Down-Regulation of CK2α Leads toUp-Regulation of the Cyclin-Dependent Kinase Inhibitor p27KIP1 in Conditions Unfavorable for the Growth of Myoblast Cells.

BACKGROUND/AIMS: Compelling evidence indicates that CK2α, which is one of the two catalytic isoforms of protein kinase CK2, is required for cell viability and plays an important role in cell proliferation and differentiation. While much is known on CK2 in the context of disease states, particularly cancer, its critical role in non-cancerous cell growth has not been extensively investigated. METHODS: In the present study, we have employed a cell line derived from rat heart with inducible down-regulation of CK2α and CK2α-knockout mouse tissue to identify CK2-mediated molecular mechanisms regulating cell growth. For this, we have performed Incucyte® live-cell analysis and applied flow cytometry, western blot, immunoprecipitation, immunohistochemistry, RT-qPCR and luciferase-based methods. RESULTS: Here, we show that lack of CK2α results in significantly delayed cell cycle progression through G1, inhibition of cyclin E-CDK2 complex, decreased phosphorylation of Rb protein at S795, and inactivation of E2F transcription factor. These events are accompanied by nuclear accumulation and up-regulation of the cyclin-dependent kinase inhibitor p27KIP1 in cells and CK2α-knockout mouse tissues. We found that increased levels of p27KIP1 are mainly attributable to post-translational modifications, namely phosphorylation at S10 and T197 amino acid residues catalyzed by Dyrk1B and AMPK, respectively, as silencing of FoxO3A transcription factor, which activates CDKN1B the gene coding for p27KIP1, does not result in markedly decreased expression levels of the corresponding protein. Interestingly, simultaneous silencing of CK2α and p27KIP1 significantly impairs cell cycle progression without increasing cell death. CONCLUSION: Taken together, our study sheds light on the molecular mechanisms controlling cell cycle progression through G1 phase when myoblasts proliferation potential is impaired by CK2α depletion. Our results suggest that elevated levels of p27KIP1, which follows CK2α depletion, contribute to delay the G1-to-S phase transition. Effects seen when p27KIP1 is down-regulated are independent of CK2α and reflect the protective role exerted by p27KIP1 under unfavorable cell growth conditions.

Statin intolerance in a referral lipid clinic.

BACKGROUND: Statins effectively prevent atherosclerotic cardiovascular disease, but rates of statin discontinuation after adverse events are high. OBJECTIVE: Describe the range and relative frequencies of adverse events potentially attributable to statins in lipid referral practice and assess statin rechallenge outcomes. METHODS: Retrospective cohort study of 642 patients with statin-associated adverse events evaluated in a referral lipid clinic between January 1, 2004 and January 27, 2011. RESULTS: Patients experiencing adverse events by organ system included 92% with musculoskeletal, 8% central nervous system, 10% liver, 8% gastrointestinal, 5% peripheral nervous system, 5% skin, and 3% other events. Overlap of organ system involvement occurred in 22.5%. At least 1 follow-up visit was made by 557 patients, among whom overall median follow-up was 25 months. Among patients treated with a statin in the clinic, 71% remained on a statin at the last follow-up visit. Patients with hepatic transaminase increases by history were numerically more likely than the overall group to resume or remain on statin treatment, whereas those reporting central nervous system or gastrointestinal symptoms trended lower for statin maintenance. Among patients who experienced an adverse event after statin rechallenge, the majority (64%) were being treated with intermittent, nondaily dosing at the time of the adverse event. CONCLUSION: Although musculoskeletal symptoms are reported by 90% of patients with statin intolerance, symptoms involving other organ systems may be more frequent than previously supposed. Understanding the range of symptoms, time course, and impact on daily activities informs counseling in patient-centered practice, but assessment of causation by statins remains challenging.

Prevalence of glucose intolerance at 6 weeks postpartum in Indian women with gestational diabetes mellitus.

AIMS: Women with a history of gestational diabetes mellitus (GDM) have an increased risk for future glucose intolerance, and should be followed up with subsequent screening for the development of diabetes or pre-diabetes at 6-12 weeks postpartum. We studied the prevalence of glucose intolerance at 6 weeks postpartum in Indian women with GDM diagnosed according to ADA criteria. MATERIALS AND METHODS: This longitudinal study, conducted at a tertiary care centre, included 75 Asian-Indian women aged ≥18 years, with a diagnosis of GDM (as per ADA criteria), who were referred to the Endocrine Department at Indraprastha Apollo Hospital, Delhi. A 2-h 75 g oral glucose tolerance test (OGTT) was performed at 6 weeks postpartum. RESULTS: Out of the 75 women who had GDM and were recommended an OGTT at 6 weeks postpartum, 17.3% did not return for the test. Out of 62 women, one-third (33.8%) developed an abnormal OGTT at 6 weeks postpartum, while 66.1% had reverted to normal glucose tolerance. Impaired fasting glucose (IFG) was seen in 14.5%, 4.8% had impaired glucose tolerance (IGT), 8% had both IFG and IGT, and 6.4% had overt type 2 diabetes. CONCLUSION: Our study emphasizes the need for compulsory follow up OGTT for women with GDM in our part of the world in view of ethnicity and prevailing socio-cultural factors.

Cathepsin-D, adiponectin, TNF-α, IL-6 and hsCRP plasma levels in subjects with diabetic foot and possible correlation with clinical variables: a multicentric study.

Diabetic foot, characterized by a pronounced inflammatory reaction, decreased collagen content and biosynthesis and accelerated degradation are crucial in wound healing. Cathepsin D, an aspartic endopeptidases implicated in cell growth, apoptosis, and its inhibitor has been reported to reverse the inhibition of collagen biosynthesis in wounded rat skin with diabetes. To date, the increased proteolytic activity of Cathepsin D in diabetic foot has not been evaluated and the pathogenic significance of the inflammation has received little attention. Of the patients [with ulcer (n=211) and without ulcer (n=208)], 89.73% had type 2 diabetes. Subjects with diabetic foot ulcer showed higher median plasma level of Cathepsin D [556.3 (312.6-587.3) RFC/ml vs 306.3 (92.6-337.3) RFC/ml], TNF-α [96.6 (79.9-121.5) ng/ml vs 8.4 (7.1-9.20) ng/ml], IL-6 [32.2 (8.52-48.4) ng/ml vs 4.9 (4.5-5.6) ng/ml], hsCRP [12.6 (11.2-14.1) mg/ml vs 3.90 (3.50-4.60) mg/ml] and lower median plasma levels of adiponectin [8.50 (7.10-9.5) ng/ml vs 13.3 (12.1-14.2) ng/ml]. A positive correlation was found between grades of ulcer, BMI, A1c and retinopathy for Cathepsin D, for adiponectin, between grades of ulcer, BMI, retinopathy, nephropathy & smoking, for IL-6, between grades of ulcer, BMI, nephropathy, CAD & smoking, for hsCRP, grades of ulcer, BMI, LDL-C, nephropathy & smoking, while total cholesterol, nephropathy, PAD, smoking and neuropathy for TNF-α.

What the future holds for gliptins.

Gliptins have revolutionised the treatment of Type 2 Diabetes Mellitus, addressing the hyperglycemia through its effects on the alpha and beta cells of the pancreas. In this article,we review the extra-glycemic effects of gliptins on central nervous system, cardiovascular biology and the bone health and concerns regarding pancreatitis and pancreatic cancer.

Inflammation, insulin resistance and carotid IMT in first degree relatives of north Indian type 2 diabetic subjects.

Inflammation is associated with insulin resistance, atherosclerosis and type 2 diabetes but whether it causes insulin resistance and accelerated atherosclerosis or an epiphenomena of insulin resistance is not clear. Thirty-eight young normoglycemic, non-obese, first degree relatives of type 2 diabetic subjects (FH(+)) and 38 control subjects without family history of diabetes (FH(-)) (age and sex matched), were studied to determine difference in inflammatory markers, insulin resistance and carotid intima-media thickness (IMT). Plasma glucose, insulin (fasting and 2h after 75gm oral glucose) lipids and serum levels of C-reactive protein (CRP), tumour necrosis factor (TNF)-alpha and fibrinogen were measured after an overnight fast of 10-12h. First degree relative group (FH(+)) have higher BMI (p<0.05), composite IMT (p<0.05) and CRP level (p<0.05), however, after adjustment for BMI, the two groups did not significantly differ. Fibrinogen was not significantly correlated with composite IMT in FH(+) group after controlling with BMI. In FH(+) group composite IMT was significantly correlated with systolic blood pressure (p<0.05), LDL-cholesterol (p<0.05), postprandial insulin level (p<0.05) and HOMA-IR (p<0.05) after adjustment of BMI. Thus insulin resistance is a major determinant of atherosclerosis in subjects with high risk of type 2 diabetes showing the strong relationship between inflammation, obesity and insulin resistance.

Postprandial hypertriglyceridemia and carotid intima-media thickness in north Indian type 2 diabetic subjects.

Hypertriglyceridemia is an important risk factor for coronary heart disease (CHD) and in the development of atherosclerosis, especially in subgroups of the population like those with type 2 diabetes. Although triglycerides are generally increased in the postprandial period, the association between postprandial triglyceride (ppTG) levels and atherosclerosis has not been investigated in north Indian type 2 diabetic subjects known to have a very high prevalence rate of premature CHD and insulin resistance. To investigate the role of ppTG levels in atherosclerosis in type 2 diabetes, we examined the correlation between ppTG levels and carotid intima-media thickness (IMT). Carotid IMT was determined by high resolution B-mode ultrasonography in 86 newly detected type 2 diabetic subjects (1-12 months duration) having good glycemic control (HbA(1C)<7%) and 45 non-diabetic subjects matched according to age and body mass index (BMI). Plasma glucose, insulin, total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides were measured after overnight fasting. Plasma insulin and glucose were also measured 2h and plasma triglycerides 4h after breakfast. The mean carotid IMT in diabetic subjects was higher than those in non-diabetic subjects (0.77+/-0.15 mm versus 0.53+/-0.16 mm, P<0.001). Based on the fasting and postprandial triglyceride levels, the diabetic subjects were divided into three groups: normo-normo (NN); normo-hyper (NH); hyper-hyper (HH) [NN: fTG<1.70 mmol/L and ppTG<2.30 mmol/L; NH: fTG<1.70 mmol/L and ppTG>2.30 mmol/L; HH: fTG>1.70 mmol/L and ppTG>2.30 mmol/L]. Carotid IMT was significantly increased in the NH (0.79+/-0.09 mm) and HH (0.82+/-0.06 mm) groups compared with the NN group (0.59+/-0.09 mm, P<0.001). Although ppTG, age, fasting LDL-cholesterol, HOMA-estimated insulin resistance, HbA(1C) were all independently correlated with carotid IMT, age and ppTG levels had the strongest statistical influence (P<0.002).