Enhancing osteoblast survival through pulsed electrical stimulation and implications for osseointegration

Electrical stimulation has been suggested as a means for promoting the direct structural and functional bonding of bone tissue to an artificial implant, known as osseointegration. Previous work has investigated the impact of electrical stimulation in different models, both in vitro and in vivo, using various electrode configurations for inducing an electric field with a wide range of stimulation parameters. However, there is no consensus on optimal electrode configuration nor stimulation parameters. Here, we investigated a novel approach of delivering electrical stimulation to a titanium implant using parameters clinically tested in a different application, namely peripheral nerve stimulation. We propose an in vitro model comprising of Ti6Al4V implants precultured with MC3T3-E1 preosteoblasts, stimulated for 72\ua0h at two different pulse amplitudes (10\ua0\ub5A and 20\ua0\ub5A) and at two different frequencies (50\ua0Hz and 100\ua0Hz). We found that asymmetric charge-balanced pulsed electrical stimulation improved cell survival and collagen production in a dose-dependent manner. Our findings suggest that pulsed electrical stimulation with characteristics similar to peripheral nerve stimulation has the potential to improve cell survival and may provide a promising approach to improve peri-implant bone healing, particularly to neuromusculoskeletal interfaces in which implanted electrodes are readily available

Complex geometry and integrated macro-porosity: Clinical applications of electron beam melting to fabricate bespoke bone-anchored implants

The last decade has witnessed rapid advancements in manufacturing technologies for biomedical implants. Additive manufacturing (or 3D printing) has broken down major barriers in the way of producing complex 3D geometries. Electron beam melting (EBM) is one such 3D printing process applicable to metals and alloys. EBM offers build rates up to two orders of magnitude greater than comparable laser-based technologies and a high vacuum environment to prevent accumulation of trace elements. These features make EBM particularly advantageous for materials susceptible to spontaneous oxidation and nitrogen pick-up when exposed to air (e.g., titanium and titanium-based alloys). For skeletal reconstruction(s), anatomical mimickry and integrated macro-porous architecture to facilitate bone ingrowth are undoubtedly the key features of EBM manufactured implants. Using finite element modelling of physiological loading conditions, the design of a prosthesis may be further personalised. This review looks at the many unique clinical applications of EBM in skeletal repair and the ground-breaking innovations in prosthetic rehabilitation. From a simple acetabular cup to the fifth toe, from the hand-wrist complex to the shoulder, and from vertebral replacement to cranio-maxillofacial reconstruction, EBM has experienced it all. While sternocostal reconstructions might be rare, the repair of long bones using EBM manufactured implants is becoming exceedingly frequent. Despite the various merits, several challenges remain yet untackled. Nevertheless, with the capability to produce osseointegrating implants of any conceivable shape/size, and permissive of bone ingrowth and functional loading, EBM can pave the way for numerous fascinating and novel applications in skeletal repair, regeneration, and rehabilitation. Statement of significance: Electron beam melting (EBM) offers unparalleled possibilities in producing contaminant-free, complex and intricate geometries from alloys of biomedical interest, including Ti6Al4V and CoCr. We review the diverse range of clinical applications of EBM in skeletal repair, both as mass produced off-the-shelf implants and personalised, patient-specific prostheses. From replacing large volumes of disease-affected bone to complex, multi-material reconstructions, almost every part of the human skeleton has been replaced with an EBM manufactured analog to achieve macroscopic anatomical-mimickry. However, various questions regarding long-term performance of patient-specific implants remain unaddressed. Directions for further development include designing personalised implants and prostheses based on simulated loading conditions and accounting for trabecular bone microstructure with respect to physiological factors such as patient\u27s age and disease status

Electropolished Titanium Implants with a Mirror-Like Surface Support Osseointegration and Bone Remodelling

This work characterises the ultrastructural composition of the interfacial tissue adjacent to electropolished, commercially pure titanium implants with and without subsequent anodisation, and it investigates whether a smooth electropolished surface can support bone formation in a manner similar to surfaces with a considerably thicker surface oxide layer. Screw-shaped implants were electropolished to remove all topographical remnants of the machining process, resulting in a thin spontaneously formed surface oxide layer and a smooth surface. Half of the implants were subsequently anodically oxidised to develop a thickened surface oxide layer and increased surface roughness. Despite substantial differences in the surface physicochemical properties, the microarchitecture and the composition of the newly formed bone were similar for both implant surfaces after 12 weeks of healing in rabbit tibia. A close spatial relationship was observed between osteocyte canaliculi and both implant surfaces. On the ultrastructural level, the merely electropolished surface showed the various stages of bone formation, for example, matrix deposition and mineralisation, entrapment of osteoblasts within the mineralised matrix, and their morphological transformation into osteocytes. The results demonstrate that titanium implants with a mirror-like surface and a thin, spontaneously formed oxide layer are able to support bone formation and remodelling

Immunomodulatory effects exerted by extracellular vesicles from <i>Staphylococcus epidermidis</i> and <i>Staphylococcus aureus</i> isolated from bone-anchored prostheses

Staphylococcus aureus and Staphylococcus epidermidis are the bacteria that most frequently cause osteomyelitis. This study aimed to determine whether staphylococci isolated from osteomyelitis associated with septic loosening of orthopedic prostheses release extracellular vesicles (EVs) and, if so, to determine tentative immunomodulatory effects on the human monocytic cell line THP-1. EVs were isolated from bacterial cultures using filtration and ultracentrifugation and characterized by scanning electron microscopy, nanoparticle tracking analysis and Western Blot. The cytotoxic effect of EVs was analyzed by NucleoCounter and lactate dehydrogenase (LDH) analyses. Confocal laser scanning microscopy was employed to visualize the uptake of EVs by THP-1 cells. Activation of the transcription factor nuclear factor-κB (NF-κB) was determined in THP1-Blue™ NF-κB cells, and the gene expression and secretion of cytokines were determined by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. All investigated strains, irrespective of their biofilm formation ability, were able to secrete EVs in vitro. The S. aureus strains produced significantly more EVs than the S. epidermidis strains. Both S. aureus-derived EVs and S. epidermidis-derived EVs were internalized by THP-1 cells, upregulated Toll-like receptor 3 (TLR3) gene expression, activated NF-κB, and promoted the gene expression and secretion of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1, matrix metallopeptidase (MMP)-9 and IL-10. Whereas EVs from both staphylococcal species upregulated the proapoptotic DNA damage-inducible transcript 4 (DDIT4) gene and downregulated the antiapoptotic B-cell lymphoma 2 (Bcl-2) gene, cytolysis was preferentially induced in S. aureus EV-stimulated cells, possibly related to the expression of cytolytic proteins predominantly in S. aureus EVs. In conclusion, staphylococcal EVs possess potent cytolytic and immunomodulatory properties

Antistaphylococcal and biofilm inhibitory activities of acetyl-11-keto-β-boswellic acid from Boswellia serrata

<p>Abstract</p> <p>Background</p> <p>Boswellic acids are pentacyclic triterpenes, which are produced in plants belonging to the genus <it>Boswellia</it>. Boswellic acids appear in the resin exudates of the plant and it makes up 25-35% of the resin. β-boswellic acid, 11-keto-β-boswellic acid and acetyl-11-keto-β-boswellic acid have been implicated in apoptosis of cancer cells, particularly that of brain tumors and cells affected by leukemia or colon cancer. These molecules are also associated with potent antimicrobial activities. The present study describes the antimicrobial activities of boswellic acid molecules against 112 pathogenic bacterial isolates including ATCC strains. Acetyl-11-keto-β-boswellic acid (AKBA), which exhibited the most potent antibacterial activity, was further evaluated in time kill studies, postantibiotic effect (PAE) and biofilm susceptibility assay. The mechanism of action of AKBA was investigated by propidium iodide uptake, leakage of 260 and 280 nm absorbing material assays.</p> <p>Results</p> <p>AKBA was found to be the most active compound showing an MIC range of 2-8 μg/ml against the entire gram positive bacterial pathogens tested. It exhibited concentration dependent killing of <it>Staphylococcus aureus </it>ATCC 29213 up to 8 × MIC and also demonstrated postantibiotic effect (PAE) of 4.8 h at 2 × MIC. Furthermore, AKBA inhibited the formation of biofilms generated by <it>S. aureus </it>and <it>Staphylococcus epidermidis </it>and also reduced the preformed biofilms by these bacteria. Increased uptake of propidium iodide and leakage of 260 and 280 nm absorbing material by AKBA treated cells of <it>S aureus </it>indicating that the antibacterial mode of action of AKBA probably occurred via disruption of microbial membrane structure.</p> <p>Conclusions</p> <p>This study supported the potential use of AKBA in treating <it>S. aureus </it>infections. AKBA can be further exploited to evolve potential lead compounds in the discovery of new anti-Gram-positive and anti-biofilm agents.</p

A qualitative study exploring perceptions and attitudes of community pharmacists about extended pharmacy services in Lahore, Pakistan

Background In recent decades, community pharmacies reported a change of business model, whereby a shift from traditional services to the provision of extended roles was observed. However, such delivery of extended pharmacy services (EPS) is reported from the developed world, and there is scarcity of information from the developing nations. Within this context, the present study was aimed to explore knowledge, perception and attitude of community pharmacists (CPs) about EPS and their readiness and acceptance for practice change in the city of Lahore, Pakistan. Methods A qualitative approach was used to gain an in-depth knowledge of the issues. By using a semi-structured interview guide, 12 CPs practicing in the city of Lahore, Pakistan were conveniently selected. All interviews were audio-taped, transcribed verbatim, and were then analyzed for thematic contents by the standard content analysis framework. Results Thematic content analysis yielded five major themes. (1) Familiarity with EPS, (2) current practice of EPS, (3) training needed to provide EPS, (4) acceptance of EPS and (5) barriers toward EPS. Majority of the CPs were unaware of EPS and only a handful had the concept of extended services. Although majority of our study respondents were unaware of pharmaceutical care, they were ready to accept practice change if provided with the required skills and training. Lack of personal knowledge, poor public awareness, inadequate physician-pharmacist collaboration and deprived salary structures were reported as barriers towards the provision of EPS at the practice settings. Conclusion Although the study reported poor awareness towards EPS, the findings indicated a number of key themes that can be used in establishing the concept of EPS in Pakistan. Over all, CPs reported a positive attitude toward practice change provided to the support and facilitation of health and community based agencies in Pakistan

Acetyl-11-keto-β-boswellic acid (AKBA); targeting oral cavity pathogens

<p>Abstract</p> <p>Background</p> <p>Boswellic acids mixture of triterpenic acids obtained from the oleo gum resin of <it>Boswellia serrata </it>and known for its effectiveness in the treatment of chronic inflammatory disease including peritumor edema. Boswellic acids have been extensively studied for a number of activities including anti inflammatory, antitumor, immunomodulatory, and inflammatory bowel diseases. The present study describes the antimicrobial activities of boswellic acid molecules against oral cavity pathogens. Acetyl-11-keto-β-boswellic acid (AKBA), which exhibited the most potent antibacterial activity, was further evaluated in time kill studies, mutation prevention frequency, postantibiotic effect (PAE) and biofilm susceptibility assay against oral cavity pathogens.</p> <p>Findings</p> <p>AKBA exhibited an inhibitory effect on all the oral cavity pathogens tested (MIC of 2-4 μg/ml). It exhibited concentration dependent killing of S<it>treptococcus mutans </it>ATCC 25175 up to 8 × MIC and also prevented the emergence of mutants of <it>S.mutans </it>ATCC 25175 at 8× MIC. AKBA demonstrated postantibiotic effect (PAE) of 5.7 ± 0.1 h at 2 × MIC. Furthermore, AKBA inhibited the formation of biofilms generated by <it>S.mutans </it>and <it>Actinomyces viscosus </it>and also reduced the preformed biofilms by these bacteria.</p> <p>Conclusions</p> <p>AKBA can be useful compound for the development of antibacterial agent against oral pathogens and it has great potential for use in mouthwash for preventing and treating oral infections.</p

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe