Doxycycline Ameliorates the Susceptibility to Aortic Lesions in a Mouse Model for the Vascular Type of Ehlers-Danlos Syndrome

Abstract

The vascular form of Ehlers-Danlos syndrome (vEDS), a rare disease with grave complications resulting from rupture of major arteries, is caused by mutations of collagen type III [␣1 chain of collagen type III (COL3A1)]. The only, recently proven, preventive strategy consists of the reduction of arterial wall stress by ␤-adrenergic blockers. The heterozygous (HT) Col3a1 knockout mouse has reduced expression of collagen III and recapitulates features of a mild presentation of the disease. The objective of this study was to determine whether changing the balance between synthesis and degradation of collagen by chronic treatment with doxycycline, a nonspecific matrix metalloproteinase (MMP) inhibitor, could prevent the development of vascular pathology in HT mice. After 3 months of treatment with doxycycline or placebo, 9-month-old HT or wild-type (WT) mice were subjected to surgical stressing of the aorta. A 3-fold increase in stress-induced aortic lesions found in untreated HT mice 1 week after intervention (cumulative score 4.5 Ϯ 0.87 versus 1.3 Ϯ 0.34 in WT, p Ͻ 0.001) was fully prevented in the doxycycline-treated group (1.1 Ϯ 0.56, p Ͻ 0.001). Untreated HT mice showed increased MMP-9 activity in the carotid artery and decreased collagen content in the aorta; however, in doxycycline-treated animals there was normalization to the levels observed in WT mice. Doxycycline treatment inhibits the activity of tissue MMP and attenuates the decrease in the collagen content in aortas of mice haploinsufficient for collagen III, as well as prevents the development of stress-induced vessel pathology. The results suggest that doxycycline merits clinical testing as a treatment for vEDS.

Chronic Treatment with a Broad-Spectrum Metalloproteinase Inhibitor, Doxycycline, Prevents the Development of Spontaneous Aortic Lesions in a Mouse Model of Vascular Ehlers-Danlos Syndrome

“…In grade 4 lesions (Fig. 2D), there was marked and abrupt attenuation of the wall thickness with abundant fibrosis and more severe fragmentation of several elastic laminae (Ramot et al, 2009;Briest et al, 2011). Cooper et al (2010) reported that grade 1 lesions were seen in 55% of studied mice and distributed equally among WT and HT mice of both sexes.…”

“…HT mice used in this study demonstrated previously described characteristics of haploinsufficiency for collagen III: reduced collagen content in aorta, particularly tunica media and increased MMP activity, especially MMP-9 (Cooper et al, 2010;Briest et al, 2011). Two gelatinases, MMP-2 and MMP-9, had been considered functionally similar and important in vascular remodeling, particularly in smooth muscle cell migration and matrix degradation (Yasumitsu et al, 1992).…”

“…The spectrum of lesions in aortic wall among HT mice had been characterized previously (Cooper et al, 2010;Briest et al, 2011) and could be divided into four grades according to severity. All grades of lesions included fragmentation of the internal elastic lamina (IEL).…”

“…We have reported previously that 3-month pretreatment with the broad-spectrum MMP inhibitor doxycycline (Doxy) protected the aortas of 9-month-old heterozygous COL3A1 KO mice from lesions induced by physical manipulations (Briest et al, 2011). In the present study, we tested a hypothesis that treatment with Doxy starting from weaning would protect the aortas of heterozygous COL3A1 KO mice from the development of spontaneous lesions in adulthood.…”

“…Our mouse model does not present a significant mortality from aortic or arterial ruptures; it does exhibit, however, a greatly increased number of histologically identifiable lesions of aorta. The HT mice from this model also have lower collagen content in aorta compared with WT mice (Cooper et al, 2010;Briest et al, 2011) and increased expression of MMPs, particularly MMP-9 (Briest at al., 2011). Thus, this model allows testing of therapeutic interventions to arrest or alleviate the progression and complications of vEDS.…”