Plasma Tissue Inhibitor of Matrix Metalloproteinase-1 Level Is Increased in Normotensive Non-Dippers in Association with Impaired Glucose Metabolism

Evaluating Blood Pressure Variability in Type 2 Diabetic Patients: An Insight into Non-Dipping Patterns and Their Clinical Implications

Background

Hypertension (HTN) is prevalent in individuals with type 2 Diabetes Mellitus (T2DM), doubling the risk of developing chronic complications. Despite normal routine checks, many patients with diabetes exhibit abnormal blood pressure (BP) profiles identified by 24-hour ambulatory Blood Pressure monitoring (ABPM). This study aimed to analyse blood pressure variability in patients with diabetes to enhance current knowledge and improve clinical practice.

Methods

This cross-sectional study obtained ethical approval from Jazan University and involved 58 patients with type 2 Diabetes Mellitus (T2DM) who adhered to the strict inclusion and exclusion criteria. Comprehensive clinical and laboratory data, including demographic, clinical, and essential laboratory parameters, were collected using a standardized form. Blood Pressure (BP) was meticulously monitored using the Sun Tech Oscar 2 ABPMR device, with measurements commencing between 8 am and 10 am, extending over 24 hours. The study calculated averages and evaluated systolic and diastolic percentage dipping during 24-hour, daytime, and night-time intervals. Participants classified as "dippers" experienced a BP reductions of at least 10%.

Results

Fifty-eight normotensive T2DM patients, with a mean age of 45.51 ± 6.7 years, were monitored over 24 months. Among the 58 individuals assessed using ABPM, a non-dipping pattern was observed in 45 participants (77.58%), whereas 13 (22.41%) exhibited a dipping pattern. Postprandial and fasting blood sugar levels were distinct; the dipper group demonstrated better post-meal glucose control (p=0.02), whereas the non-dipper group had superior fasting glucose control (p=0.04). The dipper group showed a higher 24-hour average systolic BP (p=0.00) and increased dipping percentages for systolic and diastolic BP during sleep.

Conclusion

Over 77% of ABPM-evaluated individuals showed non-dipping patterns, with a higher BMI being strongly associated. Laboratory findings revealed distinct variations in the postprandial and fasting blood sugar levels, suggesting a potential genetic predisposition.

Biochemical composition of the glomerular extracellular matrix in patients with diabetic kidney disease

In the glomeruli, mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane (GBM). The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear. The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM. Predominant components of the normal glomerular extracellular matrix (ECM) include glycosaminoglycans, proteoglycans, laminins, fibronectin-1, and several types of collagen. In patients with diabetes, multiorgan composition of extracellular tissues is anomalous, including the kidney, so that the constitution and arrangement of glomerular ECM is profoundly altered. In patients with diabetic kidney disease (DKD), the global quantity of glomerular ECM is increased. The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented, compared to control subjects. The concentration of mesangial fibronectin-1 varies depending on the stage of DKD. Mesangial type III collagen is abundant in patients with DKD, unlike normal kidneys. The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease. The GBM contains lower amount of type IV collagen in DKD compared to normal tissue. Further, genetic variants in the α3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease. Human cellular models of glomerular cells, analyses of human glomerular proteome, and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.

Tissue Inhibitor of Matrix Metalloproteinase 1 Increases With Ageing and Can Be Associated With Stroke ― Nested Case-Control Study ―

Background: Increase of collagen in the extracellular matrix occurs with ageing. We investigated whether a collagen marker, tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), was associated with risk of stroke.

Methods and Results: In a nested case-control study of 953 subjects from the general population, we evaluated determinants of TIMP-1 level and stroke risk. Mean subject age was 65.7±8.6 years (53.0% men); TIMP-1 was 72.4±28.2 pg/mL in the control group and 75.3±30.9 pg/mL in the stroke group. The relationship between TIMP-1 quartile and stroke was J-curved. Subjects in the highest TIMP-1 quartile (≥89 ng/mL) had a significantly higher OR of stroke (59–72 ng/mL; OR, 1.90; 95% CI: 1.09–3.31, P=0.023) than those in the second TIMP-1 quartile, and this tended toward significance even after adjusting for confounding factors (P=0.059). Elevation of serum TIMP-1 became more marked after age 65 years. On multiple linear regression analysis, significant determinants of TIMP-1 were older age (B=0.21 per 1 year; 95% CI: 0.52–1.07, P<0.001) and higher systolic blood pressure (SBP; B=0.19 per 1 mmHg, 95% CI: 0.08–0.42, P=0.004).

Conclusions: TIMP-1 increased with ageing and with SBP, and can be associated with stroke.

Even mild depression is associated with among-day blood pressure variability, including masked non-dipping assessed by 7-d/24-h ambulatory blood pressure monitoring

The effect of mild depression on blood pressure (BP) was assessed in 116 Japanese (32-79 years). As compared to non-depressive (Geriatric Depression Scale, GDS-15 score <5) subjects, mild depressives (GDS-15 score: 1-15) had shorter sleep duration (p = 0.021), lower subjective quality of life (health: p = 0.016; life satisfaction: p < 0.001; and happiness: p < 0.001), and higher 7-d systolic BP (p < 0.05). "Masked non-dipping" (dipping on day 1, but non-dipping on at least 1 of the following 6 d) was more frequent among depressive than non-depressive normotensives (p = 0.008). Among-day BP variability may underlie cardiovascular disease accompanying a key component of psychological depression.

Nighttime Home Blood Pressure and the Risk of Hypertensive Target Organ Damage

In ambulatory blood pressure (BP) monitoring, nighttime BP has a superior ability to predict hypertensive target organ damage than awake BP. We evaluated whether nighttime BP, assessed by a home BP monitor, was associated with hypertensive target organ damage. We measured clinic BP, out-of-clinic BP including nighttime home BP, and the urinary albumin:creatinine ratio (UACR) in 854 patients who had cardiovascular risk factors. Nighttime home BP was measured at 2:00, 3:00, and 4:00 am, in addition to clinic, awake ambulatory, nighttime ambulatory, and awake home BP. Nighttime home systolic BP (SBP) was slightly higher than nighttime ambulatory SBP (difference, 2.6 mm Hg; P <0.001). Clinic ( r =0.186), awake ambulatory ( r =0.173), nighttime ambulatory ( r =0.194), awake home ( r =0.298), and nighttime home ( r =0.311) SBPs were all associated with log-transformed UACR (all P <0.001). The correlation coefficient for the relationship between nighttime home SBP and log-transformed UACR was significantly greater than that for the relationship between nighttime ambulatory SBP and log-transformed UACR ( P <0.001). The goodness of fit of the association between SBP and UACR was improved by adding nighttime home SBP to the other SBPs ( P <0.001). Nighttime home diastolic BP also improved the goodness-of-fit of the association between diastolic BP and UACR ( P =0.001). Similar findings were observed for the left ventricular mass index in the subgroup (N=594). In conclusion, nighttime home BP is slightly different from (but comparable to) nighttime ambulatory BP. The addition of nighttime home BP to other BP measures improves the association of BP with hypertensive target organ damage.

Regulation of circadian blood pressure: from mice to astronauts

PURPOSE OF REVIEW

Circadian variation is commonly seen in healthy people; aberration in these biological rhythms is an early sign of disease. Impaired circadian variation of blood pressure (BP) has been shown to be associated with greater target organ damage and with an elevated risk of cardiovascular events independent of the BP load. The purpose of this review is to examine the physiology of circadian BP variation and propose a tripartite model that explains the regulation of circadian BP.

RECENT FINDINGS

The time-keeper in mammals resides centrally in the suprachiasmatic nucleus. Apart from this central clock, molecular clocks exist in most peripheral tissues including vascular tissue and the kidney. These molecular clocks regulate sodium balance, sympathetic function and vascular tone. A physiological model is proposed that integrates our understanding of molecular clocks in mice with the circadian BP variation among humans. The master regulator in this proposed model is the sleep-activity cycle. The equivalents of peripheral clocks are endothelial and adrenergic functions. Thus, in the proposed model, the variation in circadian BP is dependent upon three major factors: physical activity, autonomic function, and sodium sensitivity.

SUMMARY

The integrated consideration of physical activity, autonomic function, and sodium sensitivity appears to explain the physiology of circadian BP variation and the pathophysiology of disrupted BP rhythms in various conditions and disease states. Our understanding of molecular clocks in mice may help to explain the provenance of blunted circadian BP variation even among astronauts.