Cardiac Autonomic Function in Long COVID-19 Using Heart Rate Variability: An Observational Cross-Sectional Study.

BACKGROUND: Heart rate variability is a non-invasive, measurable, and established autonomic nervous system test. Long-term COVID-19 sequelae are unclear; however, acute symptoms have been studied. OBJECTIVES: To determine autonomic cardiac differences between long COVID-19 patients and healthy controls and evaluate associations among symptoms, comorbidities, and laboratory findings. METHODS: This single-center study included long COVID-19 patients and healthy controls. The heart rate variability (HRV), a quantitative marker of autonomic activity, was monitored for 24 h using an ambulatory electrocardiogram system. HRV indices were compared between case and control groups. Symptom frequency and inflammatory markers were evaluated. A significant statistical level of 5% (p-value 0.05) was adopted. RESULTS: A total of 47 long COVID-19 patients were compared to 42 healthy controls. Patients averaged 43.8 (SD14.8) years old, and 60.3% were female. In total, 52.5% of patients had moderate illness. Post-exercise dyspnea was most common (71.6%), and 53.2% lacked comorbidities. CNP, D-dimer, and CRP levels were elevated (p-values of 0.0098, 0.0023, and 0.0015, respectively). The control group had greater SDNN24 and SDANNI (OR = 0.98 (0.97 to 0.99; p = 0.01)). Increased low-frequency (LF) indices in COVID-19 patients (OR = 1.002 (1.0001 to 1.004; p = 0.030)) and high-frequency (HF) indices in the control group (OR = 0.987 (0.98 to 0.995; p = 0.001)) were also associated. CONCLUSIONS: Patients with long COVID-19 had lower HF values than healthy individuals. These variations are associated with increased parasympathetic activity, which may be related to long COVID-19 symptoms and inflammatory laboratory findings.

Bone disease in newly diagnosed lupus nephritis patients.

INTRODUCTION: Bone loss in Lupus Nephritis (LN) patients is common and multifactorial. The aim of this study was to evaluate the bone status of newly diagnosed LN patients and their correlation with inflammatory factors involved in LN physiopathology. METHODS: We studied 15 pre-menopausal patients with ≤2 months of diagnosed SLE and LN. Patients with prior kidney or bone disease were excluded. In addition to biochemical evaluation (including 25-hydroxyvitamin D3 [25(OH)D] and Monocyte Chemotactic Protein (MCP1) dosage), we performed bone biopsies followed by osteoblast culture, histomorphometric and immunohistochemistry analysis. RESULTS: LN patients presented a mean age of 29.5±10 years, a proteinuria of 4.7±2.9 g/day and an estimated glomerular filtration rate (GFR) of 37(31-87) ml/min/1,73 m2. They were on glucocorticoid therapy for 34±12 days. All patients presented vitamin D insufficiency (9.9±4.4 ng/ml, range 4-20). Urinary MCP1 correlated negatively with 25(OH)D (r = -0.53, p = 0.003) and positively with serum deoxypyridinoline (r = 0.53, p = 0.004). Osteoblasts isolated from LN bone biopsies presented a significantly higher expression of MCP-1 when compared to controls (32.0.±9.1 vs. 22.9±5.3 mean fluorescence intensities, p = 0.01). LN patients presented a significantly reduced osteoid volume, osteoid thickness, osteoid surface, mineralization surface and bone formation rate, associated with an increased eroded surface and osteoclast surface. Patient's bone specimens demonstrated a reduced immunostaining for osteoprotegerin (0.61±0.82 vs. 1.08±0.50%, p = 0.003), and an increased expression of Receptor Activator of NF-κB ligand (RANKL) (1.76±0.92 vs. 0.41±0.28%, p<0.001) when compared to controls. DISCUSSION: Newly diagnosed LN patients presented a significant disturbance in bone metabolism, characterized by an impaired bone formation and mineralization, associated with an increase in resorption parameters. Glucocorticoid use, vitamin D insufficiency and inflammation might be involved in the physiopathology of bone metabolism disturbance.

Doença óssea em pacientes com nefrite lúpica: aspectos inflamatórios / Bone disease in lupus nephritis patients: inflammatory aspects

Introdução: O comprometimento ósseo em pacientes portadoras de nefrite lúpica é comum e multifatorial. O objetivo deste trabalho foi estudar a contribuição do componente inflamatório para o comprometimento ósseo destas pacientes. Métodos: Foram estudadas 15 pacientes do sexo feminino (no menacme) com diagnóstico recente (<= 2 meses) de Lupus Eritematoso Sistêmico e Nefrite Lúpica (NL). Foram excluídos pacientes com história/evidência de doença renal ou óssea prévia. A avaliação laboratorial incluiu a dosagem de 25-hidroxivitamina D3 ([25(OH)D] e de citocinas inflamatórias associadas a fisiopatologia do lupus [Interleucina-6, Fator de necrose tumoral ? e Monocyte Chemoattractant Protein-1 (MCP-1)]. Além disso, as pacientes foram submetidas a biópsia óssea, com análise histomorfométrica, imunohistoquímica e cultura celular (estudo da proliferação e citometria de fluxo). Resultados: As pacientes lúpicas apresentavam em média 29,5±10 anos, com uma proteinúria de 4,7±2,9 g/dia, e uma taxa de filtração glomerular estimada de 37(31-87) ml/min/1,73m², e estavam em uso de glicocorticóide por 34±12 dias. Todas as pacientes apresentavam níveis insuficientes de vitamina D (9,9±4,4ng/ml, variando de 4 a 20 ng/ml). Os níveis de 25(OH)D se correlacionaram negativamente com os de todas as citocinas inflamatórias estudadas. Os níveis de MCP-1 urinário se correlacionaram negativamente com os de 25(OH)D (r= -0,53, p=0,003) e positivamente com os de deoxipiridinolina (r=0,53, p=0,004). Não observamos diferença significativa entre pacientes e controles na proliferação de osteoblastos medida pela incorporação pela timidina (82,22±8,43 vs 56,06±23,73 contagem por minuto, p=0,21). Os osteoblastos provenientes dos fragmentos ósseos das pacientes lúpicas apresentaram uma maior expressão de MCP-1, medida pela intensidade média de fluorescência (32,0±9,1 vs 22,9±5,3, p=0,01). Quando comparadas a controles, as pacientes portadoras de nefrite lúpica apresentaram valores...

Introduction: Bone disease in lupus nephritis patients is common and multifactorial. The aim of this study was evaluate the contribution of inflammatory factors to the bone disorder observed in these patients. Methods: We studied 15 female pre-menopausal patients with <= 2 months of diagnosed Systemic Erythematosus Lupus and Lupus Nephritis (LN). Subjects with prior kidney or bone disease were excluded. We measured the levels of 25-hydroxyvitamin D3 [25(OH)D] and cytokines involved in LN physiopathology [Interleucin-6, Tumor Necrosis Factor ?, and Monocyte Chemoattractant Protein-1 (MCP-1)]. Patients were submitted to bone biopsy, followed by osteoblast culture (cell proliferation and flow cytometry), histomorphometric and immunohistochemistry analysis. Results: LN patients presented a mean age of 29.5±10 years, a proteinuria of 4.7±2.9 g/day and an estimated glomerular filtration rate of 37(31-87) ml/min/1,73m². They were on glucocorticoid therapy for 34±12 days. All patients presented vitamin D insufficiency (9.9±4.4 ng/ml, range 4-20). Vitamin D levels were negatively correlated with all inflammatory cytokines. Urinary MCP-1 correlated negatively with 25-hydroxyvitamin D3 (r= -0.53, p=0.003) and positively with serum deoxypyridinoline (r=0.53, p=0.004). There were no differences between NL patients and controls in osteoblast proliferation measured by incorporation of thymidine (82.22±48.43 vs 56.07±23.73 counts per minute, respectively, p=0.21). Osteoblasts isolated from LN patients presented a significantly higher expression of MCP-1, as measured by mean fluorescence intensities (32.0±9.1 vs 22.9±5.3, p=0.01). LN patients presented a significantly reduction in two formation parameters (osteoid volume and osteoid thickness). They also presented a decrease in mineralization surface and bone formation rate, associated with an increased eroded surface and osteoclast surface. Patient's bone specimens demonstrated a reduced immunostaining...