p21 induces a senescence program and skeletal muscle dysfunction.

Recent work has established associations between elevated p21, the accumulation of senescent cells, and skeletal muscle dysfunction in mice and humans. Using a mouse model of p21 overexpression (p21OE), we examined if p21 mechanistically contributes to cellular senescence and pathological features in skeletal muscle. We show that p21 induces several core properties of cellular senescence in skeletal muscle, including an altered transcriptome, DNA damage, mitochondrial dysfunction, and the senescence-associated secretory phenotype (SASP). Furthermore, p21OE mice exhibit manifestations of skeletal muscle pathology, such as atrophy, fibrosis, and impaired physical function when compared to age-matched controls. These findings suggest p21 alone is sufficient to drive a cellular senescence program and reveal a novel source of skeletal muscle loss and dysfunction.

Characterization of cellular senescence in aging skeletal muscle.

Senescence is a cell fate that contributes to multiple aging-related pathologies. Despite profound age-associated changes in skeletal muscle (SkM), whether its constituent cells are prone to senesce has not been methodically examined. Herein, using single cell and bulk RNA-sequencing and complementary imaging methods on SkM of young and old mice, we demonstrate that a subpopulation of old fibroadipogenic progenitors highly expresses p16 Ink4a together with multiple senescence-related genes and, concomitantly, exhibits DNA damage and chromatin reorganization. Through analysis of isolated myofibers, we also detail a senescence phenotype within a subset of old cells, governed instead by p2 Cip1 . Administration of a senotherapeutic intervention to old mice countered age-related molecular and morphological changes and improved SkM strength. Finally, we found that the senescence phenotype is conserved in SkM from older humans. Collectively, our data provide compelling evidence for cellular senescence as a hallmark and potentially tractable mediator of SkM aging.

Novel small molecule inhibition of IKK/NF-κB activation reduces markers of senescence and improves healthspan in mouse models of aging.

Constitutive NF-κB activation is associated with cellular senescence and stem cell dysfunction and rare variants in NF-κB family members are enriched in centenarians. We recently identified a novel small molecule (SR12343) that inhibits IKK/NF-κB activation by disrupting the association between IKKß and NEMO. Here we investigated the therapeutic effects of SR12343 on senescence and aging in three different mouse models. SR12343 reduced senescence-associated beta-galactosidase (SA-ß-gal) activity in oxidative stress-induced senescent mouse embryonic fibroblasts as well as in etoposide-induced senescent human IMR90 cells. Chronic administration of SR12343 to the Ercc1-/∆ and Zmpste24-/- mouse models of accelerated aging reduced markers of cellular senescence and SASP and improved multiple parameters of aging. SR12343 also reduced markers of senescence and increased muscle fiber size in 2-year-old WT mice. Taken together, these results demonstrate that IKK/NF-κB signaling pathway represents a promising target for reducing markers of cellular senescence, extending healthspan and treating age-related diseases.

Exercise reduces circulating biomarkers of cellular senescence in humans.

Cellular senescence has emerged as a significant and potentially tractable mechanism of aging and multiple aging-related conditions. Biomarkers of senescent cell burden, including molecular signals in circulating immune cells and the abundance of circulating senescence-related proteins, have been associated with chronological age and clinical parameters of biological age in humans. The extent to which senescence biomarkers are affected by interventions that enhance health and function has not yet been examined. Here, we report that a 12-week structured exercise program drives significant improvements in several performance-based and self-reported measures of physical function in older adults. Impressively, the expression of key markers of the senescence program, including p16, p21, cGAS, and TNFα, were significantly lowered in CD3+ T cells in response to the intervention, as were the circulating concentrations of multiple senescence-related proteins. Moreover, partial least squares discriminant analysis showed levels of senescence-related proteins at baseline were predictive of changes in physical function in response to the exercise intervention. Our study provides first-in-human evidence that biomarkers of senescent cell burden are significantly lowered by a structured exercise program and predictive of the adaptive response to exercise.

Patient- and Therapist-Related Risk Factors for Adverse Events in Acupuncture and Moxibustion in Japan: Multicenter Survey of Acupuncture and Moxibustion Teaching Clinics.

Background/Objective: To investigate the patient- and therapist-related factors underlying adverse events (AEs) in acupuncture and moxibustion (A&M). Design: Retrospective study using data from medical records. Subjects: Patients who underwent A&M therapy in 4 clinics providing A&M over a 6-month period and their therapists. Main Outcome Measures: Survey items included the number of patients, age, sex, number of sessions, number and type of AEs, patients' underlying disease, and the therapist's years of clinical experience. The chi-squared test was used for intergroup comparisons. Spearman's rank correlation coefficient was used to analyze the correlations between the number of sessions and AEs. Logistic regression analysis was performed with AEs as the objective variable to investigate the relationships between the various parameters and AEs. Results: The analysis included 615 patients and 113 therapists. A total of 421 AEs occurred in a total of 4,369 sessions (9.6%). The number of sessions and number of AEs were significantly and positively correlated with patients (r = 0.47, P < 0.001) and therapists (r = 0.65, P < 0.001). Logistic analysis identified patient sex (adjusted odds ratio: 1.78, 95% confidence interval: [1.39-2.30]), liver disease (0.40, [0.19-0.84]), and years of clinical experience (to a cutoff of 2 or fewer years, 2-4 years: 0.65, [0.48-0.88], 5-9 years: 0.62, [0.44-0.87], 10 years or more: 0.50, [0.37-0.68]) as significant variables. Conclusions: Female sex and fewer years of clinical experience were factors that increased the risk of AEs, and underlying liver disease was a factor that decreased the risk of AEs.

Three Medicolegal Cases of Searching for the Stone: Lessons Learned Along the Journey.

We present three medicolegal cases of medical negligence settled out of court. These cases all involved patients who presented to the emergency department (ED) with a suspected diagnosis of kidney stone. Highlighted are the importance of patient communication, addressing incidental findings found during a patient's ED visit, anticipating complications, and the need for thorough documentation.

Harnessing the effects of endurance exercise to optimize cognitive health: Fundamental insights from Dr. Mark P. Mattson.

Dr. Mark Mattson has had a highly productive and impactful tenure as a neuroscientist at the Intramural Research Program of the National Institute on Aging. He has made notable contributions to understanding the mechanisms by which energetic stress, imparted by behaviors such as physical activity and periods of fasting, promotes rejuvenation and resilience within brain regions critical for learning and memory. In honor of Dr. Mattson's work, this manuscript will highlight the fascinating mechanisms by which endurance exercise training conveys beneficial effects upon the structure and function of the nervous system; that is, by mediating the synthesis and secretion of factors that directly support brain homeostasis, including brain-derived neurotrophic factor, FNDC5/irisin, ketone bodies, growth factors, cathepsin B, serotonin, and 4-hydroxynonenal. The molecular and cellular effects of these factors are discussed herein. In the face of population aging and an overwhelming surge in the prevalence of Alzheimer's disease and related disorders, Dr. Mattson's work as a champion and role model for physically active lifestyles is more important than ever.

A Biomechanical Comparison of Three Miniature Locking Plate Systems in a Rabbit Radial and Ulnar Fracture Model.

OBJECTIVE: The aim of this study was to evaluate the biomechanical properties of three different miniature locking plate systems used to fixate radial and ulnar fractures in toy breed dogs. Implant size, shape, material and locking systems differ, and their influence on the fracture healing process is unknown. In the present study, we aimed to investigate this matter in vivo using rabbit radial and ulnar fracture models. STUDY DESIGN: Eighteen rabbits were randomly divided into three groups, and the left radius and ulna were osteotomized to create fracture models. The osteotomies were then fixated using either the TITAN LOCK 1.5, Fixin micro or LCP 1.5 system. Radiographs were obtained 2, 3 and 4 weeks after surgery. Four weeks after surgery, the radiuses were collected and used for biomechanical testing or histological examinations. RESULTS: During the 4 weeks of observation, no adverse effects due to the implants occurred. The radiographic scores in each group did not differ significantly at any time point. The maximum load in the LCP group was significantly higher than that in the TITAN and Fixin groups. There was no significant difference in bending stiffness or work to failure among the groups. Initial fracture healing via woven bone was evident at histological evaluation. CONCLUSIONS: All three miniature locking plate systems provided adequate fracture stabilization 4 weeks after surgery, despite their differences, in rabbit models.

Bone regeneration by calcium phosphate-loaded carboxymethyl cellulose nonwoven sheets in canine femoral condyle defects.

The bone regeneration capacities of calcium phosphate (CaP)-loaded carboxymethyl cellulose (CMC) nonwoven sheet (CMC/CaP) were evaluated using a dog lateral femoral condyle defect model. In addition, the effect of bFGF on bone regeneration when added to CMC/CaP sheet was investigated. The CMC and CMC/CaP sheets have high operability. The new bone formation rate in the CMC/CaP group was significantly higher than that in the control and CMC groups based on micro-computed tomography and histological evaluation. In contrast, there was no significant difference between the CMC/CaP group and the CMC/CaP/f group. In conclusion, the CMC/CaP sheet has the ability to promote new bone formation and seems to be useful as a sheet-shaped bone graft substitute. The effect of the auditioning signaling molecules to the CMC/CaP sheet, such as bFGF, requires further investigation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1516-1521, 2019.

5-HT1A receptor agonists, xaliproden and tandospirone, inhibit the increase in the number of cutaneous mast cells involved in the exacerbation of mechanical allodynia in oxaliplatin-treated mice.

Oxaliplatin causes peripheral neuropathy as a major dose-limiting side effect, and the control of this neuropathy is difficult. This study was designed to investigate whether prophylactic repetitive administration of 5-HT1A receptor agonists inhibits oxaliplatin-induced mechanical allodynia in mice. Repetitive administration of 5-HT1A receptor agonists (xaliproden and tandospirone) inhibited mechanical allodynia induced by a single intraperitoneal injection of oxaliplatin. These agonists also inhibited oxaliplatin-induced mast cell migration, which is involved in the induction of mechanical allodynia. These results suggest that the prophylactic repetitive administration of 5-HT1A receptor agonists attenuates oxaliplatin-induced mechanical allodynia by inhibiting the cutaneous mast cell migration.

Regional Differences of Metabolic Response During Dynamic Incremental Exercise by (31)P-CSI.

The aim of this study was to detect the differences in muscle metabolic response of the quadriceps during incremental dynamic knee exercise using regional (31)Phosphorus Chemical Shift Imaging ((31)P-CSI). Sixteen healthy men participated in this study (age 28 ± 5 years, height 171.4 ± 3.9 cm, weight 67.1 ± 9.8 kg). The experiments were carried out with a 1.5-T superconducting magnet with a 5-in. diameter circular surface coil. The subjects performed isometric unilateral knee extension exercise to detect their maximum voluntary contraction (MVC) in prone position. Then they performed dynamic unilateral knee extension exercise in the magnet at 10, 20, 30 and 40 % of their MVC with the transmit-receive coil placed under the right quadriceps. The subjects pulled down a rope with the adjusted weight attached to the ankle at a frequency of 0.5 Hz for 380 s. Intracellular pH (pHi) was calculated from the median chemical shift of the inorganic phosphate (Pi) peak relative to phosphocreatine (PCr). The quadriceps were divided into three regions, (1) medial, (2) anterior, (3) lateral, and in comparison, there was no significant difference in Pi/PCr nor in pHi between regions, except Pi/PCr of the medial region was significantly higher than the anterior region at maximum intensity (p < 0.05). These results suggest that regional muscle metabolic response is similar in the quadriceps except at maximum intensity.

Effects of Acupuncture Stimulation on Muscle Tissue Oxygenation at Different Points.

Muscle tissue oxygenation is a critical issue in muscle complications such as pain, exhaustion, stiffness, or fatigue during and after exercise. The aim of this study was to investigate whether the changes of muscle tissue oxygenation could be observed at both erector spinae muscle at S1 level and gastrocnemius during and after acupuncture stimulation to ipsilateral erector spinae at S1 level. The subjects were ten healthy males. Muscle oxygenation was monitored by near infrared spectroscopy (NIRS), and the probes were placed on the right side of the erector spinae muscle at S1 level (Guanyuanshu, BL26) and the belly of the gastrocnemius on the right (Chengjin, BL56). The subjects lay on the bed in prone position for 10 min, followed by acupuncture insertion into the right side of BL26. The needle was left for 10 min and subjects were kept still for 10 min after removal. At BL26, oxygenated-hemoglobin (oxy-Hb) was significantly increased compared to the baseline at 10 min after insertion (p < 0.05), then continued increasing. Total hemoglobin (t-Hb) was increased at 2 min after removal (p < 0.05). Tissue-oxygen saturation (StO2) was increased at 7 min after insertion (p < 0.05). At BL56, oxy-Hb and t-Hb were increased at 6 and 2 min after removal, respectively (p < 0.05). StO2 showed no significant change. The acupuncture stimulation affected muscle tissue oxygenation differently at both stimulated and non-stimulated points in the same innervation.

Regional Differences in Muscle Energy Metabolism in Human Muscle by 31P-Chemical Shift Imaging.

Previous studies have reported significant region-dependent differences in the fiber-type composition of human skeletal muscle. It is therefore hypothesized that there is a difference between the deep and superficial parts of muscle energy metabolism during exercise. We hypothesized that the inorganic phosphate (Pi)/phosphocreatine (PCr) ratio of the superficial parts would be higher, compared with the deep parts, as the work rate increases, because the muscle fiber-type composition of the fast-type may be greater in the superficial parts compared with the deep parts. This study used two-dimensional 31Phosphorus Chemical Shift Imaging (31P-CSI) to detect differences between the deep and superficial parts of the human leg muscles during dynamic knee extension exercise. Six healthy men participated in this study (age 27±1 year, height 169.4±4.1 cm, weight 65.9±8.4 kg). The experiments were carried out with a 1.5-T superconducting magnet with a 5-in. diameter circular surface coil. The subjects performed dynamic one-legged knee extension exercise in the prone position, with the transmit-receive coil placed under the right quadriceps muscles in the magnet. The subjects pulled down an elastic rubber band attached to the ankle at a frequency of 0.25, 0.5 and 1 Hz for 320 s each. The intracellular pH (pHi) was calculated from the median chemical shift of the Pi peak relative to PCr. No significant difference in Pi/PCr was observed between the deep and the superficial parts of the quadriceps muscles at rest. The Pi/PCr of the superficial parts was not significantly increased with increasing work rate. Compared with the superficial areas, the Pi/PCr of the deep parts was significantly higher (p<0.05) at 1 Hz. The pHi showed no significant difference between the two parts. These results suggest that muscle oxidative metabolism is different between deep and superficial parts of quadriceps muscles during dynamic exercise.

Involvement of mast cells and proteinase-activated receptor 2 in oxaliplatin-induced mechanical allodynia in mice.

The chemotherapeutic agent oxaliplatin induces neuropathic pain, a dose-limiting side effect, but the underlying mechanisms are not fully understood. Here, we show the potential involvement of cutaneous mast cells in oxaliplatin-induced mechanical allodynia in mice. A single intraperitoneal injection of oxaliplatin induced mechanical allodynia, which peaked on day 10 after injection. Oxaliplatin-induced mechanical allodynia was almost completely prevented by congenital mast cell deficiency. The numbers of total and degranulated mast cells was significantly increased in the skin after oxaliplatin administration. Repetitive topical application of the mast cell stabilizer azelastine hydrochloride inhibited mechanical allodynia and the degranulation of mast cells without affecting the number of mast cells in oxaliplatin-treated mice. The serine protease inhibitor camostat mesilate and the proteinase-activated receptor 2 (PAR2) antagonist FSLLRY-NH2 significantly inhibited oxaliplatin-induced mechanical allodynia. However, it was not inhibited by the H1 histamine receptor antagonist terfenadine. Single oxaliplatin administration increased the activity of cutaneous serine proteases, which was attenuated by camostat and mast cell deficiency. Depletion of the capsaicin-sensitive primary afferents by neonatal capsaicin treatment almost completely prevented oxaliplatin-induced mechanical allodynia, the increase in the number of mast cells, and the activity of cutaneous serine proteases. These results suggest that serine protease(s) released from mast cells and PAR2 are involved in oxaliplatin-induced mechanical allodynia. Therefore, oxaliplatin may indirectly affect the functions of mast cells through its action on capsaicin-sensitive primary afferents.

Effects of xaliproden, a 5-HT1A agonist, on mechanical allodynia caused by chemotherapeutic agents in mice.

In the present study we investigated whether xaliproden, a selective 5-HT1A receptor agonist, could relieve allodynia induced by three types of chemotherapeutic agents (paclitaxel, vincristine, and oxaliplatin) in mice. A single intraperitoneal injection of paclitaxel (5mg/kg), vincristine (0.1mg/kg), or oxaliplatin (3mg/kg) time-dependently increased punctate stimulation-evoked allodynia over 10-14 days; the intensities of allodynia were similar between the treatment groups. A single oral dose of xaliproden (0.3-3mg/kg) inhibited paclitaxel-induced allodynia in a dose-dependent manner. Xaliproden (3mg/kg) administration produced a slight and no suppression of vincristine-induced and oxaliplatin-induced allodynia, respectively. The firing response of the tibial nerve to punctate stimulation increased in mice that received paclitaxel or oxaliplatin. Xaliproden (3mg/kg) markedly inhibited the firing response in the mice treated with paclitaxel, while it partially inhibited the firing response in the oxaliplatin-treated animals. Vincristine did not significantly increase the tibial nerve response. Paclitaxel significantly increased the mRNA expression of 5-HT1A receptor in the dorsal root ganglia, but not in the spinal dorsal horn. In contrast, oxaliplatin significantly increased the mRNA expression of 5-HT1A receptor in the spinal dorsal horn, but not in the dorsal root ganglia. Vincristine did not affect the mRNA expression of 5-HT1A receptor in both these regions. These results suggest that xaliproden produces acute inhibition of mechanical allodynia induced by paclitaxel, but not by vincristine and oxaliplatin, via inhibition of the hyper-response of the primary afferent neurons.

Local increase in trapezius muscle oxygenation during and after acupuncture.

PURPOSE: This study aimed to compare the trapezius muscle blood volume and oxygenation in the stimulation region and in a distant region in the same muscle during acupuncture stimulation (AS). We hypothesized that AS provokes a localized increase in muscle blood volume and oxygenation in the stimulation region. METHODS: Two sets of near-infrared spectrometer (NIRS) probes, with 40-mm light-source detector spacing, were placed on the right trapezius muscle, with a 50-mm distance between the probes. Changes in muscle oxygenation (oxy-Hb) and blood volume (t-Hb) in stimulation and distant regions (50 mm away from the stimulation point) were measured using NIRS. Nine healthy acupuncture-experienced subjects were chosen as the experimental (AS) group, and 10 healthy acupuncture-experienced subjects were chosen for the control (no AS) group. Measurements began with a 3-min rest period, followed by "Jakutaku" (AS) for 2 min, and recovery after stimulation. RESULTS: There was a significant increase in oxy-Hb (60.7 muM at maximum) and t-Hb (48.1 muM at maximum) in the stimulation region compared to the distant region. In the stimulation region, a significant increase in oxy-Hb and t-Hb compared with the pre-stimulation level was first noted at 58.5 s and 13.5 s, respectively, after the onset of stimulation. CONCLUSION: In conclusion, oxygenation and blood volume increased, indicating elevated blood flow to the small vessels, not in the distant region used in this study, but in the stimulation region of the trapezius muscle during and after a 2-min AS.