**7. ECM on UVJ**

Similar to UPJ studies, UVJ shows decreased muscle density and increased ECM components in diseased patients. In a study published in 2004, 36 UVJ segments were evaluated and MMP1 production was found significantly higher in the group with an obstructed junction. This study also found that an increased level of CD68+ macrophages was found in obstructed junctions and as a result there was an increase in cytokines and growth factors and ECM is secreted at elevated levels [23].

Oswald et al. have shown that markers of smooth muscle structure decrease in UVJ pathologies whereas collagen concentration increases significantly by examining tissue specimens of 29 patients with a refluxing ureter and comparing them with nonrefluxing tissues.

Studies showing changes in ECM composition in UVJ-related disease gives us a picture of what happens after pathological process starts. In most conditions, our knowledge lacks the information of what really starts these changes on subcellular level. There is a need for more detailed and larger studies to get a clear picture of the conditions and develop better treatment strategies.
