Rib cartilage characterization in patients affected by pectus excavatum

Current Concepts in the Etiology and Pathogenesis of Pectus Excavatum in Humans-A Systematic Review

Pectus excavatum (PE) is the most common deformity of the chest wall and is characterized by the posterior depression of the sternum and the lower costal cartilages. To date, the etiology of PE in humans remains enigmatic. Several etiologic hypotheses have been proposed over the past two centuries. However, most of them have been scientifically dismissed and now have only historic value. In this systematic review, we assess scientific publications of the past two centuries addressing the issue of the origin of PE in humans. We present and discuss the histologic, genetic, biomechanical, and experimental scientific achievements that contributed to the clarification of its etiology and pathogenesis. With no clear consensus over the exact mechanism, most recent studies agree that the primordial defect leading the deformation of the anterior chest wall in PE is related to the costal hyaline cartilage structure and function. Further studies on this subject must be carried out. Genetic studies seem to be the most promising way to understand the exact mechanism of PE's origin and pathogenesis.

Costal cartilage overgrowth does not induce pectus‑like deformation in the chest wall of a rat model

Overgrowth of the costal cartilages has been frequently reported to be an etiological factor of chest wall deformities in children. The present study aimed to investigate if induced overgrowth of the costal cartilages could lead to deformation of the chest wall in a rat model. An insulin-like growth factor 1 (IGF1) solution was directly injected under the perichondrium of the last three costal cartilages of 2-week-old rat pups. Two different concentrations, 50 µg/ml (E50) and 100 µg/ml (E100), were applied. This procedure was repeated once per week for 5 consecutive weeks. Subsequently, 14 days after the last injection, all animals were euthanized before the shape of the thoracic cage was assessed, and the diameter was measured. In addition, the last three costal cartilages were dissected before the samples were prepared and examined by light microscopy. Rats that received E100 exhibited larger sagittal and coronal rib cage diameters compared with those in the E50 and control groups. However, no deformation could be observed in the chest wall. Microscopic examinations revealed an anabolic pattern in the E100 group. The present findings suggested that locally administered IGF1 stimulated cell proliferation and tissue growth in coastal cartilages in a dose-dependent manner in vivo. However, this induced overgrowth of the costal cartilages did not result in the deformation of the chest wall.

Comorbidity Networks in Cardiovascular Diseases

Background: Cardiovascular diseases are the leading causes of mortality worldwide. One reason behind this lethality lies in the fact that often cardiovascular illnesses develop into systemic failure due to the multiple connections to organismal metabolism. This in turn is associated with co-morbidities and multimorbidity. The prevalence of coexisting diseases and the relationship between the molecular origins adds to the complexity of the management of cardiovascular diseases and thus requires a profound knowledge of the genetic interaction of diseases. Objective: In order to develop a deeper understanding of this phenomenon, we examined the patterns of comorbidity as well as their genetic interaction of the diseases (or the lack of evidence of it) in a large set of cases diagnosed with cardiovascular conditions at the national reference hospital for cardiovascular diseases in Mexico. Methods: We performed a cross-sectional study of the National Institute of Cardiology. Socioeconomic information, principal diagnosis that led to the hospitalization and other conditions identified by an ICD-10 code were obtained for 34,099 discharged cases. With this information a cardiovascular comorbidity networks were built both for the full database and for ten 10-years age brackets. The associated cardiovascular comorbidities modules were found. Data mining was performed in the comprehensive ClinVar database with the disease names (as extracted from ICD-10 codes) to establish (when possible) connections between the genetic associations of the genetic interaction of diseases. The rationale is that some comorbidities may have a stronger genetic origin, whereas for others, the environment and other factors may be stronger. Results: We found that comorbidity networks are highly centralized in prevalent diseases, such as cardiac arrhythmias, heart failure, chronic kidney disease, hypertension, and ischemic diseases. Said comorbidity networks are actually modular on their connectivity. Modules recapitulate physiopathological commonalities, e.g., ischemic diseases clustering together. This is also the case of chronic systemic diseases, of congenital malformations and others. The genetic and environmental commonalities behind some of the relations in these modules were also found by resorting to clinical genetics databases and functional pathway enrichment studies. Conclusions: This methodology, hence may allow the clinician to look up for non-evident comorbidities whose knowledge will lead to improve therapeutically designs. By continued and consistent analysis of these types of patterns, we envisaged that it may be possible to acquire, strong clinical and basic insights that may further our advance toward a better understanding of cardiovascular diseases as a whole. Hopefully these may in turn lead to further development of better, integrated therapeutic strategies.

Autologous costal chondral transplantation and costa-derived chondrocyte implantation: emerging surgical techniques

It is a great challenge to cure symptomatic lesions and considerable defects of hyaline cartilage due to its complex structure and poor self-repair capacity. If left untreated, unmatured degeneration will cause significant complications. Surgical intervention to repair cartilage may prevent progressive joint degeneration. A series of surgical techniques, including biological augmentation, microfracture and bone marrow stimulation, autologous chondrocyte implantation (ACI), and allogenic and autogenic chondral/osteochondral transplantation, have been used for various indications. However, the limited repairing capacity and the potential pitfalls of these techniques cannot be ignored. Increasing evidence has shown promising outcomes from ACI and cartilage transplantation. Nevertheless, the morbidity of autologous donor sites and limited resource of allogeneic bone have considerably restricted the wide application of these surgical techniques. Costal cartilage, which preserves permanent chondrocytes and the natural osteochondral junction, is an ideal candidate for the restoration of cartilage defects. Several in vitro and in vivo studies have shown good performance of costal cartilage transplantation. Although costal cartilage is a classic donor in plastic and cosmetic surgery, it is rarely used in skeletal cartilage restoration. In this review, we introduce the fundamental properties of costal cartilage and summarize costa-derived chondrocyte implantation and costal chondral/osteochondral transplantation. We will also discuss the pitfalls and pearls of costal cartilage transplantation. Costal chondral/osteochondral transplantation and costa-based chondrocytotherapy might be up-and-coming surgical techniques for recalcitrant cartilage lesions.

Against the Overgrowth Hypothesis: Shorter Costal Cartilage Lengths in Pectus Excavatum

BACKGROUND

Pectus excavatum is a common chest wall deformity with no known cause. A common hypothesis is that in patients with pectus excavatum, there is an overgrowth of costal cartilage relative to healthy individuals.

MATERIALS AND METHODS

We obtained radiological curvilinear three-dimensional measurements of the fourth to eighth costal cartilage and associated ribs in 16 patients with pectus excavatum and 16 age- and gender-matched controls between the ages of 6 and 32 y. An analysis of variance was used to compare bone length, cartilage length, and their ratios between patients and controls.

RESULTS

Relative to bone length, patients with pectus excavatum overall had shorter costal cartilage lengths (P < 0.001), especially on the left side (P < 0.05). We were unable to localize this observation to specific ribs during post hoc analysis.

CONCLUSIONS

This is the first study to empirically test the overgrowth hypothesis of pectus excavatum for ribs 4 through 8. Although we and others have found no evidence to support this hypothesis, we surprisingly found the alternate hypothesis to be true: patients with pectus excavatum tend to have shorter costal cartilages. Future studies should expand on these results with larger sample sizes and consider volumetric measurements longitudinally during thoracic development.

[Costal cartilage structural and functional changes in children with a funnel or keeled chest]

Congenital chest wall deformities (CCWDs) in children are severe diseases leading to cosmetic defects and diseases of the respiratory and cardiovascular systems. The most common of these deformities are funnel-shaped (pectus excavatum, FD) and keeled (pectus carinatum, KD) ones. The pathogenesis of CCWDs and the role of costal cartilage structural and functional changes in their pathogenesis have now been not well studied, which makes it difficult to elaborate pathogenetic approaches to correcting these diseases. Analysis of the literature has shown that structural and functional changes occur in the matrix and chondrocytes from the costal cartilage in FD. Similar costal cartilage changes are observed in KD. It is still unknown exactly which pathological processes are present in the costal cartilage and how they result in the development of one or other type of CCWDs. The role of amianthoid transformation (AT) of costal cartilages in these processes is also unknown. It is not improbable that it is AT drastically changing the native cartilage matrix, which is one of the key mechanisms leading to changes in its properties and to the subsequent development of FD or KD.