What Went Wrong with VEGF-A in Peripheral Arterial Disease? A Systematic Review and Biological Insights on Future Therapeutics

BACKGROUND

Of the 200 million patients worldwide affected by peripheral arterial disease (PAD), 4% will inevitably require major limb amputation. Previous systematic reviews presented a conflicting body of evidence in terms of vascular endothelial growth factor (VEGF) family member effects upon PAD natural progression. Despite that, modulation of intrinsic angiogenesis mechanisms targeting the VEGF family members still confers an attractive therapeutic target. The aim of the present study was to evaluate current evidence of VEGF modulation in the context of PAD.

METHODS

This is a systematic literature review conducted according to the PRISMA guidelines and registered under PROSPERO database [CRD42021285988]. Independent literature search was performed up to April 1, 2022, on six databases. A total of 22 eligible studies were identified [N: 3, interventional patient studies; N: 19, animal studies]. Animal studies were appraised by the SYRCLE risk of bias tool, while human participant studies were assessed by the Newcastle Ottawa scale. Overall, quality of evidence was deemed fair for both animal and human studies. Main study outcomes were percentage change of injured vessel lumen stenosis and neointimal area formation upon VEGF modulation (inhibition or activation) in comparison with control group.

FINDINGS

Nineteen animal models and three human participant studies were included in the systematic review and assessed separately. Positive modulation of VEGF-A in animal models resulted in a median decrease of 65.58% [95% CI 45.2; 71.87] in lumen stenosis [14 studies]. Furthermore, positive modulation of VEGF-A was found to reduce neointimal area proliferation by a median decrease of 63.41% [95% CI 41.6; 79.59] [14 studies]. Median end of study duration was 28 days [range: 14-84 days]. Data were insufficient to assess these outcomes with respect to VEGF-B or VEGF-C modulation. The limited number of available human studies presented inadequate outcome assessment despite their overall fair NOS grading.

INTERPRETATION

VEGF-A-positive modulation decreases lumen stenosis and neointimal hyperplasia in PAD simulation animal models. Previously identified variability among outcomes was found to strongly stem from the variability of experimental designs. Clinical applicability and safety profile of VEGF-A in the context of PAD remain to be defined by a robust and uniformly designed body of further animal model-based experiments.

Follow-up study on symptom distress in esophageal cancer patients undergoing repeated dilation

BACKGROUND

Repeated endoscopic probe dilatation is the most preferred treatment for esophageal stenosis which may cause high levels of symptom distress in the patient's home rehabilitation stage.

AIM

To explore the changes in the symptom distress level and its correlation with the dilation effect in patients with esophageal carcinoma undergoing repeated dilations for lumen stenosis.

METHODS

The difference (R2-R1) between the diameter of the esophageal stenosis opening (R1) of the patients before dilation (R1) and after dilation (R2) was calculated to describe the extent and expansion of the esophageal stenosis before and after dilation. The M.D. Anderson Symptom Inventory was used to describe the symptom distress level of patients with dilation intermittence during their stay at home and to explore the correlation between the dilation effect and symptom distress level.

RESULTS

The diameter of the esophagus (R1) increased before each dilation in patients undergoing esophageal dilation (P < 0.05). The diameter (R2) increased after dilation (P < 0.05); the dilation effect (R2-R1) decreased with the number of dilations (P < 0.05). The total symptom distress score significantly increased with the number of dilations (P < 0.05). The symptom distress scores of the patients were negatively correlated (P < 0.05) with the previous dilation effect (R2-R1) and the esophageal diameter (R2) after the previous dilation. After the 1^st to 4^th dilations, the patient's symptom distress score was negatively correlated with the esophageal diameter (R12) before the next dilation, while there was no significant correlation (P > 0.05) with the other dilations.

CONCLUSION

In patients who have undergone repeated dilations, better effect stands for lower symptom distress level and the increase in symptom distress has a prompt effect on the severity of the next occurrence of restenosis.