Multilineage differentiation potential in the infant adipose- and umbilical cord-derived mesenchymal stem cells.

BACKGROUND: This study aims to compare the biological properties of infant adipose-derived mesenchymal stem cells (infant ADSCs) from excised polydactyly fat tissue and umbilical cord-derived mesenchymal stem cells (UCSCs) in terms of proliferation and differentiation capabilities. The proliferation of infant ADSCs and UCSCs was analyzed by determining the fold changes of cell numbers and doubling time periods. METHODS: The state of senescence and replicative stress was compared by analyzing the expression of age-related genes, senescence-associated ß-galactosidase (SA-ß-gal) staining, and phosphorylated histone variant H2AX (γH2AX) immunofluorescence staining. The expression levels of superoxide dismutase ( SODs ) and genes related to multilineage differentiation were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Differentiation levels were determined using histochemical staining, immunohistochemical staining, and immunofluorescence staining. RESULTS: Infant ADSCs exhibited higher proliferation rates and expression levels of SOD1 , SOD2 , and SOD3 at passages 3-5 compared with UCSCs. Senescence related genes ( p16 , p21 , and p53 ), SA-ß-gal staining, and replicative stress analysis were reduced in infant ADSCs. The expression levels of chondrogenic genes ( COL2 and COL10 ), osteogenic genes ( RUNX2 and ALP ), adipogenic genes ( LPL ), and hepatogenic genes ( ALB and TAT ) in infant ADSC-differentiated cells were significantly higher than those in UCSCs. Histochemical and immunofluorescence staining confirmed these results. Only the expression levels of tenogenic genes ( MMP3 , DCN , and COL3 ) in infant ADSC-differentiated cells were lower than those in UCSCs. CONCLUSION: Infant ADSCs exhibit higher proliferation rates, reduced cellular senescence and replicative stress, better antioxidative activity, and higher differentiation potential toward chondrogenic, osteogenic, adipogenic and hepatogenic lineages than UCSCs.

AMP-activated protein kinase mediates lipopolysaccharide-induced proinflammatory responses and elevated bone resorption in differentiated osteoclasts.

Systemic and intracellular metabolic states are critical factors affecting immune cell functions. The metabolic regulator AMP-activated protein kinase (AMPK) senses AMP levels and mediates cellular responses to energy-restrained conditions. The ubiquitously expressed AMPK participates in various biological functions in numerous cell types, including innate immune cell macrophages and osteoclasts, which are their specialized derivatives in bone tissues. Previous studies have demonstrated that the activation of AMPK promotes macrophage polarization toward anti-inflammatory M2 status. Additionally, AMPK acts as a negative regulator of osteoclastogenesis, and upregulation of AMPK disrupts the differentiation of osteoclasts. However, the regulation and roles of AMPK in differentiated osteoclasts have not been characterized. Here, we report that inflammatory stimuli-regulated-AMPK activation of differentiated and undifferentiated osteoclasts in opposite ways. Lipopolysaccharide (LPS) inhibited the phosphorylation of AMPK in macrophages and undifferentiated osteoclasts, but it activated AMPK in differentiated osteoclasts. Inactivating AMPK decreased cellular responses against the activation of toll-like receptor signaling, including the transcriptional activation of proinflammatory cytokines and the bone resorption genes TRAP, and MMP9. The elevation of bone resorption by LPS stimulation was disrupted by AMPK inhibitor, indicating the pivotal roles of AMPK in inflammation-induced activities in differentiated osteoclasts. The AMPK activator metformin did not increase proinflammatory responses, possibly because other factors are also required for this regulation. Notably, changing the activation status of AMPK did not alter the expression levels of bone resorption genes in unstimulated osteoclasts, indicating the essential roles of AMPK in cellular responses to inflammatory stimuli but not in the maintenance of basal levels. Unlike its M2-polarizing roles in macrophages, AMPK was not responsive to the M2 stimulus of interleukin-4. Our observations revealed differences in the cellular properties of macrophages and osteoclasts as well as the complexity of regulatory mechanisms for osteoclast functions.

Influential factors of surgical decompression for ulnar nerve neuropathy in Guyon's canal.

BACKGROUND: Guyon's canal syndrome is nerve compressive pathology which can lead to sensory and/or motor function deficits. This problem is usually difficult to distinguish from cubital tunnel syndrome and relatively less common than cubital tunnel syndrome. This study evaluated the functional results and patient-reported outcomes following decompression of the ulnar nerve in Guyon's canal. METHODS: Patients who were diagnosed with Guyon's canal syndrome confirmed by electrodiagnostic studies and underwent nerve decompression surgery were included in this study. The functional improvement by examining the Froment's sign, Wartenberg's sign, static two-point discrimination, and Semmes Weinstein monofilament examination as physical examination scores was evaluated. The visual analogue scale of satisfaction and the disabilities of the arm, shoulder, and hand questionnaire were used for the postoperative patient-reported outcome evaluation. RESULTS: From 2003 to 2019, 38 cases had been enrolled with a mean age of 53 years, ranging from 19 to 85 years. There were seven patients with comorbidity of diabetes mellitus and 28 patients who received additional neurolysis combined with the Guyon's release procedure. There were 19 patients with a good response to surgery and 10 patients with a poor surgical outcome due to persistent paresthesia or weakness. After statistical analysis, it was revealed that several influential factors could have been related to a compromised functional outcome, including a symptom duration of more than 3 months, combination with additional neurolysis of ipsilateral extremity, and/or comorbidity with diabetes mellitus. CONCLUSION: It was concluded that promising functional outcomes after surgical release of ulnar neuropathy in Guyon's canal could be achieved if the patients did not need additional neurolysis or the symptom duration was within 3 months.

Adipose-Derived Mesenchymal Stem Cells From a Hypoxic Culture Improve Neuronal Differentiation and Nerve Repair.

Hypoxic expansion has been demonstrated to enhance in vitro neuronal differentiation of bone-marrow derived mesenchymal stem cells (BMSCs). Whether adipose-derived mesenchymal stem cells (ADSCs) increase their neuronal differentiation potential following hypoxic expansion has been examined in the study. Real-time quantitative reverse transcription-polymerase chain reaction and immunofluorescence staining were employed to detect the expression of neuronal markers and compare the differentiation efficiency of hypoxic and normoxic ADSCs. A sciatic nerve injury animal model was used to analyze the gastrocnemius muscle weights as the outcomes of hypoxic and normoxic ADSC treatments, and sections of the regenerated nerve fibers taken from the conduits were analyzed by histological staining and immunohistochemical staining. Comparisons of the treatment effects of ADSCs and BMSCs following hypoxic expansion were also conducted in vitro and in vivo. Hypoxic expansion prior to the differentiation procedure promoted the expression of the neuronal markers in ADSC differentiated neuron-like cells. Moreover, the conduit connecting the sciatic nerve gap injected with hypoxic ADSCs showed the highest recovery rate of the gastrocnemius muscle weights in the animal model, suggesting a conceivable treatment for hypoxic ADSCs. The percentages of the regenerated myelinated fibers from the hypoxic ADSCs detected by toluidine blue staining and myelin basic protein (MBP) immunostaining were higher than those of the normoxic ones. On the other hand, hypoxic expansion increased the neuronal differentiation potential of ADSCs compared with that of the hypoxic BMSCs in vitro. The outcomes of animals treated with hypoxic ADSCs and hypoxic BMSCs showed similar results, confirming that hypoxic expansion enhances the neuronal differentiation potential of ADSCs in vitro and improves in vivo therapeutic potential.

Risk factors in cutout of sliding hip screw in intertrochanteric fractures: an evaluation of 937 patients.

The aim of this study was designed to assess the risk factors of lag-screw cutout in the treatment of intertrochanteric fracture with a dynamic hip screw (DHS). From 2003 to 2007, 1,150 patients who had acute unilateral intertrochanteric fractures of the femur were enrolled to the study. All fractures were managed by closed reduction and internal fixation with 135° DHS devices. Patient demographics, fracture patterns, reduction and fixation and perioperative course parameters were all recorded. The follow-up period was 38 months on average (range 16-60 months). Finally, 937 patients were available for evaluation of final results in which we focused on lag-screw cutout. Excluding complications not related to screw position, 64 patients (6.8%) with screw cutout were encountered, and the remaining 873 patients had uneventful union, with the average union time of 17.5 weeks (range15-24 weeks). Upon analysis with logistic regression, the tip-apex distance (TAD) was shown to be the most important predictive factor for cutout, followed by screw position, fracture pattern, reduction and patient age. In order to decrease the risk of lag-screw cutout, it is important to ensure good fracture reduction and to place the lag screw in either the middle/middle or inferior/middle position with appropriate TAD.