Age-related macular degeneration and myeloproliferative neoplasms - A common pathway

The effect of polycythemia vera on choroidal thickness and retrobulbar blood flow

BACKGROUND

To evaluate the choroidal thickness and retrobulbar hemodynamic parameters in polycythemia vera (PV) patients in comparison with healthy individuals, and to investigate the relationship of these values with blood hematocrit levels.

METHODS

This prospective study included the 35 eyes of 35 PV patients and the 30 eyes of 30 healthy individuals. Choroidal thickness was measured at the subfoveal area and at 500 µm intervals nasal and temporal to the fovea up to a distance of 1500 µm. Color Doppler ultrasonography (CDU) was used to evaluate the retrobulbar vessels. Complete blood count values were recorded.

RESULTS

Choroidal thickness was found to be significantly lower in the PV group than in the control group at the subfoveal, nasal 500, and temporal 500 and 1000 µm measurement points (p = 0.01, p = 0.011, p = 0.04, p = 0.045, respectively). The central retinal artery (CRA) peak systolic velocity (PSV) and end diastolic velocity (EDV) values and the ophthalmic artery (OA) PSV value were significantly lower in the PV group than in the control group (p < 0.001, p < 0.001, p = 0.019, respectively). No significant difference was present between the groups in terms of CRA and OA resistive index (RI) and pulsatile index (PI) values (p = 0.388, p = 0.564, p = 0.897, p = 0.693, respectively). A negative correlation was found between the blood hematocrit levels and the subfoveal, nasal 500 µm, and temporal 500 µm choroidal thickness measurements and the CRA PSV and EDV and the OA PSV values.

CONCLUSIONS

PV may cause microvascular changes and lead to ocular vascular complications by affecting the choroidal and retrobulbar blood flow.

Revisiting Circulating Extracellular Matrix Fragments as Disease Markers in Myelofibrosis and Related Neoplasms

Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years from the earliest cancer stages (essential thrombocythemia, polycythemia vera) towards the advanced myelofibrosis stage with bone marrow failure. The JAK2V617F mutation is the most prevalent driver mutation. Chronic inflammation is considered to be a major pathogenetic player, both as a trigger of MPN development and as a driver of disease progression. Chronic inflammation in MPNs is characterized by persistent connective tissue remodeling, which leads to organ dysfunction and ultimately, organ failure, due to excessive accumulation of extracellular matrix (ECM). Considering that MPNs are acquired clonal stem cell diseases developing in an inflammatory microenvironment in which the hematopoietic cell populations are progressively replaced by stromal proliferation-"a wound that never heals"-we herein aim to provide a comprehensive review of previous promising research in the field of circulating ECM fragments in the diagnosis, treatment and monitoring of MPNs. We address the rationales and highlight new perspectives for the use of circulating ECM protein fragments as biologically plausible, noninvasive disease markers in the management of MPNs.