What is the rationale for mesenchymal stromal cells based therapies in the management of hemophilic arthropathies?

Hemophilia A and B are rare X-linked genetic bleeding disorders due to a complete or partial deficiency in the coagulation factors VIII or IX, respectively. The main treatment for hemophilia is prophylactic and based on coagulation factor replacement therapies. These treatments have significantly reduced bleeding and improved the patients' quality of life. Nevertheless, repeated joint bleedings (hemarthroses), even subclinical hemarthroses, can lead to hemophilic arthropathy (HA). This disabling condition is characterized by chronic pain due to synovial inflammation, cartilage and bone destruction requiring ultimately joint replacement. HA resembles to rheumatoid arthritis because of synovitis but HA is considered as having similarities with osteoarthritis as illustrated by the migration of immune cells, production of inflammatory cytokines, synovial hypertrophy and cartilage damage. Various drugs have been evaluated for the management of HA with limited success. The objective of the review is to discuss new therapeutic approaches with a special focus on the studies that have investigated the potential of using mesenchymal stromal cells (MSCs) in the management of HA. A systematic review of the literature has been made. Most of the studies have focused on the interest of MSCs for the delivery of missing factors VIII or IX but in some studies, more insight on the effect of MSC injection on synovial inflammation or cartilage structure were provided and put in perspective for possible clinical applications.

Gingival bleeding is a useful clinical feature in the diagnosis of hereditary bleeding disorders in children.

The search for hereditary bleeding disorders (HBD) prior to invasive procedures in children is primarily based on personal and family bleeding history. Although several scores are available, they have only been evaluated in specific situations or in adults. Our monocentric retrospective study aimed to analyze the association between clinical history and four scores (HEMSTOP, PBQ, ISTH-BAT, TOSETTO) and the diagnosis of MHC in children referred to the University Hospital of Montpellier for hemostasis investigations. A total of 117 children were retrospectively included in the study. Of these, 57 (49%) were diagnosed with HBD, with 30 having primary bleeding disorders and 27 having coagulation disorders. The diagnosis of HBD was significantly associated with gingival bleeding, which was present in 30% of HBD patients. In our population, only the HEMSTOP score showed an association with the diagnosis of HBD, but it was positive in only 48% of patients. By including gingival bleeding as a factor, we modified the HEMSTOP score, which increased its sensitivity from 0.45 to 0.53. When examining primary bleeding disorders, the modified HEMSTOP score, with the inclusion of gingival bleeding, enables us to diagnose 63% of patients (see Fig. 1).    Conclusion: Therefore, gingival bleeding should be considered a useful factor in bleeding history for HBD diagnosis. Adding this symptom to a screening score such as HEMSTOP improves its sensitivity. To confirm our findings, a prospective study is required.    Trial registration: Study registration number: NCT05214300. What is Known: • Screening for hereditary bleeding disorder diseases is a necessity and a challenge in children. • Minor disorders of primary hemostasis are the most common, but often escape standard coagulation tests. What is New: • Gingival bleeding is a frequent symptom that is easy to investigate and may point to a primary hemostasis disorder. • Adding the gingival bleeding item to a routine screening score such as HEMSTOP improves sensitivity.

Bleeding risk in hemophilia A and B carriers: comparison of factor levels determined using chronometric and chromogenic assays.

BACKGROUND: Predicting the bleeding risk in hemophilia A and B carriers (HAC, HBC) is challenging. OBJECTIVE: The objectives of this study were to describe the bleeding phenotype in HAC and HBC using the standardized Tosetto bleeding score (BS); to determine whether the BS correlates better with factor levels measured with a chromogenic assay than with factor levels measured with chronometric and thrombin generation assays; and to compare the results in HAC and HBC. METHODS: This ambispective, noninterventional study included obligate and sporadic HAC and HBC followed at a hemophilia treatment center between 1995 and 2019. RESULTS AND CONCLUSION: The median BS (3, range 0-21 vs. 3.5, range 0-15, P  = ns, respectively) and the abnormal BS rate (35.6% vs. 38.2%, P  = ns) were not significantly different in 104 HAC and 34 HBC (mean age: 38 years, 6-80 years). However, some differences were identified. The risk of factor deficiency was higher in HBC than HAC. Specifically, Factor VIII activity (FVIII):C/Factor IX activity (FIX):C level was low (<40 IU/dl) in 18.3% (chronometric assay) and 17.5% (chromogenic assay) of HAC and in 47% and 72.2% of HBC ( P  < 0.001). Moreover, the FIX:C level thresholds of 39.5 IU/dl (chronometric assay) and of 33.5 IU/dl (chromogenic assay) were associated with very good sensitivity (92% and 100%, respectively) and specificity (80% for both) for bleeding risk prediction in HBC. Conversely, no FVIII:C level threshold could be identified for HAC, probably due to FVIII:C level variations throughout life.