Supercharging irradiated allografts with mesenchymal stem cells improves acetabular bone grafting in revision arthroplasty

Purpose

The procedure of bone allografting associated with a reinforcement device is widely used for acetabulum revision. However in absence of biologic fixation of the allograft, failure of the reconstruction may occur. We made the hypothesis that it would be possible to load these grafts with bone marrow derived mesenchymal stem cells (MSC) to rescue the osteogenic capacity of an allogenic dead bone and therefore enhance incorporation of allografts with the host bone and decrease the number of failures related to the allograft.

Method

We identified 60 patients who had undergone acetabular component revision for aseptic failure of cemented implants associated with massive periacetabular osteolysis and Paprosky type 3A or 3B classification (without pelvic discontinuity) between 1996 and 2001. The study group of 30 patients received MSCs in the allograft and at the host graft junction. The average total number of MSCs received by each patient was 195,000 cells (range 86,000–254,000 cells). The control group of 30 patients had no MSCs in the allograft. Patients were matched for the size of periacetabular osteolysis (Paprosky type 3A or 3B). We compared the evolution of the allografts and evaluated cup migration and revision of the hips as end points at a minimum of 12 years or until failure.

Result

Better radiographic graft union rates and less allograft resorption were observed with allografts loaded with stem cells. Allograft resorption was significantly decreased in the group with allograft loaded with MSCs (1.2 cm² —range 0–2.3 cm²—of resorption on radiographs in the group with MSCs; versus 6 cm², range 2.1–8.5 cm² in the group without MSCs). The rate of mechanical failure was highest (p?=?0.01) among the 30 patients with allograft without stem cells (9/30; 30 %) compared with no failures for patients with allograft loaded with stem cells. Revision of the cup was necessary in nine patients in the control group. No revision was performed in the 30 patients of the study group with MSCs.

Conclusion

For acetabular defect reconstruction, loading the allograft with MSCs has resulted in a lower rate of failure as compared with allograft without MSCs.     

Intractable diffuse pulmonary diseases: Manual for diagnosis and treatment

This manual has been compiled by a joint production committee with the Diffuse Lung Disease Assembly of the Japanese Respiratory Society (JRS) to provide a practical manual for the epidemiology, diagnosis, and treatment of intractable diffuse pulmonary diseases. The contents are based upon the results of research into these diseases by the Diffuse Pulmonary Diseases Study Group (principal researcher: Sakae Homma) supported by the FY2014–FY2016 Health and Labor Sciences Research Grant on Intractable Diseases.This manual focuses on: 1) pulmonary alveolar microlithiasis, 2) bronchiolitis obliterans, and 3) Hermansky-Pudlak Syndrome with interstitial pneumonia. As these are rare/intractable diffuse lung diseases (2 and 3 were first recognized as specified intractable diseases in 2015), there have not been sufficient epidemiological studies made, and there has been little progress in formulating diagnostic criteria and severity scales; however, the results of Japan's first surveys and research into such details are presented herein. In addition, the manual provides treatment guidance and actual cases for each disease, aiming to assist in the establishment of future modalities.The manual was produced with the goal of enabling clinicians specialized in respiratory apparatus to handle these diseases in clinical settings and of further advancing future research and treatment.     

Ethanol Inhibition of Neural Stem Cell Differentiation Is Reduced by Neurotrophic Factors

Background: Ethanol exposure during development leads to various forms of neuronal damage. Because neural stem cells (NSCs) play a pivotal role in the development and maturation of the central nervous system, it is important to understand the effect of ethanol on NSC differentiation. In this study, we investigated the effect of ethanol on differentiation of cultured NSCs in the presence and absence of neurotrophic factors.
Methods: NSCs were derived from rat embryos on embryonic day 14. Cells were exposed to ethanol with or without neurotrophic factors, insulin-like growth factor-1 (IGF-1), or brain-derived neurotrophic factor (BDNF). The effect of ethanol on differentiation was quantified by measurement of optical density of each sample following to microtubule-associated protein 2 enzyme-linked immunosorbent assay and counting of the number of microtubule-associated protein 2–positive cells microscopically. In addition, cell viability of cultured cortical neurons that were exposed to similar concentrations of ethanol was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay.
Results: Ethanol (20–100 mM) inhibited NSC differentiation induced by basic fibroblast growth factor removal, whereas those concentrations of ethanol did not affect neuronal survival. Both IGF-1 and BDNF promoted generation of neurons in the absence of ethanol. Moreover, they suppressed the inhibitory effect of ethanol on NSC differentiation.
Conclusions: Ethanol inhibited NSC differentiation at concentrations much lower than what compromised neuronal survival. Ethanol-induced differential inhibition was reduced by both IGF-1 and BDNF. These results suggest that ethanol inhibits stem cell differentiation through alteration of cellular pathways related to neurotrophic factor signaling.     

Bronchiolitis obliterans

Bronchiolitis obliterans (BO) is a fibrotic lung disease involving the small conducting airways. BO may be classified by etiology and underlying disease or, more commonly, by histopathological pattern. The two major histopathological categories are (1) BO organizing pneumonia (BOOP) and proliferative bronchiolitis and (2) constrictive bronchiolitis. The former is often idiopathic in nature and may also be associated with connective tissue diseases and inhalation injury. Characteristic findings on chest imaging include alveolar infiltrates and ground glass opacities and pulmonary function tests (PFTs) usually reveal restrictive dysfunction. Constrictive bronchiolitis is associated with organ transplantation, infections, connective tissue diseases, inhalation injury, and drugs and may also have an idiopathic origin. The radiographic characteristic is a mosaic pattern on high-resolution computed tomography (HRCT) and PFTs most often reveal obstructive dysfunction. This article will attempt to review constrictive BO, including histopathology, clinical presentation, radiographic appearance, and physiological findings, for both idiopathic diseases, as well as specific clinical-associated entities.     

Hybrid-fuel bacterial flagellar motors in Escherichia coli

The bacterial flagellar motor rotates driven by an electrochemical ion gradient across the cytoplasmic membrane, either H⁺ or Na⁺ ions. The motor consists of a rotor ∼50 nm in diameter surrounded by multiple torque-generating ion-conducting stator units. Stator units exchange spontaneously between the motor and a pool in the cytoplasmic membrane on a timescale of minutes, and their stability in the motor is dependent upon the ion gradient. We report a genetically engineered hybrid-fuel flagellar motor in Escherichia coli that contains both H⁺- and Na⁺-driven stator components and runs on both types of ion gradient. We controlled the number of each type of stator unit in the motor by protein expression levels and Na⁺ concentration ([Na⁺]), using speed changes of single motors driving 1-μm polystyrene beads to determine stator unit numbers. De-energized motors changed from locked to freely rotating on a timescale similar to that of spontaneous stator unit exchange. Hybrid motor speed is simply the sum of speeds attributable to individual stator units of each type. With Na⁺ and H⁺ stator components expressed at high and medium levels, respectively, Na⁺ stator units dominate at high [Na⁺] and are replaced by H⁺ units when Na⁺ is removed. Thus, competition between stator units for spaces in a motor and sensitivity of each type to its own ion gradient combine to allow hybrid motors to adapt to the prevailing ion gradient. We speculate that a similar process may occur in species that naturally express both H⁺ and Na⁺ stator components sharing a common rotor.Molecular motors are tiny machines that perform a wide range of functions in living cells. Typically each motor generates mechanical work using a specific chemical or electrochemical energy source. Linear motors such as kinesin on microtubules or myosin on actin filaments and rotary motors such as F₁-ATPase, the soluble part of ATP-synthase, run on ATP, whereas the rotary bacterial flagellar motor embedded in the bacterial cell envelope is driven by the flux of ions across the cytoplasmic membrane (1–4). Coupling ions are known to be either protons (H⁺) or sodium ions (Na⁺) (5, 6).The bacterial flagellar motor consists of a rotor ∼50 nm in diameter surrounded by multiple stator units (7–10). Each unit contains two types of membrane proteins forming ion channels: MotA and MotB in H⁺ motors in neutrophiles (e.g., Escherichia coli and Salmonella) and PomA and PomB in Na⁺ motors in alkalophiles and Vibrio species (e.g., Vibrio alginolyticus) (1, 11). Multiple units interact with the rotor to generate torque independently in a working motor (9, 10, 12, 13). The structure and function of H⁺ and Na⁺ motors are very similar, to the extent that several functional chimeric motors have been made containing different mixtures of H⁺- and Na⁺-motor components (11). One such motor that runs on Na⁺ in E. coli combines the rotor of the H⁺-driven E. coli motor with the chimeric stator unit PomA/PotB, containing PomA from V. alginolyticus and a fusion protein between MotB from E. coli and PomB from V. alginolyticus (14).In most flagellated bacteria, motors are driven by ion-specific rotor–stator combinations. However, some species (e.g., Bacillus subtilis and Shewanella oneidensis) combine a single set of rotor genes with multiple sets of stator genes encoding both H⁺ and Na⁺ stator proteins, and it has been speculated that these stator components may interact with the rotor simultaneously, allowing a single motor to use both H⁺ and Na⁺. An appealing hypothesis that the mixture of stator components is controlled dynamically depending on the environment has arisen from the observation that the localization of both stator components depends upon Na⁺ (15). However, despite some experimental effort there is as yet no direct evidence of both H⁺ and Na⁺ stator units interacting with the same rotor (16).The rotation of single flagellar motors can be monitored in real time by light microscopy of polystyrene beads (diameter ∼1 μm) attached to truncated flagellar filaments (17). Under these conditions, the E. coli motor torque and speed are proportional to the number of stator units in both H⁺-driven MotA/MotB and Na⁺-driven PomA/PotB (17–19) motors. The maximum number of units that can work simultaneously in a single motor has been shown to be at least 11 by “resurrection” experiments, in which newly produced functional units lead to restoration of motor rotation in discrete speed increments in an E. coli strain lacking functional stator proteins (19). Stator units are not fixed permanently in a motor: Each dissociates from the motor with a typical rate of ∼2 min⁻¹, exchanging between the motor and a pool of diffusing units in the cytoplasmic membrane (20). Removal of the relevant ion gradient inactivates both H⁺ and Na⁺ stator units, most likely leading to dissociation from the motor into the membrane pool (2, 21, 22).Here we demonstrate a hybrid-fuel motor containing both H⁺-driven MotA/MotB and Na⁺-driven PomA/PotB stator components, sharing a common rotor in E. coli. We control the expression level of each stator type by induced expression from plasmids, and the affinity of Na⁺-driven stator units for the motor by external [Na⁺]. Units of each type compete for spaces around the rotor, and the motor torque is simply the sum of the independent contributions, with no evidence of direct interaction between units. Thus, we demonstrate the possibility of modularity in the E. coli flagellar motor, with ion selectivity determined by the choice of stator modules interacting with a common rotor. Our artificial hybrid motor demonstrates that species with multiple types of stator gene and a single set of rotor genes could contain natural hybrid motors that work on a similar principle (15, 16, 23).     

Midurethral autologous fascial sling surgery with reconstruction of the lower abdominal wall using the tensor fascia lata muscle flap for post‐hemipelvectomy stress urinary incontinence

Hemipelvectomy is surgery for pelvic bone neoplasms. In the case of pubic bone osteosarcoma, the distal end of the rectus abdominis muscle is severed from the pubic and ischium bones, and the pelvic floor muscles are resected en bloc with the bone, which leads to stress urinary incontinence. Cancer control is prioritized over complications, and stress urinary incontinence is generally disregarded. A 25‐year‐old woman presented with stress urinary incontinence. She had undergone a hemipelvectomy for left pubic bone osteosarcoma, and stress urinary incontinence appeared and persisted since the surgery. We carried out a reconstruction of the tissue deficit of the rectus abdominis using the tensor fascia lata muscle flap simultaneously with a midurethral autologous fascial sling anchoring to the tensor fascia lata flap. Stress incontinence was successfully improved without morbidity. This is the first reported case of midurethral suspension with reconstruction of the lower abdominal wall with the tensor fascia lata flap for post‐hemipelvectomy stress urinary incontinence.