Association between CD226 polymorphism and soluble levels in rheumatoid arthritis: Relationship with clinical activity

Objective: To study the relation between CD226 rs763361 gene polymorphism and CD226 serum level and to evaluate their role in susceptibility and disease activity of RA in a cohort of Egyptian individuals.

Methods: The serum level of CD226 was measured using a suitable ELISA kit and the CD226 rs763361 gene polymorphism was typed by PCR-RFLP for 112 RA patients and 100 healthy controls.

Results: Significant association with RA was found with CD226 T allele (OR (95%CI) = 1.6 (1.04–2.4), P = 0.032), and higher CD226 serum level (P = 0.001). Higher CD226 levels were associated with higher ESR values (P = 0.035), positive CRP (0.048), increased number of tender joints (P = 0.045), and higher DAS score (P = 0.035). Serum CD226 is an independent risk factor for the prediction of RA (P = 0.001). No correlations were found between the serum level of CD226 and different CD226 genotypes and also between them and RA activity grades.

Conclusion: The CD226 T allele may be susceptibility risk factors for the development of RA and the higher serum level of CD226 may be involved in the pathogenesis of RA in Egyptian patients. The serum level of CD226 and not CD226 genotypes could be considered as an independent risk factor for the prediction of RA within healthy individuals and also for RA disease activity.     

Intra-articular treatment with corticosteroids increases apoptosis in human rotator cuff tears

Purpose: The aim of this study is to evaluate in vivo the level of apoptosis in human rotator cuff tears and the relationship it might have with tendon degeneration.

Methods: Rotator cuff biopsies from 19 male and female patients, ages between 38 and 68 years, with and without previous corticosteroid infiltrations were collected via arthroscopy. Biopsies from seven patients with healthy rotator cuffs were used as a control group. An in situ terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed to detect the level of apoptosis, which was expressed as a percentage of apoptotic cells (PAC).

Results: PAC in patients with corticosteroid infiltrations was 76.97 ± 16.99 in all tendon rupture zones, in non-infiltrated patients was 35.89 ± 22.96, whereas in control patients was 14.48 ± 8.15. Likewise, the tendency of PAC reveals that apoptosis in control and non-infiltrated groups was different and dispersed in all tear zones; while in corticosteroid treated patients, the tendency was similar in all rupture sites.

Conclusions: This investigation leads us to conclude that the administration of corticosteroid is associated with a higher amount of apoptosis at the insertion site of the rotator cuff (rupture edge).     

The HIV Care Cascade and sub-analysis of those linked to but not retained in care: the experience from a tertiary HIV referral service in Dublin Ireland

Background: The HIV Care Cascade model can be used to measure how clinical services align with United Nations’ (UN) HIV treatment targets. Previous models have highlighted sequential losses at each step of the Cascade with a significant proportion being not retained in care (NRIC).

Objective: We aimed to assess the feasibility of meeting the UN targets and assess factors associated with, and calculate the true proportion of those, NRIC.

Methods: All people living with HIV who were linked to our service, one of three specialist HIV care providers in Dublin Ireland, from its establishment in 1993 to 1 December 2014, were included in the cohort and were categorized as linked to care, retained in care (RIC), on antiretroviral therapy (on ART), virally suppressed (HIV RNA <40copies/ml), and NRIC. An analysis of those NRIC was performed to categorize their current status through direct/indirect contact.

Results: Of 1000 patients linked to care, 78.7% (n = 787) were RIC, of whom 91.5% (n = 720) were on ART, with 89.9% (n = 644) virally suppressed. Those RIC were more likely older (p = 0.006) and non-IVDU (p < 0.001). Of 213 (21.3%) NRIC, 56 (26.3%) emigrated, 27 (12.7%) transferred care, 15 (7.0%) stopped attending but were contactable, 38 (17.8%) died, and 77 (36.1%) were lost to follow-up. After revision, 10.5% of the cohort was confirmed as NRIC, with 6 of 15 defined as “stopped attending” re-linked to care following direct contact.

Conclusions: Our HIV Care Cascade model demonstrates that the true numbers of patients NRIC may be significantly lower than previously estimated and once RIC, treatment goals approaching the United Nations Programme on HIV and AIDS targets are possible with 91.5% on treatment and almost 90% of those on treatment virally suppressed. That 40% reengaged following direct contact suggests benefit through regular monitoring and direct contact based on the HIV Care Cascade model.     

Identification of specific antibodies against the Ag85C-MPT51-HspX fusion protein (CMX) for serological screening of tuberculosis in endemic area

Objectives: Development of new tools for rapid and accurate diagnosis of tuberculosis (TB) is considered a strategy for controlling the disease. The recombinant CMX fusion protein is composed of immunodominant epitopes of the Ag85C (Rv0129c), MPT51 (Rv3803c) and the entire HspX (Rv2031c) proteins from Mycobacterium tuberculosis H37Rv (Mtb). The aim of this study was to evaluate the applicability of a test using the CMX protein in individuals suspected of TB.

Methods: Indirect ELISA was used to measure serum anti-CMX IgM and IgG in individuals with pulmonary TB.

Results: Patients with pulmonary TB had higher titers of IgM (OD = 0.502 ± 0.281) than healthy controls (OD = 0.200 ± 0.125). The cutoff for IgM-ELISA was determined using ROC curve analyzes (AUC = 0.868) with a sensitivity of 80.1% and a specificity of 78.2%. Patients with pulmonary TB also had higher titers of IgG (OD = 0.525 ± 0.391) than healthy controls (OD = 0.215 ± 0.077). The cutoff for IgG-ELISA was determined using ROC curve analyzes (AUC = 0.864) with a sensitivity of 81.7% and a specificity of 74.7%.

Conclusion: The results suggest that the recombinant protein CMX can be used in a serological test to complement the screening of individuals suspected of having active pulmonary TB.     

Rheumatoid arthritis: A single-center Egyptian experience

Objective: Demonstration of rheumatoid arthritis (RA) characteristics in a large cohort of Egyptian patients.

Methods: Retrospective analysis of data of 3219 RA patients attending the Rheumatology outpatient clinic, Kasr Alainy Hospital, Cairo University; from January 1995 till December 2015.

Results: Mean age at disease onset was 36.1 ±13.4 years; 2774 (84%) were females and mean disease duration was 12.9 ±7.9 years. Regarding number of joint affected at disease onset; polyarticular pattern was found in 77.1%, pattern of joint involvement; combined small and large joints involvement was in 83.2%, subcutaneous nodules in 14.2%, interstitial lung disease in 0.3%, secondary Sjogren’s syndrome in 10.5%, hand bony erosions at diagnosis in 20.6%. Rheumatoid factor was positive in 52%.

There was annual increase in the newly diagnosed cases (P = 0.017) reflecting increase in patients’ awareness and improvement of medical service, also annual increase in: mean age of onset (P < 0.001) reflecting changes in health measures, also in cases with monoarticular or oligoarticular patterns at disease onset (P = 0.02, 0.01 respectively) reflecting earlier diagnosis of patients and in patients with small joint involvement (P = 0.001) with a significant decline in: polyarticular pattern (P = 0.001), combined small and large joint affection (P < 0.001), and number of cases with hand bony erosions (P = 0.01) denoting earlier diagnosis, tight disease control.

Conclusion: We found a female predominance, younger age at disease onset, lower frequency of extra articular manifestations, more frequent polyarticular pattern at disease onset and less erosive disease, denoting changing referral patterns, earlier diagnosis, improved disease control in Egyptian RA patients over 2 decades.

Abbreviations: SNs: Subcutaneous nodules; 2ry SS: 2ry Sjogren’s syndrome; ILD: Interstitial lung disease; ACPA: Anti-cyclic citrullinated peptide antibodies; DMARDs: Disease modifying anti-rheumatic drugs.     

Estimation of the elastic modulus of child cortical bone specimens via microindentation

Purpose: Non-pathological child cortical bone (NPCCB) studies can provide clinicians with vital information and insights. However, assessing the anisotropic elastic properties of NPCCB remains a challenge for the biomechanical engineering community. For the first time, this paper provides elastic moduli values for NPCCB specimens in two perpendicular directions (longitudinal and transverse) and for two different structural components of bone tissue (osteon and interstitial lamellae).

Materials and Methods: Microindentation is one of the reference methods used to measure bone stiffness. Here, 8 adult femurs (mean age 82 ± 8.9 years), 3 child femurs (mean age 13.3 ± 2.1 years), and 16 child fibulae (mean age 10.2 ± 3.9 years) were used to assess the elastic moduli of adult and child bones by microindentation.

Results: For adult specimens, the mean moduli measured in this study are 18.1 (2.6) GPa for osteons, 21.3 (2.3) GPa for interstitial lamellae, and 13.8 (1.7) GPa in the transverse direction.

For child femur specimens, the mean modulus is 14.1 (0.8) GPa for osteons, lower than that for interstitial lamellae: 15.5 (1.5) GPa. The mean modulus is 11.8 (0.7) GPa in the transverse direction. Child fibula specimens show a higher elastic modulus for interstitial lamellae 15.8 (1.5) than for osteons 13.5 (1.6), with 10.2 (1) GPa in the transverse direction.

Conclusion: For the first time, NPCCB elastic modulus values are provided in longitudinal and transverse directions at the microscale level.     

Immune Profiling of T Cells Infiltrating Vitreous Humor in Tubercular Uveitis

Purpose: To assess cellular composition and local cytokine response in vitreous humor of tubercular uveitis.

Methods: Cells were collected from vitreous cassettes and peripheral blood of 8 tubercular uveitis and 5 control subjects, undergoing vitrectomy and analyzed by flow cytometry for cellular composition, activation status, proinflammatory cytokine expression, and uptake of TLR9 ligand, CpG ODN 2216.

Results: CD3 + T cells with equal proportion of CD4+ and CD8 + T cells formed major fraction of infiltrating cells. The vitreous humor showed higher expression of recent activation marker, CD69, and proinflammatory cytokines, IFN-γ and IL-17A, in CD4 + T cells as compared to peripheral blood. Lastly, intraocular CD4 + T cells showed reduced uptake of ODN 2216 than peripheral blood.

Conclusions: Our results indicate that local antigenic stimuli trigger T cell infiltration and activation of CD4 + T cells that are hyporesponsive to TLR9 stimulation. These infiltrating T cells might be responsible in further aggravating ocular inflammation.     

Complex role of IL-23R polymorphisms on ankylosing spondylitis: a meta-analysis

Background: The aim of the meta-analysis was to evaluate the association between 10 widely studied polymorphisms of interleukin-23 receptor gene (IL-23R) and ankylosing spondylitis (AS).

Methods: A comprehensive literature search, screening of eligible articles and data extraction was performed independently by two investigators. Further meta-analysis was conducted with STATA 12.0 software (Stata Corp.; College Station, TX, USA). The association between IL-23R polymorphisms and AS was evaluated by odds ratio (OR) and 95% confidence intervals (95% CI).

Results: Twenty-five case–control studies with 8431 cases and 8972 controls were included in this meta-analysis. Quantitative meta-analysis revealed that minor allele frequency (MAF) of rs1004819, rs1495965, and rs2201841 was significantly higher in the AS group (p value < .001, < .001, = .010, respectively). MAF of rs10489629, rs11209026, rs11465804, and rs1343151was significantly lower in the AS group (p value = .002, < .001, = .032, < .001, respectively). However, there is no significant difference between these two groups in rs10889677, rs11209032, and rs7517847 frequency (p value = .128, .237, .131, respectively).

Conclusions: The present study indicates that minor allele carriers of rs1004819, rs1495965, and rs2201841 are susceptible to AS. Conversely, minor alleles of rs10489629, rs11209026, rs11465804, and rs1343151 have protective effect on AS.     

Analysis of Helios gene expression and Foxp3 TSDR methylation in the newly diagnosed Rheumatoid Arthritis patients

Background: The control of auto-reactive cells is defective in rheumatoid arthritis (RA). Regulatory T (Treg) cells which play a key role in the modulation of immune responses have an impaired function in RA. Foxp3 is a master regulator of Treg cells which its expression is under the tight control of epigenetic mechanisms. In the current study, we analyzed the epigenetic modulation of the Foxp3 Treg-specific demethylated region (TSDR) and Helios gene expression to determine Treg cells alteration in RA patients.

Methods: We have recruited 20 newly diagnosed patients with RA and 41 healthy controls in our study. The measurement of Foxp3 and Helios gene expression was performed by the real-time PCR technique and the methylation level of TSDR was analyzed by bisulfite treatment and quantitative methylation-specific PCR (Q-MSP).

Results: We found that RA patients had significantly lower level of Foxp3 gene expression and TSDR demethylation compared to healthy subjects (P < 0.001 and P = 0.006, respectively). Inversely, the Helios gene expression was elevated significantly in RA patients group (P = 0.048). We also observed a significant correlation between Foxp3 and Helios gene expression (P = 0.016) as well as a significant correlation between FoxP3 expression and demethylation rate of TSDR (P = 0.010).

Conclusion: Our results suggested that both epigenetic modifications and Helios gene expression may have important roles in the pathogenesis of RA through their effects on Foxp3 gene expression.     

Th17-Inducing Conditions Lead to in vitro Activation of Both Th17 and Th1 Responses in Behcet’s Disease

Objectives: Interleukin-17 (IL-17) has been associated with the pathogenesis of various autoimmune/inflammatory diseases. The aim of this study was to investigate the expression of Th17-related immunity in an innate immunity-dominated vasculitis, namely Behcet’s disease (BD).

Methods: Peripheral blood mononuclear cells from 37 patients (age: 38.5 ± 9.8 years) with BD, and 25 healthy controls (HC) (age: 39.1 ± 9.3 years), were cultured in Th17-inducing conditions (IL-6, Phytohemagglutinin (PHA), IL-1β, and IL-23) for 6 days. Cultured cells were stained with CD4, CD8, CD3, TCR gamma/delta, CD19, interferon-γ (IFN-γ), and IL-17 antibodies to determine the intracellular cytokine secretion by flow cytometry.

Results: IL-17 expression by CD8+ and γδ+ T cells was higher in BD compared to HC (p = 0.004, p = 0.003, respectively). No differences were observed between the groups in the IL-17 production by B cells. Under Th17-inducing conditions, production of IFN-γ by CD4+, CD8+, and γδ+ T cells was also higher in BD compared to HC (p < 0.05 in all).

Conclusion: Our results suggest that under Th17-stimulating conditions, T cells express both IL-17 and IFN-γ in BD. More prominent IL-17 and IFN-γ production by all lymphocyte subsets in BD might be associated with the increased innate responses, early tissue neutrophil infiltrations and late adaptive immunity in BD.     

The clinical significance of complete class switching defect in Ataxia telangiectasia patients

Background: Ataxia telangiectasia (AT) is a primary immunodeficiency associated with recurrent infections. We aimed to investigate clinical and immunological classification in AT patients who suffer from a different spectrum of humoral immune defects.

Methods: AT patients were categorized according to the ability of class switching and patients with hyper IgM (HIgM) profile were defined as class switching defect (CSD).

Results: Serum immunoglobulin profile in 66 AT patients showed normal immunoglobulin level (22.8%), IgA deficiency (37.9%) and hypogammaglobulinemia (18.1%) in the majority of patients, while 21.2% had HIgM profile revealing CSD. CSD does not affect the frequency of infections, however, the frequency of lymphoproliferation (p < 0.001), and autoimmunity (p = 0.004) were significantly higher in this group. Neurologic symptoms in CSD patients are mild or appear after recurrent infections, therefore these patients were usually misdiagnosed as HIgM syndrome.

Conclusions: Although most of AT patients have reduced IgA levels or normal immunoglobulin levels, but a fraction of these patients may show CSD ensuing HIgM-profile. CSD poses affected individuals at higher risk of non-infectious complications.     

Pharmacokinetics and pharmacodynamics of the nucleoside sparing dual regimen containing rilpivirine plus darunavir/ritonavir in treatment-naïve HIV-1-infected individuals

Background: We aimed at investigating the antiviral activity and the pharmacokinetics of the dual antiretroviral (ARV) combination of rilpivirine plus darunavir/ritonavir 25/800/100 mg once-daily in naïve HIV-1-infected individuals (NHII) with different baseline viral loads.

Settings: Pharmacokinetic/pharmacodynamics study in ARV-naïve HIV-infected individuals.

Methods: The primary endpoint was the number of NHII with HIV-RNA < 40 copies/mL at week 48. Secondary endpoints included rilpivirine/darunavir/ritonavir pharmacokinetics, HIV-RNA decay, and changes in ECG QT interval.

Results: Thirty-six individuals were enrolled, 18 with a baseline viral load < 100,000 copies/mL (group A) and 18 with a baseline viral load > 100,000 copies/mL (group B). All but 1 (HIV-RNA = 63 copies/mL) subjects achieved viral load < 50 copies/mL by week 36, and all at week 48. Median (range) HIV-RNA reduction (Log10 copies/mL) was 1.3 (0.6–1.9) over the first week, with no differences between groups A and B. Geometric mean and 95%CI rilpivirine C_max, C_trough, AUC were 183 (165–239), 114 (104–109) ng/mL, 2966 (2704–3820) ng h/mL. No QTcF interval changes were recorded.

Conclusions: rilpivirine/darunavir/ritonavir could be efficacious, with limited short-term toxicity in ARV-naïve patients. Although rilpivirine was co-administered with ritonavir, its exposure was within ranges measured during phase III trials.     

Efficacy and safety of emtricitabine/tenofovir alafenamide (FTC/TAF) vs. emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) as a backbone for treatment of HIV-1 infection in virologically suppressed adults: subgroup analysis by third agent of a randomized,double-blind,active-controlled phase 3 trial*

Background: FTC/TAF was shown to be noninferior to FTC/TDF with advantages in markers of renal and bone safety.

Objective: To evaluate the efficacy and safety of switching to FTC/TAF from FTC/TDF by third agent (boosted protease inhibitor [PI] vs. unboosted third agent).

Methods: We conducted a 48-week subgroup analysis based on third agent from a randomized, double blind study in virologically suppressed adults on a FTC/TDF-containing regimen who switched to FTC/TAF vs. continued FTC/TDF while remaining on the same third agent.

Results: We randomized (1:1) 663 participants to either switch to FTC/TAF (N = 333) or continue FTC/TDF (N = 330), each with baseline third agent stratifying by class of third agent in the prior treatment regimen (boosted PI 46%, unboosted third agent 54%). At week 48, significant differences in renal biomarkers and bone mineral density were observed favoring FTC/TAF over FTC/TDF (p < 0.05 for all), with similar improvements in the FTC/TAF arm in those who received boosted PI vs. unboosted third agents. At week 48, virologic success rates were similar between treatment groups for those who received a boosted PI (FTC/TAF 92%, FTC/TDF 93%) and for those who received an unboosted third agent (97% vs. 93%).

Conclusions: In virologically suppressed patients switching to FTC/TAF from FTC/TDF, high rates of virologic suppression were maintained, while renal and bone safety parameters improved, regardless of whether participants were receiving a boosted PI or an unboosted third agent. FTC/TAF offers safety advantages over FTC/TDF and can be an important option as an NRTI backbone given with a variety of third agents.     

Long-Term Efficacy,Tolerability, and Renal Safety of Atazanavir/Ritonavir-based Antiretroviral Therapy in a Cohort of Treatment-Naïve Patients with HIV-1 Infection: the REMAIN Study

Background: Boosted protease inhibitors (PIs), including ritonavir-boosted atazanavir (ATV/r), are a recommended option for the initial treatment of HIV-1 infection based upon clinical trial data; however, long-term real-life clinical data are limited.

Objective: We evaluated the long-term use of ATV/r as a component of antiretroviral combination therapy in the real-life setting in the REMAIN study.

Methods: This was an observational cohort study conducted at sites across Germany, Portugal, and Spain. Retrospective historical and prospective longitudinal follow-up data were extracted every six months from medical records of HIV-infected treatment-naïve patients aged ≥ 18 years initiating a first-line ATV/r-containing regimen.

Results: Eligible patients (n = 517) were followed up for a median of 3.4 years. The proportion remaining on ATV/r at 5 years was 51.5% with an estimated Kaplan-Meier median time to treatment discontinuation of 4.9 years. Principal reasons for discontinuation were adverse events (15.9%; 8.9% due to hyperbilirubinemia) and virologic failure (6.8%). The Kaplan-Meier probability of not having virologic failure (HIV-1 RNA < 50 copies/mL) was 0.79 (95% CI: 0.75, 0.83) at five years. No treatment-emergent major PI resistance occurred. ATV/r was generally well tolerated during long-term treatment with no significant changes in estimated glomerular filtration rate over five years.

Conclusions: In a real-life clinical setting over five years, treatment-naïve patients with HIV-1 infection initiating an ATV/r-based regimen showed sustained virologic suppression, an overall treatment persistence rate of 51.5%, an absence of treatment-emergent major PI resistance mutations at virologic failure, a long-term safety profile consistent with that observed in clinical trials, and no significant decline in renal function.     

An observational study on the incidence of tuberculosis among a cohort of HIV infected adults in a setting with low prevalence of tuberculosis

Background: Tuberculosis (TB) remains a main cause of morbidity and mortality among individuals infected with HIV. We investigated the incidence of TB among a cohort of HIV infected patients attending a setting with low TB burden where screening for latent TB infection is not routinely carried out.

Methods: an observational cohort study on HIV-infected adults attending the HIV clinic at Queen Elizabeth Hospital Birmingham, UK between 1 January 2011 and 30 September 2015. Patients with culture-proven TB after HIV diagnosis, or those treated for clinical diagnosis of the infection, were classified as having “active TB”.

Results: 1824 patients were included in the study (5347 patient years of follow up), of whom 21 patients developed TB (16 microbiology confirmed). Of the 666 new HIV diagnoses, six patients developed TB within one month, giving a TB prevalence at the time of HIV diagnosis of 0.9%. The total TB incidence for the remaining 1818 patients was 2.81 cases per 1000 patient years (95% CI: 1.63–4.53). TB incidence was significantly more common among patients with CD4 ≤ 200 cells/mm³ compared to those with CD4 > 500 cells/mm³ (28.2 vs. 1.22 per 1000 patient years, p < 0.001), and in patients with VL ≥ 40 copies/mL compared to <40 copies/mL (8.30 vs. 1.42, p < 0.001).

Conclusion: In settings with low TB prevalence, early start of combined antiretroviral therapy and intensified TB case finding protocols may significantly reduce the incidence of TB.     

A multi-site community randomized trial of community health workers to provide counseling and support for patients newly entering HIV care in rural Ethiopia: study design and baseline implementation

Background: Although HIV therapy is delivered to millions globally, treatment default (especially soon after entering care) remains a challenge. Community health workers (CHWs) can provide many services for people with HIV, including in rural and resource-limited settings.

Objectives: We designed and implemented a 32 site community randomized trial throughout southern Ethiopia to assess an intervention using CHWs to improve retention in HIV care.

Methods: Sixteen district hospital and 16 local health center HIV clinics were randomized 1:1 to be intervention or control sites. From each site, we enrolled adults newly entering HIV care. Participants at intervention sites were assigned a CHW who provided: HIV and health education; counseling and social support; and facilitated communication with HIV clinics. All participants are followed through three years with annual health surveys, plus HIV clinic record abstraction including clinic visit dates. CHWs record operational data about their client contacts.

Results: 1799 HIV patients meeting inclusion criteria were enrolled and randomized: 59% were female, median age = 32 years, median CD4 + count = 263 cells/mm³, and 41% were WHO Stage III or IV. A major enrollment challenge was fewer new HIV patients initiating care at participating sites due to shortage of HIV test kits. At intervention sites, 71 CHWs were hired, trained and assigned to clients. In meeting with clients, CHWs needed to accommodate to various challenges, including HIV stigma, distance, and clients lacking cell phones.

Conclusions: This randomized community HIV trial using CHWs in a resource-limited setting was successfully launched, but required flexibility to adapt to unforeseen challenges.     

3D-printed poly(lactic acid) scaffolds for trabecular bone repair and regeneration: scaffold and native bone characterization

Purpose: Study objectives were set to (i) fabricate 3D-printed scaffolds/grafts with varying pore sizes, (ii) characterize surface and mechanical properties of scaffolds, (iii) characterize biomechanical properties of bovine trabecular bone, and (iv) evaluate attachment and proliferation of human bone marrow mesenchymal stem cells on 3D-printed scaffolds.

Materials and Methods: Poly(lactic acid) scaffolds were fabricated using 3D-printing technology, and characterized in terms of their surface as well as compressive mechanical properties. Trabecular bone specimens were obtained from bovine and characterized biomechanically under compression. Human bone marrow mesenchymal stem cells were seeded on the scaffolds, and their attachment capacity and proliferation were evaluated.

Results: Contact angles and compressive moduli of scaffolds decreased with increasing pore dimensions of 0.5 mm, 1.0 mm, and 1.25 mm. Biomechanical characterization of trabecular bone yielded higher modulus values as compared to scaffolds with all pore sizes studied. Human bone marrow mesenchymal stem cells attached to the surfaces of all scaffolds yet proliferated more on scaffolds with 1.25 mm pore size.

Conclusions: Collectively, given the similarity between 3D-printed scaffolds and native bone in terms of pore size, porosity, and appropriate mechanical properties of scaffolds, the 3D-printed poly(lactic acid) (PLA) scaffolds of this study appear as candidate substitutes for bone repair and regeneration.