Bone Marrow Mononuclear Cells Transplantation in Treatment of Established Bronchopulmonary Dysplasia: A Case Report.

BACKGROUND Bronchopulmonary dysplasia (BDP) is an incurable disease. This study reports the successful treatment of a 30-week-old neonate with established bronchopulmonary dysplasia by bone marrow mononuclear cells (BM MNCs) transplantation. CASE REPORT The preterm infant with BPD requiring continuous oxygen administration for 4 months post-delivery underwent BM MNCs. Bone marrow was obtained from the patient's iliac crests and mononuclear cells were isolated by density gradient centrifugation method. BM MNCs were delivered via endotracheal and intravenous routes. After BM MNCs transplantation, remarkable improvements were observed in oxygen saturation and lung CT as the infant was gradually weaned off oxygen supply. CONCLUSIONS BM MNCs transplantation offers promising treatment of BPD.

Background

Bronchopulmonary dysplasia (BPD), first described by Northway in 1967, is becoming more common in newborns with low birth weight and those who receive prolonged mechanical ventilation [1,2]. Despite great advances in perinatal care, the prognosis of BPD is still poor [3,4]. To date, there are few effective treatments to improve outcomes of BPD. Recently, stem cell (STC) transplantation has been tested in the management of BPD in animals. In hyperoxia-induced mice, STC transplantation reduced alveolar loss and lung inflammation, and prevented pulmonary hypertension. STC transplantation has been reported to attenuate alveolar and vascular injury, and decrease fibrosis [5-10].

Before 2014, there was no evidence available for using STC transplantation to treat established BPD in humans. In 2014, Chang published a report of 9 infants at high risk of developing BPD who received stem cells to prevent BPD [11,12].

This case study reports a preterm infant with established BPD who was successfully treated by autologous bone marrow mononuclear cell transplantation.

Case Report

A boy was born at 30-week gestation by vaginal delivery with a birth weight of 1500 gr.

Respiratory distress syndrome occurred immediately post-delivery. A chest X-ray indicated grade 2 hyaline membrane disease. The patient was supported with nasal CPAP (pressure of 5 cm H2O and 40% O2) for 1 week, then oxygen was delivered via nasal cannulas for the next 28 days. Failure to improve respiratory function resulted in a transfer to the National Children’s Hospital, where a diagnosis of BPD was made based on chest X-rays.

On admission at the National Children’s Hospital (February 12, 2016), the body weight was 1600 gr and heart rate was 140–155 beats/min. Respiratory rate was 63 breaths/min; there was cyanosis and poor air entry to both lungs. SpO2 was 80% without oxygen supply and 92% with oxygen supply at FiO2 24% through nasal cannulas. Arterial blood gas with FiO2 of 24%: pH: 7.41; PaCO2: 54 mmHg; Pa O2: 51 mmHg; BE: 8.4; HCO3–: 34.2; mmol/l. Chest X-rays showed fibrosis in both lungs (Figure 1).

Figure 1.

Chest X-ray at 35 days after delivery.

The patient underwent 3 cycles of treatment including dexamethasone, furosemide, and bronchodilator, 10 days for each cycle and an interval of 7 days between 2 cycles. However, the patient’s condition worsened, with hypercapnia and hypoxia (pH: 7.37; PaCO2: 54mmHg; PaO2: 37 mmHg; HCO3: 31.2 mmol/l, BE: 4.9, FiO2 of 24%.). The chest X-ray revealed more diffused atelectasis and air trapping in both lungs (Figure 2).

Figure 2.

Chest X-ray after 3 cycles of treatment with Dexamethasone.

After 88 days of treatment in the National Children’s Hospital, the patient was transferred to Vinmec International Hospital for consideration of stem cell transplantation to improve his respiratory function.

On admission (May 11, 2016), body weight of the infant was 3.300 gr. He was alert and had good reflexes. Heart rate was 150–160 beats/min. Respiratory rate was 65–70 breaths/min. There was evidence of chest retraction and severe cyanosis. There was poor air entry to both lungs, and moist rales were recognized on auscultation. SpO2 was 70% without oxygen supply and 92–95% with oxygen supply at FiO2 of 24% by nasal cannula.

Investigations on admission

Arterial blood gases with the FiO2 of 24%; pH 7.39, PaCO2: 43.7 mmHg, PaO2: 56 mmHg), BE: ±2, HCO3: 26.2, lactate: 1.99 mmol/l. Total blood cell count was WBC: 12 G/l; neutrophils: 12.3%; lymphocytes: 73.8% platelets: 344 G/l; and Hb: 10.1 g/dl.

On hospital day 4, a chest CT demonstrated diffuse fibrosis in both lungs, atelectasis in the upper lobes of both lungs, and significant air trapping in both lower lobes (Figure 3). BM MNC transplantation was indicated because, after long-term treatment, he could not be weaned from the oxygen supply after intensive treatment with corticosteroids.

Figure 3.

Chest CT before mononuclear cells transplantation.

After approval from the Hospital Scientific Committee and written informed consent from patient’s parents, the infant underwent BM MNCs transplantation on hospital day 22, at 4000 gr weight. The patient was anesthetized and 32 ml of bone marrow was extracted from the iliac crests. Our previous experience showed that 8 ml of bone marrow per kg body weight can be harvested safely in children [13].

BM MNCs were extracted from 32 ml bone marrow by density gradient centrifugation using Ficoll-Paque (GE Healthcare, Sweden). The final product contained 620×106 of MNCs, which were supplemented by autologous plasma up to a total of 9 ml.

The BM MNCs were characterized by flow cytometry with monoclonal antibodies specific for CD45, and CD34, conjugated with R Phycoerythrin (PE) and fluorescein isothiocyanate (FITC), respectively (Beckman Coulter, CA, USA). Cells were analyzed by Navios Cytometer (Beckman Coulter, USA). The final product contained 43.85 × 10^6 of hHSC, which had CD45 dim CD34+ phenotype. Data were collected and recorded using Navios software, version 3.2.

A volume of 0.5 ml of the extracted liquid diluted with 0.5 ml NaCl 0.9% was instilled 4 times via the endotracheal tube every 30 min.

Results

Manifestations of tracheal obstruction occurred after the 2nd and the 4th injection with decreased SpO2, cyanosis, and bradycardia. These episodes required intratracheal suction, during which the patient was supported by mechanical ventilation.

On hospital day 23, 0.75 ml fluid of BM MNCs plus 0.75 ml NaCl 0.9% was infused through the endotracheal tube at 2 ml/h. The manifestations of tracheal obstruction reoccurred for 30 min after the infusion, requiring endotracheal suction. After 4 h, 1.25 ml of mononuclear cells diluted in 3 ml NaCl 0.9% was delivered via nebulization.

On hospital day 24 (June 3, 2016), pulmonary arterial hypertension was manifested by tachycardia, cyanosis, and arterial hypotension. Immediate treatment with high-frequency oscillator ventilation and medication (milrinone and Ilomedin) was applied.

On hospital day 31, the patient was stable with no sign of pulmonary artery hypertension. CMV mode was supported with PIP. 4.5 ml of mononuclear cell plus 5 ml NaCl 0.9% was delivered through a central venous catheter in 60 min.

On hospital day 32, the patient was weaned from the mechanical ventilator and was supported with oxygen by mask at 3 L/min for 1 week. Thereafter, intermittent oxygen supply was required via nasal cannulas at 0.3–0.5 L/min for 1.5 months and then oxygen supply was weaned completely. SpO2 was at 94–100% without oxygen supply. The patient sucked well and gained weight.

On hospital day 41, the patient was discharged in stable condition.

2.5 months after discharge:

– The child developed well, body weight was 5.500 gr, and respiratory rate was 45 breaths/min.

– Arterial blood gas (FiO2 of 21%): pH: 7.4; PaCO2: 36.2 mmHg; PaO2: 64 mmHg; BE: –2; HCO3–: 22.4.

– SpO2 ranged from 95–96% without oxygen support.

5 months after discharge:

– Body weight was 6.400 gr.

– SpO2 was 96–98%.

– Arterial blood gas (FiO2 of 21%): pH: 7.36; PaO2: 71mmHg; PaCO2: 40.7. mmHg; BE: –2; HCO3–: 23 mmol/l).

10 months after discharge:

– Body weight was 8 kg; height: 76 cm.

– Respiratory rate was 35 breaths/min; good air entry to both lungs.

– SpO2 was 98–100%.

– Arterial blood gas (FiO2 of 21%): pH: 7.47, PaCO2: 25.7mmHg, PaO2: 80 mmHg, BE: –5, HCO3– 18.9 mmol/l.

– Chest X-ray (Figure 4) revealed that both lungs had mostly normal manifestations.

Figure 4.

Chest CT after mononuclear cells transplantation.

Discussion

This is the first trial using autologous BM MNCs to treat an infant with established BPD. Clinical and chest CT improvements were observed and demonstrated in our patient.

Over time, different sources of MNCs have been used to treat BPD in animals [5-10]. In humans, in 2014 and 2017, Chang et al. used cord blood mononuclear cell transplantation for preterm infants at risk of BPD, without severe adverse effects [11,12]. In this case, we demonstrated the use of autologous BM MNCs to treat established BPD. The extraction of bone marrow from the infant iliac was practical and suggests this is an alternative stem cell source when cord blood is not available.

The route of STC transplantation is still under consideration. Chang reported that intratracheal injection is safe in preterm infants [11]. However, in this case, intratracheal injection of STC resulted in bronchial obstruction and new-onset pulmonary arterial hypertension. These complications should be recognized early and managed expediently. As a result, the remaining MNCs were delivered intravenously. We conclude that the combined intratracheal and intravenous approach is a good alternative, depending on patient response.

Conclusions

The results of this study suggest that BM MNCs reduces lungs fibrosis and improves respiratory function of BPD. This approach offers promising treatment of BPD.