TLR4 expression on monocyte subsets in myocardial infarction.

BACKGROUND: Monocyte toll-like receptor 4 (TLR4) has been implicated in the pathogenesis of atherosclerosis with increased levels in myocardial infarction. The aim of this study was to assess the numbers of TLR4(+) monocytes in each monocyte subset in MI, the expression of TLR4 and association with markers of monocyte activation, inflammation, myocardial damage and postmyocardial infarction (MI) cardiac contractility. METHODS: Surface expression of TLR4 and numbers of TLR4-expressing monocytes were quantified by flow cytometry of venous blood in 50 patients with ST-elevation MI (STEMI), 48 with non-STEMI (NSTEMI) and 40 with stable coronary artery disease (CAD). These parameters were measured on days 1, 3, 7 and 30 post-MI in STEMI patients. Three monocyte subsets were defined as CD14(++) CD16(-) CCR2(+) (Mon1), CD14(++) CD16(+) CCR2(+) (Mon2) and CD14(+) CD16(++) CCR2(-) (Mon3). Plasma inflammatory cytokines were assessed using cytometric bead arrays. RESULTS: There was a significant increase in counts of TLR4(+) Mon1 and Mon2 in STEMI patients and TLR4(+) Mon2 in NSTEMI patients compared with controls with CAD. Monocyte TLR4(+) expression was similar between the groups, and was not changed during follow-up in STEMI patients. Plasma interleukin-6 (IL6) levels correlated positively with TLR4(+) Mon2 count (r = 0.54, P < 0.001), but negatively with TLR4 expression on Mon2 (r = -0.33, P = 0.021). CONCLUSION: Following treatment of acute MI, TLR4 expression by individual monocyte subsets is unchanged. An increase in TLR4(+) Mon1 and Mon2 count in patients with STEMI and TLR(+) Mon2 count in those with NSTEMI is due to an increase in monocyte subset count and not to changes in TLR4 expression. Monocyte counts but not TLR4 expression correlate positively with plasma IL6 levels. We suggest that TLR4 expression may not be a reliable marker of monocyte activation in MI.

Monocyte-derived and CD34+/KDR+ endothelial progenitor cells in heart failure.

BACKGROUND: Endothelial progenitor cells (EPCs) are known to be altered in heart failure (HF), but monocyte-derived EPCs in HF have not been assessed. We aimed to characterize monocyte-derived EPCs in systolic HF. METHODS AND RESULTS: We recruited 128 subjects with systolic HF: 50 South Asian (SA), 50 white, and 28 African-Caribbean (AC), for interethnic comparisons. Additionally, SAs with HF were compared with 40 SAs with coronary artery disease (CAD) without HF (disease controls [DCs]) and 40 SA healthy controls (HCs). Counts of CD34(+) and kinase domain receptor (KDR)(+) monocytes attributed to specific monocyte subsets (CD14(++) /CD16(-) [Mon1], CD14(++)/CD16(+) [Mon2], and CD14(+)/CD16(++) [Mon3]) and monocyte expression of vascular endothelial growth factor (VEGF) receptor 1 were analyzed by flow cytometry. We also enumerated CD34(+)/KDR(+) EPCs derived from mononuclear cells ('classic' EPC definition). RESULTS: SAs with HF had significantly reduced counts of CD34(+) monocytes, attributed to the Mon1 and Mon2 subsets. KDR(+) Mon1 counts were 4.5-fold increased in DCs as compared with HCs, but significantly reduced in HF subjects vs. DCs. VEGF receptor type 1 expression on Mon1 and Mon2 cells was significantly reduced in HF patients as compared with DCs. Also, CD34(+)/KDR(+) EPC numbers were reduced in HF subjects. Whites had significantly fewer KDR(+) Mon3 cells than ACs, but significantly more CD34(+) Mon2 cells than SAs and ACs. VEGF receptor type 1 expression by Mon1 cells was predictive for left ventricular ejection fraction after adjustment for ethnicity (ß = - 0.25. P = 0.039). CD34(+) Mon2 counts correlated with measures of microvascular endothelial function, and were predictive of the future risk of hospital admission. CONCLUSIONS: Circulating counts of monocyte-derived EPCs are significantly altered in HF, with significant ethnic differences in the levels of monocyte-derived EPCs.

The CD14++CD16+ monocyte subset and monocyte-platelet interactions in patients with ST-elevation myocardial infarction.

AIM: Monocytes contribute to both myocardial damage and repair by virtue of subset heterogeneity. The dynamics and functional characteristics of the three human monocyte subsets, including the unique CD14++CD16+ subset, and their contributions to monocyte platelet aggregates (MPAs) following ST-elevation myocardial infarction (STEMI) are unknown. We aimed to examine dynamic changes and relation to left ventricular ejection fraction (LVEF) of the three human monocyte subsets and their aggregates with platelets following STEMI. METHODS: Three monocyte subsets, CD14++CD16-CCR2+ ('classical', Mon1), CD14++CD16+CCR2+ ('intermediate', Mon2) and CD14+CD16++CCR2- ('non-classical', Mon3), and their contribution to MPAs were analyzed by flow cytometry in 50 patients with STEMI, 40 patients with stable coronary artery disease (CAD) and 40 healthy volunteers. Study parameters were measured within 24 h of primary percutaneous coronary intervention (PCI) (day1) and on days 3, 7 and 30. Monocyte activation was assessed by measuring the nuclear factor κB (NFκB) pathway. LVEF was assessed 6 weeks after STEMI. Correlations between monocyte subsets/MPAs and plasma cytokines and troponin were assessed. RESULTS: We observed marked differences in subset dynamics, with a prominent increase in Mon2 (P < 0.0001) but no changes in Mon3. Significant increases in Mon2 CD14 (P = 0.002) and CCR2 (P < 0.0001) expression, and reduction in CD16 expression (P = 0.001) were seen. NFκB pathway activity increased most prominently in Mon2 (P = 0.007). Mon2 count correlated with peak troponin (r = 0.31, P = 0.04) and plasma interleukin (IL)-6 (r = 0.65, P < 0.0001) and IL-10 (r = 0.34, P = 0.017). Mon1 correlated with IL-6 (r = 0.55, P < 0.0001). Reduced Mon2 expression of CD16 on day 1 was independently predictive of higher LVEF (ß = -0.37, P = 0.013). The increase in MPA count following STEMI persisted at 1 month. CONCLUSION: The Mon2 'intermediate' subset has unique dynamic and functional characteristics following STEMI and significant correlations with troponin, plasma cytokines and convalescent left ventricular function. The persistent increase in MPA count 30 days after STEMI may affect monocyte subset functional activity.

Immunophenotypic characterization of human monocyte subsets: possible implications for cardiovascular disease pathophysiology.

OBJECTIVES: Monocytes include several subsets with different and sometimes divergent roles in immunity, atherogenesis and reparative processes. OBJECTIVES: We aimed to perform detailed immunophenotypic and functional characterization of human monocyte subsets. PATIENTS/METHODS: Analysis of surface markers of blood and bone marrow monocyte subsets and functional characterization of blood monocyte subsets in healthy volunteers was performed using flow cytometry. RESULTS: In the present study, we show the presence of three subsets which could be unequivocally distinguished by surface expression of CD14, CD16 and CCR2 as CD14(+)CD16(-)CCR2(+) (Mon1), CD14(+)CD16(+)CCR2(+) (Mon2) and CD14(low)CD16(+)CCR2(-) (Mon3) subsets. In comparison with the classic Mon1, the Mon2 subset had the highest expression of Tie2, CXCR4, CD163, CD115, receptors to inter-cellular adhesion molecule-1 (ICAM-1), vascular endothelial growth factor (VEGF), and the highest surface levels of apolipoprotein B and ferritin. In contrast, Mon3 had maximal expression of VCAM-1 receptors and CD204. The Mon2 and Mon3 subsets had significantly lower activity of the NFκB pathway than Mon1. Mon1 and Mon2 had similar phagocytic activity, which was significantly higher compared with Mon3. All three subsets were present in bone marrow, although the relative proportion of Mon2 in bone marrow was about 2.5-fold higher compared with that seen in blood. Significant differences in cytokine production in response to endotoxin stimulation were observed between the three monocyte subsets. CONCLUSION: Given their immunophenotypic similarity, the newly characterized Mon2 population may represent the previously reported pluripotent progenitor/pro-angiogenic monocytes.

The inferior hypogastric plexus: a different view.

The morphology of the inferior hypogastric plexus has been demonstrated in a series of dissections of nulliparous cadavers. Each cadaver was embalmed in a solution containing a significant proportion of methanol which preserved the pliability of the tissues enabling the nerve plexi to be clearly demonstrated. These structures are not normally encountered during general gynaecological surgery and clinicians are often unaware of the possible consequences of injury during vaginal delivery or sustained constipation. Denervation of pelvic organs, with subsequent reinnervation over the medium term, may account for a variety of obstetric and gynaecological syndromes.

Re-examination of the medullary rootlets of the accessory and vagus nerves.

The vagus (X) and cranial root of the accessory nerve (crXI) are traditionally described as arising from a series of rootlets from the medulla oblongata. Descriptions of the number of rootlets vary, and the existence of the crXI is contested. Here we report the results of dissections in six embalmed adult human specimens (11 sides). The rootlets forming the vagus were counted at three positions. At emergence from the brainstem there were between 12 and 21 rootlets, at the jugular foramen the range was 12-17, and midway between these two points it was 6-12. In addition, the origin of the most caudal X rootlet (cX) and the most rostral XI rootlet (rXI) was recorded in relation to the spino-medullary junction, defined as the caudal border of the olivary eminence. The position of the cX varied between -1 and +8 mm (median = +2 mm on left, +3.75 mm on right). The rXI varied between -5 and +7 mm (median = -0.5 mm on left, +1.75 mm on right). In five sides, rXI was above the caudal border of the olivary eminence and as such can be defined as being of cranial origin. These observations show the arrangement of rootlets contributing to the vagus to be more complex than what was described previously and provide evidence for the variable existence of a cranial root of the accessory nerve.

Therapeutic implications of hypertension-induced glomerular injury. Comparison of enalapril and a combination of hydralazine, reserpine, and hydrochlorothiazide in an experimental model.

Systemic hypertension does not always reflect concomitant glomerular hypertension. At similar levels of systemic hypertension, glomerular injury occurs only in kidneys that lack protective preglomerular vasoconstriction, which results in glomerular hypertension. indeed, glomerular hypertension and glomerular injury do not develop in rats with spontaneous hypertension that have effective preglomerular vasoconstriction. In the experiments reported herein, the normal adaptive response (afferent arteriolar dilation) to a reduction of one and five-sixths of the renal mass in rats with spontaneous hypertension was examined to ascertain whether that response would expose the remaining nephrons to the injurious effects of high perfusion pressure. In addition, the efficacies of two different antihypertensive regimens were compared. Rats with spontaneous hypertension received either no therapy, or a combination of hydralazine, reserpine, and hydrochlorothiazide, or the angiotensin converting enzyme inhibitor enalapril. Three weeks after ablation of one and five-sixths of the renal mass, blood pressure, glomerular filtration rate, urinary protein excretion, and histologic injury scores for mesangial expansion and glomerulosclerosis were determined. Untreated rats with hypertension had severe glomerulosclerosis and mesangial expansion. Both antihypertensive regimens normalized systemic blood pressure and reduced glomerulosclerosis. However, enalapril was more effective than the combination of hydralazine, reserpine, and hydrochlorothiazide in reducing the exaggerated glomerular filtration rate (0.52 +/- 0.40 versus 0.82 +/- 0.10 ml per minute; p less than 0.05), the injury score for mesangial expansion (79 versus 103; p less than 0.05), and the degree of proteinuria (32 +/- 4 versus 42 +/- 3 mg per 24 hours; p less than 0.05). Persistence of hyperfiltration accompanied by increased mesangial expansion, may lead to progression of glomerular damage despite "adequate" control of systemic hypertension, as observed in rats treated with a combination of hydralazine, reserpine, and hydrochlorothiazide.