Breastfeeding, Cellular Immune Activation, and Myocardial Recovery in Peripartum Cardiomyopathy

• The impact of breastfeeding on prolactin, cellular immune activation, and myocardial recovery was analyzed in 100 women with peripartum cardiomyopathy • Cardiac function was assessed by echocardiography at presentation and at serial intervals over the first year postpartum • The levels of circulating prolactin were assessed by ELISA, and cellular immunophenotyping by flow cytometry, and compared between breastfeeding and nonbreastfeeding women • Prolactin levels were higher in breastfeeding women and correlated with significant increases in CD8+ T cells • Despite significantly higher prolactin levels and increased CD8+ cells, myocardial recovery was similar in breastfeeding and nonbreastfeeding women The etiology of peripartum cardiomyopathy remains unknown. One hypothesis is that an increase in the 16-kDa form of prolactin is pathogenic and suggests that breastfeeding may worsen peripartum cardiomyopathy by increasing prolactin, while bromocriptine, which blocks prolactin release, may be therapeutic. An autoimmune etiology has also been proposed. The authors investigated the impact of breastfeeding on cellular immunity and myocardial recovery for women with peripartum cardiomyopathy in the IPAC (Investigations in Pregnancy Associated Cardiomyopathy) study. Women who breastfed had elevated prolactin, and prolactin levels correlated with elevations in CD8 + T cells. However, despite elevated prolactin and cytotoxic T cell subsets, myocardial recovery was not impaired in breastfeeding women

Myocardial Damage Detected by Late Gadolinium Enhancement Cardiac Magnetic Resonance Is Uncommon in Peripartum Cardiomyopathy

In peripartum cardiomyopathy, the prevalence of focal myocardial damage detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance is important to elucidate mechanisms of myocardial injury and cardiac dysfunction. LGE equates irreversible myocardial injury, but LGE prevalence in peripartum cardiomyopathy is uncertain. Among 100 women enrolled within the Investigations of Pregnancy Associated Cardiomyopathy cohort, we recruited 40 women at 13 centers to undergo LGE cardiovascular magnetic resonance, enrolled within the first 13 weeks postpartum. Follow-up scans occurred at 6 months postpartum, and death/transplant rates at 12 months. Baseline characteristics did not differ significantly in the parent cohort according to cardiovascular magnetic resonance enrollment except for mechanical circulatory support. LGE was noted only in 2 women (5%) at baseline. While left ventricular dysfunction with enlargement was prevalent at baseline cardiovascular magnetic resonance scans (eg, ejection fraction 38% [Q1-Q3 31-50%], end diastolic volume index=108 mL/m [Q1-Q3 83-134 mL/m ]), most women demonstrated significant improvements at 6 months, consistent with a low prevalence of LGE. LGE was not related to baseline clinical variables, ejection fraction, New York Heart Association heart failure class, or mortality. Neither of the 2 women who died exhibited LGE. LGE was inversely associated with persistent left ventricular ejection fraction at 6 months ( =0.006). Factors other than focal myocardial damage detectable by LGE explain the initial transient depressions in baseline left ventricular ejection fraction, yet focal myocardial damage may contribute to persistent myocardial dysfunction and hinder recovery in a small minority. Most women exhibit favorable changes in ventricular function over 6 months. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01085955

Myocardial Damage Detected by Late Gadolinium Enhancement Cardiac Magnetic Resonance Is Uncommon in Peripartum Cardiomyopathy

In peripartum cardiomyopathy, the prevalence of focal myocardial damage detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance is important to elucidate mechanisms of myocardial injury and cardiac dysfunction. LGE equates irreversible myocardial injury, but LGE prevalence in peripartum cardiomyopathy is uncertain. Among 100 women enrolled within the Investigations of Pregnancy Associated Cardiomyopathy cohort, we recruited 40 women at 13 centers to undergo LGE cardiovascular magnetic resonance, enrolled within the first 13 weeks postpartum. Follow-up scans occurred at 6 months postpartum, and death/transplant rates at 12 months. Baseline characteristics did not differ significantly in the parent cohort according to cardiovascular magnetic resonance enrollment except for mechanical circulatory support. LGE was noted only in 2 women (5%) at baseline. While left ventricular dysfunction with enlargement was prevalent at baseline cardiovascular magnetic resonance scans (eg, ejection fraction 38% [Q1-Q3 31-50%], end diastolic volume index=108 mL/m [Q1-Q3 83-134 mL/m ]), most women demonstrated significant improvements at 6 months, consistent with a low prevalence of LGE. LGE was not related to baseline clinical variables, ejection fraction, New York Heart Association heart failure class, or mortality. Neither of the 2 women who died exhibited LGE. LGE was inversely associated with persistent left ventricular ejection fraction at 6 months ( =0.006). Factors other than focal myocardial damage detectable by LGE explain the initial transient depressions in baseline left ventricular ejection fraction, yet focal myocardial damage may contribute to persistent myocardial dysfunction and hinder recovery in a small minority. Most women exhibit favorable changes in ventricular function over 6 months. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01085955

Circulating T-Cell Subsets, Monocytes, and Natural Killer Cells in Peripartum Cardiomyopathy: Results From the Multicenter IPAC Study

•Immune cell subsets were examined in healthy postpartum and peripartum cardiomyopathy (PPCM) women.•In the early postpartum, PPCM women had lower NK and higher CD3+CD4–CD8–CD38+ T cell levels.•Levels largely normalized by 6 months postpartum. The aim of this work was to evaluate the hypothesis that the distribution of circulating immune cell subsets, or their activation state, is significantly different between peripartum cardiomyopathy (PPCM) and healthy postpartum (HP) women. PPCM is a major cause of maternal morbidity and mortality, and an immune-mediated etiology has been hypothesized. Cellular immunity, altered in pregnancy and the peripartum period, has been proposed to play a role in PPCM pathogenesis. The Investigation of Pregnancy-Associated Cardiomyopathy (IPAC) study enrolled 100 women presenting with a left ventricular ejection fraction of <0.45 within 2 months of delivery. Peripheral T-cell subsets, natural killer (NK) cells, and cellular activation markers were assessed by flow cytometry in PPCM women early (<6 wk), 2 months, and 6 months postpartum and compared with those of HP women and women with non–pregnancy-associated recent-onset cardiomyopathy (ROCM). Entry NK cell levels (CD3–CD56+CD16+; reported as % of CD3– cells) were significantly (P < .0003) reduced in PPCM (6.6 ± 4.9% of CD3– cells) compared to HP (11.9 ± 5%). Of T-cell subtypes, CD3+CD4–CD8–CD38+ cells differed significantly (P < .004) between PPCM (24.5 ± 12.5% of CD3+CD4–CD8– cells) and HP (12.5 ± 6.4%). PPCM patients demonstrated a rapid recovery of NK and CD3+CD4–CD8–CD38+ cell levels. However, black women had a delayed recovery of NK cells. A similar reduction of NK cells was observed in women with ROCM. Compared with HP control women, early postpartum PPCM women show significantly reduced NK cells, and higher CD3+CD4–CD8–CD38+ cells, which both normalize over time postpartum. The mechanistic role of NK cells and “double negative” (CD4–CD8–) T regulatory cells in PPCM requires further investigation