Fetal musculoskeletal malformations with a poor outcome: ultrasonographic, pathologic, and radiographic findings

Tendon mechanical properties are enhanced via recombinant lysyl oxidase treatment

Tendon mechanical properties are significantly compromised in adult tendon injuries, tendon-related birth defects, and connective tissue disorders. Unfortunately, there currently is no effective treatment to restore native tendon mechanical properties after postnatal tendon injury or abnormal fetal development. Approaches to promote crosslinking of extracellular matrix components in tendon have been proposed to enhance insufficient mechanical properties of fibrotic tendon after healing. However, these crosslinking agents, which are not naturally present in the body, are associated with toxicity and significant reductions in metabolic activity at concentrations that enhance tendon mechanical properties. In contrast, we propose that an effective method to restore tendon mechanical properties would be to promote lysyl oxidase (LOX)-mediated collagen crosslinking in tendon during adult tissue healing or fetal tissue development. LOX is naturally occurring in the body, and we previously demonstrated LOX-mediated collagen crosslinking to be a critical regulator of tendon mechanical properties during new tissue formation. In this study, we examined the effects of recombinant LOX treatment on tendon at different stages of development. We found that recombinant LOX treatment significantly enhanced tensile and nanoscale tendon mechanical properties without affecting cell viability or collagen content, density, and maturity. Interestingly, both tendon elastic modulus and LOX-mediated collagen crosslink density plateaued at higher recombinant LOX concentrations, which may have been due to limited availability of adjacent lysine residues that are near enough to be crosslinked together. The plateau in crosslink density at higher concentrations of recombinant LOX treatments may have implications for preventing over-stiffening of tendon, though this requires further investigation. These findings demonstrate the exciting potential for a LOX-based therapeutic to enhance tendon mechanical properties via a naturally occurring crosslinking mechanism, which could have tremendous implications for an estimated 32 million acute and chronic tendon and ligament injuries each year in the U.S.

Anterior Abdominal Wall Defects, Diaphragmatic Hernia, and Other Major Congenital Malformations of the Musculoskeletal System in Barbados, 1993-2012

This study describes the prevalence and patterns of major congenital malformations of the musculoskeletal system and the resulting morbidity and mortality. It is a retrospective population-based study over the period 1993 to 2012. The overall prevalence of major congenital malformations of the musculoskeletal system was 9.02/10,000 live births. The prevalences of omphalocele, gastroschisis, and diaphragmatic hernia were 2.53, 2.22, and 1.42 per 10,000 live births, respectively. The case fatality ratio for the omphalocele, gastroschisis, and diaphragmatic hernia was 12.5, 28.5, and 67%, respectively. In conclusion, the prevalence rate of the major congenital malformations of the musculoskeletal system was higher than those reported in retrospective studies from other countries and remained static during the study period. These defects were associated with a high mortality rate and contributed significantly to the overall neonatal mortality in this country.

Thanatophoric dysplasia. Correlation among bone X-ray morphometry, histopathology, and gene analysis

OBJECTIVE

Documentation through X-ray morphometry and histology of the steady phenotype expressed by FGFR3 gene mutation and interpolation of mechanical factors on spine and long bones dysmorphism.

MATERIALS AND METHODS

Long bones and spine of eight thanatophoric dysplasia and three age-matched controls without skeletal dysplasia were studied after pregnancy termination between the 18th and the 22nd week with X-ray morphometry, histology, and molecular analysis. Statistical analysis with comparison between TD cases and controls and intraobserver/interobserver variation were applied to X-ray morphometric data.

RESULTS

Generalized shortening of long bones was observed in TD. A variable distribution of axial deformities was correlated with chondrocyte proliferation inhibition, defective seriate cell columns organization, and final formation of the primary metaphyseal trabeculae. The periosteal longitudinal growth was not equally inhibited, so that decoupling with the cartilage growth pattern produced the typical lateral spurs around the metaphyseal growth plates. In spine, platyspondyly was due to a reduced height of the vertebral body anterior ossification center, while its enlargement in the transversal plane was not restricted. The peculiar radiographic and histopathological features of TD bones support the hypothesis of interpolation of mechanical factors with FGFR3 gene mutations.

CONCLUSIONS

The correlated observations of X-ray morphometry, histopathology, and gene analysis prompted the following diagnostic workup for TD: (1) prenatal sonography suspicion of skeletal dysplasia; (2) post-mortem X-ray morphometry for provisional diagnosis; (3) confirmation by genetic tests (hot-spot exons 7, 10, 15, and 19 analysis with 80-90% sensibility); (4) in negative cases if histopathology confirms TD diagnosis, research of rare mutations through sequential analysis of FGFR3 gene.

Advances in evaluating the fetal skeleton

In this review, we discuss aspects of the prenatal diagnosis of fetal skeletal malformations, concentrating on the advantages offered by different imaging techniques and the approaches that are of value in evaluating a suspected skeletal dysplasia. We also briefly address the findings in some of the commoner malformations of the fetal skeleton that may be encountered.

Cranial vault defects: the description of three cases that illustrate a spectrum of anomalies

Three cases of cranial vault defects in fetuses are described. All 3 cases underwent postmortem examination, and in 2 of them postmortem magnetic resonance imaging was also performed. The phenotypical differences between the cases illustrate a spectrum of cranial vault defects, associated anomalies, and pathogenic mechanisms involved in the etiology of this rare malformation. All 3 cases were male, and the cranial vault defects corresponded to exencephaly with acrania/acalvaria caused by amniotic band syndrome, acalvaria, and acrania presenting in a chorangiopagus parasiticus twin.