The role of the kynurenine pathway in cardiovascular disease.

The kynurenine pathway (KP) serves as the primary route for tryptophan metabolism in most mammalian organisms, with its downstream metabolites actively involved in various physiological and pathological processes. Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) serve as the initial and pivotal enzymes of the KP, with IDO playing important and intricate roles in cardiovascular diseases. Multiple metabolites of KP have been observed to exhibit elevated concentrations in plasma across various cardiovascular diseases, such as atherosclerosis, hypertension, and acute myocardial infarction. Multiple studies have indicated that kynurenine (KYN) may serve as a potential biomarker for several adverse cardiovascular events. Furthermore, Kynurenine and its downstream metabolites have complex roles in inflammation, exhibiting both inhibitory and stimulatory effects on inflammatory responses under different conditions. In atherosclerosis, upregulation of IDO stimulates KYN production, mediating aromatic hydrocarbon receptor (AhR)-induced exacerbation of vascular inflammation and promotion of foam cell formation. Conversely, in arterial calcification, this mediation alleviates osteogenic differentiation of vascular smooth muscle cells. Additionally, in cardiac remodeling, KYN-mediated AhR activation exacerbates pathological left ventricular hypertrophy and fibrosis. Interventions targeting components of the KP, such as IDO inhibitors, 3-hydroxyanthranilic acid, and anthranilic acid, demonstrate cardiovascular protective effects. This review outlines the mechanistic roles of KP in coronary atherosclerosis, arterial calcification, and myocardial diseases, highlighting the potential diagnostic, prognostic, and therapeutic value of KP in cardiovascular diseases, thus providing novel insights for the development and application of related drugs in future research.

Epigallocatechin-3-gallate inhibits osteogenic differentiation of vascular smooth muscle cells through the transcription factor JunB.

Medial arterial calcification (MAC) accompanying chronic kidney disease (CKD) leads to increased vessel wall stiffness, myocardial ischemia, heart failure, and increased cardiovascular morbidity and mortality. Unfortunately, there are currently no drugs available to treat MAC. The natural polyphenol epigallocatechin-3-gallate (EGCG) has been demonstrated to protect against cardiovascular disease; however, whether EGCG supplementation inhibits MAC in CKD remains unclear. In this study, we utilize a CKD-associated MAC model to investigate the effects of EGCG on vascular calcification and elucidate the underlying mechanisms involved. Our findings demonstrate that EGCG treatment significantly reduces calcium phosphate deposition and osteogenic differentiation of VSMCs in vivo and in vitro in a dose-dependent manner. In addition, through RNA sequencing (RNA-seq) analysis, we show a significant activation of the transcription factor JunB both in CKD mouse arteries and in osteoblast-like VSMCs. Notably, EGCG effectively suppresses CKD-associated MAC by inhibiting the activity of JunB. In addition, overexpression of JunB can abolish while knockdown of JunB can enhance the inhibitory effect of EGCG on the osteogenic differentiation of VSMCs. Furthermore, EGCG supplementation inhibits MAC in CKD via modulation of the JunB-dependent Ras/Raf/MEK/ERK signaling pathway. In conclusion, our study highlights the potential therapeutic value of EGCG for managing CKD-associated MAC, as it mitigates this pathological process through targeted inactivation of JunB.

Quantitative Abdominal Arterial Calcification Correlates with Kidney Transplant Waitlist Mortality.

INTRODUCTION: The scarcity of available organs for kidney transplantation has resulted in a substantial waiting time for patients with end-stage kidney disease. This prolonged wait contributes to an increased risk of cardiovascular mortality. Calcification of large arteries is a high-risk factor in the development of cardiovascular diseases, and it is common among candidates for kidney transplant. The aim of this study was to correlate abdominal arterial calcification (AAC) score value with mortality on the waitlist. METHODS: We modified the coronary calcium score and used it to quantitate the AAC. We conducted a retrospective clinical study of all adult patients who were listed for kidney transplant, between 2005 and 2015, and had abdominal computed tomography scan. Patients were divided into two groups: those who died on the waiting list group and those who survived on the waiting list group. RESULTS: Each 1,000 increase in the AAC score value of the sum score of the abdominal aorta, bilateral common iliac, bilateral external iliac, and bilateral internal iliac was associated with increased risk of death (HR 1.034, 95% CI: 1.013, 1.055) (p = 0.001). This association remained significant even after adjusting for various patient characteristics, including age, tobacco use, diabetes, coronary artery disease, and dialysis status. CONCLUSION: The study highlights the potential value of the AAC score as a noninvasive imaging biomarker for kidney transplant waitlist patients. Incorporating the AAC scoring system into routine imaging reports could facilitate improved risk assessment and personalized care for kidney transplant candidates.

Breast arterial calcification is associated with sarcopenia in peri- and post-menopausal women.

PURPOSE: Breast arterial calcification (BAC) refers to medial calcium deposition in breast arteries and is detectable via mammography. Sarcopenia, which is characterised by low skeletal muscle mass and quality, is associated with several serious clinical conditions, increased morbidity, and mortality. Both BAC and sarcopenia share common pathologic pathways, including ageing, diabetes, and chronic kidney disease. Therefore, this study evaluated the relationship between BAC and sarcopenia as a potential indicator of sarcopenia. METHODS: This study involved women aged >40. BAC was evaluated using digital mammography and was defined as vascular calcification. Sarcopenia was assessed using abdominal computed tomography. The cross-sectional skeletal mass area was measured at the third lumbar vertebra level. The skeletal mass index was obtained by dividing the skeletal mass area by height in square meters(m2). Sarcopenia was defined as a skeletal mass index of ≤38.5 cm2/m2. A multivariable model was used to evaluate the relationship between BAC and sarcopenia. RESULTS: The study involved 240 participants. Of these, 36 (15 %) were patients with BAC and 204 (85 %) were without BAC. Sarcopenia was significantly higher among the patients with BAC than in those without BAC (72.2 % vs 17.2 %, P < 0.001). The multivariable model revealed that BAC and age were independently associated with sarcopenia (odds ratio[OR]: 7.719, 95 % confidence interval[CI]: 3.201-18.614, and P < 0.001 for BAC and OR: 1.039, 95 % CI: 1.007-1.073, P = 0.01 for age). CONCLUSION: BAC is independently associated with sarcopenia. BAC might be used as an indicator of sarcopenia on screening mammography.

ß,γ-Methylene-ATP and its metabolite medronic acid affect both arterial media calcification and bone mineralization in non-CKD and CKD rats.

Arterial media calcification or pathological deposition of calcium-phosphate crystals in the vessel wall contributes significantly to the high mortality rate observed in patients with CKD. Extracellular nucleotides (ie, ATP or UTP) regulate the arterial calcification process by interacting with (1) purinergic receptors and (2) breakdown via ecto-nucleotidases, such as ectonucleotide pyrophosphatase/phosphodiesterase NPP1 or NPP3, affecting the local levels of calcification inhibitor, pyrophosphate, and stimulator inorganic phosphate (PPi/Pi ratio). Also, it has been shown that ATP analogs (ie, ß,γ-methylene-ATP [ß,γ-meATP]) inhibit vascular smooth muscle cell calcification in vitro. In the first experiment, daily dosing of ß,γ-meATP (2 mg/kg) was investigated in rats fed a warfarin diet to trigger the development of non-CKD-related arterial medial calcifications. This study showed that ß,γ-meATP significantly lowered the calcium scores in the aorta and peripheral vessels in warfarin-exposed rats. In a second experiment, daily dosing of 4 mg/kg ß,γ-meATP and its metabolite medronic acid (MDP) was analyzed in rats fed an adenine diet to promote the development of CKD-related arterial medial calcification. Administration of ß,γ-meATP and MDP did not significantly decrease aortic calcification scores in this model. Moreover, both compounds induced deleterious effects on physiological bone mineralization, causing an imminent risk for worsening the already compromised bone status in CKD. Due to this, it was not possible to raise the dosage of both compounds to tackle CKD-related arterial calcification. Again, this points out the difficult task of targeting solely ectopic calcifications without negatively affecting physiological bone mineralization. On the other hand, aortic mRNA expression of Enpp1 and Enpp3 was significantly and positively associated with aortic calcification scores, suggesting that normalizing the aortic NPP1/3 activity to control values might be a possible target to treat (CKD-induced) arterial media calcifications.

Endovascular retrieval of an entrapped balloon in a tibial artery.

Balloon entrapment is a rare complication of angioplasty in calcified or recalcitrant lesions. A 65-year-old man with chronic limb-threatening ischemia underwent balloon angioplasty of his heavily calcified tibial arteries with a low-profile, tapered, compliant balloon. The balloon became entrapped within the posterior tibial artery and required multiple endovascular maneuvers to deflate and separate the balloon from the calcified arterial wall. This case report describes several adjunctive techniques for retrieval of an entrapped balloon in small, calcified arteries before consideration of surgical removal. These techniques allow for minimally invasive retrieval and continuation of endovascular treatment thereafter.

Prevalence and progression of arterial calcifications on computed tomography in humans with knee osteoarthritis.

OBJECTIVES: Ectopic bone deposition plays an important role in osteoarthritis (OA) and in arterial wall disease. We aimed to investigate the prevalence and progression of arterial calcifications on whole-body computed tomography (CT) in persons with knee OA. METHODS: We included 118 (36 male) participants who satisfied the clinical American College of Rheumatology classification criteria for knee OA. Baseline investigations included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Kellgren-Lawrence grading. At baseline and after two years, a whole-body CT was performed using the same scanner and protocol. Calcifications were quantified in the carotid, brachiocephalic, coronary, thoracic aortic, abdominal aortic, iliac, femoropopliteal and crural arteries. Multivariable linear and logistic regression modeling was used for analyses. RESULTS: At baseline males were 66.9 ± 7.7 and females were 68.0 ± 5.6 years old. Calcifications were common, all participants except two females had some calcification, and prevalence ranged between 41.8% and 94.4% for various arterial beds. Baseline femoropopliteal calcifications were associated with a higher Kellgren-Lawrence grade (more severe knee OA). Median annual progression rate was 13.1% in males and 15.7% in females. Structural OA severity was not associated with progression, but a five points lower (worse) WOMAC was associated with 1% faster progression of arterial calcifications (p= 0.008). CONCLUSION: Around age 70 nearly all persons with knee OA have arterial calcifications, which progress substantially. For further investigation into shared causality intervention studies are needed.

Arterial Calcification Disappearance in Breast Imaging: A Key Indicator for Transition to Invasive Ductal Carcinoma.

A woman in her 70s, initially suspected of having fibroadenoma due to a well-defined mass in her breast, underwent regular mammography and ultrasound screenings. Over several years, no appreciable alterations in the mass were observed, maintaining the fibroadenoma diagnosis. However, in the fourth year, an ultrasound indicated slight enlargement and peripheral irregularities in the mass, even though the mammography images at that time showed no alterations. Interestingly, mammography images over time showed the gradual disappearance of previously observed arterial calcification around the mass. Pathological examination eventually identified the mass as invasive ductal carcinoma. Although the patient had breast tissue arterial calcification typical of atherosclerosis, none was present around the tumor-associated arteries. This case highlights the importance of monitoring arterial calcification changes in mammography, suggesting that they are crucial indicators in breast cancer diagnosis, beyond observing size and shape alterations.

Assessing breast arterial calcification in mammograms and its implications for atherosclerotic cardiovascular disease risk.

PURPOSE: Breast arterial calcifications (BAC) are incidentally observed on mammograms, yet their implications remain unclear. We investigated lifestyle, reproductive, and cardiovascular determinants of BAC in women undergoing mammography screening. Further, we investigated the relationship between BAC, coronary arterial calcifications (CAC) and estimated 10-year atherosclerotic cardiovascular (ASCVD) risk. METHODS: In this cross-sectional study, we obtained reproductive history and CVD risk factors from 215 women aged 18 or older who underwent mammography and cardiac computed tomographic angiography (CCTA) within a 2-year period between 2007 and 2017 at hospital. BAC was categorized as binary (present/absent) and semi-quantitatively (mild, moderate, severe). CAC was determined using the Agatston method and recorded as binary (present/absent). Adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated, accounting for age as a confounding factor. ASCVD risk over a 10-year period was calculated using the Pooled Cohort Risk Equations. RESULTS: Older age, systolic and diastolic blood pressures, higher parity, and younger age at first birth (≤28 years) were significantly associated with greater odds of BAC. Women with both BAC and CAC had the highest estimated 10-year risk of ASCVD (13.30 %). Those with only BAC (8.80 %), only CAC (5.80 %), and no BAC or CAC (4.40 %) had lower estimated 10-year risks of ASCVD. No association was detected between presence of BAC and CAC. CONCLUSIONS: These findings support the hypothesis that BAC on a screening mammogram may help to identify women at potentially increased risk of future cardiovascular disease without additional cost and radiation exposure.

Pedal medial arterial calcification influences the outcomes of isolated infra-malleolar interventions for chronic limb-threatening ischemia.

OBJECTIVE: Inframalleolar disease is present in most diabetic patients presenting with tissue loss. Inframalleolar (pedal) artery disease and pedal medial arterial calcification (pMAC) are associated with major amputation in patients with chronic limb-threatening ischemia (CLTI). This study aimed to examine the impact of pMAC on the outcomes after isolated inframalleolar (pedal artery) interventions. METHODS: A database of lower extremity endovascular intervention for patients with tissue loss between 2007 and 2022 was retrospectively queried. Patients with CLTI were selected, and those undergoing isolated inframalleolar intervention on the dorsalis pedis and medial and lateral tarsal arteries and who had foot x-rays were identified. X-rays were assessed blindly for pMAC and scored on a scale of 0 to 5. Patients with concomitant superficial femoral artery and tibial interventions were excluded. Intention to treat analysis by the patient was performed. Amputation-free survival (survival without major amputation) was evaluated. RESULTS: A total of 223 patients (51% female; 87% Hispanic; average age, 66 years; 323 vessels) underwent isolated infra-malleolar intervention for tissue loss. All patients had diabetes, 96% had hypertension, 79% had hyperlipidemia, and 63% had chronic renal insufficiency (55% of these were on hemodialysis). Most of the patients had Wound, Ischemia, and foot Infection (WIfI) stage 3 disease and had various stages of pMAC: severe (score = 5) in 48%, moderate (score = 2-4) in 31%, and mild (score = 0-1) in 21% of the patients. Technical success was 94%, with a median of one vessel treated per patient. All failures were in severe pMAC. Overall, major adverse cardiovascular events was 0.9% at 90 days after the procedure. Following the intervention, most patients underwent a planned forefoot amputation (single digit, multiple digits, ray amputation, or trans-metatarsal amputation). WIfI ischemic grade was improved by 51%. Wound healing at 3 months was 69%. Those not healing underwent below-knee amputations. The overall 5-year amputation-free survival rate was 35% ± 9%. The severity of pMAC was associated with decreased AFS. CONCLUSIONS: Increasing severity of pMAC influences the technical and long-term outcomes of infra-malleolar intervention in diabetes. Severe pMAC is associated with amputation and should be considered as a variable in the shared decision-making of diabetic patients with CLTI.

Pedal medial arterial calcification in diabetic foot ulcers: A significant risk factor of amputation and mortality.

AIMS: Pedal medial arterial calcification (MAC) is frequently observed in individuals with diabetic foot ulcers (DFUs). However, the impact of pedal MAC on individuals with DFUs remains uncertain. The main aim of this study was to evaluate the association between pedal MAC with amputation and mortality outcomes. METHODS: A prospective, observational cohort study was conducted at West China Hospital from January 2012 to December 2021. Logistic regression analyses, Kaplan-Meier survival method, and Cox proportional hazards models were employed to evaluate the relationship between pedal MAC and amputation as well as mortality. RESULTS: A total of 979 patients were enrolled in the study. Peripheral artery disease (PAD) was observed in 53% of patients with DFUs, and pedal MAC was found in 8%. Over a median follow-up of 46 (23-72) months, foot amputation was performed on 190 patients, and mortality occurred in 246 patients. Pedal MAC showed a significant association with amputation both in unadjusted analysis (odds ratio [OR] = 2.98, 95% confidence interval [CI] = 1.86-4.76, p < .001) and after adjusting sex, age, albumin levels, hemoglobin levels, and diabetic retinopathy status (OR 2.29, 95% CI 1.33-3.93, p = .003). The risk of amputation was found to be twofold higher in individuals with PAD and pedal MAC compared to those with PAD alone (OR 2.05, 95% CI 1.10-3.82, p = .024). Furthermore, the presence of pedal MAC was significantly associated with an increased risk of mortality (p = .005), particularly among individuals with DFUs but without PAD (HR 4.26, 95% CI 1.90-9.52, p < .001), rather than in individuals presenting with both DFUs and PAD. CONCLUSION: The presence of pedal MAC is significantly associated with both amputation and mortality in individuals with DFUs. Moreover, pedal MAC could provide additional value to predict amputation other than PAD.

Intravascular ultrasound-guided, lithotrispy facilitated angioplasty for treating a heavily calcified renal artery stenosis.

A 63-year-old woman with uncontrolled hypertension despite taking 5 antihypertensive medications was referred for percutaneous renal artery intervention.

Imaging of intracranial arterial disease: a comparison between MRI and unenhanced CT.

Background and purpose: Arterial calcifications on unenhanced CT scans and vessel wall lesions on MRI are often used interchangeably to portray intracranial arterial disease. However, the extent of pathology depicted with each technique is unclear. We investigated the presence and distribution of these two imaging findings in patients with a history of cerebrovascular disease. Materials and methods: We analyzed CT and MRI data from 78 patients admitted for stroke or TIA at our institution. Vessel wall lesions were assessed on 7 T MRI sequences, while arterial calcifications were assessed on CT scans. The number of vessel wall lesions, severity of intracranial internal carotid artery (iICA) calcifications, and overall presence and distribution of the two imaging findings were visually assessed in the intracranial arteries. Results: At least one vessel wall lesion or arterial calcification was assessed in 69 (88%) patients. Only the iICA and vertebral arteries (VA) showed a substantial number of both calcifications and vessel wall lesions. The other vessels showed almost exclusively vessel wall lesions. The number of vessel wall lesions was associated with the severity of iICA calcification (p = 0.013). Conclusions: The number of vessel wall lesions increases with the severity of iICA calcifications. Nonetheless, the distribution of vessel wall lesions on MRI and arterial calcifications on CT shows remarkable differences. These findings support the need for a combined approach to examine intracranial arterial disease.

Role of klotho and fibroblast growth factor 23 in arterial calcification, thickness, and stiffness: a meta-analysis of observational studies.

This meta-analysis was conducted to clarify the role of klotho and fibroblast growth factor 23 (FGF-23) in human arterial remodeling across recent studies, in terms of arterial calcification, thickness, and stiffness. A systematic literature search was conducted on five databases for articles up to December 2023. Arterial calcification, thickness, and stiffness were determined using the calcification score and artery affected, carotid intima-media thickness (CIMT), and pulse wave velocity (PWV), respectively. Sixty-two studies with a total of 27,459 individuals were included in this meta-analysis. Most studies involved chronic kidney disease patients. Study designs were mostly cross-sectional with only one case-control and nine cohorts. FGF-23 was positively correlated with arterial calcification (r = 0.446 [0.254-0.611], p < 0.0001 and aOR = 1.36 [1.09-1.69], p = 0.006), CIMT (r = 0.188 [0.02-0.354], p = 0.03), and PWV (r = 0.235 [0.159-0.310], p < 0.00001). By contrast, Klotho was inversely correlated with arterial calcification (r = - 0.388 [- 0.578 to - 0.159], p = 0.001) and CIMT (r = - 0.38 [- 0.53 to - 0.207], p < 0.00001). In conclusion, FGF-23 and Klotho were associated with arterial calcification, thickness, and stiffness, clarifying their role in arterial remodeling processes.

Natural history of ENPP1 deficiency: Nationwide Turkish Cohort Study of autosomal-recessive hypophosphataemic rickets type 2.

OBJECTIVE: Autosomal-recessive hypophosphataemic rickets type 2 (ARHR2) is a rare disease that is reported in survivors of generalized arterial calcification of infancy (GACI). DESIGN, PATIENTS AND MEASUREMENT: The objective of this study was to characterize a multicenter paediatric cohort with ARHR2 due to ectonucleotide pyrophosphatase/phosphodiesterase family member 1 (ENPP1) deficiency and with a diagnosis of GACI or GACI-related findings. The clinical, biochemical and genetic characteristics of the patients were retrospectively retrieved. RESULTS: We identified 18 patients from 13 families diagnosed with ARHR2. Fifteen of the patients had an ENPP1 variation confirmed with genetic analyses, and three were siblings of one of these patients, who had clinically diagnosed hypophosphataemic rickets (HRs) with the same presentation. From nine centres, 18 patients, of whom 12 (66.7%) were females, were included in the study. The mean age at diagnosis was 4.2 ± 2.2 (1.6-9) years. The most frequently reported clinical findings on admission were limb deformities (66.6%) and short stature (44.4%). At diagnosis, the mean height SD was -2.2 ± 1.3. Five of the patients were diagnosed with GACI in the neonatal period and treated with bisphosphonates. Other patients were initially diagnosed with ARHR2, but after the detection of a biallelic variant in the ENPP1 gene, it was understood that they previously had clinical findings associated with GACI. Three patients had hearing loss, and two had cervical fusion. After the treatment of HRs, one patient developed calcification, and one developed intimal proliferation. CONCLUSION: ARHR2 represents one manifestation of ENPP1 deficiency that usually manifests later in life than GACI. The history of calcifications or comorbidities that might be associated with GACI will facilitate the diagnosis in patients with ARHR2, and patients receiving calcitriol and phosphate medication should be carefully monitored for signs of calcification or intimal proliferation.

Generation of induced pluripotent stem cell line from a patient suffering from arterial calcification due to deficiency of CD73 (ACDC).

Arterial calcification due to deficiency of CD73 (ACDC) is an adult onset, rare genetic vascular disorder signified by calcium deposition in lower extremity arteries and joints of hands and feet. Mutations in NT5E gene has been shown to be responsible for the inactivation of enzyme CD73 causing calcium buildup. Here, we report a iPSC line generated from a patient showing signs of ACDC and carrying a missense mutation in NT5E (c.1126A→G,p.T376A) gene. This iPSC line shows normal morphology, pluripotency, karyotype, and capability to differentiate into three germ layers, making it useful for disease modeling and investigating pathological mechanisms of ACDC.

ENPP1 in Blood and Bone: Skeletal and Soft Tissue Diseases Induced by ENPP1 Deficiency.

The enzyme ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) codes for a type 2 transmembrane glycoprotein that hydrolyzes extracellular ATP to generate pyrophosphate (PPi) and adenosine monophosphate, thereby contributing to downstream purinergic signaling pathways. The clinical phenotypes induced by ENPP1 deficiency are seemingly contradictory and include early-onset osteoporosis in middle-aged adults and life-threatening vascular calcifications in the large arteries of infants with generalized arterial calcification of infancy. The progressive overmineralization of soft tissue and concurrent undermineralization of skeleton also occur in the general medical population, where it is referred to as paradoxical mineralization to highlight the confusing pathophysiology. This review summarizes the clinical presentation and pathophysiology of paradoxical mineralization unveiled by ENPP1 deficiency and the bench-to-bedside development of a novel ENPP1 biologics designed to treat mineralization disorders in the rare disease and general medical population.

Intracranial arteriosclerosis and the risk of dementia: A population-based cohort study.

BACKGROUND: The impact of intracranial arteriosclerosis on dementia remains largely unclear. METHODS: In 2339 stroke-free and dementia-free participants (52.2% women, mean age 69.5 years) from the general population, we assessed intracranial carotid artery calcification (ICAC) and vertebrobasilar artery calcification (VBAC) as proxy for arteriosclerosis. Associations with dementia were assessed using Cox models. In addition, indirect effects through cerebral small vessel disease (cSVD) and subcortical brain structure volumes were assessed using causal mediation analyses. RESULTS: During a median of 13.4 years (25th-75th percentiles 9.9-14.5) of follow-up, 282 participants developed dementia. Both ICAC presence (hazard ratio [HR]: 1.53, 95% confidence interval [CI]: 1.00-2.32]) and volume (HR per standard deviation: 1.19, 95% CI: 1.01-1.40) increased dementia risk. For VBAC, severe calcifications increased dementia risk (HR for third vs first volume tertile: 1.89, 95% CI: 1.00-3.59). These effects were mediated partly through increased cSVD (percentage mediated for ICAC: 13% and VBAC: 24%). DISCUSSION: Intracranial arteriosclerosis increases the risk of dementia.