 This study is an open prospective clinical trial. The objective is to evaluate the effect of autologous exosomes rich plasma on cutaneous wound healing. The participants are patients with intractable cutaneous ulcers e.g. rheumatic disease, peripheral arterial disease, chronic venous insufficiency, decubitus or burns. The participants will be treated autologous exosomes rich plasma every day for 28 days. The cutaneous wound healing will be evaluated by the length, width and depth of the wound. 