Differences in coronary microvascular lesions in coronary heart disease and hypertension:an autopsy study of elderly patients

Background In the case of hypertension, lesions in the microvessels of the target organs precede and deteriorate futher after arteriosclerosis in the small arteries. Thus coronary microvascular lesion (CML) was considered the crucial factor contributing to damage to the target organs. The purpose of this study is to observe the characteristics and differences of CML in autopsies of elderly patients with essential hypertension (EHT), coronary heart disease (CHD), or EHT with CHD, given the same degree of left ventricular wall thickness (LVWT).Methods A retrospective study was performed on 246 cases of patients over 60 years old with EHT, CHD, or EHT with CHD, and on 26 cases without cardiovascular disease as controls , out of a total of 3195 consecutive autopsied cases. The arterioles (with diameter 10 -60 μm) and the capillaries in the cardiac muscle layer were examined by haematoxylin and eosin staining, elastic van Gieson staining, and CD31 immunohistochemistry. To quantify CML severity, measurements were taken of arteriole density (AD), the ratio of wall-to-lumen area of arteriole (RWL), and capillary density (CD), using light microscopy and computer image analysis. Based on LVWT, the cases were divided into four degrees, from Ⅰ to Ⅳ. The EHT, CHD, and EHT with CHD groups all rated LVWT Ⅰ -Ⅳ, and the control group rated LVWT Ⅰ. SAS software was used for statistical analysis.Results With the aggravation of LVWT, both AD and RWL increased while CD decreased significantly in the EHT group (P<0. 05 -0. 0001); there were similar but more severe changes in the EHT with CHD group (P<0. 001 -0. 0001); and AD increased (P <0.001) while RWL and CD did not change significantly in the CHD group.Conclusion Comparing EHT with CHD patients, there are similar patterns of change to AD, but different patterns of change to RWL and CD. CML is much more severe in EHT patients with CHD. We conclude that CML is one of the main causes of decreased coronary flow reserve and myocardial damage in both EHT patients and EHT patients with CHD.

EFFECTS OF DIABETES ON HEARING AND COCHLEAR STRUCTURES

Diabetes mellitus (DM) is a chronic systemic disease characterized by hyperglycemia, with various patho-genic mechanisms. From absolute or relative insulin deficiency, patients with DM often demonstrate vari-ous levels of metabolic disorders. Major clinical manifestations of DM include metabolic disorders, vascu-lar lesions, circulatory disturbances and neurologic complications. Along with advances in DM research, re-ports of DM related tinnitus and hearing impairment have increased continuously. Research on DM related auditory system dysfunction has focused on cochlear microcirculation, cellular homeostasis, genetics and ag-ing. Cochlear microcirculation plays an important role in cochlear physiology and its disorders are associat-ed with many inner ear diseases. Ischemia and subsequent reperfusion seen in cochlear microcirculation dis-orders are important factors in hearing damage. Understanding cochlear microcirculation and structural as well as functional changes in DM patients with hearing loss and their causal factors will help reveal patho-genic mechanisms in diabetic hearing loss and provide new ideas in developing interventions and preventing damages caused by diabetes.