Telehealth utilization barriers among Alabama parents of pediatric patients during COVID-19 outbreak.

BACKGROUND: Telehealth can improve access to evidence-based care at a lower cost for patients, especially those living in underserved and remote areas. The barriers to the widespread adoption of telehealth have been well documented in the literature. However, the barriers may not be the same for pediatric patients, who must rely on their parents or guardians to make healthcare decisions. This paper presents some of the leading barriers parents or guardians of pediatric patients report in using telehealth to meet their children's healthcare needs. METHODS: This cross-sectional survey was conducted in a tertiary care pediatric Emergency Department (ED) at a children's hospital in Alabama between September 2020 to December 2020. The parents or guardians of pediatric patients were asked about their reasons for not using telehealth despite having healthcare needs for their children, whether they canceled or rescheduled healthcare provider visits and facility visits, and whether the child's health conditions changed over the past three months. Descriptive analyses were conducted that explored the distribution of telehealth use across the variables listed above. RESULTS: Five hundred ninety-seven parents or guardians of pediatric patients participated in the survey, and 578 answered the question of whether they used telehealth or not over the past three months. Of them, 33.1% used telehealth, 54.3% did not, and 12.6% did not have healthcare needs for their child. The leading reason for not using telehealth was that the doctor or health provider did not give them a telehealth option, the second main reason was that they did not know what telehealth is, and the third leading reason was that the parents did not think telehealth would help meet healthcare needs for their child. CONCLUSIONS: This study highlights the telehealth utilization barriers among underserved pediatric populations, including the need for physicians to proactively offer telehealth options to parents or guardians of pediatric patients. Improving health literacy is of paramount importance, given that a substantial proportion of parents were not familiar with telehealth. Policymakers and healthcare organizations should raise awareness about the benefits of telehealth which can improve healthcare access for underserved pediatric patients.

Telehealth use among pediatric Alabama Medicaid enrollees, March-December 2020: Variations by race/ethnicity & place of residence.

During the early days and months of the COVID-19 pandemic, healthcare facilities experienced a slump in non-COVID-related visits, and there was an increasing interest in telehealth to deliver healthcare services for adult and pediatric patients. The study investigated telehealth use variation by race/ethnicity and place of residence for the pediatric enrollees of the Alabama Medicaid program. This retrospective observational study examined Alabama Medicaid claims data from March to December 2020 for enrollees less than 19 years. There were 637,792 pediatric enrollees in the Alabama Medicaid program during the study period, and 16.9% of them had used telehealth to meet healthcare needs. This study employed a multivariate Poisson mixed-effects model with robust error variance to obtain differences in telehealth utilization and found that Non-Hispanic Black children were 80% as likely, Hispanic children were 55% as likely, and Asian Children were 46% as likely to have used telehealth compared to Non-Hispanic White children. Pediatric enrollees in large rural areas and isolated areas were significantly less likely (IRR: 0.90 for both, p<0.05) to use telehealth than those in urban areas. This study's findings suggest that attention needs to be paid to addressing race/ethnicity disparities in accessing telehealth services.

Effect of table inclination angle on videolaryngoscopy and direct laryngoscopy: Operator's muscle activation and laryngeal exposure analysis.

BACKGROUND: Optimal vocal cord visualization depends on the patient's anatomical factors, characteristics of the laryngoscope, and the operator's muscle action. This study evaluated the effect of table inclination and three different laryngoscopic methods on procedural variables. The primary aim of this study is to compare differences in laryngoscopic view among clinicians based on the instrument used and table orientation. The secondary aim is to determine differences in upper extremity muscle activity based on laryngoscope use and table inclination. METHODS: Fifty-five anesthesia providers with different experience levels performed intubations on a manikin using three angles of table inclination and three laryngoscopy methods. Time to intubation, use of optimization maneuvers, glottic view, operator's comfort level, and upper extremity muscle activation measured by surface electromyography were evaluated. RESULTS: Table inclination of 15° and 30° significantly reduced intubation time and the need for optimization maneuvers. Fifteen degrees inclination gave the highest comfort level. Anterior deltoid muscle intensity was decreased when table inclination at 15° and 30° was compared to a flat position. CONCLUSION: Table inclination of 15° reduces intubation time and the need to use optimization maneuvers and is associated with higher operator's comfort levels than 0° and 30° inclination in a simulated scenario using a manikin. Different upper extremity muscle groups are activated during laryngoscopy, with the anterior deltoid muscle exhibiting significantly higher activation levels with direct laryngoscopy at zero-degree table inclination.

Disparities by race and insurance-status in declines in pediatric ED utilization during the COVID19 pandemic.

Pediatric Emergency Department (ED) utilization in the U.S. saw large declines during the COVID19 pandemic. What is relatively unexplored is whether the extent of declines differed by race and insurance status. An observational study was conducted using electronic medical record (EMR) data from the largest pediatric ED in Alabama for 2020 and 2019. The four subgroups of interest were African-American (AA), Non-Hispanic White (NHW), privately insured (PRIVATE), and publicly insured or self-insured (PUBLIC-SELF). Percentage changes in the 7-day moving average between dates in 2020 and 2019 were computed for total and high-severity ED visits by subgroup. Trends in percentage changes were plotted. T-tests were used to compare mean changes between subgroups. Large percentage declines in total ED visits and somewhat smaller percentage declines in high-severity visits were observed from March 2020. Declines were consistently larger for AA than NHW and for PUBLIC-SELF than PRIVATE. T-test results indicated mean date-specific percentage declines were significantly larger for AA than NHW for total visits (-38.92% [95% CI: -41.1, -36.8] versus -29.11% [95% CI: -30.8, -27.4]; p<0.001) and high-severity visits (-24.31% [95% CI: -26.2, -22.4] versus -19.49% [95% CI:-21.2, -17.8]; p<0.001), and larger for PUBLIC-SELF than PRIVATE for total visits (-36.32% [95% CI:-38.4, -34.3] versus 27.63% [95% CI:-29.2, -26.0]; p<0.001) and high-severity visits (-21.72% [95% CI: -23.5, -19.9] versus -20.01% [95% CI: -21.7, -18.3]; p = 0.04). In conclusion, significant differences by race and insurance status were observed in the decline in ED visits during the COVID19 pandemic, including high-severity visits. Minority-race and publicly insured or self-insured children often depend on the ED for health needs, lacking a usual source of care. Thus, these findings have worrisome implications regarding unmet healthcare needs and future exacerbations in health disparities.

Prolonged Glycemic Adaptation Following Transition From a Low- to High-Carbohydrate Diet: A Randomized Controlled Feeding Trial.

OBJECTIVE: Consuming ≥150 g/day carbohydrate is recommended for 3 days before an oral glucose tolerance test (OGTT) for diabetes diagnosis. For evaluation of this recommendation, time courses of glycemic changes following transition from a very-low-carbohydrate (VLC) to high-carbohydrate diet were assessed with continuous glucose monitoring (CGM). RESEARCH DESIGN AND METHODS: After achieving a weight loss target of 15% (±3%) on the run-in VLC diet, participants (18-50 years old, BMI ≥27 kg/m2) were randomly assigned for 10 weeks to one of three isoenergetic diets: VLC (5% carbohydrate and 77% fat); high carbohydrate, high starch (HC-Starch) (57% carbohydrate and 25% fat, including 20% refined grains); and high carbohydrate, high sugar (HC-Sugar) (57% carbohydrate and 25% fat, including 20% sugar). CGM was done throughout the trial (n = 64) and OGTT at start and end (n = 41). All food was prepared in a metabolic kitchen and consumed under observation. RESULTS: Glucose metrics continued to decline after week 1 in the HC-Starch and HC-Sugar groups (P < 0.05) but not VLC. During weeks 2-5, fasting and 2-h glucose (millimoles per liter per week) decreased in HC-Starch (fasting -0.10, P = 0.001; 2 h -0.10, P = 0.04). During weeks 6-9, 2-h glucose decreased in HC-Starch (-0.07, P = 0.01) and fasting and 2-h glucose decreased in HC-Sugar (fasting -0.09, P = 0.001; 2 h -0.09, P = 0.003). The number of participants with abnormal glucose tolerance by OGTT remained 10 (of 16) in VLC at start and end but decreased from 17 to 9 (of 25) in both high-carbohydrate groups. CONCLUSIONS: Physiological adaptation from a low- to high-carbohydrate diet may require many weeks, with implications for the accuracy of diabetes tests, interpretation of macronutrient trials, and risks of periodic planned deviations from a VLC diet.

Nocardiosis in renal transplant patients.

Renal transplant patients are immunosuppressed and are at increased risk of opportunistic infections, including Nocardia infection. In renal transplant patients, information on the incidence and risk factors associated with nocardiosis is limited. To address the incidence and risk factors associated with nocardiosis in a large renal transplant population, we used the US Renal Data System (USRDS). Sequelae of allograft failure or rejection after infection were also examined. Demographics, clinical risk factors, Nocardia diagnosis, and allograft failure following Nocardia infection were queried in USRDS renal transplant patients using International Classification of Diseases, Ninth Revision (ICD-9) codes in billing claims and Centers for Medicare and Medicaid Services Form 2728. Generalized linear models were used to determine the risk factors associated with nocardiosis, and Cox proportional hazards models were used to examine the association of risk factors with graft failure among patients with Nocardia infection. Of 203,233 renal transplant recipients identified from 2001 to 2011, 657 (0.32%) were diagnosed with Nocardia infection. Pneumonia was the most frequent presentation (15.2%), followed by brain abscess (8.4%). Numerous factors associated with increased Nocardia infection included age >65 years (OR=2.10, 95% CI 1.71 to 2.59), history of transplant failure (OR=1.28, CI 1.02 to 1.60) or history of rejection (OR=4.83, CI 4.08 to 5.72), receipt of a deceased donor transplant (OR=1.23, CI 1.03 to 1.46), and treatment with basiliximab (OR=1.25, CI 1.00 to 1.55), cyclosporine (OR=1.30, CI 1.03 to 1.65), tacrolimus (OR=2.45, CI 2.00 to 3.00), or thymoglobulin (OR=1.89, CI 1.59 to 2.25). In patients with nocardiosis administration of antithymocyte globulin (HR=2.76), chronic obstructive pulmonary disease (HR=2.47), and presentation of Nocardia infection with brain abscess (HR=1.85) were associated with an increased risk of graft failure. This study provides new information to enhance early recognition and targeted treatment of nocardiosis in renal transplant patients.

Autophagy and Inflammation Regulation in Acute Kidney Injury.

Autophagy at an appropriate juncture in the cell cycle exerts protective effects in acute kidney injury (AKI), whereas abnormal autophagy may lead to cell death. Inflammatory response plays a pivotal role in the pathophysiological process of kidney injury and repair during AKI. Several studies have reported an interaction between autophagy and inflammation in the pathogenesis of AKI. This review outlines recent advances in the investigation of the role of autophagy in inflammatory response regulation based on the following aspects. (1) Autophagy inhibits inflammatory responses induced in AKI through the regulation of mTOR and AMPK pathways and the inhibition of inflammasomes activation. (2) Autophagy can also help in the regulation of inflammatory responses through the nuclear factor kappa B pathway, which is beneficial to the recovery of kidney tissues. These studies reviewed here provide better insight into the mechanisms underlying the protective effects of the autophagy-inflammatory pathway. Through this review, we suggest that the autophagy-inflammatory pathway may serve as an alternative target for the treatment of AKI.

Folic Acid Supplement Use and Increased Risk of Gestational Hypertension.

Current results regarding the effect of folic acid (FA) supplement use on gestational hypertension (GH) and preeclampsia are limited and inconsistent. We aimed to investigate whether FA supplement use was associated with GH and preeclampsia. Participants from the Tongji Maternal and Child Health Cohort with information on periconceptional FA supplement use and diagnosis of GH/preeclampsia were included (n=4853). Robust Poisson regression was used to assess the association of FA supplement use and GH and preeclampsia. Among the 4853 participants in this study, 1161 (23.9%) and 161 (3.3%) women were diagnosed with GH and preeclampsia, respectively. The risk ratio of developing GH was higher in women who used ≥800 µg/d FA supplement from prepregnancy through midpregnancy than nonusers (risk ratio, 1.33 [1.08-1.65]). After adjusting for social-demographic, reproductive, lifestyle factors, family history of hypertension, other supplement use, and gestational weight gain, the adverse association remained significant (risk ratio, 1.32 [1.06-1.64]). Restricting the analysis among women with normal weight, without family history of hypertension, and without gestational diabetes mellitus, the positive FA-GH association still existed. We did not find any significant association between FA supplement use and preeclampsia regardless of adjustment. High-dose (≥800 µg/d) FA supplement use from prepregnancy through midpregnancy was associated with increased risk of GH. Attention should be given to avoid the potential risk of GH due to inappropriate FA supplement use in women who are planning or capable of pregnancy.

Utility of color flow Doppler ultrasound to identify peripheral intravenous catheter position in adult surgical patients.

OBJECTIVE: To evaluate color flow Doppler flow ultrasound compared to standard clinical techniques, to detect the intravascular position of peripheral intravenous catheters in adult surgical patients. METHODS: A prospective study was conducted in adult (>18 years old) patients scheduled to undergo elective surgery. Peripheral intravenous catheter position was evaluated with standard clinical techniques (free flow of fluid from a hanging bag, easy saline injection, and aspiration of blood), and with color flow Doppler ultrasound proximal to the insertion site to identify intravascular catheter position. Comparative test performance was carried out. RESULTS: In total, 174 patients were enrolled. The venous catheter was deemed to be intravascular in 92.53% (n = 161) and 90.23% (n = 157) based on clinical evaluation and color flow Doppler, respectively (p = 0.206). Moderate to substantial agreement between the two approaches was found. Cohen's kappa was 0.64 (95% CI 0.43-0.83). Specificity of clinical judgment to detect catheter extravascular position was only 58.82%, when the color flow Doppler technique was set as the gold standard. Free flow from a hanging bag method showed the best agreement with color flow Doppler to determine intravascular position of a catheter (p = 0.3173, kappa = 0.68), with sensitivity of 98.09% and specificity of 64.71%. CONCLUSION: Color flow Doppler is a specific tool complementary to sensitive clinical indicators to detect peripheral venous catheter infiltration. The ability of color flow Doppler to accurately determine the position of a peripheral venous catheter depends on experience and familiarity with the tool by providers, who can master the technique with education and training.

Corrigendum: Autophagy and Inflammation Regulation in Acute Kidney Injury.

[This corrects the article DOI: 10.3389/fphys.2020.576463.].

Intrapartum epidural catheter displacement: Comparison of three dressing methods (Migración de catéter epidural intraparto: Comparación de tres métodos de fijación).

AIM: To compare the effect on epidural catheter migration of three different types of dressing used in labor. INTRODUCTION: Failure of labor epidural is due to multiple factors including catheter migration. Epidural catheter migration has been showed to be related to body mass index and patient position. The dressing technique also influences catheter migration and the risk of epidural failure. METHODS: Patients were randomly allocated to one of three groups based on type of dressing of labor epidural: TegadermTM (Group T), TegadermTM with sticky pad (Group P), and TegadermTM with Steri-StripTM (Group S). Measured variables included parity, gestational age, body mass index (BMI), level of puncture and distance of epidural catheter migration. RESULTS: There was an overall difference in epidural catheter migration (ECM) distance among different groups (p<0.05). Pairwise comparison revealed only a significant difference between groups P and T (0.76±1.35 vs. -0.14±1.03, p<0.01). CONCLUSION: Taping the lumbar epidural catheter used for labor analgesia with TegadermTM is inferior to TegadermTM with sticky pad or with Steri-StripTM in terms of catheter migration. There is no association of catheter migration and BMI.

Objetivo: Comparar el efecto de tres diferentes tipos de fijación sobre la migración del catéter epidural durante el trabajo de parto. Introducción: El fallo del bloqueo epidural en el trabajo de parto se debe a múltiples factores incluyendo la migración de catéter. La migración de catéter epidural se ha relacionado con el índice de masa corporal y la posición, así como con movimientos del paciente. La técnica de fijación también afecta la migración de catéter y el riesgo de bloqueo epidural fallido. Método: Las pacientes fueron aleatorizadas y asignadas a uno de tres grupos según el tipo de fijación: TegadermTM (Grupo T), TegadermTM con almohadilla adhesiva (Grupo P) y Tegaderm TM con Steri-StripTM (Grupo S). Las variables evaluadas incluyeron paridad, edad gestacional, índice de masa corporal (IMC), nivel de punción y distancia de migración del catéter epidural. Resultados: Se detectó una diferencia en la distancia de migración de catéter epidural entre los diferentes grupos (p<0.05). La comparación reveló diferencia únicamente entre los grupos P y T (0.76±1.35 vs. -0.14±1.03, p<0.01). Conclusión: TegadermTM como método de fijación de catéter epidural en el trabajo de parto resultó ser inferior al TegadermTM con almohadilla adhesiva o con Steri-StripTM en términos de migración de catéter. No existe una asociación entre migración de catéter epidural e IMC.

Are Anesthesiology Providers Good Guessers? Heart Rate and Oxygen Saturation Estimation in a Simulation Setting.

BACKGROUND: Anesthesia providers may need to interpret the output of vital sign monitors based on auditory cues, in the context of multitasking in the operating room. This study aims to evaluate the ability of different anesthesia providers to estimate heart rate and oxygen saturation in a simulation setting. METHODS: Sixty anesthesia providers (residents, nurse anesthetics, and anesthesiologists) were studied. Four scenarios were arranged in a simulation context. Two baseline scenarios with and without waveform visual aid, and two scenarios with variation of heart rate and/or oxygen saturation were used to assess the accuracy of the estimation made by the participants. RESULTS: When the accurate threshold for the heart rate was set at less than 5 beats per minute, the providers only had a correct estimation at two baseline settings with visual aids (p=0.22 and 0.2237). Anesthesia providers tend to underestimate the heart rate when it increases. Providers failed to accurately estimate oxygen saturation with or without visual aid (p=0.0276 and 0.0105, respectively). Change in recording settings significantly affected the accuracy of heart rate estimation (p < 0.0001), and different experience levels affected the estimation accuracy (p=0.041). CONCLUSION: The ability of anesthesia providers with different levels of experience to assess baseline and variations of heart rate and oxygen saturation is unsatisfactory, especially when oxygen desaturation and bradycardia coexist, and when the subject has less years of experience.

Evaluation of Anesthesiology Residents' Supervision Skills: A Tool to Assess Transition Towards Independent Practice.

Problem Anesthesiologists are often expected to supervise residents, nurse anesthetists, and anesthesiologist assistants in their practice. Development of a supervisory skill set is important during anesthesiology training and has a potential impact on the quality of patient care. During anesthesiology residency training, residents develop different competencies through direct supervision by a staff anesthesiologist. However, there is significant variability among anesthesia residency programs in the United States in terms of the opportunity residents have to supervise other anesthesia providers. The supervisory competency is not routinely evaluated during residency training. Intervention This study aimed at evaluating an educational seminar to foster the competency of supervision in anesthesiology. The 90-minute seminar included a live lecture and a series of workshops. The lecture had a duration of 45 minutes followed by three workshops of 15 minutes each. The workshops consisted of different simulated case scenarios with the participation of actors and a manikin as a patient. A debriefing session took place after the scenarios. Every resident included in the study participated in the workshops. The workshops were aligned with the learning objectives of the educational strategy. Context The study included 12 junior anesthesiology residents supervised by 24 senior residents during simulated clinical encounters. Quality of supervision, using the nine-item Quality of Supervision Questionnaire validated by De Oliveira Filho, and self-perception were evaluated before and after the educational intervention consisting of a face-to-face seminar and individual workshops administered during each encounter. Impact There was a significant difference between the overall means among senior residents for the quality of supervision measured by a nine-item quality of supervision questionnaire before and after the educational intervention program (3.11 ± 0.29 vs 3.96 ± 0.17, p < 0.01). There was no significant difference between the overall means for the self-perception of the senior residents before and after the intervention program (3.51 ± 0.54 vs. 3.48 ± 0.20). Lessons learned A bimodal educational intervention combining face-to-face seminars and workshops is effective to improve the quality of supervision in senior residents; however, it does not change the self-perception of the supervisory process. Addition of this type of educational intervention to the anesthesiology residency curriculum would add to the development of the supervisory competency and warrants further research in clinical situations.

Role of glucocorticoid-induced leucine zipper (GILZ) in inflammatory bone loss.

TNF-α plays a key role in the development of rheumatoid arthritis (RA) and inflammatory bone loss. Unfortunately, treatment of RA with anti-inflammatory glucocorticoids (GCs) also causes bone loss resulting in osteoporosis. Our previous studies showed that overexpression of glucocorticoid-induced leucine zipper (GILZ), a mediator of GC's anti-inflammatory effect, can enhance osteogenic differentiation in vitro and bone acquisition in vivo. To investigate whether GILZ could antagonize TNF-α-induced arthritic inflammation and protect bone in mice, we generated a TNF-α-GILZ double transgenic mouse line (TNF-GILZ Tg) by crossbreeding a TNF-α Tg mouse, which ubiquitously expresses human TNF-α, with a GILZ Tg mouse, which expresses mouse GILZ under the control of a 3.6kb rat type I collagen promoter fragment. Results showed that overexpression of GILZ in bone marrow mesenchymal stem/progenitor cells protected mice from TNF-α-induced inflammatory bone loss and improved bone integrity (TNF-GILZ double Tg vs. TNF-αTg, n = 12-15). However, mesenchymal cell lineage restricted GILZ expression had limited effects on TNF-α-induced arthritic inflammation as indicated by clinical scores and serum levels of inflammatory cytokines and chemokines.

Crosstalk between bone marrow-derived mesenchymal stem cells and regulatory T cells through a glucocorticoid-induced leucine zipper/developmental endothelial locus-1-dependent mechanism.

Bone marrow is a reservoir for regulatory T (T(reg)) cells, but how T(reg) cells are regulated in that environment remains poorly understood. We show that expression of glucocorticoid (GC)-induced leucine zipper (GILZ) in bone marrow mesenchymal lineage cells or bone marrow-derived mesenchymal stem cells (BMSCs) increases the production of T(reg) cells via a mechanism involving the up-regulation of developmental endothelial locus-1 (Del-1), an endogenous leukocyte-endothelial adhesion inhibitor. We found that the expression of Del-1 is increased ∼4-fold in the bone tissues of GILZ transgenic (Tg) mice, and this increase is coupled with a significant increase in the production of IL-10 (2.80 vs. 0.83) and decrease in the production of IL-6 (0.80 vs. 2.33) and IL-12 (0.25 vs. 1.67). We also show that GILZ-expressing BMSCs present antigen in a way that favors T(reg) cells. These results indicate that GILZ plays a critical role mediating the crosstalk between BMSCs and T(reg) in the bone marrow microenvironment. These data, together with our previous findings that overexpression of GILZ in BMSCs antagonizes TNF-α-elicited inflammatory responses, suggest that GILZ plays important roles in bone-immune cell communication and BMSC immune suppressive functions.

Impact of targeted PPARγ disruption on bone remodeling.

Peroxisome proliferator-activated receptor gamma (PPARγ), known as the master regulator of adipogenesis, has been regarded as a promising target for new anti-osteoporosis therapy due to its role in regulating bone marrow mesenchymal stem/progenitor cell (BMSC) lineage commitment. However, the precise mechanism underlying PPARγ regulation of bone is not clear as a bone-specific PPARγ conditional knockout (cKO) study has not been conducted and evidence showed that deletion of PPARγ in other tissues also have profound effect on bone. In this study, we show that mice deficiency of PPARγ in cells expressing a 3.6 kb type I collagen promoter fragment (PPAR(fl/fl):Col3.6-Cre) exhibits a moderate, site-dependent bone mass phenotype. In vitro studies showed that adipogenesis is abolished completely and osteoblastogenesis increased significantly in both primary bone marrow culture and the BMSCs isolated from PPARγ cKO mice. Histology and histomorphometry studies revealed significant increases in the numbers of osteoblasts and surface in the PPARγ cKO mice. Finally, we found that neither the differentiation nor the function of osteoclasts was affected in the PPARγ cKO mice. Together, our studies indicate that PPARγ plays an important role in bone remodeling by increasing the abundance of osteoblasts for repair, but not during skeletal development.

Role of glucocorticoid-induced leucine zipper (GILZ) in bone acquisition.

Glucocorticoids (GCs) have both anabolic and catabolic effects on bone. However, no GC anabolic effect mediator has been identified to date. Here we show that targeted expression of glucocorticoid-induced leucine zipper (GILZ), a GC anti-inflammatory effect mediator, enhances bone acquisition in mice. Transgenic mice, in which the expression of GILZ is under the control of a 3.6-kb rat type I collagen promoter, exhibited a high bone mass phenotype with significantly increased bone formation rate and osteoblast numbers. The increased osteoblast activity correlates with enhanced osteogenic differentiation and decreased adipogenic differentiation of bone marrow stromal cell cultures in vitro. In line with these changes, the mRNA levels of key osteogenic regulators (Runx2 and Osx) increased, and the level of adipogenic regulator peroxisome proliferator-activated receptor (PPAR) γ2 decreased significantly. We also found that GILZ physically interacts with C/EBPs and disrupts C/EBP-mediated PPARγ gene transcription. In conclusion, our results showed that GILZ is capable of increasing bone acquisition in vivo, and this action is mediated via a mechanism involving the inhibition of PPARγ gene transcription and shifting of bone marrow MSC/progenitor cell lineage commitment in favor of the osteoblast pathway.

Stromal cell-derived factor-1ß potentiates bone morphogenetic protein-2-stimulated osteoinduction of genetically engineered bone marrow-derived mesenchymal stem cells in vitro.

Skeletal injuries are among the most prevalent clinical problems and bone marrow-derived mesenchymal stem/stromal cells (BMSCs) have successfully been used for the treatment thereof. Stromal cell-derived factor-1 (SDF-1; CXCL12) is a member of the CXC chemokine family with multiple splice variants. The two most abundant variants, SDF-1α and SDF-1ß, share identical amino acid sequences, except for four additional amino acids at the C-terminus of SDF-1ß, which may mediate surface stabilization via glycosaminoglycans and protect SDF-1ß from proteolytic cleavage, rendering it twice as potent as SDF-1α. Increasing evidence suggests that SDF-1 is involved in bone formation through regulation of recruitment, engraftment, proliferation, and differentiation of stem/progenitor cells. The underlying molecular mechanisms, however, have not yet been fully elucidated. In this study, we tested the hypothesis that SDF-1ß can potentiate bone morphogenetic protein-2 (BMP-2)-stimulated osteogenic differentiation and chemotaxis of BMSCs in vitro. Utilizing retrovirus-mediated gene transfer to generate novel Tet-Off-SDF-1ß BMSCs, we found that conditional SDF-1ß expression is tightly regulated by doxycycline in a dose-dependent and temporal fashion, leading to significantly increased SDF-1ß mRNA and protein levels. In addition, SDF-1ß was found to enhance BMP-2-stimulated mineralization, mRNA and protein expression of key osteogenic markers, and regulate BMP-2 signal transduction via extracellular signal-regulated kinases 1/2 (Erk1/2) phosphorylation in genetically engineered BMSCs in vitro. We also showed that SDF-1ß promotes the migratory response of CXC chemokine receptor 4 (CXCR4)-expressing BMSCs in vitro. Taken together, these data support that SDF-1ß can play an important role in BMP-2-stimulated osteogenic differentiation of BMSCs and may exert its biological activity in both an autocrine and paracrine fashion.

Glucocorticoid-induced leucine zipper (GILZ) antagonizes TNF-α inhibition of mesenchymal stem cell osteogenic differentiation.

Tumor necrosis factor-alpha (TNF-α) is a potent proinflammatory cytokine that inhibits osteoblast differentiation while stimulating osteoclast differentiation and bone resorption. TNF-α activates MAP kinase pathway leading to inhibition of osterix (Osx) expression. TNF-α also induces the expression of E3 ubiquitin ligase protein Smurf1 and Smurf2 and promotes degradation of Runx2, another key transcription factor regulating osteoblast differentiation and bone formation. We showed previously that overexpression of glucocorticoid (GC)-induced leucine zipper (GILZ) enhances osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). We and others also showed that GILZ is a GC effecter and mediates GC anti-inflammatory activity. In this study, we asked the question whether GILZ retains its osteogenic activity while functioning as an anti-inflammatory mediator. To address this question, we infected mouse bone marrow MSCs with retroviruses expressing GILZ and induced them for osteogenic differentiation in the presence or absence of TNF-α. Our results show that overexpression of GILZ antagonized the inhibitory effects of TNF-α on MSC osteogenic differentiation and the mRNA and protein expression of Osx and Runx2, two pivotal osteogenic regulators. Further studies show that these antagonistic actions occur via mechanisms involving GILZ inhibition of TNF-α-induced ERK MAP kinase activation and protein degradation. These results suggest that GILZ may have therapeutic potential as a novel anti-inflammation therapy.