated the significantly upregulated expression of lncRNA H19, and the knockdown of lncRNA H19 or miR675, a downstream functional unit of H19, could significantly obscure the chondrogenic differentiation induced by E7. In conclusion, this study confirmed the independent role of E7 in the adhesion and viability of BMSCs and revealed the pro-chondrogenic effect of E7 on BMSCs via the H19/miR675 axis. These results could help establish new therapeutic strategies based on employing endogenous BMSCs for cartilage tissue regeneration.

Arthroscopic and Open Procedures Result in Similar Calcaneal Tunnels for Anatomical Reconstruction of Lateral Ankle Ligaments

Purpose

The purpose of this study was to validate the accuracy and reliability of arthroscopic markers of distal insertion of the calcaneofibular ligament (CFL), and to compare the calcaneus bone tunnels of the CFL that were made under arthroscopy and open procedures.

Methods

Fifty-seven patients who underwent lateral ankle ligament reconstruction procedures were enrolled and divided into open (n = 24) and arthroscopic groups (n = 33). Lateral ankle radiography was performed postoperatively, and the calcaneus bone tunnels referenced to several landmarks, including the subtalar joint, calcaneus superior edge, fibular tip, angulation with fibula axis, cross point of the fibular and tangential line of the fibular obscure tubercle cross point of the tangential lines of the talar posterior edge and deepest point of the subtalar joint, and cross point of the fibular axis and perpendicular line across fibular tip. These results were compared between the two groups.

Results

No significant intergroup differences were observed between the parameters. When the bone tunnels of the CFL were referenced to the cross point of tangential lines of the talar posterior edge and deepest point of the subtalar joint, and the cross point of the fibular axis and perpendicular line across fibular tip, the coefficient variations were very high, which indicated that the locations of the bone tunnels were scattered over a large area in both groups.

Conclusions

Arthroscopic and open procedures achieved similar results for calcaneus bone tunnel making of the CFL. However, large variations were observed in both groups.

Level of Evidence

Level III, retrospective cohort study.

Favourable clinical, arthroscopic and radiographic outcomes after autologous osteoperiosteal transplantation for massive medial cystic osteochondral defects of the talus

PURPOSE

The purpose of this study was to retrospectively evaluate the clinical, arthroscopic and radiological outcomes of autologous osteoperiosteal transplantation for massive cystic osteochondral defects of the talus.

METHODS

Cases of autologous osteoperiosteal transplantation for medial massive cystic defects of the talus between 2014 and 2018 were reviewed. The visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, Foot and Ankle Outcome Score (FAOS), and Ankle Activity Scale (AAS) were assessed preoperatively and postoperatively. The Magnetic Resonance Observation of Cartilage Tissue (MOCART) system and the International Cartilage Repair Society (ICRS) score were evaluated after surgery. The ability to return to daily activity and sport, as well as complications, were recorded.

RESULTS

Twenty-one patients were available for follow-up, with a mean follow-up of 60.1 ± 11.7 months. All subscales of preoperative FAOS had significant (P < 0.001) improvement at the final follow-up. The mean AOFAS and VAS scores significantly (P < 0.001) improved from 52.4 ± 12.4 preoperatively to 90.9 ± 5.2 at the last follow-up and from 7.9 ± 0.8 to 1.5 ± 0.9, respectively. The mean AAS decreased from 6.0 ± 1.4 preinjury to 1.4 ± 0.9 postinjury and then increased to 4.6 ± 1.4 at the final follow-up (P < 0.001). All 21 patients resumed daily activities after a mean of 3.1 ± 1.0 months. Fifteen patients (71.4%) returned to sports after a mean of 12.9 ± 4.1 months. All patients underwent follow-up MRI with a mean MOCART score of 68.6 ± 5.9. Eleven patients underwent second-look arthroscopy, and the average ICRS was 9.4 ± 0.8. No donor site morbidity was found in any patient during the follow-up.

CONCLUSION

Autologous osteoperiosteal transplantation provided favourable clinical, arthroscopic and radiographic outcomes in patients with massive cystic osteochondral defects of the talus during a minimum 3-year follow-up.

LEVEL OF EVIDENCE

IV.

Acute Distal Rupture of the Calcaneus-Fibular Ligament Near the Calcaneus Insertion: Magnetic Resonance Imaging for Diagnostic Value and Comparison to Surgical Findings-A Retrospective Case Series Study

Distal rupture of the calcaneus-fibular ligament (CFL) was unique and important, because it is crucial to diagnose this type of injury before surgical intervention. In the present study, we collected several imaging characteristics based on MRI and tried to determine whether those clues can be used to diagnose distal rupture of CFL specifically and sensitively. Several imaging characteristics based on MRI were collected and used to diagnose and determine the location of CFL injury. All these clues on preoperative MRI were verified by operative findings and postoperative roentgenography. The interobserver agreement for the quality of the MRI images had a p value of .6 (McNemar test) and a Cohen's kappa of 65.2% (confidence interval, 50.5%-79.9%), and the agreement of the 2 observers was categorized as substantial. The sensitivity and specificity of distal rupture of CFL between 2 observers were 76.3%, 91.4% and 72.2%, 85.55%, respectively. The sensitivity and specificity of MRI clues were calculated as follows: hyperintense signal changes (86.1%, 38.6%), peroneal sheath fluid (63.9%, 74.7%), wave or laxity of the ligament (80.6%, 51.8%), fluid exudation around the ligament (80.6%, 51.8%), bone marrow edema on the calcaneus insertion (2.8%, 91.6%), avulsion fracture of the calcaneus (0%, 96.4%), incongruency or disruption of the ligament (69.4%, 77.1%), and exudation on the subtalar joint (52.8%, 71.1%). Preoperative MRI scans are a useful tool to diagnose distal injury of the CFL.

Midterm Outcomes of Talocalcaneal Coalition Arthroscopic Resection in Adults

BACKGROUND

Arthroscopic resection of the talocalcaneal coalition (TCC) has been reported to be associated with good short-term outcomes. However, the midterm outcomes of this approach remain uncertain.

METHODS

We performed a retrospective study of patients who underwent arthroscopic resection for symptomatic TCC. The patients were divided into 2 groups (group P, patients with isolated posterior facet coalition; and group MP, patients with both middle and posterior facet coalition). The preoperative and postoperative visual analog scale (VAS) scores for pain and American Orthopaedic Foot & Ankle Society (AOFAS) scale scores were calculated. The postoperative AOFAS and VAS scores between the 2 groups were analyzed. Patient satisfaction was also assessed.

RESULTS

Thirty-two patients were included in this study. The mean age at the time of surgery was 26.0±8.5 years, and the mean follow-up period was 56.9±18.0 months. Thirteen (41%) patients were in group P, whereas 19 (59%) patients were in group MP. Postoperative VAS and AOFAS scores improved more significantly than preoperative scores. At the final follow-up, excellent and good subjective outcomes were attained in 26 patients (81%), fair and poor outcomes in 6 patients (19%). There were no statistical differences in the postoperative AOFAS (91.0±7.0 vs 85.8±10.8, P = .532) and VAS score (2.1±1.7 vs 4.0±2.6, P = .537) between patients with the ratio of coalition/posterior facet more than or less than 50%. There were no statistical differences in postoperative VAS score (1.8±1.3 vs 2.6±2.2, P = .236) and AOFAS score (92.5±5.6 vs 89.2±8.7, P = .297) between group P (n=13) and group MP (n=19), either. Three patients (9.4%) had complications, including these notable findings: 1 patient complained of restricted dorsal flexion, 1 with computed tomography-proven coalition recurrence, and 1 with partial tibial nerve injury.

CONCLUSION

We found that TCC arthroscopic resection was generally associated with reasonable outcomes at midterm follow-up.

LEVEL OF EVIDENCE

Level IV, case series.

Comparison of Autologous Osteoperiosteal and Osteochondral Transplantation for the Treatment of Large, Medial Cystic Osteochondral Lesions of the Talus

BACKGROUND

Autologous osteoperiosteal transplantation (AOPT) using graft harvested from the iliac crest is used to treat large cystic osteochondral lesions of the talus (OLTs). However, no studies have compared clinical and radiologic outcomes between AOPT and autologous osteochondral transplantation (AOCT) using graft harvested from the nonweightbearing zone of the femoral condyle of the ipsilateral knee in patients with large cystic OLTs.

PURPOSE

To compare clinical and radiologic outcomes between patients undergoing AOPT and those undergoing AOCT for large cystic OLTs.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Between March 2015 and March 2018, patients who underwent AOCT and AOPT to treat medial large cystic OLTs (>10 mm) were retrospectively evaluated. For comparability, the 2 groups were matched 1:1 based on their characteristics, including sex, age, body mass index, side of injury, follow-up period, and the preoperative cyst volume. After propensity score matching, 23 patients were enrolled in each group for the analysis. Clinical outcomes were assessed using the visual analog scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) score, and the Tegner score. Donor-site morbidity was recorded according to the symptoms, including pain, stiffness, swelling, and discomfort. In addition, the Lysholm score was used to assess the most common knee donor-site morbidity. Radiologic outcomes were evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) score, and the International Cartilage Regeneration & Joint Preservation Society (ICRS) score was obtained during second-look surgery.

RESULTS

The mean follow-up period was about 48 months. There were no significant differences in patient characteristics and lesion volumes between groups. Postoperative ankle pain VAS score, AOFAS score, and Tegner score were not significantly different between groups at final follow-up. Total donor-site morbidity (P = .004) and discomfort morbidity (P = .009) were significantly lower in the AOPT group than in the AOCT group. However, the Lysholm score showed no significant difference between the donor knee and the opposite knee (P = .503) in the AOCT group. The MOCART and ICRS scores were not significantly different between groups.

CONCLUSION

Clinical and radiologic outcomes of patients who underwent AOPT from the iliac crest were found to be comparable with those of patients who underwent AOCT from the ipsilateral knee for the treatment of medial large cystic OLTs. These results may be helpful for orthopaedic surgeons to decide appropriate treatments for patients with large cystic OLTs.

A new classification of talocalcaneal coalitions based on computed tomography for operative planning

BACKGROUND

Current classifications emphasize the morphology of the coalition, however, subtalar joint facets involved should also be emphasized.

OBJECTIVE

The objective of this study was to develop a new classification system based on the articular facets involved to cover all coalitions and guide operative planning.

METHODS

Patients were diagnosed with talocalcaneal coalition using a CT scan, between January 2009 and February 2021. The coalition was classified into four main types according to the shape and nature of the coalition: I, inferiorly overgrown talus or superiorly overgrown calcaneus; II, both talus and calcaneus overgrew; III, coalition with an accessory ossicle; IV, complete osseous coalition (I-III types are non-osseous coalition). Then each type was further divided into three subtypes according to the articular facets involved. A, the coalition involving the anterior facets; M, the coalition involving the middle facets, and P, the coalition involving the posterior facets. Interobserver reliability was measured at the main type (based on nature and shape) and subtype (articular facet involved) using weighted Kappa. Results There were 106 patients (108 ft) included in this study. Overall, 8 ft (7.5%) were classified as type I, 75 ft (69.4%) as type II, 7 ft (6.5%) as type III, and 18 ft (16.7%) as type IV. Twenty-nine coalitions (26.9%) involved the posterior facets only (subtype-P), 74 coalitions (68.5%) involved both the middle and posterior facets (subtype-MP), and five coalitions (4.6%) simultaneously involved the anterior, middle, and posterior facets (subtype-AMP). Type II-MP coalition was the most common. The value of weighted Kappa for the main type was 0.93 (95%CI 0.86-0.99) (p<0.001), and the value for the subtype was 0.78 (95%CI 0.66-0.91) (p<0.001).

CONCLUSION

A new classification system of the talocalcaneal coalition to facilitate operative planning was developed.

Open Versus Endoscopic Osteotomy of Posterosuperior Calcaneal Tuberosity for Haglund Syndrome: A Retrospective Cohort Study

Background:

Although endoscopic calcaneoplasty and retrocalcaneal debridement have been extensively applied to treat Haglund syndrome, evidence of the value of the endoscopic procedure remains to be fully established.

Purpose/Hypothesis:

The purpose of this study was to compare the postoperative outcomes and the amount of osteotomy between open and endoscopic surgery for the treatment of Haglund syndrome. It was hypothesized that endoscopic calcaneoplasty would lead to higher patient satisfaction and lower complication rates compared with open surgical techniques.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

The following postoperative outcomes were compared between the open surgery group (n = 20) and the endoscopic surgery group (n = 27): visual analog scale for pain, American Orthopaedic Foot & Ankle Society ankle-hindfoot scale, Foot Function Index, Tegner score, Ankle Activity Score, and 36-Item Short Form Health Survey; postoperative complications; and duration of surgery. To determine the extent of resection, the authors compared the calcaneal height ratio, calcaneal resection ratio, calcaneal resection angle, pitch line, and Haglund deformity height between groups. The learning curve for endoscopic calcaneoplasty was also calculated.

Results:

There were no significant differences between the open and endoscopic groups on any outcome score. Two patients in the open group reported temporary paresthesia around the incisional site, indicating sural nerve injuries; no complication was reported in the endoscopy group. None of the parameters for extent of resection were statistically significant between the groups. The duration of surgery was 44.90 ± 10.52 and 65.39 ± 11.12 minutes in the open and endoscopy groups, respectively (P = .001). Regarding the learning curve for endoscopic calcaneoplasty (6 surgeons; 27 follow-up patients; 9 patients lost to follow-up), the duration of surgery reached a steady point of 55.68 ± 4.19 minutes after the fourth operation.

Conclusion:

The results of this study indicated that the endoscopy procedure was as effective as the open procedure. The endoscopic procedure required significantly more time than the open procedure, and the duration of the endoscopic procedure was shortened only after the fourth operation, suggesting that it requires high technical skills and familiarity with the anatomic relationships.

Enhanced removal of Congo red dye from aqueous solution by surface modified activated carbon with bacteria

AIMS

The adsorption behaviour and mechanisms of the surface modified activated carbon with bacteria was evaluated.

METHODS AND RESULTS

16S rRNA was employed to identify the hydrocarbon-degrading bacteria. The bacteria was characterized by TEM and electron microscope. The surface modified activated carbon with bacteria was characterized by SEM. The adsorption behaviour was tested by static adsorption and dynamic adsorption.

CONCLUSION

The adsorption efficiency of the modified activated carbon was high when pH was weak acidic, and the adsorption capacity increased with the increase of temperature ranging from 20 to 35°C. The adsorption capacity peaked at 234·6 mg g^-1 at 25°C, which was sixfold higher than that of activated carbon. The pseudo-first-order kinetic can more accurately assess Congo red adsorption on the two adsorbents. The adsorption of Congo red by bacteria surface modified activated carbon fitted well with the Langmuir's model. The adsorption process was endothermic, and the biological floccules were formed during the adsorption. The physical adsorption is the main driving force.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results indicate that the bacteria surface-modified activated carbon can be used effectively as an adsorbent to eliminate Congo red from aqueous solutions.

Calcaneoplasty coupled with an insertional Achilles tendon reattachment procedure for the prevention of secondary calcaneal impingement: a retrospective study

Background:

Posterior heel pain may occur after an Achilles insertional rupture reattachment procedure and could be attributed to an impingement between the calcaneal tuberosity and Achilles tendon, which could be observed using postoperative magnetic resonance imaging (MRI). Moreover, such impingement, which may be associated with postoperative pain symptoms, could be relieved by calcaneoplasty.

Methods:

Postoperative Visual Analog Pain Scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS) score, Foot Function Index (FFI), Ankle Activity Score (AAS), and Tegner score were obtained and compared between 10 patients who underwent calcaneoplasty (calcaneoplasty group) and 11 patients who did not receive calcaneoplasty (non-calcaneoplasty group). Several signs of calcaneal tuberosity impingement identified in MRI were also compared between the two groups, which included retrocalcaneal bursitis, postoperative tendinopathy, tendon calcification, bone marrow edema, increased Achilles tendon diameter, and bony spurs.

Results:

The VAS score was 2.00 ± 1.41 and 2.18 ± 1.83 (p = 0.803), the AOFAS score was 90.60 ± 4.22 and 81.82 ± 7.77 (p = 0.005), the FFI was 5.00 ± 2.86 and 17.18 ± 15.92 (p = 0.028), the AAS was 5.50 ± 2.55 and 5.82 ± 2.04 (p = 0.750), and the Tegner score was 4.30 ± 1.49 and 4.45 ± 1.21 (p = 0.797) in the calcaneoplasty and non-calcaneoplasty groups, respectively. The AOFAS score and FFI were significantly different between the groups. MRI findings revealed that the non-calcaneoplasty group had significant signs of calcaneal impingement compared with the calcaneoplasty group.

Conclusions:

Secondary calcaneal impingement due to insertional tendon enlargement may occur, and prophylactic calcaneoplasty coupled with an insertional reattachment procedure could achieve promising postoperative outcomes for patients with insertional Achilles tendon rupture.

[Complexity of Detecting CRISPR/Cas9-Mediated Homologous Recombination in Zebrafish]

Homology-directed (HD) genome modification offers an opportunity to precisely modify the genome. Despite reported successful cases, for many loci, precise genome editing remains challenging and inefficient in vivo. Here we report an effort to precisely knock-in a GFP reporter into gad locus mediated by CRISPR/Cas9 system in the zebrafish Danio rerio. PCR artifact was detected in testing for homologous recombination (HR), but was mitigated by optimizing PCR condition and decreasing the injected targeting plasmid concentration. Under this optimized condition, time course analysis revealed a decline of the HR-positive embryos at embryogenesis progressed. GFP signals also diminished at later developmental stages. The GFP signals were consistent with PCR detection, both of which suggested the loss of targeted insertion events at later stages. Such loss of insertion might be one underlying reason for the inability to obtain germ-line transgenic lines with GFP knocked into the gad locus. Our results suggest that the low HR efficiency associated with CRISPR-mediated knock-in is in part due to loss of insertion after targeted integration into the gad locus.

Optimal Outcomes for Acute Avulsion Fracture of the Achilles Tendon Treated With the Insertional Reattachment Technique: A Case Series of 31 Cases With Over 2 Years of Follow-up

BACKGROUND

Avulsion fracture of the Achilles tendon is a less common but debilitating disorder. There is a paucity of literature on this problem.

PURPOSE

To present a retrospective case series assessing the clinical outcomes of avulsion fracture of the Achilles tendon after a reattachment procedure and to identify potential factors predicting postoperative outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A consecutive case series of 35 patients with acute insertional rupture of the Achilles tendon who received a reattachment procedure between 2011 and 2017 were reviewed. All patients were measured and classified by magnetic resonance imaging (MRI) and surgical findings. Patient-reported outcomes were evaluated using the visual analog scale (VAS) for pain, American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale, Foot Function Index (FFI), Tegner score, and Ankle Activity Score (AAS). The range of motion and single-legged heel raise test were also conducted for both ankles.

RESULTS

Thirty-one out of 35 (88.57%) patients were followed up for an average of 43.65 months. The VAS pain score and AOFAS Ankle-Hindfoot score improved from 4.87 ± 1.61 preoperatively to 2.07 ± 1.57 postoperatively and from 58.32 ± 18.66 preoperatively to 87.32 ± 7.53 postoperatively, respectively (both P < .001). The mean FFI, AAS, and Tegner scores after the operation were 11.84 ± 1.62, 5.71 ± 2.18, and 4.61 ± 1.31, respectively. Compared with the intact ankle, the mean deficit in dorsiflexion in the involved ankle was 9.54°± 6.25° (range, 0.59°-23.70°; P < .001) and the mean deficit in plantarflexion in the involved ankle was 6.31°± 4.02° (range, 0.24°-14.92°; P < .001). Thirty patients could perform the single-legged heel raise on the operative leg. A larger body mass index was associated with worse postoperative AOFAS and FFI outcomes. Longer follow-up predicted statistically significantly better FFI scores. Better postoperative dorsiflexion was associated with better postoperative FFI, AAS, and Tegner scores, and a statistically significant interaction was found between the VAS score and plantarflexion deficit. Age, preoperative insertional tenderness, Haglund deformity, and MRI classification showed little association with postoperative outcomes.

CONCLUSION

This study demonstrated that the reattachment procedure for acute avulsion fracture of the Achilles tendon can achieve firm fixation and promising outcomes.

Sex-related differences in response to zinc pyrithione shampoo vs. non-anti-dandruff shampoo

OBJECTIVE

Sex-related differences in skin properties may be expected to impact dandruff formation and treatment. A meta-analysis approach was undertaken to investigate potential differences between males and females in response to zinc pyrithione (ZnPT) treatment vs. non-anti-dandruff (AD) shampoo. A separate pooled statistical analysis of ceramide and total protein loss endpoints was also undertaken to assess potential sex-related differences in stratum corneum properties that might influence response to ZnPT vs. non-AD shampoo in subjects with dandruff.

METHODS

The meta-analysis approach included data from 17 half-head, double-blind, randomized studies (N = 2088) undertaken in Asia to assess the effectiveness of 1% ZnPT shampoo and/or non-AD shampoo in reducing dandruff severity, as assessed by Total Weighted Head Score Adherent Flake (TWHS-AF) methodology. Treatment duration was 4 weeks, with TWHS-AF measured at weekly intervals. Data from an additional three studies (N = 143) conducted in Asia were included in the pooled analysis of ceramide levels and protein loss from scalp skin of subjects with dandruff.

RESULTS

Response to 1% ZnPT vs. non-AD shampoo was greater in males than in females at all time points; after 4 weeks, the between-treatment difference in TWHS-AF was -17.5 (95% confidence interval [CI] -19.5, -15.5) in males and -11.1 (-13.2, -8.9) in females. Sex-related differences were observed between males and females in response to both 1% ZnPT and non-AD shampoos. Males had a stronger response than females to treatment with 1% ZnPT shampoo, while dandruff decreased to a greater extent in females than in males when using non-AD shampoo. Statistically significant sex-related differences in ceramide levels and total protein loss were observed (both P < 0.01). Ceramide levels were 0.76 times lower (95% CI 0.60, 0.97) in males than in females, while total protein loss was 1.4 times greater (95% CI 1.1, 1.9) in males than in females.

CONCLUSION

Males show a greater response than females to 1% ZnPT shampoo, while females show a greater response than males to non-AD shampoo. These findings may in part be explained by the sex-related differences observed in stratum corneum properties, which may make males more prone to dandruff than females.

Effectiveness of rubber seed oil and flaxseed oil to enhance the α-linolenic acid content in milk from dairy cows

This experiment was conducted to investigate effect of rubber seed oil compared with flaxseed oil when fed alone or in combination on milk yield, milk composition, and α-linolenic acid (ALA) concentration in milk of dairy cows. Forty-eight mid-lactation Holstein dairy cows were randomly assigned to 1 of 4 treatments according to a completely randomized design. Cows were fed a basal diet (control; CON) or a basal diet supplemented with 4% rubber seed oil (RO), 4% flaxseed oil (FO), or 2% rubber seed oil plus 2% flaxseed oil (RFO) on a dry matter basis for 9 wk. Feed intake, milk protein percentage, and milk fat levels did not differ between the treatments. Cows fed the RO, FO, or RFO treatments had a higher milk yield than the CON group (up to 10.5% more), whereas milk fat percentages decreased. Compared with the CON, milk concentration of ALA was substantially higher in cows receiving RO or RFO, and was doubled in cows receiving FO. The ALA yield (g/d) increased by 31.0, 70.3, and 33.4% in milk from cows fed RO, FO, or RFO, respectively, compared with the CON. Both C18:1 trans-11 (vaccenic acid) and C18:2 cis-9,trans-11 (conjugated linoleic acid; CLA) levels were higher in cows fed added flaxseed or rubber seed oil. The CLA yield (g/d) increased by 336, 492, and 484% in cows fed RO, FO, or RFO, respectively, compared with the CON. The increase in vaccenic acid, ALA, and CLA was greater in cows fed RFO than in cows fed RO alone. Compared with the CON, the milk fat from cows fed any of the dietary supplements had a higher concentration of unsaturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids; conversely, the saturated fatty acids levels in milk fat were 30.5% lower. Insulin and growth hormones were not affected by dietary treatments; however, we noted an increase in both cholesterol and nonesterified fatty acids levels in the RO, FO, or RFO treatments. These results indicate that rubber seed oil and flaxseed oil will increase milk production and the concentration of functional fatty acids (ALA, vaccenic acid, and CLA) in milk fat while decreasing the content of saturated fatty acids.

Runx2-Modified Adipose-Derived Stem Cells Promote Tendon Graft Integration in Anterior Cruciate Ligament Reconstruction

Runx2 is a powerful osteo-inductive factor and adipose-derived stem cells (ADSCs) are multipotent. However, it is unknown whether Runx2-overexpressing ADSCs (Runx2-ADSCs) could promote anterior cruciate ligament (ACL) reconstruction. We evaluated the effect of Runx2-ADSCs on ACL reconstruction in vitro and in vivo. mRNA expressions of osteocalcin (OCN), bone sialoprotein (BSP) and collagen I (COLI) increased over time in Runx2-ADSCs. Runx2 overexpression inhibited LPL and PPARγ mRNA expressions. Runx2 induced alkaline phosphatase activity markedly. In nude mice injected with Runx2-ADSCs, promoted bone formation was detected by X-rays 8 weeks after injection. The healing of tendon-to-bone in a rabbit model of ACL reconstruction treated with Runx2-ADSCs, fibrin glue only and an RNAi targeting Runx2, was evaluated with CT 3D reconstruction, histological analysis and biomechanical methods. CT showed a greater degree of new bone formation around the bone tunnel in the group treated with Runx2-ADSCs compared with the fibrin glue group and RNAi Runx2 group. Histology showed that treatment with Runx2-ADSCs led to a rapid and significant increase at the tendon-to-bone compared with the control groups. Biomechanical tests demonstrated higher tendon pullout strength in the Runx2-ADSCs group at early time points. The healing of the attachment in ACL reconstruction was enhanced by Runx2-ADSCs.

Intra-articular delivery of anti-Hif-2α siRNA by chondrocyte-homing nanoparticles to prevent cartilage degeneration in arthritic mice

Hypoxia-inducible factor-2α (Hif-2α) is a potential therapeutic target for osteoarthritis (OA), but the application of this target in the delivery of therapeutic agents to chondrocytes remains a challenge. A chondrocyte-targeting vector was constructed in a previous study to enhance transfection efficiency and specificity of chondrocytes in vivo. This study used vectors to deliver small-interfering RNA (siRNA) and silenced Hif-2α expression to prevent cartilage degeneration in OA-affected mice. After siRNA transfection was conducted by cartilage-targeting nanoparticles, the protein levels of Hif-2α, matrix metalloproteinases (MMP-13, -9), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-4, -5), vascular endothelial growth factor (VEGF), type X collagen and nuclear factor (NF)-κB in interleukin-1-beta (IL-1β)-stimulated chondrocytes were determined. Chondrocyte-targeting ability was also determined by fluorescein isothiocyanate (FITC)-labeled siRNA tracking under a confocal microscope. OA model was established by surgically destabilizing the knee joints of a mouse. Hif-2α siRNA was then delivered intra-articularly with nanoparticles in vivo. Cartilage degeneration and synovium inflammation in the knee joints were analyzed by histomorphometry. IL-1β levels in the synovial fluid were also measured by enzyme-linked immunosorbent assay. In vitro assay results showed that catabolic factors, including Hif-2α, MMP-13 and -9, ADAMTS-4, VEGF, collagen type X and NF-κB, were downregulated after Hif-2α-siRNA transfection by chondrocyte-targeting nanoparticles. In vivo assay results with FITC-labeled siRNA tracking also confirmed that nanoparticles promoted the local concentration and prolonged the retention time of siRNA in the cartilage. Histological analysis results confirmed that nanoparticle-mediated siRNA maintained cartilage integrity and alleviated synovium inflammation. IL-1β levels decreased after siRNA was silenced by nanoparticles. Thus, chondrocyte-targeting nanoparticles could deliver Hif-2α siRNA to cartilage and specifically inhibit the expression of catabolic proteins.

TRPV1 activation impedes foam cell formation by inducing autophagy in oxLDL-treated vascular smooth muscle cells

Vascular smooth muscle cells (VSMCs) are an important origin of foam cells besides macrophages. The mechanisms underlying VSMC foam cell formation are relatively little known. Activation of transient receptor potential vanilloid subfamily 1 (TRPV1) and autophagy have a potential role in regulating foam cell formation. Our study demonstrated that autophagy protected against foam cell formation in oxidized low-density lipoprotein (oxLDL)-treated VSMCs; activation of TRPV1 by capsaicin rescued the autophagy impaired by oxLDL and activated autophagy–lysosome pathway in VSMCs; activation of TRPV1 by capsaicin impeded foam cell formation of VSMCs through autophagy induction; activation of TRPV1 by capsaicin induced autophagy through AMP-activated protein kinase (AMPK) signaling pathway. This study provides evidence that autophagy plays an important role in VSMC foam cell formation and highlights TRPV1 as a promising therapeutic target in atherosclerosis.

Surface modification on polycaprolactone electrospun mesh and human decalcified bone scaffold with synovium-derived mesenchymal stem cells-affinity peptide for tissue engineering

Synovium-derived mesenchymal stem cells (SMSC) have been studied for over a decade since first being successfully isolated in 2001. These cells demonstrate the most promising therapeutic efficacy for musculoskeletal regeneration of the MSC family, particularly for cartilage regeneration. However, the mobilization and transfer of MSCs to defective or damaged tissues and organs in vivo with high accuracy and efficiency has been a major problem in tissue engineering (TE). In the present study, we identified a seven amino acid peptide sequence [SMSCs-affinity peptide (LTHPRWP; L7)] through phage display technology that has a high specific affinity to SMSCs. Our analysis suggested that L7 efficiently and specifically interacted with SMSCs without any species specificity. Thereafter, L7 was covalently conjugated onto both polycaprolactone (PCL) electrospun meshes and human decalcified bone scaffolds (hDBSc) to investigate its TE applications. After 24 h coculture with human SMSCs (hSMSCs), L7-conjugated PCL electrospun meshes had significantly more adherent hSMSCs than the control group, and the cells expanded well. Similar results were obtained using hDBSs. These results suggest that the novel L7 peptide sequence has a high specific affinity to SMSCs. Covalently conjugating this peptide to either artificial polymer material (PCL mesh) or natural material (hDBS) significantly enhances the adhesion of SMSCs. This method is applicable to a wide range of potential SMSC-based TE applications, particularly to cartilage regeneration, via surface modification on various type of materials.

Nanoparticle delivery of the bone morphogenetic protein 4 gene to adipose-derived stem cells promotes articular cartilage repair in vitro and in vivo

PURPOSE

To evaluate the effect of poly(lactic-co-glycolic acid) (PLGA) nanoparticles delivering pDC316-BMP4-EGFP plasmid into rabbit adipose-derived stem cells (ADSCs) in vitro and chondrogenesis of the bone morphogenetic protein 4 (BMP-4)--transfected ADSCs seeded onto poly(L-lactic-co-glycolic acid) (PLLGA) scaffold in a rabbit model.

METHODS

Cell viability and transfection efficiency of PLGA nanoparticles were measured by Cell Counting Kit-8 (Dojindo, Kumamoto, Japan) and flow cytometry. The BMP-4 and chondrogenesis markers were detected by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Thirty rabbits (60 knees) with full-thickness cylinder articular cartilage defects (diameter, 4.5 mm; depth, 0.8 mm) on the femoral trochlea were divided into a group in which the BMP-4--transfected ADSCs were seeded onto PLLGA scaffold and implanted into the defects (group ABNP), a group with untransfected ADSCs seeded onto scaffold (group ABP), and a group with a scaffold without cells (group P). Outcomes were evaluated by histology, Rudert score, Pineda score, and scanning electronic microscopy by 2 blinded observers at weeks 6 and 12 postoperatively. Statistical analyses were performed with analysis of variance and the Kruskal-Wallis test. The statistical significance level was set at P < .05.

RESULTS

The expression of chondrogenesis-related genes and proteins was significantly increased in BMP-4--transfected ADSCs in vitro (P < .05). The cell viability was 79.86% ± 5.04% after 24 hours. The transfection efficiency was 25.86% ± 4.27% after 72 hours. Defects in group ABNP showed the best in vivo cartilage regeneration. At week 12, the Rudert scores in group ABNP (7.00 ± 1.75) were better than those in group ABP (6.00 ± 2.00) or group P (5.00 ± 1.75) (P < .05), as were the Pineda scores (2.50 ± 3.00, 5.00 ± 2.00, and 6.00 ± 1.75, respectively; P < .001).

CONCLUSIONS

BMP-4 plasmid can be successfully delivered into ADSCs by PLGA nanoparticles and promoted in vitro chondrogenesis. When compared with the control cells, BMP-4--transfected ADSCs seeded onto PLLGA scaffold significantly improve in vivo chondrogenesis in a rabbit articular defect model.

CLINICAL RELEVANCE

PLGA nanoparticles and BMP-4 have potential for gene therapy in the treatment of chondral defects of the knee.

Microstructural characterization of Ti-6Al-4V alloy subjected to the duplex SMAT/plasma nitriding

In this study, microstructural characterization of Ti-6Al-4V alloy, subjected to the duplex surface mechanical attrition treatment (SMAT)/nitriding treatment, leading to improve its mechanical properties, was carried out through novel and original samples preparation methods. Instead of acid etching which is limited for morphological characterization by scanning electron microscopy (SEM), an original ion polishing method was developed. Moreover, for structural characterization by transmission electron microscopy (TEM), an ion milling method based with the use of two ions guns was also carried out for cross-section preparation. To demonstrate the efficiency of the two developed methods, morphological investigations were done by traditional SEM and field emission gun SEM. This was followed by structural investigations through selected area electron diffraction (SAED) coupled with TEM and X-ray diffraction techniques. The results demonstrated that ionic polishing allowed to reveal a variation of the microstructure according to the surface treatment that could not be observed by acid etching preparation. TEM associated to SAED and X-ray diffraction provided information regarding the nanostructure compositional changes induced by the duplex SMAT/nitriding process.

Detection of ADAMTS-4 activity using a fluorogenic peptide-conjugated Au nanoparticle probe in human knee synovial fluid

A disintegrin and metalloproteinase with thrombospondin motif-4 (ADAMTS-4) plays a pivotal role in degrading aggrecan, which is an early event in cartilage degrading joint diseases such as osteoarthritis (OA). Detection of ADAMTS-4 activity could provide useful clinical information for early diagnosis of such diseases and disease-modifying therapy. Therefore, we developed a ADAMTS-4 detective fluorescent turn-on AuNP probe (ADAMTS-4-D-Au probe) by conjugating gold nanoparticles with a FITC-modified ADAMTS-4-specific peptide (DVQEFRGVTAVIR). When the ADAMTS-4-D-Au probe was incubated with ADAMTS-4, the fluorescence recovered and fluorescence intensity markedly increased in proportion to concentrations of ADAMTS-4 and the probe. A nearly 3-fold increase in fluorescent intensity in response to only 3.9 pM of ADAMTS-4 was detected, whereas almost no fluorescence recovery was observed when the probe was incubated with matrix metalloproteinase (MMP)-1, -3, and -13. These results indicate a relative high sensitivity and specificity of the probe. Moreover, ADAMTS-4-D-Au probe was used to detect ADAMTS-4 activity in synovial fluid from 11 knee surgery patients. A substantial increase in fluorescent intensity was observed in the acute joint injury group as compared to the chronic joint injury and end-stage OA groups, indicating that this simple and low-cost sensing system might serve as a new detection method for ADAMTS-4 activity in biological samples and in screens for inhibitors for ADAMTS-4-related joint diseases. Additionally, this probe could be a potential biomarker for early diagnosis of cartilage-degrading joint diseases.

Surface nanocrystallization of Ti-6Al-4V alloy: microstructural and mechanical characterization

In this study, microstructural and mechanical properties of Ti-6Al-4V alloy, before and after the SMA treatment (SMAT) as well as the duplex SMAT/Nitriding process at different treatment conditions, were investigated in order to deepen the knowledge of these properties for biomedical devices. For that purpose, tribological (wear resistance, coefficient of friction) and mechanical (Vickers microhardness) tests were performed. To carry out the microstructural and surface topographical characterization of the samples, the scanning electron microscopy (SEM) and the 3D-SEM reconstruction from stereoscopic images have been used. By means of profiles deduced from the 3D images, the surface roughness has been calculated. The obtained results allowed to find an interesting SMAT condition which, followed by nitriding at low temperature, can greatly improve tribological and mechanical properties of Ti-6Al-4V alloy. It was also shown from SEM characterization and the original method of 3D-SEM reconstruction, that SMAT can reduce the machined grooves and consequently the roughness of the samples decreases. Moreover, we demonstrated, for the first time, that instead of usual etching method, the ionic polishing allowed to reveal the grains, the grain boundaries and the twins as well as the surface nanocrystalline layer generated by SMAT. Thus, the thickness of the SMATed layer decreases with the nitriding temperature, whereas the surface grain size increases.

One-step articular cartilage repair: combination of in situ bone marrow stem cells with cell-free poly(L-lactic-co-glycolic acid) scaffold in a rabbit model

Focal full-thickness articular cartilage defects are challenging to repair. The purpose of this study was to find a simple, effective 1-step articular cartilage repair method. Because stem cell niches produce a microenvironment for stem cell self-renewal, proliferation, and differentiation, we integrated in situ bone marrow stem cells with an implanted poly(L-lactic-co-glycolic acid) (PLLGA) scaffold. Marrow stem cells grew and proliferated on cell-free PLLGA scaffolds, which were evaluated by scanning electronic microscopy (SEM) and Cell Counting Kit-8 (Dojindo, Kumamoto, Japan). Twenty-seven rabbits (54 knees) with large cylinder femoral trochlear cartilage defects were created and repaired with microfracture and cell-free PLLGA scaffold implantation (group 1), microfracture (group 2), or cell-free PLLGA scaffold implantation (group 3).Outcomes were evaluated by magnetic resonance imaging, International Cartilage Repair Society scores, histology, and immunohistochemistry. The repair effects were better in group 1 than in groups 2 and 3. In group 1, hyaline-like cartilage formed at week 24. Magnetic resonance imaging showed homogeneous signals as the adjacent normal cartilage. Collagen type II and toluidine blue were stained positively as normal cartilage tissue, and the color and thickness of regenerated tissue were similar to surrounding normal tissue. The combination of microfracture and cell-free PLLGA scaffold implantation used endogenous marrow stem cells in situ and promoted hyaline-like cartilage regeneration rapidly and effectively.

Targeted delivery of non-viral vectors to cartilage in vivo using a chondrocyte-homing peptide identified by phage display

Gene therapy is a promising method for osteoarthritis and cartilage injury. However, specifically delivering target genes into chondrocytes is a great challenge because of their non-vascularity and the dense extracellular matrix of cartilage. In our study, we identified a chondrocyte-affinity peptide (CAP, DWRVIIPPRPSA) by phage display technology. Subsequent analysis suggests that the peptide can efficiently interact specifically with chondrocytes without any species specificity. Polyethylenimine (PEI) was covalently modified with CAP to construct a non-viral vector for cartilage-targeted therapy. To investigate the cartilage-targeting property of the CAP-modified vector, FITC-labeled CAP conjugated PEI/DNA particles were injected into rabbit knee joints, and visualized under confocal microscope. Higher concentrations of CAP-modified vector were detected in the cartilage and specifically taken up by chondrocytes compared with a randomly scrambled peptide (SP)-modified vector. To evaluate cartilage-targeting transfection efficiency, the GFP and luciferase genes were delivered into knee joints using CAP- and SP-modified PEI. Cartilage transfections mediated by CAP-modified PEI were much more efficient and specific than those by SP-modified PEI. This result suggests that CAP-modified PEI could be used as a specific cartilage-targeting vector for cartilage disorders.

Molecular cloning and mRNA expression profiling of the first specific jasmonate biosynthetic pathway gene allene oxide synthase from Hyoscyamus niger

In the endeavor to enhance the production of pharmaceutically valuable tropane alkaloids including hyoscyamine and scopolamine in Hyoscyamus niger, methyl jasmonate (MeJA) showed significant stimulation both in tropane biosynthetic pathway enzymes activities and tropane alkaloids yields. Therefore it was speculated that genetic engineering of jasmonate biosynthetic pathway might enhance the endogenous jasmonate concentration, followed by stimulating the production of tropane alkaloids. Herein a full-length cDNA encoding allene oxide synthase (AOS, EC 4.2.1.92), the first committed step enzyme in jasmonate biosynthetic pathway was reported (named HnAOS, GenBank accession: EF532599). HnAOS was a novel member of the cytochrome P450 (CYP74A) subfamily. Real-time quantitative PCR analysis showed that HnAOS mRNA accumulated mainly in stems, and responded significantly to wounding or methyl jasmonate.

[Molecular cloning and expression profile of a jasmonate biosynthetic pathway gene allene oxide cyclase from Hyoscyamus niger]

Hyoscyamus niger L. is a medicinal plant which produces a class of jasmonate-responsive pharmaceutical secondary metabolites named as tropane alkaloids. As a family of signaling phytohormones, jasmonates play significant roles in the biosynthesis of many plant secondary metabolites. In jasmonate biosynthetic pathway of plants, allene oxide cyclase (AOC, [...] EC 5.3.99.6 [...]) catalyzes the most important step. Here we cloned a cDNA from H. niger, named HnAOC (GenBank accession: AY708383), which was 1044 bp long, with a 747 bp open reading frame (ORF) encoding a polypeptide of 248 amino acid residues. Southern blot analysis indicated that it was a multi-copy gene. RT-PCR analysis revealed that the expression of HnAOC was regulated by various stresses and elicitors, with methyl-jasmonate showing the most prominent inducement. The characterization of HnAOC would be helpful for improving the production of valuable secondary metabolites by regulating the biosynthesis ofjasmonates.

[Isolation and expression profiling of the Pto-like gene SsPto from Solanum surattense]

A novel Pto-like gene (designated as SsPto) is cloned from yellow-fruit nightshade (Solanum surattense). The full-length cDNA of SsPto is 1331 bp long with an open reading frame of 960 bp encoding a polypeptide of 320 amino acid residues. The deduced SsPto protein has a calculated molecular weight of 36.21 kDa with an isoelectric point of 6.18. Multiple sequence alignment shows that SsPto protein shares 71.4% and 71.6% identities to Pto proteins from Lycopersicon pimpinellifolium and L. hirsutum respectively. Genomic Southern blot analysis indicates the presence of a small family of SsPto in the S. surattense genome. SsPto is found to be constitutively expressed in the S. surattense plant with the highest expression in stems. However, under induction by TMV for 6 days, SsPto expresses the highest in roots. Further expression analysis reveals that the signaling components of defense/stress pathways, such as methyl jasmonate (MeJA), salicylic acid (SA), gibberellic acid (GA3) and hydrogen peroxide (H2O2), up-regulate the SsPto transcript levels over the control. Cold treatment, nevertheless, has no significant effect on SsPto expression whereas SsPto expression is down-regulated by dark treatment. Our findings suggest that this novel stress- and pathogen-inducible SsPto from S. surattense may participate not only in the defense/stress responsive pathways, but also in diverse processes of plant's growth and development.

Diacylglycerol and fatty acids synergistically increase cardiomyocyte contraction via activation of PKC

Lipid signaling pathways are thought to play a prominent role in transducing extracellular signals into contractile responses in cardiac muscle. Two putative lipid messengers, diacyglycerol and arachidonic acid, can be generated via distinct phospholipases in separate signaling pathways, but certain stimuli cause them to be elevated in parallel. We tested the hypothesis that these lipids function as comessengers in ventricular myocytes by activating protein kinase C (PKC). In previous work, we demonstrated that the diacylglycerol analog dioctanoylglycerol (diC(8)) can be stimulatory or inhibitory toward myocyte twitches depending on how it is applied. Here we report that arachidonic acid and other cis-unsaturated fatty acids (UFA), at concentrations too low for direct effects, synergistically enhance the stimulatory effects of diC(8) and convert inhibitory effects of diC(8) into stimulation of myocyte twitches. Intracellular Ca(2+) transients changed in parallel with twitch amplitude, suggesting regulation of Ca(2+) homeostasis by these lipids. cis-UFA also interacted synergistically with the PKC activator phorbol 12-myristate 13-acetate to promote positive inotropic responses. Responses were blocked by the PKC antagonists chelerythrine chloride, bisindolylmaleimide, and Gö-6976. DiC(8) and arachidonic acid also synergistically translocated PKC-epsilon and PKC-alpha in intact myocytes. We propose that PKC integrates diacylglycerol and cis-UFA signals in the heart, resulting in preferential activation of positive inotropic mechanisms.

Endothelin-1 and photoreleased diacylglycerol increase L-type Ca2+ current by activation of protein kinase C in rat ventricular myocytes

The amphotericin B-perforated whole-cell patch clamp technique was used to determine the modulation of L-type Ca2+ channels by protein kinase C (PKC)-mediated pathways in adult rat ventricular myocytes. Application of 10 nM endothelin-1 (ET-1) increased peak Ca2+ current (ICa) by 28.2 +/- 2.5 % (n = 13) and slowed current decay. These effects were prevented by the endothelin receptor antagonist PD145065 (10 microM) and by the PKC inhibitor chelerythrine (8 microM). To establish if direct activation of PKC mimicked the ET-1 effect, the active and inactive phorbol esters (phorbol-12-myristate-13-acetate and 4alpha-phorbol-12, 13-didecanoate) were tested. Both phorbol esters (100 nM) resulted in a small (approximately 10%) increase in ICa, suggesting PKC-independent effects. Bath application of dioctanoylglycerol (diC8), a diacylglycerol (DAG) analogue which is capable of directly activating PKC, caused a gradual decline in peak ICa (50.4 +/- 6.2 %, n = 5) and increased the rate of current decay. These effects were unaffected by the PKC inhibitor chelerythrine (8 microM). Intracellular photorelease of caged diC8 with 3 or 10 s exposure to UV light produced a concentration-dependent increase in peak ICa (20. 7 +/- 8.5 % (n = 8) for 3 s UV and 60.8 +/- 11.4 % (n = 13) for 10 s UV), which could be inhibited by chelerythrine. Our results demonstrate that both ET-1 and intracellularly photoreleased diC8 increase ICa by a PKC-mediated pathway, which is in direct contrast to the PKC-independent inhibition of ICa produced by bath-applied diC8. We conclude that specific cellular pools of DAG are crucially important in the regulation of ICa by PKC.

Cardiac troponin I gene knockout: a mouse model of myocardial troponin I deficiency

Troponin I is a subunit of the thin filament-associated troponin-tropomyosin complex involved in calcium regulation of skeletal and cardiac muscle contraction. We deleted the cardiac isoform of troponin I by using gene targeting in murine embryonic stem cells to determine the developmental and physiological effects of the absence of this regulatory protein. Mice lacking cardiac troponin I were born healthy, with normal heart and body weight, because a fetal troponin I isoform (identical to slow skeletal troponin I) compensated for the absence of cardiac troponin I. Compensation was only temporary, however, as 15 days after birth slow skeletal troponin I expression began a steady decline, giving rise to a troponin I deficiency. Mice died of acute heart failure on day 18, demonstrating that some form of troponin I is required for normal cardiac function and survival. Ventricular myocytes isolated from these troponin I-depleted hearts displayed shortened sarcomeres and elevated resting tension measured under relaxing conditions and had a reduced myofilament Ca sensitivity under activating conditions. The results show that (1) developmental downregulation of slow skeletal troponin I occurs even in the absence of cardiac troponin I and (2) the resultant troponin I depletion alters specific mechanical properties of myocardium and can lead to a lethal form of acute heart failure.

Role of intracellular Ca2+ and pH in positive inotropic response of cardiomyocytes to diacylglycerol

Diacylglycerol has been hypothesized to mediate the positive inotropic response of myocardium to the alpha-adrenergic agonists angiotensin II and endothelin. The mechanism of action of diacylglycerol was examined here in adult rat ventricular myocytes by releasing dioctanoylglycerol (diC8) intracellularly from a caged compound while monitoring Ca2+ transients and pH with fluorescent indicators. DiC8 caused a three- to fourfold increase in twitch amplitude and a twofold increase in the systolic Ca2+ transient. No other parameter was consistently influenced by diC8, including the kinetics of Ca2+ cycling, the Ca2+ content of the sarcoplasmic reticulum, or the myofilament Ca2+ sensitivity. DiC8 also had no detectable effect on intracellular pH or Na+/H+ antiport activity. Consistent with this finding, the Na+/H+ exchange inhibitor N-ethylisopropyl amiloride was without effect on the positive inotropic response to diC8. The marked enhancement of systolic Ca2+ by diC8 suggests that the process of excitation-contraction coupling is an important and possibly preferred target of diacylglycerol-protein kinase C signaling in myocardium.

Arachidonic acid stimulates protein kinase C-epsilon redistribution in heart cells

Arachidonic acid is elevated in a variety of cell types in response to extracellular stimuli, and has been hypothesized to exert at least some of its intracellular actions via activation of protein kinase C. Here we show that arachidonic acid stimulates a unique pattern of translocation of the epsilon-isoform of protein kinase C in isolated adult rat cardiac myocytes. Using western blot analysis, the majority of epsilon-protein kinase C was found in a cytosolic fraction in unstimulated cells. Treatment with 50 microM arachidonic acid caused a transient increase of epsilon-protein kinase C in a membrane fraction within 1 minute, then after 5–20 minutes most was found in a filament/nuclear fraction. Immunofluorescence and confocal microscopy of the filament fraction revealed a striated staining pattern with epsilon-protein kinase C localized near the Z-line where actin filaments are anchored and where transverse tubules are closely apposed to the myofilaments. delta-Protein kinase C, another isoform highly expressed in these cells, did not redistribute significantly in response to arachidonic acid, but in response to phorbol ester displayed a predominantly nuclear localization. Arachidonic acid also stimulated phosphorylation of the thin filament protein, troponin I, consistent with a filament localization for activated PKC. The physiological relevance of these findings was supported by the observation that 50 microM arachidonic acid promoted a 2.3-fold enhancement of myocyte twitch amplitude, an effect that was significantly blocked by the protein kinase C antagonist chelerythrine. Moreover, the onset of this physiological response correlated in time with translocation of epsilon-protein kinase C to the filaments. The results suggest that arachidonic acid initiates a redistribution of epsilon-protein kinase C to myofilament structures at or near the Z-line where this isozyme would be strategically located to regulate myofilament function and excitation-contraction coupling.

Positive inotropy mediated by diacylglycerol in rat ventricular myocytes

Many neurohormones stimulate phospholipid hydrolysis and elevate diacylglycerol in the mammalian heart, but the physiological consequences of these intracellular events are unclear. Regulation of myocardial contraction by diacylglycerol was investigated in the present study by releasing the diacylglycerol analogue dioctanoylglycerol (diC8) within adult rat ventricular myocytes by using a light-sensitive caged compound. This approach permitted us to avoid exposure of myocytes to extracellular diC8 and yet to control the amount of diC8 released into the cells. Photorelease of diC8 produced a slowly developing (half-time, 1.9 +/- 0.1 minute; n = 26) but robust (406 +/- 42%) enhancement of twitch amplitude in electrically paced myocytes (0.5 Hz, 1 mmol/L Ca2+, Ringer's solution [pH 7.4], 22 degrees C). This positive inotropic effect was dose dependent, stereospecific for the S-enantiomer of diC8, synergistically enhanced by arachidonic acid, and blocked by the protein kinase C inhibitor chelerythrine. The data provide evidence that diacylglycerol can induce a strong positive inotropic effect in mammalian ventricular muscle, possibly by activating protein kinase C. By contrast, perfusion of diC8 extracellularly onto myocytes caused a 42 +/- 2% decline in twitch amplitude, in accordance with previous reports. To account for this dependence on how diC8 is applied, we postulate that diC8 has distinct physiological actions at intracellular and extracellular sites. The peptide neurohormone endothelin-1, which elevates diacylglycerol in cardiac tissues, produced a positive inotropic effect that was similar to the response to photoreleased diC8. The diacylglycerol/protein kinase C pathway has now become a good candidate for mediator of at least a component of the positive inotropy associated with agents that stimulate phospholipid turnover in adult mammalian myocardium.