C-peptide in diabetes: A player in a dual hormone disorder?

C-peptide, a byproduct of insulin synthesis believed to be biologically inert, is emerging as a multifunctional molecule. C-peptide serves an anti-inflammatory and anti-atherogenic role in type 1 diabetes mellitus (T1DM) and early T2DM. C-peptide protects endothelial cells by activating AMP-activated protein kinase α, thus suppressing the activity of NAD(P)H oxidase activity and reducing reactive oxygen species (ROS) generation. It also prevents apoptosis by regulating hyperglycemia-induced p53 upregulation and mitochondrial adaptor p66shc overactivation, as well as reducing caspase-3 activity and promoting expression of B-cell lymphoma-2. Additionally, C-peptide suppresses platelet-derived growth factor (PDGF)-beta receptor and p44/p42 mitogen-activated protein (MAP) kinase phosphorylation to inhibit vascular smooth muscle cells (VSMC) proliferation. It also diminishes leukocyte adhesion by virtue of its capacity to abolish nuclear factor kappa B (NF-kB) signaling, a major pro-inflammatory cascade. Consequently, it is envisaged that supplementation of C-peptide in T1DM might ameliorate or even prevent end-organ damage. In marked contrast, C-peptide increases monocyte recruitment and migration through phosphoinositide 3-kinase (PI-3 kinase)-mediated pathways, induces lipid accumulation via peroxisome proliferator-activated receptor γ upregulation, and stimulates VSMC proliferation and CD4+ lymphocyte migration through Src-kinase and PI-3K dependent pathways. Thus, it promotes atherosclerosis and microvascular damage in late T2DM. Indeed, C-peptide is now contemplated as a potential biomarker for insulin resistance in T2DM and linked to increased coronary artery disease risk. This shift in the understanding of the pathophysiology of diabetes from being a single hormone deficiency to a dual hormone disorder warrants a careful consideration of the role of C-peptide as a unique molecule with promising diagnostic, prognostic, and therapeutic applications.

Prevalence and anatomical factors associated with stent under-expansion in non-severely calcified lesions

BACKGROUND

Stent underexpansion, typically related to lesion calcification, is the strongest predictor of adverse events after percutaneous coronary intervention (PCI). Although uncommon, underexpansion may also occur in non-severely calcified lesions.

AIM

We sought to identify the prevalence and anatomical characteristics of underexpansion in non-severely calcified lesions.

METHODS

We included 993 patients who underwent optical coherence tomography-guided PCI of 1051 de novo lesions with maximum calcium arc <180°. Negative remodeling (NR) was the smallest lesion site external elastic lamina diameter that was also smaller than the distal reference. Stent expansion was evaluated using a linear regression model accounting for vessel tapering; underexpansion required both stent expansion <70% and stent area <4.5mm2.

RESULTS

Underexpansion was observed in 3.6% of non-heavily calcified lesions (38/1051). Pre-stent maximum calcium arc and thickness were greater in lesions with versus without underexpansion (median 119° vs. 85°, p = 0.002; median 0.95 mm vs. 0.78 mm, p = 0.008). NR was also more common in lesions with underexpansion (44.7% vs. 24.5%, p = 0.007). In the multivariable logistic regression model, larger and thicker eccentric calcium, mid left anterior descending artery (LAD) location, and NR were associated with underexpansion in non-severely calcified lesions. The rate of underexpansion was especially high (30.7%) in lesions exhibiting all three morphologies. Two-year TLF tended to be higher in underexpanded versus non-underexpanded stents (9.7% vs. 3.7%, unadjusted hazard ratio [95% confidence interval] = 3.02 [0.92, 9.58], p = 0.06).

CONCLUSION

Although underexpansion in the absence of severe calcium (<180°) is uncommon, mid-LAD lesions with NR and large and thick eccentric calcium were associated with underexpansion.

Mortality and Morbidity Among Adult Liver Retransplant Recipients

BACKGROUND

Liver transplantation (LT) is life-saving procedure for patients with end-stage liver failure with up to 20% of patients suffering graft failure following primary transplantation. Retransplantation (ReLT) remains the only definitive treatment for irreversible graft failure.

AIMS

We aimed to explore the postoperative outcomes following liver ReLT.

METHODS

Patients who had received a liver transplant between 2003 and 2016 were retrospectively identified using the Scientific Registry of Transplant Recipients (SRTRs). Patients were stratified based on previous liver transplant history. The primary outcomes of this study were 5-year postoperative mortality, morbidity, and length of hospital stay following LT.

RESULTS

60,554 (96%) recipients were first LT recipients and 2524 (4%) were ReLT recipients. Compared with first LT, ReLT recipients had significantly higher rates of mortality (OR 1.93, 95%CI 1.76-2.12), overall morbidity (OR 1.80, 95%CI 1.65-1.96), and prolonged length of stay (OR 1.66, 95%CI 1.52-1.81) on multivariate analysis. Morbidity including cardiovascular (CVD) complications (OR 1.32, 95%CI 1.08-1.60), graft failure (OR 2.18, 95%CI 1.84-2.57), infection (OR 2.13, 95%CI 1.82-2.50), and hemorrhage (OR 2.67, 95%CI 2.00-3.61) were significantly greater in ReLT recipients. Compared to first LT, ReLT patients had a significant increase in overall 5-year mortality (p < 0.001), 5-year mortality due to CVD complications (p < 0.001), infection (p = 0.009), but not graft failure (p = 0.3543).

CONCLUSION

ReLT is associated with higher rates of 5-year mortality, overall morbidity, CVD morbidity, infection, and graft failure. Higher 5-year mortality in ReLT is due to CVD and infections. These results could be used in preoperative patient assessment and prognostic counseling for ReLT.

Utility of optical coherence tomography in acute coronary syndromes

Studies utilizing intravascular imaging have replicated the findings of histopathological studies, identifying the most common substrates for acute coronary syndromes (ACS) as plaque rupture, erosion, and calcified nodule, with spontaneous coronary artery dissection, coronary artery spasm, and coronary embolism constituting the less common etiologies. The purpose of this review is to summarize the data from clinical studies that have used high-resolution intravascular optical coherence tomography (OCT) to assess culprit plaque morphology in ACS. In addition, we discuss the utility of intravascular OCT for effective treatment of patients presenting with ACS, including the possibility of culprit lesion-based treatment by percutaneous coronary intervention.

A novel nephrectomy-specific respiratory failure index using the ACS-NSQIP dataset

PURPOSE

Post-operative pulmonary failure is a major complication of nephrectomy that may lead to severe morbidity and mortality. Hence, we aimed to derive a nephrectomy-specific post-operative respiratory failure index.

METHODS

Our cohort was derived from The American College of Surgeons-National Surgical Quality Improvement Program database between 2005 and 2019. The outcome of interest was post-operative respiratory failure (PRF) defined as any incidence of unplanned intubation post-operatively or requiring mechanical ventilation post-operatively for a period > 48 h. A multivariable logistic regression model was constructed, and model calibration and performance were assessed using a ROC analysis and the Hosmer-Lemeshow test. Finally, we derived the nephrectomy-specific respiratory failure (NSRF) index and compared it to Gupta's index.

RESULTS

Seventy-nine thousand five hundred and twenty-three patients underwent nephrectomy between the years 2005 and 2019 of which nine hundred and sixty-two patients developed PRF. The final NSRF model encompassed ten variables: age, smoking status, American society of anesthesiology class, abnormal creatinine (≥ 1.5 mg/dL), anemia (< 36%), functional health status, chronic obstructive pulmonary disease, surgical approach, emergency case, and obesity (≥ 40 kg/m²). The NSRF ROC analysis provided C-statistic = 0.78, calibration R² = 0.99, and proper goodness of fit. In comparison, the C-statistics of Gupta's index was found to be 0.71 (p value < 0.001).

CONCLUSION

The NSRF is a procedure tailored index for predicting post-operative respiratory failure. It is a valuable tool in the pre-operative evaluation setting that can help identify high-risk patients who will require additional respiratory evaluation and preparation for their surgery.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention: Practical Application

Optical coherence tomography (OCT) provides high-resolution imaging of coronary arteries and can be used to optimize percutaneous coronary intervention (PCI). Intracoronary OCT, however, has had limited adoption in clinical practice. Novelty and relative complexity of OCT interpretation compared with the more established intravascular ultrasound, lack of a standardized algorithm for PCI guidance, paucity of data from randomized trials, and lack of rebate for intravascular imaging have contributed to the modest practical adoption of OCT. We provide a practical step-by-step guide on how to use OCT in PCI, including device set-up, simplified image interpretation, and an algorithmic approach for PCI. optimization.

Preoperative MELD score predicts mortality and adverse outcomes following radical cystectomy: analysis of American College of Surgeons National Surgical Quality Improvement Program

BACKGROUND

The model for end-stage liver disease (MELD) has been widely used to predict the mortality and morbidity of various surgical procedures.

OBJECTIVES

We aimed to correlate a high preoperative MELD score with adverse 30-day postoperative complications following radical cystectomy.

DESIGN AND METHODS

Patients who underwent elective, non-emergency radical cystectomy were identified from the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database from 2005 to 2017. Patients were categorized according to a calculated MELD score. The primary outcomes of this study were 30-day postoperative mortality, morbidity, and length of hospital stay following radical cystectomy. For further sensitivity analysis, propensity score matching was used to yield a total of 1387 matched pairs and primary outcomes were also assessed in the matched cohort.

RESULTS

Compared with patients with a MELD < 10, those with MELD ⩾ 10 had significantly higher rates of mortality [odds ratio (OR) = 1.71, p = 0.004], major complications (OR = 1.42, p < 0.001), and prolonged hospital stay (OR = 1.29, p < 0.001) on multivariate analysis. Following risk-adjustment for race, propensity-matched groups revealed that patients with MELD score ⩾ 10 were significantly associated with higher mortality (OR = 1.85, p = 0.008), major complications (OR = 1.34, p < 0.001), yet similar length of hospital stay (OR = 1.17, p = 0.072).

CONCLUSION

MELD score ⩾ 10 is associated with higher mortality and morbidity in patients undergoing radical cystectomy compared with lower MELD scores. Risk-stratification using MELD score may assist clinicians in identifying high-risk patients to provide adequate preoperative counseling, optimize perioperative conditions, and even consider nonsurgical alternatives.

Visfatin: An emerging adipocytokine bridging the gap in the evolution of cardiovascular diseases

Visfatin/nicotinamide phosphoribosyltransferase (NAMPT) is an adipokine expressed predominately in visceral fat tissues. High circulating levels of visfatin/NAMPT have been implicated in vascular remodeling, vascular inflammation, and atherosclerosis, all of which pose increased risks of cardiovascular events. In this context, increased levels of visfatin have been correlated with several upregulated pro-inflammatory mediators, such as IL-1, IL-1Ra, IL-6, IL-8, and TNF-α. Furthermore, visfatin is associated with leukocyte recruitment by endothelial cells and the production of adhesion molecules such as vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, and E-selectin, which are well known to mediate the progression of atherosclerosis. Moreover, diverse angiogenic factors have been found to mediate visfatin-induced angiogenesis. These include matrix metalloproteinases, vascular endothelial growth factor, monocyte chemoattractant protein 1, and fibroblast growth factor 2. This review aims to provide a comprehensive overview of the pro-inflammatory and angiogenic actions of visfatin, with a focus on the pertinent signaling pathways whose dysregulation contributes to the pathogenesis of atherosclerosis. Most importantly, some hypotheses regarding the integration of the aforementioned factors with the plausible atherogenic effect of visfatin are put forth for consideration in future studies. The pharmacotherapeutic potential of modulating visfatin's roles could be important in the management of cardiovascular disease, which continues to be the leading cause of death worldwide.

Lipid-Lowering Therapies for Atherosclerosis: Statins, Fibrates, Ezetimibe and PCSK9 monoclonal antibodies

Cardiovascular disease (CVD) remains the primary cause of global morbidity and mortality. CVD includes various life-threatening conditions such as myocardial infarction, stroke and peripheral arterial diseases. In this context, atherosclerosis continues to play the principal role in the pathogenesis of these conditions. Atherosclerosis emanates from a set of modifiable and non-modifiable risk factors that include age, male gender, family history, obesity, smoking, diabetes mellitus and hypertension. Recent evidence classifies atherosclerosis as a latent disease affecting all-sized arteries with a predilection for arterial branching points of decreased or absent blood supply. Atherosclerosis is not only a lipid metabolism disorder, but is also a chronic inflammatory one. In this review, we provide a synoptic discussion of the underlying pathological mechanisms of atherosclerosis along with the currently applied therapeutic interventions. We then discuss the classical lipid-lowering therapies as well as the newly discovered therapies. For the classical therapies, we point out the importance of statins and ezetimibe in reducing plasma cholesterol levels by virtue of their effects on synthesis, reuptake and intestinal absorption of cholesterol. We also discuss the role of fibrates in modulating lipid metabolism and improving the ratio of high-density to low-density density lipoproteins. We then focus on the more recent molecular and genetic interventions exemplified by proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies, evinacumab, and microRNA inhibitors. Special attention is also given to clinical trials involving these therapies.

Visfatin: A Possible Role in Cardiovasculo-Metabolic Disorders

Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is an adipocytokine with several intriguing properties. It was first identified as pre-B-cell colony-enhancing factor but turned out to possess enzymatic functions in nicotinamide adenine dinucleotide biosynthesis, with ubiquitous expression in skeletal muscles, liver, cardiomyocytes, and brain cells. Visfatin exists in an intracellular (iNAMPT) and extracellular (eNAMPT) form. Intracellularly, visfatin/iNAMPT plays a regulatory role in NAD⁺ biosynthesis and thereby affects many NAD-dependent proteins such as sirtuins, PARPs, MARTs and CD38/157. Extracellularly, visfatin is associated with many hormone-like signaling pathways and activates some intracellular signaling cascades. Importantly, eNAMPT has been associated with several metabolic disorders including obesity and type 1 and 2 diabetes. In this review, a brief overview about visfatin is presented with special emphasis on its relevance to metabolic diseases. Visfatin/NAMPT appears to be a unique molecule with clinical significance with a prospective promising diagnostic, prognostic, and therapeutic applications in many cardiovasculo-metabolic disorders.