Epigenetic memory of coronavirus infection in innate immune cells and their progenitors

Inflammation can trigger lasting phenotypes in immune and non-immune cells. Whether and how human infections and associated inflammation can form innate immune memory in hematopoietic stem and progenitor cells (HSPC) has remained unclear. We found that circulating HSPC, enriched from peripheral blood, captured the diversity of bone marrow HSPC, enabling investigation of their epigenomic reprogramming following coronavirus disease 2019 (COVID-19). Alterations in innate immune phenotypes and epigenetic programs of HSPC persisted for months to 1 year following severe COVID-19 and were associated with distinct transcription factor (TF) activities, altered regulation of inflammatory programs, and durable increases in myelopoiesis. HSPC epigenomic alterations were conveyed, through differentiation, to progeny innate immune cells. Early activity of IL-6 contributed to these persistent phenotypes in human COVID-19 and a mouse coronavirus infection model. Epigenetic reprogramming of HSPC may underlie altered immune function following infection and be broadly relevant, especially for millions of COVID-19 survivors.

Putting It All Together: Clinical Considerations in the Care of Critically Ill Obstetric Patients with COVID-19

Pregnant patients with severe acute respiratory syndrome coronavirus 2, the virus responsible for the clinical condition newly described in 2019 as coronavirus disease 2019 (COVID-19) and illness severity to warrant intensive care have a complex disease process that must involve multiple disciplines. Guidelines from various clinical societies, along with direction from local health authorities, must be considered when approaching the care of an obstetric patient with known or suspected COVID-19. With a rapidly changing landscape, a simplified and cohesive perspective using guidance from different clinical society recommendations regarding the critically-ill obstetric patient with COVID-19 is needed. In this article, we synthesize various high-level guidelines of clinical relevance in the management of pregnant patients with severe disease or critical illness due to COVID-19. KEY POINTS: · When caring for severely ill obstetric patients with COVID-19, one must be well versed in the complications that may need to be managed including, but not limited to adult respiratory distress syndrome with need for mechanical ventilation, approach to refractory hypoxemia, hemodynamic shock, and multiorgan system failure.. · Prone positioning can be done safely in gravid patients but requires key areas of support to avoid abdominal compression.. · For the critically ill obstetric patient with COVID-19, the focus should be on supportive care as a bridge to recovery rather than delivery as a solution to recovery..

Relationships between results of the Ortolani method of hip joint palpation and distraction index, Norberg angle, and hip score in dogs

OBJECTIVE

To determine whether results of the Ortolani method of hip joint palpation in dogs were related to distraction index (DI), Norberg angle, or radiographic hip score.

DESIGN

Cross-sectional study.

ANIMALS

459 clinically normal dogs.

PROCEDURE

Dogs were sedated for radiography and palpation of the hip joints. Results of hip joint palpation were classified as negative, mild positive, moderate positive, or severe positive. Distraction indices were measured for all dogs. Norberg angles were measured for 380 dogs for which ventrodorsal hip-extended radiographic projections were available. Hip scores assigned by the Orthopedic Foundation for Animals (OFA) were available for 95 dogs.

RESULTS

Age, weight, and sex were not significantly associated with results of hip joint palpation. There was moderate correlation between results of hip joint palpation and DI (r = 0.636), low-moderate correlation between results of hip joint palpation and OFA hip scores (rs = 0.437), and weak negative correlation (r = -0.236) between results of hip joint palpation and Norberg angle. For joints without degenerative joint disease (DJD), there was a significant linear relationship between results of hip palpation and DI; however, for joint with DJD, there was not. Results of hip joint palpation were 5.3-fold as likely to be negative for dogs with DJD as for dogs without.

CLINICAL IMPLICATIONS

Results of hip joint palpation were at best moderately correlated with radiographic measures of hip joint laxity. Therefore, hip joint palpation should be combined with hip-extended and stress radiography when assessing hip joint quality.

Correlation between longitudinal bone growth, growth hormone, and insulin-like growth factor-I in prepubertal dogs

OBJECTIVE

To determine the association between longitudinal bone growth and concentrations of growth hormone (GH) and insulin-like growth factor-I (IGF-I) in serum from prepubertal dogs. Animals-6 male 14-week-old German Shepherd Dogs.

PROCEDURE

Blood was obtained every 30 minutes for 14 consecutive days. Concentrations of GH and IGF-I in serum were determined, using a canine-specific radioimmunoassay and conventional radioimmunoassay after acid-ethanol extraction, respectively. Simultaneous biplanar radiography was performed daily to measure bone growth. Spectral analysis was used to estimate specific features of GH secretion during an extended period. Multiple linear regression with different lag times between independent and dependent variables was used to determine the strongest predictors of bone growth.

RESULTS

The power spectra of GH concentrations in serum had a primary peak at a frequency of 0.02 cycles/h or a periodicity of 50 h/cycle. A significant determinant of longitudinal bone growth was a lag time of 1 day in concentration of GH in serum. The relationship between IGF-I concentration in serum and bone growth was not significant.

CONCLUSIONS

The primary frequency of GH secretion is outside the time frame of a single day and the concentration of GH in serum is a primary determinant of bone growth.

CLINICAL RELEVANCE

A better understanding of the components of bone growth provide discernment to improved diagnosis and treatment of abnormal bone growth.

Relationship between degenerative joint disease and hip joint laxity by use of distraction index and Norberg angle measurement in a group of cats

OBJECTIVE

To determine the relationship between degenerative joint disease (DJD) and passive laxity of the hip joint in a group of cats.

DESIGN

Prospective study.

ANIMALS

A select (nonrandomized) group of 78 cats.

PROCEDURE

Standard hip-extended radiographic views and compression and distraction views of the pelvis were obtained from cats during sedation. Radiographs were evaluated, using an Orthopedic Foundation for Animals (OFA)-like scoring system for dogs. Passive joint laxity was measured, using Norberg angle (NA) and distraction index (DI). Hip laxity in cats with DJD was compared with hip laxity in cats without DJD.

RESULTS

Hip dysplasia (HD) was subjectively diagnosed radiographically in 25 of 78 (32%) cats using the OFA-like scoring system. Nineteen cats had mild HD 4 had moderate HD, and 2 had severe HD. Fifteen of the 25 cats with HD had DJD. The NA ranged from 56 to 105. The mean NA in cats with DJD was (84 degrees) significantly lower than in cats without DJD (95 degrees). The DI ranged from 0.2 to 0.84. The mean DI for cats with DJD was (0.6) significantly higher than that for cats without DJD (0.49). Cats with a DI < 0.4 did not have DJD. Cats had an increased likelihood of having DJD with increased laxity in the coxofemoral joint, as measured by NA or DI.

CLINICAL IMPLICATIONS

The mean NA for radiographically normal cats (92.4 degrees) was lower than that in radiographically normal dogs (103 degrees). The overall mean DI for cats in this group (0.51) is similar to dogs of breeds with high joint laxity, such as the Labrador Retriever (0.5). As in dogs, there is a relationship between DJD and laxity in the hip joint of cats.

Within- and between-examiner repeatability of distraction indices of the hip joints in dogs

OBJECTIVE

To evaluate in vivo repeatability of the distraction index method of evaluating hip joint laxity in dogs.

ANIMALS

31 two-year-old Labrador Retrievers.

PROCEDURE

Each dog was anesthetized and radiographically evaluated for hip joint laxity 4 times: twice by an experienced examiner and twice by an examiner who had no previous knowledge of or training in the technique prior to the first day of testing. Distraction indices (DI) were determined from the radiographs and intraclass correlation coefficients were calculated to evaluate the repeatability of DI measurements between and within examiners.

RESULTS

Intraclass correlation coefficients were high (range, 0.85 to 0.94). Lower limits of the 95% confidence intervals for the intraclass correlation coefficients ranged from 0.75 to 0.89.

CONCLUSIONS

Between- and within-examiner repeatabilities of DI measurements were high, suggesting that the technique is clinically reliable.

CLINICAL RELEVANCE

Distraction index is a reliable measure of hip joint laxity and a good predictor of the risk of development of degenerative joint disease associated with hip dysplasia in dogs. Establishment of high repeatability of DI measurements suggests that the stress-radiographic method may be used by multiple examiners with the expectation of comparable and consistent results.

Biomechanical characterization of passive laxity of the hip joint in dogs

OBJECTIVE

To investigate the in vitro load/displacement characteristics of the hip joints in dogs as a function of joint position.

SAMPLE POPULATION

10 hip joints from 5 healthy dogs.

PROCEDURE

A material test system was used to generate load/displacement curves for each joint. Joints were mounted in a custom-designed jig that held the joint in fixed anatomic orientations while plotting displacement and corresponding applied loads. All hips were cycled between 40 N of compression and 80 N of distraction. Each hip was tested at 10 degrees increments from 30 degrees flexion to 70 degrees extension.

RESULTS

When the hips were in a neutral orientation (approximately a standing position), load/displacement curves were characteristically sigmoidal (tri-phasic), indicating that, in this position, displacement was not highly dependent on load. The curves had a central low-stiffness region in which most of the lateral displacement took place. In contrast, when hips were positioned at the extremes of flexion and extension, this central, low-stiffness region was less distinct, and load/displacement curves were more linear, indicating a proportional relation between load and displacement. The load/displacement curve of 1 hip joint in the study deviated markedly from the others in a pattern consistent with cavitation of the synovial fluid.

CONCLUSIONS

When the hip joint is positioned in a neutral position, load-displacement behavior is sigmoidal, whereas when the hip joint is in an extended position, load/displacement behavior is more linear.

CLINICAL RELEVANCE

Establishing load/displacement behavior of the hip joints in dogs was an important exercise in establishing the position for and estimating the repeatability of a clinical stress-radiographic method for quantitating joint laxity in dogs.

Synovial fluid cavitation during distraction radiography of the coxofemoral joint in dogs

OBJECTIVE

To determine risk factors for, and prevalence and short- and long-term effects of synovial fluid cavitation during distraction radiography.

DESIGN

Multicenter prevalence survey.

ANIMALS

6,649 purebred dogs comprising 129 breeds.

PROCEDURE

Radiographs from the PennHIP (University of Pennsylvania Hip Improvement Program) Laboratory were subjectively evaluated for evidence of cavitation. Multiple logistic regression was used to determine whether sex, breed, age, weight, distraction index (DI), or examining veterinarian was associated with cavitation. Short-term effects of cavitation were assessed by comparing DI for the hip with cavitation with DI for the contralateral hip in dogs with unilateral cavitation. Long-term effects of cavitation were assessed by comparing DI before and after cavitation was detected.

RESULTS

Cavitation was detected in 279 (4.2%) of the radiographs analyzed. Male dogs, Golden Retrievers, and heavier dogs were at a decreased risk for cavitation. Irish Wolfhounds, Irish Setters, Rhodesian Ridgebacks, and Weimaraners had an increased risk for cavitation. Age and DI were not risk factors for cavitation. Mean DI was 0.08 greater in hips with cavitation than in paired hips without cavitation. Significant differences were not detected between DI before and after cavitation, but only 7 dogs were included in this analysis.

CLINICAL IMPLICATIONS

Cavitation is rare during distraction radiography and can increase measured DI. Radiographs should be routinely examined to ensure accurate reporting of DI.