Pulmonary arterial hypertension in systemic sclerosis is associated with profound impairment of microvascular endothelium-dependent vasodilatation

Vascular endothelial injury assessed with functional techniques in systemic sclerosis patients with pulmonary arterial hypertension versus systemic sclerosis patients without pulmonary arterial hypertension: a systematic review and meta-analysis

Microvascular dysfunction is one of the hallmarks of systemic sclerosis (SSc). The presence of pulmonary-arterial-hypertension (PAH) in SSc-patients is associated with poor prognosis. This is a systematic review and meta-analysis of studies assessing microvascular and endothelial injury with functional techniques in SSc-patients with PAH (SSc-PAH) compared to those without PAH (SSc-non-PAH) (PROSPERO: CRD42021236212). Literature search involved PubMed, the-Cochrane-Library, Web-of-Science, Scopus and manual search of article references. Studies assessing microvascular function by all available functional methods were considered eligible. Preclinical studies and studies using structural nailfold-videocapillaroscopy or biomarkers were excluded. Newcastle-Ottawa-Scale (NOS) was applied to evaluate the quality of retrieved studies. From a total of 602 retrieved articles, four studies (n = 159 participants) were included in meta-analysis; three studies were of high quality (NOS ≥ 7). In pooled analysis, a marginally significant impaired microvascular function was observed in SSc-PAH compared to SSc-non-PAH patients [SMD - 0.71, 95% CI (- 1.53, 0.12)], with significant between-study heterogeneity (I² = 80%, p = 0.002). Among the studies examining endothelium-dependent and -independent vasodilation with LDF-iontophoresis, SSc-PAH subjects had significantly impaired endothelium-dependent-vasodilation [Ach-stimulated %change WMD - 216.79, 95% CI (- 337.87, - 95.71), I² = 0%, p = 0.40], but no significant differences in endothelium-independent-vasodilation [SNP-stimulated %change WMD 90.84, 95% CI (- 82.52, 264.19), I² = 44%, p = 0.18] compared with SSc-non-PAH subjects. In sensitivity analysis including only studies where SSc-PAH patients were diagnosed by right-heart-catheterization, a borderline difference between the two groups was noted [SMD - 1.09, 95% CI (- 2.30, 0.13), I² = 82%, p = 0.004]. SSc-PAH patients showed marginally impaired microvascular function in the pooled analysis, as well as impaired endothelium-dependent-vasodilation in subgroup analysis compared with SSc-non-PAH patients. Vascular endothelial dysfunction could be involved in high cardiovascular risk of patients with SSc and PAH.

The emerging application of semi-quantitative and quantitative capillaroscopy in systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease with high morbidity and mortality, characterized by autoimmunity, obliterative vasculopathy involving mainly the microvasculature, and fibrosis. SSc-specific nailfold capillaroscopic changes have been defined, and nailfold capillaroscopy (NFC) is now unequivocally accepted to be a cornerstone for the early diagnosis of SSc. However, the use of NFC in patients already diagnosed with SSc is still not standardized. Several studies have shown that NFC abnormalities correlate with disease activity and severity and are predictive for disease worsening, such as occurrence of new digital ulcers. More importantly, successful treatment has been shown to diminish NFC abnormalities in severe SSc cases. These findings support the importance of NFC in monitoring patients with SSc and even its role as an outcome measure in SSc clinical trials. It is a matter of debate if Semi-quantitative and Quantitative NFC would be a more sensitive tool than qualitative NFC for meeting these objectives. This review is presenting the emerging application of Semi-quantitative and Quantitative NFC in SSc and its potential benefits.

Relationships Between Type 2 Diabetes, Neuropathy, and Microvascular Dysfunction: Evidence From Patients With Cryptogenic Axonal Polyneuropathy

OBJECTIVE

This study investigated whether the relationship between neuropathy and microvascular dysfunction in patients with type 2 diabetes is independent of diabetes-related factors. For this purpose, we compared skin microvascular function in patients with type 2 diabetes with that of patients with cryptogenic axonal polyneuropathy (CAP), a polyneuropathy of unknown etiology.

RESEARCH DESIGN AND METHODS

Cross-sectional information was collected from 16 healthy controls (HCs), 16 patients with CAP, 15 patients with type 2 diabetes with polyneuropathy (DPN), and 11 patients with type 2 diabetes without polyneuropathy. Axonal degeneration was assessed with skin biopsy and nerve conduction studies. Microvascular skin vasodilation was measured using laser Doppler fluxmetry combined with iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP).

RESULTS

Patients with CAP and DPN demonstrated a similar decrease in intraepidermal nerve fiber density and sural sensory nerve action potential compared with HCs. The vasodilator response to ACh was similar among patients with CAP (relative mean difference based on log values 13.3%; 95% CI -35.0 to 97.7%; P = 0.652) but was lower in the patients with diabetes with neuropathy (157.5%; 42.0-366.7%; P = 0.003) and without neuropathy (174.2%; 44.2-421.3%; P = 0.003) compared with HCs. No significant differences were found between the groups of patients with diabetes (P = 0.845). The vasodilator response to SNP was not significantly different among the groups (P = 0.082).

CONCLUSIONS

In this study, endothelium-dependent vasodilation was reduced in patients with type 2 diabetes regardless of the presence of polyneuropathy, whereas microvascular vasodilation was normal in patients with CAP. These data suggest that in type 2 diabetes, neuropathy does not contribute to impaired microvascular endothelium-dependent vasodilation and vice versa. In addition, this study suggests that impaired microvascular vasodilation does not contribute to CAP.

Methods for the morphological and functional evaluation of microvascular damage in systemic sclerosis

Systemic sclerosis is a connective tissue disease characterized by alterations in microvascular structure and function. In these patients, numerous studies have demonstrated a relationship between capillary morphology and peripheral blood perfusion. Nailfold videocapillaroscopy reveals the peripheral microvascular morphology and thus allows classification and scoring of capillary abnormalities with respect to different microangiopathy patterns (early, active, and late). Laser Doppler flowmetry and laser speckle contrast analysis can be used to estimate cutaneous blood flow through microvessels and to assess and quantify blood perfusion at peripheral sites. These two methods are also used to identify changes in digital blood perfusion after the infusion of vasodilators.