Analgesic Effect of Intra-Articular Injection of Temperature-Responsive Hydrogel Containing Bupivacaine on Osteoarthritic Pain in Rats

Detecting inbreeding depression in structured populations

Measuring inbreeding and its consequences on fitness is central for many areas in biology including human genetics and the conservation of endangered species. However, there is no consensus on the best method, neither for quantification of inbreeding itself nor for the model to estimate its effect on specific traits. We simulated traits based on simulated genomes from a large pedigree and empirical whole-genome sequences of human data from populations with various sizes and structures (from the 1,000 Genomes project). We compare the ability of various inbreeding coefficients ([Formula: see text]) to quantify the strength of inbreeding depression: allele-sharing, two versions of the correlation of uniting gametes which differ in the weight they attribute to each locus and two identical-by-descent segments-based estimators. We also compare two models: the standard linear model and a linear mixed model (LMM) including a genetic relatedness matrix (GRM) as random effect to account for the nonindependence of observations. We find LMMs give better results in scenarios with population or family structure. Within the LMM, we compare three different GRMs and show that in homogeneous populations, there is little difference among the different [Formula: see text] and GRM for inbreeding depression quantification. However, as soon as a strong population or family structure is present, the strength of inbreeding depression can be most efficiently estimated only if i) the phenotypes are regressed on [Formula: see text] based on a weighted version of the correlation of uniting gametes, giving more weight to common alleles and ii) with the GRM obtained from an allele-sharing relatedness estimator.

Composite Hydrogel of Poly(vinyl alcohol) Loaded by Citrus hystrix Leaf Extract, Chitosan, and Sodium Alginate with In Vitro Antibacterial and Release Test

Citrus hystrix leaves have been used traditionally as a spice, a traditional medicine for respiratory and digestive disorders, and a remedy for bacterial infections. This study reports on the synthesis of composite hydrogels using the freeze-thaw method with poly(vinyl alcohol) (PVA) as the building block loaded by C. hystrix leaf extract (CHLE). Additionally, chitosan (CS) and sodium alginate (SA) were also loaded, respectively, to increase the antibacterial activity and to control the extract release of the composite hydrogels. The combinations of the compositions were PVA, PVA/CHLE, PVA/CHLE/CS, PVA/CHLE/SA, and PVA/CHLE/SA/CS. The internal morphology of the hydrogels shows some changes after the PVA/CHLE hydrogel was loaded by CS, SA, and SA/CS. The analysis of the Fourier transform infrared (FTIR) spectra confirmed the presence of PVA, CHLE, CS, and SA in the composite hydrogels. From the X-ray diffraction (XRD) characterization, it was shown that the composite hydrogels maintained their semicrystalline properties with decreasing crystallinity degree after being loaded by CS, SA, and SA/CS, as also supported by differential scanning calorimetry (DSC) characterization. The compressive strength of the PVA/CHLE hydrogel decreases after the loading of CS, SA, and SA/CS, so that it becomes more elastic. Despite being loaded in the composite hydrogels, the CHLE retained its antibacterial activity, as evidenced in the in vitro antibacterial test. The loading of CS succeeded in increasing the antibacterial activity of the composite hydrogels, while the loading of SA resulted in the decrease of the antibacterial activity. The release of extract from the composite hydrogels was successfully slowed down after the loading of CS, SA, and SA/CS, resulting in a controlled release following the pseudo-Fickian diffusion. The cytotoxic activity test proved that all hydrogel samples can be used safely on normal cells up to concentrations above 1000 μg/mL.

Eugenol alleviates acrylamide-induced rat testicular toxicity by modulating AMPK/p-AKT/mTOR signaling pathway and blood-testis barrier remodeling

This study aimed to investigate the effects of eugenol treatment on reproductive parameters in acrylamide (ACR)-intoxicated rats. The study evaluated alterations in relative testes and epididymides weights, sperm quality, serum hormonal status, seminal plasma amino acids, testicular cell energy and phospholipids content, oxidative and nitrosative stress parameters, adenosine monophosphate-activated protein kinase/ phosphoinositide 3-kinase/phosphor-protein kinase B/mammalian target of rapamycin (AMPK/PI3K/p-AKT/mTOR) signaling pathway, blood-testis barrier (BTB) remodeling markers, testicular autophagy and apoptotic markers, as well as histopathological alterations in testicular tissues. The results revealed that eugenol treatment demonstrated a significant improvement in sperm quality parameters, with increased sperm cell concentration, progressive motility live sperm, and a reduction in abnormal sperm, compared to the ACR-intoxicated group. Furthermore, eugenol administration increased the levels of seminal plasma amino acids in a dose-dependent manner. In addition, eugenol treatment dose-dependently improved testicular oxidative/nitrosative stress biomarkers by increasing oxidized and reduced glutathione levels and reducing malondialdehyde and nitric oxide contents as compared to ACRgroup. However, eugenol treatment at a high dose restored the expression of AMPK, PI3K, and mTOR genes, to levels comparable to the control group, while significantly increasing p-AKT content compared to the ACRgroup. In conclusion, the obtained findings suggest the potential of eugenol as a therapeutic agent in mitigating ACR-induced detrimental effects on the male reproductive system via amelioration of ROS-mediated autophagy, apoptosis, AMPK/p-AKT/mTOR signaling pathways and BTB remodeling.

Effectiveness of a Novel Temperature-Responsive Hydrogel (PF72) for Postoperative Pain Relief in Breast Augmentation

Breast augmentation can cause severe postoperative pain, leading to an increased length of hospital stay. Postoperative pain management following breast surgery has traditionally involved intravenous and oral analgesics. However, the misuse of opioids can cause severe complications. As a result, several alternative methods have been suggested. Fifty patients were included in this study. All the patients underwent dual-plane pocket dissection using the transaxillary approach and received smooth-type breast implants. The intervention group included 25 patients who received PF72 combined with ropivacaine, and the control group included 25 patients who received only bupivacaine. The Numerical Rating Scale (NRS) score was used to evaluate each patient's pain. Three hours after the surgery, the average NRS scores of the control and intervention groups were 3.75 and 2.48, respectively. Six hours after the operation, the NRS scores of the control and intervention groups increased to 4.77 and 3.02, respectively. PF72 combined with ropivacaine was more effective than only bupivacaine for pain control in patients who underwent breast augmentations.

Role of hydrogels in osteoarthritis: A comprehensive review

Osteoarthritis (OA) is a chronic, degenerative, and age-related disease. It is characterized by chronic inflammation, progressive articular cartilage destruction, and subchondral bone sclerosis. The current effective treatment for OA is limited. Hydrogel is a kind of unique carrier with well-known biocompatibility, softness, and high water content among various biomaterials. Hydrogels are developed for different biomedical applications, for instance, drug delivery, and tissue engineering. To date, a variety of hydrogels-based therapies have been used in OA patients or animal models. In this review, we comprehensively summarized the potential role of hydrogels in chondrocytes proliferation, apoptosis, and inflammatory component production and discussed the impact of hydrogels on OA development. The collection of this information will help better understand the present progress of hydrogels in OA.

Pathological Characteristics of Monosodium Iodoacetate-Induced Osteoarthritis in Rats

BACKGROUND

This study aimed to identify pain-related behavior and pathological characteristics of the knee joint in rats with monosodium iodoacetate (MIA)-induced osteoarthritis (OA).

METHODS

Knee joint inflammation was induced by intra-articular injection of MIA (4 mg/50 µL, n = 14) in 6-week-old male rats. Knee joint diameter, weight-bearing percentage on the hind limb during walking, the knee bending score, and paw withdrawal to mechanical stimuli were measured to evaluate edema and pain-related behavior for 28 d after MIA injection. Histological changes in the knee joints were evaluated using safranin O fast green staining on days 1, 3, 5, 7, 14, and 28 after OA induction (n = 3, respectively). Changes in bone structure and bone mineral density (BMD) were examined 14 and 28 d after OA (n = 3, respectively) using micro-computed tomography (CT).

RESULTS

The knee joint diameter and knee bending scores of the ipsilateral joint significantly increased 1 d after MIA injection, and the increased knee joint diameter and knee bending score persisted for 28 d. Weight-bearing during walking and paw withdrawal threshold (PWT) decreased from 1 and 5 d, respectively, and were maintained up to 28 d after MIA. Cartilage destruction started on day 1, and Mankin scores for bone destruction significantly increased for 14 d, as shown by micro-CT imaging.

CONCLUSION

The present study demonstrated that histopathological structural changes in the knee joint due to inflammation started soon after MIA injection, which induced OA pain from inflammation-related acute pain to spontaneous and evoked associated chronic pain.

Effect of temperature-responsive hydrogel on femoral and sciatic nerve blocks using bupivacaine in Beagle dogs

OBJECTIVES

To compare the duration of regional anesthesia of the pelvic limb using bupivacaine with and without a temperature-responsive hydrogel (TRH) in dogs.

METHODS

Under anesthesia using medetomidine (10 μg·kg^-1 ), alfaxalone (2 mg·kg^-1 ), and isoflurane, seven healthy male Beagles received four injections of 0.5% bupivacaine (1 mg·kg^-1 with 5 μg·ml^-1 epinephrine) to block the femoral and sciatic nerves bilaterally via ultrasound with nerve stimulation guidance. Bupivacaine was used on one pelvic limb (Bup treatment), and bupivacaine with TRH was used on the contralateral limb (Bup-TRH treatment). The nerve block was considered successful upon the absence of responses to pinching the digital pads and mid-tibial skin of both pelvic limbs with mosquito forceps; the pinch, proprioception, and locomotion tests were performed before (baseline) and at each hour after the nerve block until sensory and motor functions returned to baseline. The effect of TRH on nerve blocks was analyzed using a linear mixed model.

RESULTS

The duration of the sensory nerve block at the digital pads and mid-tibial skin was longer with Bup-TRH (8.0 ± 1.6 h and 10.9 ± 1.6 h, respectively) than with Bup treatment (3.7 ± 2.0 h and 8.0 ± 1.6 h, respectively). Motor block times of proprioception and locomotion were longer with Bup-TRH (9.3 ± 1.6 and 12.7 ± 1.5 h, respectively) than with Bup treatment (4.6 ± 1.9 and 9.6 ± 1.5 h, respectively). No complications were observed.

CLINICAL SIGNIFICANCE

TRH extended the duration of regional anesthesia of the pelvic limb using bupivacaine.

The Role of Polymeric Biomaterials in the Treatment of Articular Osteoarthritis

Osteoarthritis is a high-prevalence joint disease characterized by the degradation of cartilage, subchondral bone thickening, and synovitis. Due to the inability of cartilage to self-repair, regenerative medicine strategies have become highly relevant in the management of osteoarthritis. Despite the great advances in medical and pharmaceutical sciences, current therapies stay unfulfilled, due to the inability of cartilage to repair itself. Additionally, the multifactorial etiology of the disease, including endogenous genetic dysfunctions and exogenous factors in many cases, also limits the formation of new cartilage extracellular matrix or impairs the regular recruiting of chondroprogenitor cells. Hence, current strategies for osteoarthritis management involve not only analgesics, anti-inflammatory drugs, and/or viscosupplementation but also polymeric biomaterials that are able to drive native cells to heal and repair the damaged cartilage. This review updates the most relevant research on osteoarthritis management that employs polymeric biomaterials capable of restoring the viscoelastic properties of cartilage, reducing the symptomatology, and favoring adequate cartilage regeneration properties.

Effects of miniscrew-facilitated micro-osteoperforations on the rate of orthodontic tooth movement : A split-mouth, randomized controlled trial

PURPOSE

The aim of the present split-mouth randomized controlled trial was to evaluate the effects of miniscrew-facilitated micro-osteoperforations (MOPs) on the rate of orthodontic tooth movement during canine retraction.

METHODS

A total of 20 young adult patients (mean age 16.5 years) with the indication for bilateral maxillary first premolar extraction were included in the study. The MOPs were randomly applied to either the right or left side of the mouth with miniscrews (1.5 mm width, 8 mm length) to the extraction area, 28 days apart. The canine distalization continued for 3 months. The closure of the extraction space was measured by using a digital analysis program on the pre- and postdigital study models for both the control and experiment sides.

RESULTS

The mean rate of extraction space closure on the MOP side was 2.51 ± 1.41 mm and on the control side was 2.88 ± 1.32 mm. There was no statistically significant difference between the groups (p > 0.05).

CONCLUSION

Overall, we found that MOPs did not significantly affect the rate of orthodontic tooth movement during canine retraction.

Assessing the Safety and Utility of Wound VAC Temporization of the Sarcoma or Benign Aggressive Tumor Bed Until Final Margins Are Achieved

BACKGROUND

Local recurrence of microinvasive sarcoma or benign aggressive pathologies can be limb- and life-threatening. Although frozen pathology is reliable, tumor microinvasion can be subtle or missed, having an impact on surgical margins and postoperative radiation planning. The authors' service has begun to temporize the tumor bed after primary tumor excision with a wound vacuum-assisted closure (VAC) pending formal margin analysis, with coverage performed in the setting of final negative margins.

METHODS

This retrospective analysis included all patients managed at a tertiary referral cancer center with VAC temporization after soft tissue sarcoma or benign aggressive tumor excision from 1 January 2000 to 1 January 2019 and at least 2 years of oncologic follow-up evaluation. The primary outcome was local recurrence. The secondary outcomes were distant recurrence, unplanned return to the operating room for wound/infectious indications, thromboembolic events, and tumor-related deaths.

RESULTS

For 62 patients, VAC temporization was performed. The mean age of the patients was 62.2 ± 22.3 years (median 66.5 years; 95% confidence interval [CI] 61.7-72.5 years), and the mean age-adjusted Charlson Comorbidity Index was 5.3 ± 1.9. The most common tumor histology was myxofibrosarcoma (51.6%, 32/62). The mean volume was 124.8 ± 324.1 cm³, and 35.5% (22/62) of the cases were subfascial. Local recurrences occurred for 8.1% (5/62) of the patients. Three of these five patients had planned positive margins, and 17.7% (11/62) of the patients had an unplanned return to the operating room. No demographic or tumor factors were associated with unplanned surgery.

CONCLUSIONS

The findings showed that VAC-temporized management of microinvasive sarcoma and benign aggressive pathologies yields favorable local recurrence and unplanned operating room rates suggestive of oncologic and technical safety. These findings will need validation in a future randomized controlled trial.

Randomized trial of poloxamer 407-based ropivacaine hydrogel after thoracoscopic pulmonary resection

BACKGROUND

We conducted a comparative study to evaluate the efficacy of poloxamer 407-based ropivacaine hydrogel at the wound site (Gel) and continuous thoracic paravertebral block (On-Q) for postoperative pain following thoracoscopic pulmonary resection.

METHODS

This prospective, randomized, noninferiority study included 89 patients randomized into the two groups; Gel (poloxamer 407-based 0.75% ropivacaine, 22.5 mg) and On-Q (0.2% ropivacaine, 4 mg/hour for 48 hours). The primary outcome measure was total fentanyl consumption and secondary outcome measures were the need for rescue analgesia and pain intensity using the numeric rating scale (NRS).

RESULTS

There was no significant difference in total fentanyl consumption between the Gel group and the On-Q group (1504.29 ± 315.72 mcg vs 1560.32 ± 274.81 mcg, p = 0.374). Pain intensity using the NRS between the Gel group and the On-Q group demonstrated no statistical differences (6 hours: 3.56 vs 3.55, p = 0.958; 24 hours: 3.21 vs 3.00, p = 0.250; 48 hours: 2.75 vs 2.49, p = 0.233; and 72 hours: 2.39 vs 2.33, p = 0.811), and there was no significant difference in the frequency of analgesic rescue medication use (3.70 vs 3.33, p = 0.417).

CONCLUSIONS

We confirm the noninferiority of Gel compared with On-Q for acute postoperative pain following thoracoscopic pulmonary resection. Considering a technical simplicity and low systemic toxicity of the local injection of Gel, this analgesic modality may be worthy of further research and is thus considered to have potential as a viable alternative to On-Q for regional analgesia.

Effect of docosahexaenoic acid on in vitro growth of bovine oocytes

PURPOSE

The present study investigated the effects of docosahexaenoic acid (DHA) on the growth of bovine oocytes.

METHODS

Oocytes and granulosa cell complexes (OGCs) were collected from early antral follicles (0.4-0.7 mm) on the surface of ovaries harvested from a slaughterhouse. The OGCs were cultured with 0, 1, and 10 μmol/L docosahexanoic acid (DHA) for 16 days.

RESULTS

Antrum formation of the OGCs and the number of granulosa cells (GCs) surrounding the oocytes were comparable among groups, whereas supplementation of 0.1 μmol/L of DHA significantly improved oocyte growth. Oocytes grown with DHA had a higher fertilization rate, acetylation levels of H4K12, and ATP contents, as well as a lower lipid content compared with those grown without DHA. In addition, GCs surrounding OGCs grown with DHA had low lipid content compared with vehicle counterparts. Furthermore, when GCs were cultured in vitro, DHA increased ATP production, mitochondrial membrane potential, and reduced lipid content and levels of reactive oxygen species. RNA-seq of GCs revealed that DHA increased CPT1A expression levels and affect genes associated with focal adhesion, oxidative phosphorylation, and PI3K-AKT etc.

CONCLUSION

The results suggest that DHA supplementation affects granulosa cell characteristics and supports oocyte growth in vitro.

Intraarticular Injection of Infliximab-Loaded Thermosensitive Hydrogel Alleviates Pain and Protects Cartilage in Rheumatoid Arthritis

Purpose

Pain and cartilage destruction caused by rheumatoid arthritis (RA) are major challenges during clinical treatment. Traditional systemic administration not only has obvious side effects but also provides limited relief for local symptoms in major joints. Local delivery of therapeutics for RA treatment is a potential strategy but is limited by rapid intraarticular release.

Materials and Methods

In this study, we prepared a thermoresponsive injectable hydrogel by mixing pluronic F127 (F127) and hyaluronic acid (HA) with poly (γ-glutamic acid) (PGA) incorporating infliximab (IFX), a new generation monoclonal antibody drug. We investigated the biocompatibility of the hydrogel and its IFX release profile. In vivo, we studied the clinical manifestations (articular skin temperature and joint diameter), detected cytokines in the synovial fluid and cartilage, performed behavioral studies on pain relief, and evaluated the cartilage protection effect.

Results

A thermoresponsive hydrogel was successfully prepared by mixing F127, HA, and PGA with injectable properties. The F127-HA-PGA hydrogel had a porous structure with interconnected pores. The infliximab-loaded thermosensitive hydrogel exhibited good biocompatibility and biodegradability and sustained release properties. Intraarticular injection of the IFX-loaded F127-HA-PGA hydrogel could alleviate the expression of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-17 (IL-17), in the synovial fluid and cartilage as well as relieve pain and inhibit cartilage destruction in RA.

Conclusion

The double effect on pain relief and cartilage protection indicated the significant potential of the IFX-loaded injectable hydrogel for RA treatment in major joint lesions.

Analgesic Tolerance Development during Repetitive Electric Stimulations Is Associated with Changes in the Expression of Activated Microglia in Rats with Osteoarthritis

Electric stimulation is used for managing osteoarthritic (OA) pain; however, little is known about the development of analgesic tolerance during repeated stimulations and the relation of spinal microglia with OA pain. We investigated the changes in the analgesic effects of repeated electric stimulations and the relation between the development of analgesic tolerance and spinal microglial expression in rats with OA. To induce OA, monosodium iodoacetate was injected into the synovial space of the right knee joint of the rats (n = 185). Repeated high frequency, low frequency, or sham transcutaneous electric nerve stimulation (TENS) was performed to the ipsilateral knee joint for 20 min in rats with OA (n = 45). Minocycline or minocycline plus TENS (HF, LF, or sham) was treated in OA rats with repeated TENS-induced tolerance (n = 135). Immunohistochemistry of the microglia in the L3–L5 spinal segments was performed. Knee joint pain during passive movement of the knee joint were quantified using the knee-bend score and the proportion of activated microglia was calculated as primary variables. Paw withdrawal threshold (hypersensitivity to mechanical stimuli) was assessed and the resting and activated microglia were counted as secondary variables. Repeated applications decreased the analgesic effect of TENS on OA pain and failed to reduce the expression of activated microglia in the spinal cord. However, spinal microglial inhibition by minocycline restored the analgesic effect of TENS on OA pain in TENS-tolerant OA rats. TENS combined with minocycline treatment improved knee joint pain and mechanical hypersensitivity in TENS-tolerant OA rats, and inhibited the expression of activated microglia in the spinal cord. These results suggest a possible relationship between repetitive electric stimulation-induced analgesic tolerance for OA pain control and changes in microglia activation.

Pain-Relieving Effect of 4.4 MHz of Pulsed Radiofrequency on Acute Knee Arthritis in Rats

OBJECTIVE

Drug injections and surgery are popular treatments for knee joint osteoarthritis. However, these treatments are invasive, and new noninvasive treatments with similar or better efficacy are needed. Here, we evaluated the application of 4.4 MHz of pulsed radiofrequency (PRF) as a new treatment.

METHODS

Acute arthritis was induced by injection of carrageenan into the intra-articular space of the knee in male rats. At 4.5 hours after arthritis induction, PRF with the treatment protocol of three seconds on and off was applied to the affected knee joint for 20 minutes. The changes in pain behavior were evaluated by comparing the peak weight load values of both hind paws at pretreatment and four, six, seven, eight, and 24 hours after treatment. And we also used Western blotting and immunohistochemistry to measure the inflammatory changes in the synovial membrane of the inflamed knee.

RESULTS

We found that the 20-minute application of PRF with the treatment protocol significantly recovered the weight load reduction at six-, seven-, and eight-hour time points after carrageenan injection. COX-2 and IL-1β levels were significantly reduced in the inflamed rats after PRF application at six and eight hours post-carrageenan injection. Immunohistochemistry showed that PRF significantly reduced inflammatory cell infiltration at six hours post-carrageenan injection.

CONCLUSIONS

. Our results indicate that noninvasive PRF application inhibited pain-related behavior and decreased inflammatory cytokine expression in the inflamed knee joints of rats. Accordingly, PRF application can serve as a potential therapeutic treatment to relieve pain associated with peripheral joint/tissue damage or inflammation.

Surface-based modeling of muscles: Functional simulation of the shoulder

Musculoskeletal simulations are an essential tool for studying functional implications of pathologies and of potential surgical outcomes, e.g., for the complex shoulder anatomy. Most shoulder models rely on line-segment approximation of muscles with potential limitations. Comprehensive shoulder models based on continuum-mechanics are scarce due to their complexity in both modeling and computation. In this paper, we present a surface-based modeling approach for muscles, which simplifies the modeling process and is efficient for computation. We propose to use surface geometries for modeling muscles, and devise an automatic approach to generate such models, given the locations of the origin and insertion of tendons. The surfaces are expressed as higher-order tensor B-splines, which ensure smoothness of the geometrical representation. They are simulated as membrane elements within a finite element simulation. This is demonstrated on a comprehensive model of the upper limb, where muscle activations needed to perform desired motions are obtained by using inverse dynamics. In synthetic examples, we demonstrate our proposed surface elements both to be easy to customize (e.g., with spatially varying material properties) and to be substantially (up to 12 times) faster in simulation compared to their volumetric counterpart. With our presented automatic approach of muscle wrapping around bones, the humeral head is exemplified to be wrapped physiologically consistently with surface elements. Our functional simulation is shown to successfully replicate a tracked shoulder motion during activities of daily living. We demonstrate surface-based models to be a numerically stable and computationally efficient compromise between line-segment and volumetric models, enabling anatomical correctness, subject-specific customization, and fast simulations, for a comprehensive simulation of musculoskeletal motion.

Transcutaneous Electrical Nerve Stimulation Reduces Knee Osteoarthritic Pain by Inhibiting Spinal Glial Cells in Rats

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is commonly used for pain control. However, the effects of TENS on osteoarthritis (OA) pain and potential underlying mechanisms remain unclear.

OBJECTIVE

The objective of this study was to investigate the effect of TENS on OA pain treatment and underlying mechanisms related to glial cell inhibition.

DESIGN

This was an experimental study.

METHODS

OA was induced by injection of monosodium iodoacetate into the synovial space of the right knee joint of rats. High-frequency (HF) TENS (100 Hz), low-frequency (LF) TENS (4 Hz), or sham TENS was applied to the ipsilateral knee joint for 20 minutes. Paw withdrawal threshold (PWT), weight bearing, and knee bend score (KBS) were measured. Immunohistochemistry for microglia and astrocytes was performed with L3 to L5 spinal segment samples. To investigate the effects of glial inhibition on OA pain, minocycline, l-α-aminoadipate, or artificial cerebrospinal fluid was injected intrathecally, and PWT and KBS were measured.

RESULTS

Compared with sham TENS, both HF TENS and LF TENS significantly increased PWT, decreased KBS, and inhibited activated microglia in the L3 to L5 segments but did not decrease the total number of microglia, except in the L4 segment (HF TENS). Astrocyte expression was significantly decreased in the L3 to L5 segments following LF TENS and in the L3 segment following HF TENS. Compared with artificial cerebrospinal fluid, both minocycline and l-α-aminoadipate increased PWT and decreased KBS.

LIMITATIONS

These results cannot be generalized to humans.

CONCLUSIONS

TENS alleviates OA pain in rats by inhibiting activated microglia and reducing astrocyte expression in the spinal cord. Although these results may not be generalizable to chronic pain in patients with OA, within the limitation of the experimental animal model used in the present study, they suggest a possible mechanism and preclinical evidence supporting further experimentation or clinical use of TENS in humans.

Alginate encapsulation for bupivacaine delivery and mesenchymal stromal cell immunomodulatory cotherapy

PURPOSE

Mesenchymal stromal cells (MSCs) are used to treat various inflammatory conditions. In parallel, to mitigate pain associated with inflammation, analgesics or opioids are prescribed, often with significant side effects. Local anesthetics (LAs) offer a promising alternative to these medications. However, their short duration and negative effects on anti-inflammatory MSCs have limited their therapeutic effectiveness. To mitigate these negative effects and to move toward developing a cotherapy, we engineered a sustained release bupivacaine alginate-liposomal construct that enables up to 4 days of LA release. By encapsulating MSC in alginate (eMSC), we demonstrate that we can further increase drug concentration to clinically relevant levels, without compromising eMSC viability or anti-inflammatory function.

MATERIALS AND METHODS

MSCs were freely cultured or encapsulated in alginate microspheres ± TNFα/IFN-γ and were left untreated or dosed with bolus, liposomal, or construct bupivacaine. After 24, 48, and 96 hours, the profiles were assessed to quantify secretory function associated with LA-MSC interactions. To approximate LA exposure over time, a MATLAB model was generated.

RESULTS

eMSCs secrete similar levels of IL-6 and prostaglandin E2 (PGE2) regardless of LA modality, whereas free MSCs secrete larger amounts of IL-6 and lower amounts of anti-inflammatory PGE2. Modeling the system indicated that higher doses of LA can be used in conjunction with eMSC while retaining eMSC viability and function. In general, eMSC treated with higher doses of LA secreted similar or higher levels of immunomodulatory cytokines.

CONCLUSION

eMSCs, but not free MSC, are protected from LA, regardless of LA modality. Increasing the LA concentration may promote longer and stronger pain mitigation while the protected eMSCs secrete similar, if not higher, immunomodulatory cytokine levels. Therefore, we have developed an approach, using eMSC and the LA construct that can potentially be used to reduce pain as well as improve MSC anti-inflammatory function.

A "best fit" approach for synergistic surface parameters to guide the design of candidate implant surfaces

Human bone resorption surfaces can provide a template for endosseous implant surface design. We characterized the topography of such sites using four synergistic parameters (fractal dimension, lacunarity, porosity, and surface roughness) and compared the generated values with those obtained from two groups of candidate titanium implant surfaces. For the first group (n = 5/group): grit-blasted acid etched (BAE), BAE with either discrete calcium phosphate crystal deposition or nanotube formation, machined titanium with nanotubes, or a nanofiber surface; each measured synergistic parameter was statistically compared with that of the resorbed bone surface and scored for inclusion in a "best fit" analysis. The analysis informed changes that could be made to a candidate implant surface to render it a closer "best fit" to that of the resorbed bone surface. In a second group of either titanium or titanium alloy implants their micro-topography, created by dual acid etching, was the same for each material substrate; but their nanotopographic complexity was changed by varying the degree of calcium phosphate crystalline deposits. These implants were also used in vivo where bone anchorage was tested using a tensile disruption test; and the "best fit" of synergistic parameters coincided with the best biological outcome for both titanium and titanium alloy implants. In conclusion, the four chosen synergistic parameters can be used to guide the sub-micron surface design of candidate implants, and our "best fit" approach is capable of identifying the surfaces with the best biological outcomes. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2165-2177, 2019.

Preclinical studies of ropivacaine extended-release from a temperature responsive hydrogel for prolonged relief of pain at the surgical wound

Postoperative pain is a common form of acute pain that has been treated commonly by local anesthetics through regional nerve blocking. In this study, a series of experiments were conducted using rats to investigate the pharmacokinetic, distribution, and efficacy of a temperature responsive hydrogel-based drug delivery device (PF-72) containing ropivacaine (0.75%) for extended relief of postoperative pain by allowing the prolonged release of ropivacaine. When the ropivacaine was administered using PF-72, its concentration-time curve (AUC_last) and peak concentration (C_max) were 577.0 h*ng/mL and 271.9 ng/mL, respectively. In contrast when the ropivacaine solution was administered using saline solution, its AUC_last and C_max were 982.8 h*ng/mL and 423.6 ng/mL, respectively. In the tissue distribution study, the peak concentration and mean area under the curve of the ropivacaine in injection area (target tissue) were found about 2-fold higher in the case of PF-72 compared with the case of conventional ropivacaine solution. These results clearly demonstrate the capability of PF-72 hydrogel to retain the ropivacaine at the injection site for an extended period. Effective extended (at least 24 h) pain relief of ropivacaine administered using PF-72 was found in the pharmacodynamic study of prolonged analgesic effect. The results of this study indicated that local drug delivery by PF-72 hydrogel formulation may be an effective method to achieve extended relief of pain. Other advantages of ropivacaine administration using PF-72 include reduced systemic side effects and high localization of a drug in target tissues.

Genetics of platelet traits in ischaemic stroke: focus on mean platelet volume and platelet count

Purpose/Aim of the study: The aim of this review is to summarize the role of genetic variants affecting mean platelet volume (MPV) and platelet count (PLT) leading to higher platelet reactivity and in turn to thrombotic events like stroke and cardiovascular diseases.

MATERIALS AND METHODS

A search was conducted in PUBMED, MEDLINE, EMBASE, PROQUEST, Science Direct, Cochrane Library, and Google Scholar related to the studies focussing on genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis that have been employed to identify the genetic variants influencing MPV and PLT.

RESULTS

Antiplatelet agents underscore the crucial role of platelets in the pathogenesis of stroke. Higher platelet reactivity in terms of mean platelet volume (MPV) and platelet count (PLT) contributes significantly to the interindividual variation in platelet reaction at the site of vessel wall injury. Some individuals encounter thrombotic events as platelets get occluded at the site of vessel wall injury whereas others heal the injury without occluding the circulation. Evidence suggests that MPV and PLT have a strong genetic component. High throughput techniques including genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis have identified different genetic variants influencing MPV and PLT.

CONCLUSIONS

Identification of complex genetic cross talks affecting PLT and MPV might help to develop novel treatment strategies in treating neurovascular diseases like stroke.

Injectable collagen/RGD systems for bone tissue engineering applications

Imbalance crosslink density and polymer concentration gradient is formed within the traditional alginate hydrogel using calcium chloride as a crosslinking agent in external gelation for instantaneously process. In this studying, type I collagen (Col I) blended calcium salt form of poly(γ-glutamic acid) (γCaPGA) was mixing with RGD-modified alginate with convenient gelation process and suitable for practical use. The hydrophilicity of the resulting hydrogels was evaluated through swelling tests, water retention capacity tests, and water vapor permeation tests. Mineralization was qualitatively evaluated by alizarin red dyeing at day 14, verifying the deposition of calcium. The in vitro osteogenic differentiation is monitored by determining the early and late osteocalcin (OCN) and osteopontin (OPN) markers with MG63 cells. Obtained results demonstrated that no extremely changes in mechanical properties. After 14 days of culture, hydrogels significantly stimulated OCN/OPN gene expressions and MG63 cell proliferation. Unusually, γCaPGA with RGD-modified alginate appeared better calcium deposition in 14 days than the other. However, addition of Col I can counterpoise RGD effect in blood coagulation and platelet adhesion made the hydrogel more flexibility and selectively in use. This studying provided that non-covalently crosslinked hydrogel by γCaPGA with alginate can be upgrading by RGD and Col I in water uptake capability, obviously effective for MG63 cells and are remarkably biocompatible and exhibited no cytotoxicity. Moreover, results also displayed the injectable process without complicated procedure, have high cost/performance ratio and have great potential for bone regeneration.

Heritability and longitudinal outcomes of spelling skills in individuals with histories of early speech and language disorders

This study examined the spelling skills in middle childhood and adolescence in individuals with histories of early childhood speech sound disorders (SSD) with and without language impairment (LI). Youth without such histories were also included (No SSD/LI group). The heritability of spelling skills at each age level was estimated. Children with SSD were classified as SSD-only, SSD with LI but without childhood apraxia of speech (SSD + LI/ No CAS), and CAS and LI (CAS + LI). The SSD-only group did not differ in spelling from the No SSD/LI group, suggesting that SSD-only did not increase risk for poor spelling. The SSD + LI/No CAS and CAS + LI groups had poorer spelling skills than the SSD-only and No SSD/LI groups. Spelling was associated with phonological awareness in the middle childhood and adolescent samples and with rapid automatized naming in the adolescent sample. Heritability of spelling skills was stronger in adolescence than in middle childhood. Differences in the correlates of spelling and in heritability at the two ages suggest developmental changes in the factors contributing to spelling.

Precision-guided long-acting analgesia by Gel-immobilized bupivacaine-loaded microsphere

Peripheral nerve blockade (PNB) is a conventional strategy for the management of acute postoperative pain. However, the short duration of the associated analgesia and the potential systemic toxicity due to the low molecular weights of local anesthetics limit their application. Methods: An in situ forming injectable Gel-microsphere (Gel-MS) system consisting of PLGA-PEG-PLGA Gel (Gel) and Gel-immobilized bupivacaine-loaded microsphere (MS/BUP) was prepared for precision-guided long-acting analgesia. A series of in vitro characterizations, such as scanning electron microscopy, rheology analysis, confocal laser scanning microscopy, drug release, and erosion and degradation, were carried out. After that, the in vivo analgesia effect of the Gel-MS system, the immobilization effect of Gel on the MS, and biocompatibility of the system were evaluated using a sciatic nerve block model. Results: The BUP release from the Gel-MS system was regulated by both the inner MS and the outer Gel matrix, demonstrating sustained BUP release in vitro for several days without an initial burst release. More importantly, incorporation of the Gel immobilized the MS and hindered the diffusion of MS from the injection site because of its in situ property, which contributed to a high local drug concentration and prevented systemic side effects. In vivo, a single injection of Gel-MS/BUP allowed rats to maintain sensory and motor blockade significantly longer than treatment with MS/BUP (P < 0.01) or BUP-loaded Gel (Gel-BUP, P < 0.01). Histopathological results demonstrated the excellent biodegradability and biocompatibility of the Gel-MS system without neurotoxicity. Conclusion: This precision-guided long-acting analgesia, which provides an in situ and sustained release of BUP, is a promising strategy for long-acting analgesia, and could represent a potential alternative for clinical pain management.

An in situ-forming phospholipid-based phase transition gel prolongs the duration of local anesthesia for ropivacaine with minimal toxicity

An injectable, phospholipid-based phase transition gel (PPTG) has been developed for prolonging the release of ropivacaine (RO) for local anesthesia. PPTG was prepared by mixing phospholipids, medium-chain triglyceride and ethanol. Prior to injection, the PPTG is in a sol state with low viscosity. After subcutaneous injection, the PPTG rapidly forms a gel in situ, which acts as a drug release depot as verified by in vitro release profiles and in vivo pharmacokinetics. Administering RO-PPTG to rats led to a significantly smaller initial burst release than administering RO solution or RO base suspension. Nerve blockade in guinea pigs lasted 3-fold longer after injection of RO-PPTG than after injection of RO solution. RO-PPTG showed good biocompatibility and excellent degradability in vivo. These results suggest that this PPTG-based depot system may be useful for sustained release of local anesthetics to prolong analgesia without causing systemic toxicity.

STATEMENT OF SIGNIFICANCE

The sustained release of local anesthetics at the surgical site after a single injection is the optimal method to control post-surgical pain. In situ forming implant is an attractive alternative for the sustained release of local anesthetics. However, its practical use is highly limited by certain drawbacks including high viscosity, involved toxic organic solvents and fast drug release. To date, phospholipids-based phase transition gel (PPTG) is emerging for clinical development because of the non-toxicity, biocompatibility and ready availability of phospholipids in body. Thus, we present a novel strategy for sustained release of local anesthetics to control post-surgical pain based on PPTG, which showed a prolonged duration of nerve blockade and excellent biocompatibility.

Localized bone regeneration around dental implants using recombinant bone morphogenetic protein-2 and platelet-derived growth factor-BB in the canine

OBJECTIVES

To test whether or not one of two biological mediators (recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human platelet-derived growth factor (rhPDGF-BB)) is superior to the other and compared with control groups for bone regeneration around implants based on histomorphometrical outcome measures.

MATERIALS AND METHODS

Box-type defects (10 × 5 × 5 mm) were prepared on the buccal sides of the left and right edentulous ridge in ten mongrel dogs. Implants were placed at each site, the defects either received (i) bovine-derived particulated bone mineral (DBBM) mixed with rhBMP-2 and a collagen membrane (CM) (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB and CM (DBBM/PDGF), (iii) DBBM and CM (DBBM) and (iv) empty control (control). Animals were euthanized post-surgery at 8 weeks and 16 weeks. Histomorphometrical analyses were performed.

RESULTS

The mean percentages of regenerated area within total defect area amounted to 56.95% for DBBM/BMP-2, 48.86% for DBBM/PDFG, 33.44% for DBBM and 1.59% for control at 8 weeks, and 26.79% for DBBM/BMP-2, 23.78% for DBBM/PDFG, 30.21% for DBBM and 5.07% for control at 16 weeks with no statistically significant differences between the groups (P > 0.05). The mean amount of regenerated bone was 26.97% for DBBM/BMP-2, 22.02% for DBBM/PDFG, 5.03% for DBBM and 1.25% for control at 8 weeks, and at 16 weeks, these values were lower in the two groups with biological mediators (DBBM/BMP-2 = 13.35%; DBBM/PDGF = 6.96%) and only slightly increased in group DBBM (10.68%) and the control group (4.95%) compared with 8 weeks. The first bone-to-implant contact values on the buccal side were minimal for DBBM/BMP-2 (0.57 mm) and maximal for control (3.72 mm) at 8 weeks.

CONCLUSIONS

The use of biological mediators (rhBMP-2 and rhPDGF-BB) can increase the amount of bone regeneration at dehiscence-type defects compared with controls at 8 weeks, but not at 16 weeks due to enhanced hard tissue remodeling processes.