Diabetic Covid-19 severity: Impaired glucose tolerance and pathologic bone loss.

Diabetes mellitus (DM), hypertension, and cardiovascular diseases (CVDs) are the leading chronic comorbidities that enhance the severity and mortality of COVID-19 cases. However, SARS-CoV-2 mediated deregulation of diabetes pathophysiology and comorbidity that links the skeletal bone loss remain unclear. We used both streptozocin-induced type 2 diabetes (T2DM) mouse and hACE2 transgenic mouse to enable SARS-CoV-2-receptor binding domain (RBD) mediated abnormal glucose metabolism and bone loss phenotype in mice.

Exercise-Linked Skeletal Irisin Ameliorates Diabetes-Associated Osteoporosis by Inhibiting the Oxidative Damage-Dependent miR-150-FNDC5/Pyroptosis Axis.

Recent evidence suggests that physical exercise (EX) promotes skeletal development. However, the impact of EX on the progression of bone loss and deterioration of mechanical strength in mice with type 2 diabetic mellitus (T2DM) remains unexplored. In the current study, we investigated the effect of EX on bone mass and mechanical quality using a diabetic mouse model.

Bicortical versus unicortical fixation of plated clavicular fractures: A biomechanical study.

Purpose: To compare the biomechanical properties of three plate stabilization techniques for midshaft clavicle fractures: anatomical bicortical locking construct, anatomical unicortical locking construct, and reconstruction bicortical locking construct.

Methods: We analyzed superior plating of the clavicle using an anatomical clavicle plate (Acumed) with both bicortical or unicortical screw fixation and a locking reconstruction plate (DePuy-Synthes). Twenty-one fourth generation composite clavicles were used for non-destructive stiffness testing in axial loading, bending, and torsion.

In Vitro Comparison between the Pulvertaft Weave and the Modified Core Suture Pulvertaft Weave.

The Pulvertaft weave was described more than 50 years ago and is still used in tendon transfers. The aim of this study was to evaluate the strength of a modified core suture Pulvertaft weave technique and compare it to the original Pulvertaft weave traditionally used in tendon transfer surgery. 12 extensor pollicis longus tendons and extensor indices proprius tendons were harvested from fresh frozen cadavers.

Probiotics Stimulate Bone Formation in Obese Mice via Histone Methylations.

Manipulation of the gut microbiome can prevent pathologic bone loss. However, the effects of probiotics on mitochondrial epigenetic remodeling and skeletal homeostasis in the high-fat diet (HFD)-linked obesity remains to be explored. Here, we examined the impact of probiotics supplementation on mitochondrial biogenesis and bone homeostasis through the histone methylation mechanism in HFD fed obese mice.

Exosomal lncRNA-H19 promotes osteogenesis and angiogenesis through mediating Angpt1/Tie2-NO signaling in CBS-heterozygous mice.

Emerging evidence indicates that the growth of blood vessels and osteogenesis is tightly coordinated during bone development. However, the molecular regulators of intercellular communication in the bone microenvironment are not well studied. Therefore, we aim to investigate whether BMMSC-Exo promotes osteogenesis and angiogenesis via transporting lnc-H19 in the CBS- heterozygous mouse model.

Dual pitch screw design provides equivalent fixation to upsized screw diameter in revision pedicle screw instrumentation: a cadaveric biomechanical study.

Background Context: There are situations that require the replacement of pedicle screws. They are often exchanged when loose or broken or to accommodate a different sized rod or pedicle screw system. Traditionally, pedicle screws are replaced by up-sizing the core diameter until an interference fit is obtained.

A consideration of factors affecting palliative oral appliance effectiveness for obstructive sleep apnea: a scoping review.

Study Objectives: This scoping review allows physicians, researchers, and others interested in obstructive sleep apnea to consider effectiveness of oral appliances (OAs). The intent is to improve understanding of OA effectiveness by considering morphologic interaction in patients with obstructive sleep apnea.

Methods: Morphologic and biomechanical criteria for positional alterations of the mandible assessed success rates of OA appliances.

Headless Compression Screw Fixation for Proximal Phalanx Fractures: A Biomechanical Study.

Proximal phalanx fractures are common injuries of the hand with multiple treatment options. Intramedullary (IM) screw fixation has become more widely used, and early outcomes are promising. However, biomechanical data regarding this type of fixation are sparse.

Biomechanics of the Injured Fibula Following Plate Fixation of a Concomitant Tibia Fracture To Fix or Not to Fix?

Background: The mechanical role of supplemental fibula fixation in both bone lower leg fractures is not well defined. The benefit of fibula plate fixation in this context is controversial. The purpose of this study was to ascertain the mechanical contributions of the fibula under three conditions (intact, fractured, or plated fibula) following standard tibia locked plating.

Hydrogen Sulfide Promotes Bone Homeostasis by Balancing Inflammatory Cytokine Signaling in CBS-Deficient Mice through an Epigenetic Mechanism.

Previously, we have shown hyperhomocysteinemia (HHcy) to have a detrimental effect on bone remodeling, which is associated with osteoporosis. During transsulfuration, Hcy is metabolized into hydrogen sulfide (HS), a gasotransmitter molecule known to regulate bone formation. Therefore, in the present study, we examined whether HS ameliorates HHcy induced epigenetic and molecular alterations leading to osteoporotic bone loss.

Musculoskeletal Outcomes from Chronic High-Speed, High-Impulse Resistance Exercise.

While bones and muscles adapt to mechanical loading, it appears that very specific types of stimuli must be applied to achieve osteogenesis. Our study assessed musculoskeletal outcomes to 30 training sessions on an Inertial Exercise Trainer (Newnan, GA). Subjects (n=13) performed workouts with their left leg, while their right served as an untreated control.

Hydrogen sulfide epigenetically mitigates bone loss through OPG/RANKL regulation during hyperhomocysteinemia in mice.

Hydrogen sulfide (HS) is a novel gasotransmitter produced endogenously in mammalian cells, which works by mediating diverse physiological functions. An imbalance in HS metabolism is associated with defective bone homeostasis. However, it is unknown whether HS plays any epigenetic role in bone loss induced by hyperhomocysteinemia (HHcy).

Inhibition of CaMKK2 Enhances Fracture Healing by Stimulating Indian Hedgehog Signaling and Accelerating Endochondral Ossification.

Approximately 10% of all bone fractures do not heal, resulting in patient morbidity and healthcare costs. However, no pharmacological treatments are currently available to promote efficient bone healing. Inhibition of Ca /calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) reverses age-associated loss of trabecular and cortical bone volume and strength in mice.

Assessment of Distal Radioulnar Joint Stability After Reconstruction With the Brachioradialis Wrap.

Background: The brachioradialis (BR) wrap technique is an option to restore the stability of the distal radioulnar joint (DRUJ). The technique capitalizes on the BR's advantageous insertion point on the radial styloid and the ability of the BR to be harvested with minimal to no deficit. The tendon can then be wrapped around the radius and ulna, tunneling under the pronator quadratus and extensor compartments and secured back into its insertion to provide stability.

Optimal radial force and size for palliation in gastroesophageal adenocarcinoma: a comparative analysis of current stent technology.

Background: The optimal use of esophageal stents for malignant and benign esophageal strictures continues to be plagued with variability in pain tolerance, migration rates, and reflux-related symptoms. The aim of this study was to evaluate the differences in radial force exhibited by a variety of esophageal stents with respect to the patient's esophageal stricture.

Methods: Radial force testing was performed on eight stents manufactured by four different companies using a hydraulic press and a 5000 N force gage.

Micro-computed tomography assisted distal femur metaphyseal blunt punch compression for determining trabecular bone strength in mice.

Shorter generation time and the power of genetic manipulation make mice an ideal model system to study bone biology as well as bone diseases. However their small size presents a challenge to perform strength measurements, particularly of the weight-bearing cancellous bone in the murine long bones. We recently developed an improved method to measure the axial compressive strength of the cancellous bone in the distal femur metaphysis in mice.

Polyaxial Screws in Locked Plating of Tibial Pilon Fractures.

This study examined the axial and torsional stiffness of polyaxial locked plating techniques compared with fixed-angle locked plating techniques in a distal tibia pilon fracture model. The effect of using a polyaxial screw to cross the fracture site was examined to determine its ability to control relative fracture site motion. A laboratory experiment was performed to investigate the biomechanical stiffness of distal tibia fracture models repaired with 3.

Inhibition of CaMKK2 reverses age-associated decline in bone mass.

Decline in bone formation is a major contributing factor to the loss of bone mass associated with aging. We previously showed that the genetic ablation of the tissue-restricted and multifunctional Ca(2+)/calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) stimulates trabecular bone mass accrual, mainly by promoting anabolic pathways and inhibiting catabolic pathways of bone remodeling. In this study, we investigated whether inhibition of this kinase using its selective cell-permeable inhibitor STO-609 will stimulate bone formation in 32 week old male WT mice and reverse age-associated of decline in bone volume and strength.

Mitochondrial epigenetics in bone remodeling during hyperhomocysteinemia.

Increased levels of homocysteine (Hcy), known as hyperhomocysteinemia (HHcy), is an independent risk factor of various diseases. Clinical studies report that people born with severe HHcy develop skeletal malformations with weaker bone. Studies also report that altered mitochondrial dynamics and altered epigenetics contribute to weaker bones and bone diseases.

The role of homocysteine in bone remodeling.

Bone remodeling is a very complex process. Homocysteine (Hcy) is known to modulate this process via several known mechanisms such as increase in osteoclast activity, decrease in osteoblast activity and direct action of Hcy on bone matrix. Evidence from previous studies further support a detrimental effect on bone via decrease in bone blood flow and an increase in matrix metalloproteinases (MMPs) that degrade extracellular bone matrix.

Inhibition of Ca²⁺/calmodulin-dependent protein kinase kinase 2 stimulates osteoblast formation and inhibits osteoclast differentiation.

Bone remodeling, a physiological process characterized by bone formation by osteoblasts (OBs) and resorption of preexisting bone matrix by osteoclasts (OCs), is vital for the maintenance of healthy bone tissue in adult humans. Imbalances in this vital process result in pathological conditions including osteoporosis. Owing to its initial asymptomatic nature, osteoporosis is often detected only after the patient has sustained significant bone loss or a fracture.

Bone loss following spinal cord injury in a rat model.

The current study was undertaken to follow the time course of bone loss in the proximal tibia of rats over several weeks following thoracic contusion spinal cord injury (SCI) of varying severity. It was hypothesized that bone loss would be more pronounced in the more severely injured animals, and that hindlimb weight bearing would help prevent bone loss. Twenty-six female Sprague-Dawley rats (200-225 g, 6-7 weeks old) received standard thoracic (T9) injuries at energies of 6.

Xenograft bone inclusion improves incorporation of hydroxyapatite cement into cancellous defects.

Objectives: Hydroxyapatite cement (HAC) is biocompatible and osteoconductive, but its slow resorption limits new bone formation. The purpose of this investigation was to determine the effects of adding partially demineralized xenograft cortical bone in an established animal model.

Methods: Eight 6-month-old female New Zealand white rabbits were used.