Michael J. DeSarno

Comparative Decellularization and Recellularization of Normal versus Emphysematous Human Lungs

Acellular whole human lung scaffolds represent a unique opportunity for ex vivo tissue engineering. However, it remains unclear whether lungs from individuals with chronic lung diseases such as chronic obstructive pulmonary disease (COPD) can be appropriately decellularized and recellularized. To assess this, cadaveric human lungs from normal (non-smoking) patients and from patients with COPD (smoking history) were decellularized and found by histochemical and immunohistochemical staining, electron microscopy, and mass spectrometry to retain characteristic histological architecture and extracellular matrix components (ECM) reflecting either normal or COPD, particularly emphysematous, origin. Inoculation of human bronchial epithelial cells, endothelial progenitor cells, bone marrow-derived mesenchymal stem cells, and lung fibroblasts via airway or vascular routes into small, excised segments of the decellularized lungs demonstrated that normal lung scaffolds robustly supported initial engraftment and growth of each cell type for up to one month. In contrast, despite initial binding, all cell types inoculated into decellularized emphysematous lungs did not survive beyond one week. However, cell attachment and proliferation on solubilized ECM homogenates of decellularized normal and emphysematous lungs coated onto tissue culture plates was comparable and not impaired, suggesting that the 3-dimensional decellularized emphysematous scaffolds may lack the necessary ECM architecture to support sustained cell growth.

Three-dimensional scaffolds of acellular human and porcine lungs for high throughput studies of lung disease and regeneration

Acellular scaffolds from complex whole organs such as lung are being increasingly studied for ex vivo organ generation and for in vitro studies of cell-extracellular matrix interactions. We have established effective methods for efficient de and recellularization of large animal and human lungs including techniques which allow multiple small segments (∼ 1-3 cm(3)) to be excised that retain 3-dimensional lung structure. Coupled with the use of a synthetic pleural coating, cells can be selectively physiologically inoculated via preserved vascular and airway conduits. Inoculated segments can be further sliced for high throughput studies. Further, we demonstrate thermography as a powerful noninvasive technique for monitoring perfusion decellularization and for evaluating preservation of vascular and airway networks following human and porcine lung decellularization. Collectively, these techniques are a significant step forward as they allow high throughput in vitro studies from a single lung or lobe in a more biologically relevant, three-dimensional acellular scaffold.

The Nonallergic Asthma of Obesity. A Matter of Distal Lung Compliance

RATIONALE The pathogenesis of asthma in obesity is poorly understood, but may be related to breathing at low lung volumes. OBJECTIVES To determine if lung function in obese patients with asthma and control subjects would respond differently to weight loss. METHODS Lung function was evaluated by conventional clinical tests and by impulse oscillometry in female late-onset, nonallergic patients with asthma and control subjects before, and 12 months after, bariatric surgery. MEASUREMENTS AND MAIN RESULTS Patients with asthma (n = 10) had significantly lower FEV1 (79.8 ± 10.6 vs. 95.5 ± 7.0%) and FVC (82.4 ± 13.2 vs. 93.7 ± 8.9%) compared with control subjects (n = 13). There were no significant differences in FRC or TLC at baseline. Twelve months after surgery, control subjects had significant increases in FEV1 (95.5 ± 7.0 to 100.7 ± 5.9), FVC (93.6 ± 8.9 to 98.6 ± 8.3%), FRC (45.4 ± 18.5 to 62.1 ± 15.3%), and TLC (84.8 ± 15.0 to 103.1 ± 15.3%), whereas patients with asthma had improvement only in FEV1 (79.8 ± 10.6 to 87.2 ± 11.5). Control subjects and patients with asthma had a significantly different change in respiratory system resistance with weight loss: control subjects exhibited a uniform decrease in respiratory system resistance at all frequencies, whereas patients with asthma exhibited a decrease in frequency dependence of resistance. Fits of a mathematical model of lung mechanics to these impedance spectra suggest that the lung periphery was more collapsed by obesity in patients with asthma compared with control subjects. CONCLUSIONS Weight loss decompresses the lung in both obese control subjects and patients with asthma, but the more pronounced effects of weight loss on lung elastance suggest that the distal lung is inherently more collapsible in people with asthma.

The effect of age and emphysematous and fibrotic injury on the re-cellularization of de-cellularized lungs.

Use of de-cellularized cadaveric lungs as 3-dimensional scaffolds for ex vivo lung tissue generation offers a new potential therapeutic approach for clinical lung transplantation. However, it is likely that some of the available cadaveric human lungs may be from older donors or from donors with previously existing structural lung diseases such as emphysema or pulmonary fibrosis. It is not known whether these lungs will be suitable for either de-cellularization or re-cellularization. To investigate this, we assessed the effects of advanced age, representative emphysematous and fibrotic injuries, and the combination of advanced age and emphysematous injury and found significant differences both in histologic appearance and in the retention of extracellular matrix (ECM) and other proteins, as assessed by immunohistochemistry and mass spectrometry, between the different conditions. However, despite these differences, binding, retention and growth of bone marrow-derived mesenchymal stromal cells (MSCs) over a 1-month period following intratracheal inoculation were similar between the different experimental conditions. In contrast, significant differences occurred in the growth of C10 mouse lung epithelial cells between the different conditions. Therefore, age, lung injury, and the cell type used for re-cellularization may significantly impact the usefulness of de-cellularized whole lungs for ex vivo lung tissue regeneration.

The effects of storage and sterilization on de-cellularized and re-cellularized whole lung.

Despite growing interest on the potential use of de-cellularized whole lungs as 3-dimensional scaffolds for ex vivo lung tissue generation, optimal processing including sterilization and storage conditions, are not well defined. Further, it is unclear whether lungs need to be obtained immediately or may be usable even if harvested several days post-mortem, a situation mimicking potential procurement of human lungs from autopsy. We therefore assessed effects of delayed necropsy, prolonged storage (3 and 6 months), and of two commonly utilized sterilization approaches: irradiation or final rinse with peracetic acid, on architecture and extracellular matrix (ECM) protein characteristics of de-cellularized mouse lungs. These different approaches resulted in significant differences in both histologic appearance and in retention of ECM and intracellular proteins as assessed by immunohistochemistry and mass spectrometry. Despite these differences, binding and proliferation of bone marrow-derived mesenchymal stromal cells (MSCs) over a one month period following intratracheal inoculation was similar between experimental conditions. In contrast, significant differences occurred with C10 mouse lung epithelial cells between the different conditions. Therefore, delayed necropsy, duration of scaffold storage, sterilization approach, and cell type used for re-cellularization may significantly impact the usefulness of this biological scaffold-based model of ex vivo lung tissue regeneration.

Combined Anatomic Factors Predicting Risk of Anterior Cruciate Ligament Injury for Males and Females

Background: Knee joint geometry has been associated with risk of suffering an anterior cruciate ligament (ACL) injury; however, few studies have utilized multivariate analysis to investigate how different aspects of knee joint geometry combine to influence ACL injury risk. Hypotheses: Combinations of knee geometry measurements are more highly associated with the risk of suffering a noncontact ACL injury than individual measurements, and the most predictive combinations of measurements are different for males and females. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 88 first-time, noncontact, grade III ACL-injured subjects and 88 uninjured matched-control subjects were recruited, and magnetic resonance imaging data were acquired. The geometry of the tibial plateau subchondral bone, articular cartilage, and meniscus; geometry of the tibial spines; and size of the femoral intercondylar notch and ACL were measured. Multivariate conditional logistic regression was used to develop risk models for ACL injury in females and males separately. Results: For females, the best fitting model included width of the femoral notch at its anterior outlet and the posterior-inferior–directed slope of the lateral compartment articular cartilage surface, where a millimeter decrease in notch width and a degree increase in slope were independently associated with a 50% and 32% increase in risk of ACL injury, respectively. For males, a model that included ACL volume and the lateral compartment posterior meniscus to subchondral bone wedge angle was most highly associated with risk of ACL injury, where a 0.1 cm3 decrease in ACL volume (approximately 8% of the mean value) and a degree decrease in meniscus wedge angle were independently associated with a 43% and 23% increase in risk, correspondingly. Conclusion: Combinations of knee joint geometry measurements provided more information about the risk of noncontact ACL injury than individual measures, and the aspects of geometry that best explained the relationship between knee geometry and the risk of injury were different between males and females. Consequently, a female with both a decreased femoral notch width and an increased posterior-inferior–directed lateral compartment tibial articular cartilage slope combined or a male with a decreased ACL volume and decreased lateral compartment posterior meniscus angle were most at risk for sustaining an ACL injury.

Outcomes are not different for patient-matched versus nonmatched treatment in subjects with chronic recurrent low back pain: a randomized clinical trial.

BACKGROUND CONTEXT Classification schemas for low back pain (LBP), such as the Treatment-Based Classification and the Movement System Impairment, use common clinical features to subgroup patients with LBP and are purported to improve treatment outcomes. PURPOSE To assess if providing matched treatments based on patient-specific clinical features led to superior treatment outcomes compared with an unmatched treatment for subjects with chronic recurrent LBP. STUDY DESIGN This study is a randomized controlled trial. PATIENT SAMPLE Subjects (n=124) with LBP (≥12 months) with or without recurrences underwent a standardized clinical examination to group them into one of two strata: ineligible or eligible for stabilization exercises based on the Treatment-Based Classification schema. Subjects underwent additional clinical tests to assign them to one of the five possible Movement System Impairment categories. OUTCOME MEASURES Questionnaires were collected electronically at Week 0 (before treatment), Week 7 (after the 6-week 1-hour treatment sessions), and 12 months. Using the Oswestry disability index (0-100) and the Numeric Pain Rating Scale (0-10), the primary analysis was performed using the intention-to-treat principle. Secondary outcomes included fear-avoidance beliefs and psychosocial work-related and general health status. METHODS After subjects were categorized based on their particular clinical features using both the Treatment-Based Classification and Movement System Impairment schemas, they were randomized into one of two treatments using a 3:1 ratio for matched or unmatched treatments. The treatments were trunk stabilization exercise or Movement System Impairment-directed exercises. RESULTS Of the patients allocated to treatment for this study, 76 received a matched treatment and 25 received an unmatched treatment. After treatment, both groups showed a statistically significant improvement in the primary outcome measures and almost all the secondary measures; however, the matched treatment group did not demonstrate superior outcomes at Week 7 or 12 months, except on one of the secondary measures (Graded Chronic Pain Scale [Disability Scale]) (p=.01). CONCLUSIONS Providing a matched treatment based on either the Treatment-Based Classification or the Movement System Impairment classification schema did not improve treatment outcomes compared with an unmatched treatment for patients with chronic LBP, except on one secondary disability measure.

Tibial articular cartilage and meniscus geometries combine to influence female risk of anterior cruciate ligament injury

Tibial plateau subchondral bone geometry has been associated with the risk of sustaining a non‐contact ACL injury; however, little is known regarding the influence of the meniscus and articular cartilage interface geometry on risk. We hypothesized that geometries of the tibial plateau articular cartilage surface and meniscus were individually associated with the risk of non‐contact ACL injury. In addition, we hypothesized that the associations were independent of the underlying subchondral bone geometry. MRI scans were acquired on 88 subjects that suffered non‐contact ACL injuries (27 males, 61 females) and 88 matched control subjects that were selected from the injured subjects teammates and were thus matched on sex, sport, level of play, and exposure to risk of injury. Multivariate analysis of the female data revealed that increased posterior‐inferior directed slope of the middle articular cartilage region and decreased height of the posterior horn of the meniscus in the lateral compartment were associated with increased risk of sustaining a first time, non‐contact ACL injury, independent of each other and of the slope of the tibial plateau subchondral bone. No measures were independently related to risk of non‐contact ACL injury among males.

Individuals with Non-Specific Low Back Pain in an Active Episode Demonstrate Temporally Altered Torque Responses and Direction-Specific Enhanced Muscle Activity Following Unexpected Balance Perturbations

Individuals with a history of non-specific low back pain (LBP) while in a quiescent pain period demonstrate altered automatic postural responses (APRs) characterized by reduced trunk torque contributions and increased co-activation of trunk musculature. However, it is unknown whether these changes preceded or resulted from pain. To further delineate the relationship between cyclic pain recurrence and APRs, we quantified postural responses following multi-directional support surface translations, in individuals with non-specific LBP, following an active pain episode. Sixteen subjects with and 16 without LBP stood on two force plates that were translated unexpectedly in 12 directions. Net joint torques of the ankles, knees (sagittal only), hips, and trunk, in the frontal and sagittal planes, were quantified and the activation of 12 muscles of the lower limb unilaterally and the dorsal and ventral trunk, bilaterally, were recorded using surface electromyography (EMG). Peaks and latencies to peak joint torques, rates of torque development (slopes), and integrated EMGs characterizing baseline and active muscle contributions were analyzed for group by perturbation direction (torques) and group by perturbation by epoch interaction (EMG) effects. In general, the LBP cohort demonstrated APRs that were of similar torque magnitude and rate but peaked earlier compared to individuals without LBP. Individuals with LBP also demonstrated increased muscle activity following perturbation directions in which the muscle was acting as a prime mover and reduced muscle activity in opposing directions, proximally and distally, with some proximal asymmetries. These altered postural responses may reflect increased muscle spindle sensitivity. Given that these motor alterations are demonstrated proximally and distally, they likely reflect the influence of central nervous system processing in this cohort.

A decreased volume of the medial tibial spine is associated with an increased risk of suffering an anterior cruciate ligament injury for males but not females

Measurements of tibial plateau subchondral bone and articular cartilage slope have been associated with the risk of suffering anterior cruciate ligament (ACL) injury. Such single‐plane measures of the tibial plateau may not sufficiently characterize its complex, three‐dimensional geometry and how it relates to knee injury. Further, the tibial spines have not been studied in association with the risk of suffering a non‐contact ACL injury. We questioned whether the geometries of the tibial spines are associated with non‐contact ACL injury risk, and if this relationship is different for males and females. Bilateral MRI scans were acquired on 88 ACL‐injured subjects and 88 control subjects matched for sex, age and sports team. Medial and lateral tibial spine geometries were characterized with measurements of length, width, height, volume and anteroposterior location. Analyses of females revealed no associations between tibial spine geometry and risk of ACL injury. Analyses of males revealed that an increased medial tibial spine volume was associated with a decreased risk of ACL injury (OR = 0.667 per 100 mm3 increase). Smaller medial spines could provide less resistance to internal rotation and medial translation of the tibia relative to the femur, subsequently increasing ACL strains and risk of ACL injury.