Highly dynamic changes of regional HBV epidemiology over two decades.

BACKGROUND & AIM: HBV epidemiology is highly heterogeneous and rapidly evolving worldwide: we studied its last two-decades dynamics in a large single center cohort. METHODS: In all consecutive HBsAg-positive subjects firstly admitted (2000-2019) at the Pisa-University-Hospital Hepatology-Referral-Center, demographic, virologic and clinical variables were analyzed by admission decade (2000-2009 vs 2010-2019) and origin (Italian vs non-Italian natives). RESULTS: Of 2003, 1878 (93.7%) subjects were eligible: 1798(95.7%) with HBV-chronic [126(7%) HDV, 72(4%) HCV, 11(0.6%) HIV co-infected] and 80(4.3%) HBV-primary infections (93.7% Italians). Among 1589(88.4%) mono-infected, 496(31.2%) were immigrants, younger than Italians [34.0(5.1-77.1)-52.5(10.0-87.2) years], with female prevalence [204/496(41.1%)-340/1093(31.1%); p<0.001] increasing overtime (14.6-45.0%; p<0.001). Italians aged across decades [50.3(11.1-87.2)-56.2(10.0-86.7) years; p<0.001], HBeAg-positivity remained stable (12.3-14.5%) and acute hepatitis increased (4.0-8.0%; p = 0.003). CHB declined [439/721(60.9%)-320/868(36.9%); p<0.001] whereas HBeAg-negative infection increased [277/626(44.2%)-538/755(71.3%); p<0.001]. Cirrhosis declined [195/721(27.0%)-125/868(14.4%); p<0.001], except in anti-HDV-patients [93/126(73.8%); 42(45.1%) non-Italians], younger than HBV-mono-infected (47.4-57.6 years; p<0.001). CONCLUSION: Effective preventive health care policies and immigration flows account for increasing prevalence of HBeAg-negative infection across the last two decades. Antiviral therapy mitigated disease progression in aging Italian CHB but not in CHD patients, mainly young immigrants, emphasizing the unmet need of effective CHD therapies; HBeAg-positive CHB and acute hepatitis B persist in non-vaccinated Italian adults, prompting vaccination in the elderly with risky behaviors.

Continually high insulin levels impair Akt phosphorylation and glucose transport in human myoblasts.

Chronic hyperinsulinemia is both a marker and a cause for insulin resistance. This study analyzes the effect of long-term exposure to high insulin levels on the insulin-signaling pathway and glucose transport in cultured human myoblasts. Human myoblasts were grown in the presence of low (107 pmol/L, SkMC-L) or high (1430 pmol/L, SkMC-H) insulin concentrations for 3 weeks. Glucose transport, insulin receptor (IR), and IR substrate 1 (IRS1) phosphorylation, phosphatidylinositol 3'-kinase (PI3K) activity, as well as Akt-Ser473 phosphorylation have been investigated at the end of the incubation period and after a further short-term insulin stimulation. At the end of the incubation period, IR, IRS1, p85/PI3K, Akt, and GLUT4 protein expression levels were similar in both culture conditions. Basal glucose transport was similar in SkMC-L and SkMC-H, but after short-term insulin stimulation significantly increased (P < .01) only in SkMC-L. IR binding was down-regulated in SkMC-H (P < .01), but IR and IRS1 tyrosine phosphorylation and PI3K activity were significantly higher (P < .01) in SkMC-H than SkMC-L. Despite increased PI3K activation, Akt-Ser473 phosphorylation was similar in SkMC-L and SkMC-H. After a short-term insulin stimulation (10 nmol/L insulin for 10 minutes), IR and IRS1 tyrosine phosphorylation, PI3K activation, and Akt-Ser473 phosphorylation significantly increased (P < .01 and P < .05 for Akt) in SkMC-L but not in SkMC-H. Serine phosphorylation of IRS1 was similar in SkMC-L and SkMC-H. Moreover, in the SkMC-H, insulin stimulation was associated with the inhibition of IRS1 tyrosine dephosphorylation (P < .05). In summary, continuous exposure of cultured myoblasts to high insulin levels induces a persistent up-regulation of IR, IRS1, and PI3K activity associated with the demodulation of insulin signaling. Moreover, the impairment of the insulin-signaling steps between PI3K and Akt is concomitant with the desensitization of glucose transport. These alterations may contribute to the derangement insulin-signaling pathway states of hyperinsulinemia such as obesity and type 2 diabetes.

High insulin levels impair intracellular receptor trafficking in human cultured myoblasts.

Chronic hyperinsulinemia is both a marker and a cause for insulin resistance. This study analyzes the effect of long-term exposure to high insulin levels on insulin-insulin receptor metabolism in human myoblasts. Cells were grown in the presence of low (107 pM, SkMC-L) or high (1430 pM, SkMC-H) insulin concentrations. Insulin receptor (IR) phosphorylation, IR internalization, dissociation and recycling, as well as insulin degradation have been investigated. Basal IR phosphorylation was higher in SkMC-H than in SkMC-L (P<0.01) but after acute insulin stimulation (10nM insulin for 10 min), IR phosphorylation increased (P<0.01) in SkMC-L, but not in SkMC-H. Chronic hyperinsulinism significantly decreased insulin-IR complex internalization (P<0.01). Nevertheless the t(1/2) value of receptor internalization was similar in both cells. Intracellular dissociation of insulin-IR complex was slightly but significantly lower in SkMC-H than in SkMC-L. Finally, SkMC-H showed a complete, but significantly delayed recycling of IR to plasma membrane (t(1/2)=20 min versus SkMC-L t(1/2)=7 min). The time course of intracellular degradation measured by HPLC, showed whenever studied, significantly (P<0.01) higher levels of intracellular intact insulin in cells exposed to high insulin concentrations. Nevertheless, the patterns of insulin degradation were over-imposable between SkMC-H and SkMC-L. In summary, continuous exposure of cultured myoblasts to high insulin levels induces subtle derangements of intracellular receptor trafficking and insulin degradation. These alterations may contribute to the insulin resistance of hyperinsulinemic states such as obesity and Type 2 Diabetes.